Eclipsing Binaries with Possible Tertiary Components

NASA Astrophysics Data System (ADS)

Snyder, LeRoy F.

2013-05-01

Many eclipsing binary star systems (EBS) show long-term variations in their orbital periods which are evident in their O-C (observed minus calculated period) diagrams. This research carried out an analysis of 324 eclipsing binary systems taken from the systems analyzed in the Bob Nelson's O-C Files database. Of these 18 systems displayed evidence of periodic variations of the arrival times of the eclipses. These rates of period changes are sinusoidal variations. The sinusoidal character of these variations is suggestive of Keplerian motion caused by an orbiting companion. The reason for these changes is unknown, but mass loss, apsidal motion, magnetic activity and the presence of a third body have been proposed. This paper has assumed light time effect as the cause of the sinusoidal variations caused by the gravitational pull of a tertiary companion orbiting around the eclipsing binary systems. An observed minus calculated (O-C) diagram of the 324 systems was plotted using a quadratic ephemeris to determine if the system displayed a sinusoidal trend in theO-C residuals. After analysis of the 18 systems, seven systems, AW UMa, BB PEG, OO Aql, V508 Oph, VW Cep, WCrv and YY ERI met the benchmark of the criteria of a possible orbiting companion. The other 11 systems displayed a sinusoidal variation in the O-C residuals of the primary eclipses but these systems in the Bob Nelson's O-C Files did not contain times of minimum (Tmin) of the secondary eclipses and therefore not conclusive in determining the presents of the effects of a tertiary companion. An analysis of the residuals of the seven systems yields a light-time semi-amplitude, orbital period, eccentricity and mass of the tertiary companion as the amplitude of the variation is proportional to the mass, period and inclination of the 3rd orbiting body. Knowing the low mass of the tertiary body in the seven cases the possibility of five of these tertiary companions being brown dwarfs is discussed.

Green Chromatographic Separation of Coumarin and Vanillins Using Subcritical Water as the Mobile Phase.

PubMed

Kayan, Berkant; Akay, Sema; Yang, Yu

2016-08-01

Pure water was used as the eluent for separation of coumarin, vanillin and ethyl vanillin at temperatures ranging from 100 to 200°C using a homemade subcritical water chromatography (SBWC) system. Chromatographic separations were performed on five commercial columns including XTerra MS C18, XBridge C18, Zorbax RRHD Eclipse Plus, Zorbax SB-Phenyl and Zorbax SB-C18 columns. The retention time of all three solutes decreased with increasing water temperature. The shortest retention time among all acceptable separations, less than 4 min, was achieved on the Zorbax SB-C18 column at 200°C. While separations on the XTerra MS C18 column resulted in fronting peaks and a degradation peak from ethyl vanillin on the Zorbax RRHD Eclipse Plus column was observed, all three other columns yielded reasonable separations under SBWC conditions. In addition to separation of the standard test mixture, separation of coumarin contained in a skincare cream sample was also carried out using SBWC. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simultaneous determination of apatinib and its four major metabolites in human plasma using liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

PubMed

Ding, Juefang; Chen, Xiaoyan; Dai, Xiaojian; Zhong, Dafang

2012-05-01

Apatinib, also known as YN968D1, is a novel antiangiogenic agent that selectively inhibits vascular endothelial growth factor receptor-2. Currently, apatinib is undergoing phase II/III clinical trials in China for the treatment of solid tumors. Apatinib is extensively metabolized in humans, and its major metabolites in circulation include cis-3-hydroxy-apatinib (M1-1), trans-3-hydroxy-apatinib (M1-2), apatinib-25-N-oxide (M1-6), and cis-3-hydroxy-apatinib-O-glucuronide (M9-2). To investigate the pharmacokinetics of apatinib and its four major metabolites in patients with advanced colorectal cancer, a sensitive and selective liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of apatinib, M1-1, M1-2, M1-6, and M9-2 in human plasma. After a simple protein precipitation using acetonitrile as the precipitation solvent, all the analytes and the internal standard vatalanib were separated on a Zorbax Eclipse XDB C(18) column (50 mm × 4.6 mm, 1.8 μm, Agilent) using acetonitrile: 5 mmol/L ammonium acetate with 0.1% formic acid as the mobile phase with gradient elution. A chromatographic total run time of 9 min was achieved. Mass spectrometry detection was conducted through electrospray ionization in positive ion multiple reaction monitoring modes. The method was linear over the concentration range of 3.00-2000 ng/mL for each analyte. The lower limit of quantification for each analyte was 3.00 ng/mL. The intra-assay precision for all the analytes was less than 11.3%, the inter-assay precision was less than 13.8%, and the accuracy was between -5.8% and 3.3%. The validated method was successfully applied to a clinical pharmacokinetic study following oral administration of 500 mg apatinib mesylate in patients with advanced colorectal cancer. Copyright © 2012 Elsevier B.V. All rights reserved.

[Study on the fingerprint of Morus alba from different habitats by HPLC].

PubMed

Chen, Cheng; Li, Hong-Bo; Wang, Liu-Ping; Li, Yun-Rong; Xin, Ning

2012-12-01

To establish HPLC fingerprint of Morus alba from different habitats by HPLC and provide basis for its quality control. HPLC analysis was performed on an Agilent XDB C18 Column (4.6 mm x 250 mm, 5 microm), gradient eluted composed of acetonitrile and 0.3% phosphate acid. The column temperature was set at 35 degrees C and the flow rate was 0.5 mL/min. The detective wavelength was 290 nm. The HPLC fingerprint for 10 batches of Morus alba was studied on their similarity. There were twelve common peaks in the fingerprint. The similarity of 7 batches was above 0.9 and the other batches had low similarity. The HPLC fingerprint can be used for quality control of Morus alba with high characteristics and specificity.

Distinction between critical current effects and intrinsic anomalies in the point-contact Andreev reflection spectra of unconventional superconductors

NASA Astrophysics Data System (ADS)

He, Ge; Wei, Zhong-Xu; Brisbois, Jérémy; Jia, Yan-Li; Huang, Yu-Long; Zhou, Hua-Xue; Ni, Shun-Li; Silhanek, Alejandro V.; Shan, Lei; Zhu, Bei-Yi; Yuan, Jie; Dong, Xiao-Li; Zhou, Fang; Zhao, Zhong-Xian; Jin, Kui

2018-04-01

Not Available Project supported by the National Key Basic Research Program of China (Grant Nos. 2015CB921000, 2016YFA0300301, and 2017YFA0302902), the National Natural Science Foundation of China (Grant Nos. 11674374 and 1474338), the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Grant No. QYZDB-SSW-SLH008), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB07020100 and XDB07030200), the Beijing Municipal Science and Technology Project (Grant No. Z161100002116011), the Fonds de la Recherche Scientifique–FNRS and the ARC Grant 13/18-08 for Concerted Research Actions, financed by the French Community of Belgium (Wallonia-Brussels Federation). Jérémy Brisbois acknowledges the support from F.R.S.–FNRS (Research Fellowship), The work of Alejandro V Silhanek is partially supported by PDR T.0106.16 of the F.R.S.–FNRS..

Vigabatrin in dried plasma spots: validation of a novel LC-MS/MS method and application to clinical practice.

PubMed

Kostić, Nađa; Dotsikas, Yannis; Jović, Nebojša; Stevanović, Galina; Malenović, Anđelija; Medenica, Mirjana

2014-07-01

This paper presents a LC-MS/MS method for the determination of antiepileptic drug vigabatrin in dried plasma spots (DPS). Due to its zwitterionic chemical structure, a pre-column derivatization procedure was performed, aiming to yield enhanced ionization efficiency and improved chromatographic behaviour. Propyl chloroformate, in the presence of propanol, was selected as the best derivatization reagent, providing a strong signal along with reasonable run time. A relatively novel sample collection technique, DPS, was utilized, offering easy sample handling and analysis, using a sample in micro amount (∼5μL). Derivatized vigabatrin and its internal standard, 4-aminocyclohexanecarboxylic acid, were extracted by liquid-liquid extraction (LLE) and determined in positive ion mode by applying two SRM transitions per analyte. A Zorbax Eclipse XDB-C8 column (150×4.6mm, 5μm particle size) maintained at 30°C, was utilized with running mobile phase composed of acetonitrile: 0.15% formic acid (85:15, v/v). Flow rate was 550μL/min and total run time 4.5min. The assay exhibited excellent linearity over the concentration range of 0.500-50.0μg/mL, which is suitable for the determination of vigabatrin level after per os administration in children and youths with epilepsy, who were on vigabatrin therapy, with or without co-medication. Specificity, accuracy, precision, recovery, matrix-effect and stability were also estimated and assessed within acceptance criteria. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of pharmacokinetic profiles of moxifloxacin in Caesarean versus non-pregnant sectioned women by fully validated HPLC with fluorescence detection.

PubMed

Nemutlu, Emirhan; Kir, Sedef; Eroglu, Hakan; Katlan, Doruk; Ozek, Aykut; Özyüncü, Özgür; Oyüncü, Ozgür; Beksaç, M Sinan

2010-07-01

In this study, a simple, rapid, cost-effective, and sensitive reversed-phase high-performance liquid chromatographic method has been developed and validated for the analysis of moxifloxacin in plasma. The chromatographic separation was achieved on a Zorbax Eclipse XDB-C18 column (150 mm x 4.6 mm i.d.) connected to a Phenomenex C(18) column (4 mm x 3.0 mm i.d.) using a mixture of acetonitrile: 15 mM citrate buffer (pH 3) (23:77, v/v) as the mobile phase with isocratic system at a flow rate of 1 mL/min. Fluorescence detection was employed with excitation at 290 nm and emission at 500 nm. Lomefloxacin was used as internal standard. Plasma samples were prepared with addition of acetonitrile only. The method was fully validated according to the International Conference on Harmonization (ICH) guidelines. The results of the validation parameters were: linearity range, 3-6000 ng/mL (R(2) = 0.9994); mean recovery, 100.48 %; limit of quantification, 5 ng/mL; limit of detection, 1 ng/mL; and intra- and inter-day precision less than 3.2% and 5.1%, respectively. The robustness of the method was evaluated and confirmed with fractional factorial design. After validation studies, the method was applied in order to conclude the effects of pregnancy on postoperative pharmacokinetic profiles of moxifloxacin. For this aim, moxifloxacin was given to non-pregnant women (n=9) and caesarean-sectioned women (n=6) as a single intravenous dose (400 mg Avelox(R) infusion). Plasma samples were analyzed in order to compare pharmacokinetic profiles of pregnants and non-pregnants. Peak serum concentrations of non-pregnant and caesarean-sectioned women at the arterial port after the infusion were 4.95 +/- 1.50 and 1.56 +/- 0.16 microg/mL, respectively. The mean elimination half-life, volume of distribution and calculated area under the concentration-time curve (AUC)(0-infinity) were 5.54 +/- 0.73 h, 65.58 +/- 6.30 L and 49.95 +/- 6.30 microg.h/mL for non-pregnant women and 3.50 +/- 0.37 h, 215.85 +/- 24.87 L and 10.53 +/- 0.66 microg.h/mL for caesarean-sectioned women, respectively. These results indicated that pregnancy has a significant effect on the pharmacokinetics of moxifloxacin.

Evidence for a Dayside Thermal Inversion and High Metallicity for the Hot Jupiter WASP-18b

NASA Astrophysics Data System (ADS)

Sheppard, Kyle; Mandell, Avi M.; Tamburo, Patrick; Gandhi, Siddarth; Pinhas, Arazi; Madhusudhan, Nikku; Deming, Drake

2018-01-01

Hot Jupiters have been vital in revealing the structural and atmospheric diversity of gas-rich planets. Since they are exposed to extreme conditions and relatively easy to observe through transit and eclipse spectroscopy, hot Jupiters provide a window into a unique part of parameter space, allowing us to better understand both atmospheric physics and planetary structure. Additionally, constraints on the structure and composition of exoplanetary atmospheres allow us to test and generalize planetary formation models. We find evidence for a strong thermal inversion in the dayside atmosphere of the highly irradiated hot Jupiter WASP-18b (Teq=2400K, M=10MJ) based on Hubble Space Telescope secondary eclipse observations and Spitzer eclipse photometry. We report a 4.7σ detection of CO, and a non-detection of water vapor as well as all other relevant species (e.g., TiO, VO). The most probable atmospheric retrieval solution indicates a C/O ratio of 1 and an extremely high metallicity (C/H=~283x solar). If confirmed with future observations, WASP-18b would be the first example of a planet with a non-oxide driven thermal inversion and an atmospheric metallicity inconsistent with that predicted for Jupiter-mass planets.

Application of high performance liquid chromatography for the profiling of complex chemical mixtures with the aid of chemometrics.

PubMed

Ni, Yongnian; Zhang, Liangsheng; Churchill, Jane; Kokot, Serge

2007-06-15

In this paper, chemometrics methods were applied to resolve the high performance liquid chromatography (HPLC) fingerprints of complex, many-component substances to compare samples from a batch from a given manufacturer, or from those of different producers. As an example of such complex substances, we used a common Chinese traditional medicine, Huoxiang Zhengqi Tincture (HZT) for this research. Twenty-one samples, each representing a separate HZT production batch from one of three manufacturers were analyzed by HPLC with the aid of a diode array detector (DAD). An Agilent Zorbax Eclipse XDB-C18 column with an Agilent Zorbax high pressure reliance cartridge guard-column were used. The mobile phase consisted of water (A) and methanol (B) with a gradient program of 25-65% (v/v, B) during 0-30min, 65-55% (v/v, B) during 30-35min and 55-100% (v/v, B) during 35-60min (flow rate, 1.0mlmin(-1); injection volume, 20mul; and column temperature-ambient). The detection wavelength was adjusted for maximum sensitivity at different time periods. A peak area matrix with 21objectsx14HPLC variables was obtained by sampling each chromatogram at 14 common retention times. Similarities were then calculated to discriminate the batch-to-batch samples and also, a more informative multi-criteria decision making methodology (MCDM), PROMETHEE and GAIA, was applied to obtain more information from the chromatograms in order to rank and compare the complex HZT profiles. The results showed that with the MCDM analysis, it was possible to match and discriminate correctly the batch samples from the three different manufacturers. Fourier transform infrared (FT-IR) spectra taken from samples from several batches were compared by the common similarity method with the HPLC results. It was found that the FT-IR spectra did not discriminate the samples from the different batches.

Liquid Chromatography with Post-Column Reagent Addition of Ammonia in Methanol Coupled to Negative Ion Electrospray Ionization Tandem Mass Spectrometry for Determination of Phenoxyacid Herbicides and their Degradation Products in Surface Water

PubMed Central

Raina, Renata; Etter, Michele L.

2010-01-01

A new liquid chromatography (LC)-negative ion electrospray ionization (ESI−)–tandem mass spectrometry (MS/MS) method with post-column addition of ammonia in methanol has been developed for the analysis of acid herbicides: 2,4-dichlorophenoxy acetic acid, 4-chloro-o-tolyloxyacetic acid, 2-(2-methyl-4-chlorophenoxy)butyric acid, mecoprop, dichlorprop, 4-(2,4-dichlorophenoxy) butyric acid, 2,4,5-trichlorophenoxy propionic acid, dicamba and bromoxynil, along with their degradation products: 4-chloro-2-methylphenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and 3,5-dibromo-4-hydroxybenzoic acid. The samples were extracted from the surface water matrix using solid-phase extraction (SPE) with a polymeric sorbent and analyzed with LC ESI− with selected reaction monitoring (SRM) using a three-point confirmation approach. Chromatography was performed on a Zorbax Eclipse XDB-C18 (50 × 4.6 mm i.d., 1.8 μm) with a gradient elution using water-methanol with 2 mM ammonium acetate mobile phase at a flow rate of 0.15 mL/min. Ammonia in methanol (0.8 M) was added post-column at a flow rate of 0.05 mL/min to enhance ionization of the degradation products in the MS source. One SRM transition was used for quantitative analysis while the second SRM along with the ratio of SRM1/SRM2 within the relative standard deviation determined by standards for each individual pesticide and retention time match were used for confirmation. The standard deviation of ratio of SRM1/SRM2 obtained from standards run on the day of analysis for different phenoxyacid herbicides ranged from 3.9 to 18.5%. Limits of detection (LOD) were between 1 and 15 ng L−1 and method detection limits (MDL) with strict criteria requiring <25% deviation of peak area from best-fit line for both SRM1 and SRM2 ranged from 5 to 10 ng L−1 for acid ingredients (except dicamba at 30 ng L−1) and from 2 to 30 ng L−1 for degradation products. The SPE-LC-ESI− MS/MS method permitted low nanogram-per-liter determination of pesticides and degradation products for surface water samples. PMID:20212919

[Standardisation and validation of an HPLC method for determining serum posaconazole levels in Colombia].

PubMed

Cáceres, Diego H; Zapata, Juan David; Granada, Sinar D; Cano, Luz E; Naranjo, Tonny W

Colombia currently does not have a specialised service for measuring antifungal levels in serum, which is of prime importance for the proper treatment and correct management of invasive fungal infections. To standardise and validate a simple, sensitive, and specific protocol, based on high performance liquid chromatography, complying with the parameters recommended by the Food and Drug Administration, to detect, identify, and quantify serum concentrations of posaconazole. A high performance liquid chromatography Agilent series-1 200 equipment was used with ultraviolet diode array detector and analytical column-Eclipse XDB-C18. Posaconazole-SCH56592 (batch IRQ-PAZ-10-X-103) was used as the primary control and itraconazole (batch ZR051211PUC921) was used as an internal control. The validation was performed taking into account all criteria recommended by the Food and Drug Administration (selectivity, calibration curves, recovery, accuracy, precision, sensitivity, reproducibility, and stability of the sample). The most suitable chromatographic conditions were the following: column temperature 25°C, ultraviolet detection at 261nm, 50μl injection volume, flow volume 0.8ml/min, 10min running time, mobile phase of acetonitrile:water (70:30), and final retention times of 3.4 and 7.2min for posaconazole and itraconazole, respectively, with a wide and reliable quantification range (0.125μg/ml to 16μg/ml). Using these parameters, the method was selective, R 2 in the calibration curves was≥0.99, and the percentage recovery was 98.7%, with a coefficient of variation less than 10%. The relative error for accuracy and the coefficient of variation for precision were less than 15%, all meeting the acceptance criteria recommended by the Food and Drug Administration. The selectivity and chromatographic purity of the obtained signal, as well as the standardised limits of detection and quantification, make this method an excellent tool for therapeutic monitoring of patients treated with posaconazole. Copyright © 2016 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

Wenzhouxiangella sediminis sp. nov. isolated from coastal sediment

USDA-ARS?s Scientific Manuscript database

A novel Gram-stain-negative, non-spore-forming, no flagellum, facultatively anaerobic, oxidase-negative, catalase- positive, rod-shaped strain, designated XDB06**T, was isolated from coastal sediment of Xiaoshi Island, Weihai, China. Optimal growth occurred at 37 °C, pH 7.5 and with 4.0% (w/v) NaCl....

Evidence for a Dayside Thermal Inversion and High Metallicity for the Hot Jupiter WASP-18b

NASA Astrophysics Data System (ADS)

Sheppard, Kyle B.; Mandell, Avi M.; Tamburo, Patrick; Gandhi, Siddharth; Pinhas, Arazi; Madhusudhan, Nikku; Deming, Drake

2017-12-01

We find evidence for a strong thermal inversion in the dayside atmosphere of the highly irradiated hot Jupiter WASP-18b ({T}{eq}=2411 {{K}}, M=10.3 {M}J) based on emission spectroscopy from Hubble Space Telescope secondary eclipse observations and Spitzer eclipse photometry. We demonstrate a lack of water vapor in either absorption or emission at 1.4 μm. However, we infer emission at 4.5 μm and absorption at 1.6 μm that we attribute to CO, as well as a non-detection of all other relevant species (e.g., TiO, VO). The most probable atmospheric retrieval solution indicates a C/O ratio of 1 and a high metallicity ({{C}}/{{H}}={283}-138+395× solar). The derived composition and T/P profile suggest that WASP-18b is the first example of both a planet with a non-oxide driven thermal inversion and a planet with an atmospheric metallicity inconsistent with that predicted for Jupiter-mass planets at > 2σ . Future observations are necessary to confirm the unusual planetary properties implied by these results.

Characterization of constituents in Stellera chamaejasme L. by rapid-resolution liquid chromatography-diode array detection and electrospray ionization time-of-flight mass spectrometry.

PubMed

Zhao, Liang; Lou, Zi-Yang; Zhu, Zhen-Yu; Zhang, Guo-Qing; Chai, Yi-Feng

2008-01-01

A reliable and rapid method based on rapid-resolution liquid chromatography-diode array detection (RRLC-DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF/MS) has been developed for the isolation and characterization of multiple constituents in the root of Stellera chamaejasme L., which was extracted by sonication with methanol in an optimized procedure. Separation of the multiple constituents was achieved on an Agilent Zorbax XDB-C18 (50x3.0 mm i.d.; 1.8 microm) column using a gradient elution at a flow rate of 0.4 mL/min. The detection wavelength was 210 nm. Mass spectra were acquired in both positive and negative modes. A formula database of the known chemical constituents in the root of Stellera chamaejasme L. was established by an Agilent software. Twenty-two obvious peaks appeared in the total ion chromatogram and nine of them were characterized by TOF/MS. The RRLC-DAD and ESI-TOF/MS method with ultrasonic extraction would be useful for rapid and effective characterization of chemical constituents in the root of Stellera chamaejasme L. Copyright (c) 2007 John Wiley & Sons, Ltd.

Tip-Pressure-Induced Incoherent Energy Gap in CaFe2As2

NASA Astrophysics Data System (ADS)

Jia-Xin, Yin; Ji-Hui, Wang; Zheng, Wu; Ang, Li; Xue-Jin, Liang; Han-Qing, Mao; Gen-Fu, Chen; Bing, Lv; Ching-Wu, Chu; Hong, Ding; Shu-Heng, Pan

2016-06-01

Not Available Supported by the National Natural Science Foundation of China under Grant No 11227903, the National Basic Research Program of China under Grant Nos 2015CB921300 and 2012CB933000, the State of Texas through TcSUH, and the Strategic Priority Research Program B of Chinese Academy of Sciences under Grant Nos XDB07030000, XDB04040300 and Y4VX092X81.

Ionic Liquid-Bonded Fused Silica as a New Solid-Phase Microextraction Fiber for the Liquid Chromatographic Determination of Bisphenol A as an Endocrine Disruptor.

PubMed

Mohammadnezhad, Nasim; Matin, Amir Abbas; Samadi, Naser; Shomali, Ashkan; Valizadeh, Hassan

2017-01-01

Linear ionic liquid bonded to fused silica and its application as a solid-phase microextraction fiber for the extraction of bisphenol A (BPA) from water samples were studied. After optimization of microextraction conditions (15 mL sample volume, extraction time of 40 min, extraction temperature of 30 ± 1°C, 300 μL acetonitrile as the desorption solvent, and desorption time of 7 min), the fiber was used to extract BPA from packed mineral water, followed by HPLC-UV on an XDB-C18 column (150 × 4.6 mm id, 3.5 μm particle) with a mobile phase of acetonitrile-water (45 + 55%, v/v) and flow rate of 1 mL . min-1). A low LOD (0.20 μg . L-1) and good linearity (0.9977) in the calibration graph indicated that the proposed method was suitable for the determination of BPA.

HPLC-FLD determination of 4-nonylphenol and 4-tert-octylphenol in surface water samples.

PubMed

Cruceru, Ioana; Iancu, Vasile; Petre, Jana; Badea, Irinel Adriana; Vladescu, Luminita

2012-05-01

A simple, sensitive and reliable HPLC-FLD method for the routine determination of 4-nonylphenol, 4-NP and 4-tert-octylphenol, 4-t-OP content in water samples was developed. The method consists in a liquid-liquid extraction of the target analytes with dichloromethane at pH  3.0-3.5 followed by the HPLC-FLD analysis of the organic extract using a Zorbax Eclipse XDB C8 column, isocratic elution with a mixed solvent acetonitrile/water 65:35, at a flow rate of 1.0 mL/min and applying a column temperature of 40°C. The method was validated and then applied with good results for the determination of 4-NP and 4-t-OP in Ialomiţa River water samples collected each month during 2006. The concentration levels of 4-NP and 4-t-OP vary between 0.08-0.17 μg/L with higher values of 0.24-0.37 μg/L in the summer months for 4-NP, and frequently <0.05 μg/L but also between 0.06-0.09 μg/L with higher values of 0.12-0.16 μg/L in July and August for 4-t-OP and were strongly influenced by sesonial and anthropic factors. The method was also applied on samples collected over 2 years 2007 and 2008 from urban wastewaters discharged into sewage or directly into the rivers by economic agents located in 30 Romanian towns. Good results were obtained when the method was used for analysis of effluents discharged into surface waters by 16 municipal wastewater treatment plants, during the year 2008.

Development and validation of a rapid ultra-high performance liquid chromatography diode array detector method for Vitex agnus-castus.

PubMed

Högner, C; Sturm, S; Seger, C; Stuppner, H

2013-05-15

A rapid ultra-high performance liquid chromatography diode array detector (UHPLC-DAD) method was developed and validated for the simultaneous determination of all classes of non-volatile phytochemicals (iridoids, flavonoids and diterpenes) in Vitex agnus-castus (Lamiaceae) fruits, a traditional medicinal plant used against premenstrual symptoms (PMS) and other disorders. Seven marker compounds, 3,4-dihydroxybenzoic acid, p-hydroxybenzoic acid, agnuside, 5-hydroxykaempferol-3,6,7,4'-tetramethylether, 1,2-dibenzoic acid glucose, methoxy-vitexilactone, and vitetrifolin D were isolated from the methanol extract of V. agnus-castus to be used as reference substances. Chromatographic separation was performed on a Zorbax Eclipse XDB-C18 (50mm×2.1mm) UHPLC column with 1.8μm particle size, within 20min. A solvent gradient from 0.5% acetic acid to acetonitrile at a flow rate of 0.6mL/min was used as mobile phase. Analyte detection and quantification was realized at 210nm and 260nm. The UHPLC-DAD assay was validated for the quantitative analysis of agnuside, isovitexin, casticin, 5-hydroxykaempferol-3,6,7,4'-tetramethylether and vitetrifolin D. It was found to be specific, accurate, precise, and reproducible for the quantification of these compound within a concentration range of 0.7-500.0μg/mL for casticin and 5-hydroxykaempferol-3,6,7,4'-tetramethylether, 1.4-1000.0μg/mL for isovitexin and agnuside, and 12.4-1000.0μg/mL for vitetrifolin D. Intra- and inter-day variations showed relative standard deviations (RSD) of less than 3.9% and 6.4%, respectively. Tentatively assignment of 62 chromatographic features found in the UHPLC-DAD assay was carried out by coupling the UHPLC instrument to a quadrupole time-of-flight mass spectrometer via an electrospray ionization interface (ESI-QTOF-MS) operated in positive and negative ion mode. By using the established quantitative UHPLC-DAD assay to asses agnuside, isovitexin, casticin, 5-hydroxykaempferol-3,6,7,4'-tetramethylether and vitetrifolin D in V. agnus-castus derived preparations as extracts, tinctures and tablets, the applicability of the developed assay to phytopharmaceuticals was successfully proven. Copyright © 2013 Elsevier B.V. All rights reserved.

The Xeno-glycomics database (XDB): a relational database of qualitative and quantitative pig glycome repertoire.

PubMed

Park, Hae-Min; Park, Ju-Hyeong; Kim, Yoon-Woo; Kim, Kyoung-Jin; Jeong, Hee-Jin; Jang, Kyoung-Soon; Kim, Byung-Gee; Kim, Yun-Gon

2013-11-15

In recent years, the improvement of mass spectrometry-based glycomics techniques (i.e. highly sensitive, quantitative and high-throughput analytical tools) has enabled us to obtain a large dataset of glycans. Here we present a database named Xeno-glycomics database (XDB) that contains cell- or tissue-specific pig glycomes analyzed with mass spectrometry-based techniques, including a comprehensive pig glycan information on chemical structures, mass values, types and relative quantities. It was designed as a user-friendly web-based interface that allows users to query the database according to pig tissue/cell types or glycan masses. This database will contribute in providing qualitative and quantitative information on glycomes characterized from various pig cells/organs in xenotransplantation and might eventually provide new targets in the α1,3-galactosyltransferase gene-knock out pigs era. The database can be accessed on the web at http://bioinformatics.snu.ac.kr/xdb.

Photometric Study of The Solar Type, Total Eclipsing Binary, TYC 2853-18-1

NASA Astrophysics Data System (ADS)

Samec, Ronald G.; Figg, E. R.; Faulkner, D.; Van Hamme, W.

2009-12-01

We present an analysis of the Solar-Type eclipsing binary, TYC 2853-18-1 (Persei), based on observations taken at the National Undergraduate Research Observatory (NURO) and the Southeastern Association for Research in Astronomy (SARA) in the Fall, 2007 and Spring, 2008. Light curves, a period study and a synthetic light curve solution are presented for this variable which was recently discovered by TYCHO as an eclipsing binary (2006, IBVS 5700). Our CCD observations of TYC 2853-18-1 [GSC 2853 0018, RA(2000) = 02h 47m 07.996s, DEC(2000) = +41° 22’ 32.80"] were taken on 20,27 December, 2007 at Lowell Observatory with the 0.81-m reflector with NURO time and 25 November, 3 December, 2007 and 19 February, 2008 via remote observing from Kitt Peak with SARA. NURO observations were take with the thermoelectrically cooled (<-100C) 2KX2K CCD NASACAM. Standard BVRcIc Johnson-Cousins filters were used. Our light curve solution was calculated with the 2004 Wilson code. Mean times of eclipse include, HJDMinI = 2454516.6131(±0.0005), 2454440.52974(±0.00008), 2454438.7605 (±0.0001), 2454462.6464 (±0.0003), HJDMinII = 2454455.71985 (±0.00060), 255462.7943 (±0.0002). These, including the epoch by ROTSE (2006, IBVS 5699) and the epoch calculated by the Wilson code, yielded the following ephemeris: HJD Hel Min I =2451370.8753(±.0.0010)d + 0.2949039 (±0.0000001)E Our unspotted Wilson code solution reveals TYC 2853-18-1 to be a W-type W UMa contact binary with unequal eclipse depths (amplitudes are 0.72 and 0.61 mags in V). It has shallow contact (8% fill-out) and a brief, but total eclipse. Its curves dictate a mass ratio of 2.62±0.01, a component temperature difference of only 73±5 ° K and an inclination of 82.0±0.2°. Spot activity is indicated by night to night variations. We wish to thank the NURO and SARA for their allocation of observing time, as well as NASA and the AAS for their support in paying for travel and publication expenses.

Modeling Amateur Radio Soundings of the Ionospheric Response to the 2017 Great American Eclipse

NASA Astrophysics Data System (ADS)

Frissell, N. A.; Katz, J. D.; Gunning, S. W.; Vega, J. S.; Gerrard, A. J.; Earle, G. D.; Moses, M. L.; West, M. L.; Huba, J. D.; Erickson, P. J.; Miller, E. S.; Gerzoff, R. B.; Liles, W.; Silver, H. W.

2018-05-01

On 21 August 2017, a total solar eclipse traversed the continental United States and caused large-scale changes in ionospheric densities. These were detected as changes in medium- and high-frequency radio propagation by the Solar Eclipse QSO Party citizen science experiment organized by the Ham Radio Science Citizen Investigation (hamsci.org). This is the first eclipse-ionospheric study to make use of measurements from a citizen-operated, global-scale HF propagation network and develop tools for comparison to a physics-based model ionosphere. Eclipse effects were observed ±0.3 hr on 1.8 MHz, ±0.75 hr on 3.5 and 7 MHz, and ±1 hr on 14 MHz and are consistent with eclipse-induced ionospheric densities. Observations were simulated using the PHaRLAP raytracing toolkit in conjunction with the eclipsed SAMI3 ionospheric model. Model results suggest 1.8, 3.5, and 7 MHz refracted at h≥125 km altitude with elevation angles θ≥22°, while 14 MHz signals refracted at h < 125 km with elevation angles θ < 10°.

rac-(S,S)-Bis(1-ferrocenylbut-3-en-yl) ether.

PubMed

Xie, Hao-Jun; Zhao, Chun-Zheng; Sun, Jun; Chen, Si; Wang, Jian-Jun

2013-01-01

The title complex, [Fe2(C5H5)2(C18H20O)], formed by dehydration of 1-ferrocenylbut-3-en-1-ol, crystallizes as a racemic compound. The central C-O-C fragment, in which the C atoms are the chiral centers, is characterized by an angle of 116.26 (10)° at the O atom. One ferrocene group shows a staggered conformation whereas the other shows an eclipsed conformation.

Graphene/Mo2C heterostructure directly grown by chemical vapor deposition

NASA Astrophysics Data System (ADS)

Deng, Rongxuan; Zhang, Haoran; Zhang, Yanhui; Chen, Zhiying; Sui, Yanping; Ge, Xiaoming; Liang, Yijian; Hu, Shike; Yu, Guanghui; Jiang, Da

2017-06-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 1402342, 11574338, and 11274333), the Hundred Talents Program of Chinese Academy of Sciences, the International Collaboration and Innovation Program on High Mobility Materials Engineering, Chinese Academy of Sciences (Grant No. KGZD-EW-303), and the "Strategic Priority Research Program (B)" of the Chinese Academy of Sciences (Grant No. XDB04040300).

British Observations of the 18 August 1868 Total Solar Eclipse from Guntoor, India

NASA Astrophysics Data System (ADS)

Orchiston, Wayne; Lee, Eun-Hee; Ahn, Young-Sook

The total solar eclipse of 18 August 1868 was observed in Aden, India, Siam (present-day Thailand) and the Dutch East Indies (present-day Indonesia). One Indian expedition was sponsored by the Royal Astronomical Society, and led by Major J.F. Tennant. In this chapter we describe the observing team and instruments, discuss their observations, and conclude with some remarks on the place of the 1868 eclipse in solar studies and later nineteenth century European astronomical expeditions to India.

Simultaneous determination of five free and total flavonoids in rat plasma by ultra HPLC-MS/MS and its application to a comparative pharmacokinetic study in normal and hyperlipidemic rats.

PubMed

Wang, Xiaofan; Zhao, Xu; Gu, Liqiang; Lv, Chunxiao; He, Bosai; Liu, Zhenzhen; Hou, Pengyi; Bi, Kaishun; Chen, Xiaohui

2014-03-15

A simple and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (uHPLC-MS/MS) method has been developed for the simultaneous determination of five free flavonoids (amentoflavone, isorhamnetin, naringenin, kaempferol and quercetin) and their total (free and conjugated) forms, and to compare the pharmacokinetics of these active ingredients in normal and hyperlipidemic rats. The free and total forms of these flavonoids were extracted by liquid-liquid extraction with ethyl acetate. The conjugated flavonoids were deconjugated by the enzyme β-Glucuronidase and Sulfatase. Chromatographic separation was accomplished on a ZORBAX Eclipse XDB-C8 USP L7 column using gradient elution. Detection was performed on a 4000Q uHPLC-MS/MS system from AB Sciex using negative ion mode in the multiple reaction monitoring (MRM) mode. The lower limits of quantification were 2.0-5.0ng/mL for all the analytes. Intra-day and inter-day precision were less than 15% and accuracy ranged from -9.3% to 11.0%, and the mean extraction recoveries of analytes and internal standard (IS) from rat plasma were all more than 81.7%. The validated method was successfully applied to a comparative pharmacokinetic study of five free and total analytes in rat plasma. The results indicated that the absorption of five total flavonoids in hyperlipidemia group were significantly higher than those in normal group with similar concentration-time curves. Copyright © 2014 Elsevier B.V. All rights reserved.

Eclipse project QF-106 and C-141A climbs out under tow on first tethered flight December 20, 1997

NASA Technical Reports Server (NTRS)

1997-01-01

TOW LAUNCH DEMONSTRATION - The Kelly Space & Technology (KST)/USAF/NASA Eclipse project's modified QF-106 climbs out under tow by a USAF C-141A on the project's first tethered flight on December 20, 1997. The successful 18-minute-long flight reached an altitude of 10,000 feet. NASA's Dryden Flight Research Center, Edwards, California, hosted the project, providing engineering and facility support as well as the project pilot. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

Eclipse project QF-106 and C-141A takeoff on first tethered flight December 20, 1997

NASA Technical Reports Server (NTRS)

1997-01-01

TOW ROPE TAKEOFF - The Kelly Space & Technology (KST)/USAF Eclipse project's modified QF-106 and a USAF C-141A takeoff for the project's first tethered flight on December 20, 1997. The successful 18-minute-long flight reached an altitude of 10,000 feet. NASA's Dryden Flight Research Center, Edwards, California, hosted the project, providing engineering and facility support as well as the project pilot. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

Is an eclipse described in the Odyssey?

PubMed

Baikouzis, Constantino; Magnasco, Marcelo O

2008-07-01

Plutarch and Heraclitus believed a certain passage in the 20th book of the Odyssey ("Theoclymenus's prophecy") to be a poetic description of a total solar eclipse. In the late 1920s, Schoch and Neugebauer computed that the solar eclipse of 16 April 1178 B.C.E. was total over the Ionian Islands and was the only suitable eclipse in more than a century to agree with classical estimates of the decade-earlier sack of Troy around 1192-1184 B.C.E. However, much skepticism remains about whether the verses refer to this, or any, eclipse. To contribute to the issue independently of the disputed eclipse reference, we analyze other astronomical references in the Epic, without assuming the existence of an eclipse, and search for dates matching the astronomical phenomena we believe they describe. We use three overt astronomical references in the epic: to Boötes and the Pleiades, Venus, and the New Moon; we supplement them with a conjectural identification of Hermes's trip to Ogygia as relating to the motion of planet Mercury. Performing an exhaustive search of all possible dates in the span 1250-1115 B.C., we looked to match these phenomena in the order and manner that the text describes. In that period, a single date closely matches our references: 16 April 1178 B.C.E. We speculate that these references, plus the disputed eclipse reference, may refer to that specific eclipse.

Period analysis of the eclipsing binary AI Dra

NASA Astrophysics Data System (ADS)

Zasche, P.; Uhlář, R.; Svoboda, P.

2010-03-01

The eclipsing binary system AI Dra reveals changes of its orbital period. These variations could be described as a result of orbiting the eclipsing pair around a common center of mass with two unseen companions with the periods about 18 and 43 years together with a steady period increase. Fourteen new minima observations were carried out by the authors.

Molecular structure and conformations of para-methylbenzene sulfonamide and ortho-methylbenzene sulfonamide: gas electron diffraction and quantum chemical calculations study.

PubMed

Petrov, Vjacheslav M; Girichev, Georgiy V; Oberhammer, Heinz; Petrova, Valentina N; Giricheva, Nina I; Bardina, Anna V; Ivanov, Sergey N

2008-04-03

The molecular structure and conformational properties of para-methylbenzene sulfonamide (4-MBSA) and ortho-methylbenzene sulfonamide (2-MBSA) have been studied by gas electron diffraction (GED) and quantum chemical methods (B3LYP/6-311+G** and MP2/6-31G**). Quantum chemical calculations predict the existence of two conformers for 4-MBSA with the S-N bond perpendicular to the benzene plane and the NH2 group either eclipsing or staggering the S-O bonds of the SO2 group. Both conformers possess CS symmetry. The eclipsed form is predicted to be favored by DeltaE = 0.63 kcal/mol (B3LYP) or 1.00 kcal/mol (MP2). According to the calculations, the S-N bond in 2-MBSA can possess planar direction opposite the methyl group (phi(C2C1SN) = 180 degrees ) or nonplanar direction (phi(C2C1SN) approximately 60 degrees ). In both cases, the NH2 group can adopt eclipsed or staggered orientation, resulting in a total of four stable conformers. The nonplanar eclipsed conformer (C1 symmetry) and the planar eclipsed form (CS symmetry) are predicted to be favored. According to the GED analysis, the saturated vapor over solid 4-MBSA at T = 151(3) degrees C consists as mixture of the eclipsed (78(19) %) and staggered (22(19) %) forms. The saturated vapor over solid 2-MBSA at T = 157(3) degrees C consists as a mixture of the nonplanar eclipsed (69(11) %) and planar eclipsed (31(11) %) forms.

Optimisation for subcritical fluid extraction of 17-methyltestosterone with 1,1,1,2-tetrafluoroethane for HPLC analysis.

PubMed

Han, Yuqian; Ma, Qinchuan; Lu, Jie; Xue, Yong; Xue, Changhu

2012-12-15

A simple, rapid and sensitive method was developed for determination of 17α-methyltestosterone in aquatic products by extraction with subcritical 1,1,1,2-tetrafluoroethane (R134a) extraction and high performance liquid chromatography (HPLC). Response surface methodology (RSM) was adopted to optimise extraction pressure, temperature and co-solvent volume. The optimum extraction conditions predicted within the experimental ranges were as follows: pressure 5 MPa, temperature 31°C, and co-solvent volume 3.35ml. The analysis was carried out on XDB-C(18) column (4.6 mm × 250 mm, 5 μm) with the mobile phase acetonitrile-water (55:45, v/v), flow rate 0.8 ml/min, temperature 30°C and wavelength 245 nm. Good linearity of detection was obtained for 17α-methyltestosterone between concentrations of 50-250 ng/ml, r(2)=0.999. The method was validated using samples fortified with 17α-methyltestosterone at levels of 10, 30 and 50 ng/g, the mean recovery exceeds 90%, and the RSD values were less than 10%. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Is an eclipse described in the Odyssey?

PubMed Central

Baikouzis, Constantino; Magnasco, Marcelo O.

2008-01-01

Plutarch and Heraclitus believed a certain passage in the 20th book of the Odyssey (“Theoclymenus's prophecy”) to be a poetic description of a total solar eclipse. In the late 1920s, Schoch and Neugebauer computed that the solar eclipse of 16 April 1178 B.C.E. was total over the Ionian Islands and was the only suitable eclipse in more than a century to agree with classical estimates of the decade-earlier sack of Troy around 1192–1184 B.C.E. However, much skepticism remains about whether the verses refer to this, or any, eclipse. To contribute to the issue independently of the disputed eclipse reference, we analyze other astronomical references in the Epic, without assuming the existence of an eclipse, and search for dates matching the astronomical phenomena we believe they describe. We use three overt astronomical references in the epic: to Boötes and the Pleiades, Venus, and the New Moon; we supplement them with a conjectural identification of Hermes's trip to Ogygia as relating to the motion of planet Mercury. Performing an exhaustive search of all possible dates in the span 1250–1115 B.C., we looked to match these phenomena in the order and manner that the text describes. In that period, a single date closely matches our references: 16 April 1178 B.C.E. We speculate that these references, plus the disputed eclipse reference, may refer to that specific eclipse. PMID:18577587

Solar Eclipse Effect on Shelter Air Temperature

NASA Technical Reports Server (NTRS)

Segal, M.; Turner, R. W.; Prusa, J.; Bitzer, R. J.; Finley, S. V.

1996-01-01

Decreases in shelter temperature during eclipse events were quantified on the basis of observations, numerical model simulations, and complementary conceptual evaluations. Observations for the annular eclipse on 10 May 1994 over the United States are presented, and these provide insights into the temporal and spatial changes in the shelter temperature. The observations indicated near-surface temperature drops of as much as 6 C. Numerical model simulations for this eclipse event, which provide a complementary evaluation of the spatial and temporal patterns of the temperature drops, predict similar decreases. Interrelationships between the temperature drop, degree of solar irradiance reduction, and timing of the peak eclipse are also evaluated for late spring, summer, and winter sun conditions. These simulations suggest that for total eclipses the drops in shelter temperature in midlatitudes can be as high as 7 C for a spring morning eclipse.

Extension of the carotenoid test to superficially porous C18 bonded phases, aromatic ligand types and new classical C18 bonded phases.

PubMed

Lesellier, E

2012-11-30

The recent introduction of new stationary phases for liquid chromatography based on superficially porous particles, called core-shell or fused-core, dramatically improved the separation performances through very high efficiency, due mainly to reduced eddy diffusion. However, few studies have evaluated the retention and selectivity of C18 phases based on such particles, despite some retention order change reported in literature between some of these phases. The carotenoid test has been developed a few years ago in the goal to compare the chromatographic properties of C18 bonded phases. Based on the analysis of carotenoid pigments by using Supercritical Fluid Chromatography (SFC), it allows, with a single analysis, to measure three main properties of reversed phase chromatography stationary phases: hydrophobicity, polar surface activity and shape selectivity. Previous studies showed the effect of the endcapping treatment, the bonding density, the pore size, and the type of bonding (monomeric vs. polymeric) on these studied properties, and described the classification map used for a direct column comparison. It was applied to ten ODS superficially porous stationary phases, showing varied chromatographic behaviors amongst these phases. As expected, due to the lower specific surface area, these superficially porous phases are less hydrophobic than the fully porous one. In regards of the polar surface activity (residual silanols) and to the shape selectivity, some of these superficially porous phases display close chromatographic properties (Poroshell 120, Halo C18, Ascentis Express, Accucore C18, Nucleoshell C18 on one side and Aeris Wide pore, Aeris peptide and Kinetex XDB on the other side), whereas others, Kinetex C18 and Halo peptide ES C18 display more specific ones. Besides, they can be compared to classical fully porous phases, in the goal to improve method transfer from fully to superficially porous particles. By the way, the paper also report the extension of the test to other ligands such as naphtyl, cholester, phenyl-hexyl, or to the new ODS bonded phases, such as charge surface hybrid phases, High Strength Silica, and Hybrid ones, and also presents results for identical brands using different particle size, such as Luna and Synergi phases. Phenyl-hexyl and napthyl ligands show rather close properties, low hydrophobicity, high polar surface activity and specific shape selectivity, whereas, at the opposite, the cholester phase display a polymeric behavior and a high hydrophobicity. Finally, additional classical (fully porous particles) C18 bonded phases are also reported to complete the data set presented in previous papers. Copyright © 2012 Elsevier B.V. All rights reserved.

Searching for planets around eclipsing binary stars using timing method: NSVS 14256825

NASA Astrophysics Data System (ADS)

Nasiroglu, Ilham; Goździewski, Krzysztof; Słowikowska, Aga; Krzeszowski, Krzysztof; Żejmo, Michal; Zola, Staszek; Er, Huseyin

2018-04-01

We present four new mid eclipse times and an updated O-C diagram of the short period eclipsing binary NSVS14256825. The new data follow the (O-C) trend and its model proposed in Nasiroglu et al. (2017). The (O-C) diagram shows quasi-periodic variations that can be explained with the presence of a brown-dwarf in a quasi-circular circumbinary orbit.

A new study of the interacting binary star V356 Sgr

NASA Technical Reports Server (NTRS)

Polidan, R. S.

1988-01-01

Results on V356 Sgr from IUE and Voyager ultraviolet (500 to 3200 A) observations obtained in 1986 and 1987, primarily during 2 total eclipses are presented. The eclipse of Aug. 15, 1986 was fully covered with IUE low dispersion images and 9 hr of Voyager UVS data. The eclipse of Mar. 25, 1987 was covered with IUE low dispersion images and 1 high dispersion SWP image. During both eclipses the total strength of the emission lines is found to be invariant. An uneclipsed UV continuum is detected at wavelengths shorter than 1500 A. The high dispersion SWP spectrum reveals that the emission lines are extremely broad, almost symmetrical emissions with weak, slightly blue shifted absorption components. No evidence of carbon, C I, C II, C III, or C IV, is seen in the emission or absorption spectrum of V356 Sgr in eclipse. Models for this binary system are presented.

A validated stability-indicating HPLC method for determination of varenicline in its bulk and tablets

PubMed Central

2011-01-01

A simple, sensitive and accurate stability-indicating HPLC method has been developed and validated for determination of varenicline (VRC) in its bulk form and pharmaceutical tablets. Chromatographic separation was achieved on a Zorbax Eclipse XDB-C8 column (150 mm × 4.6 mm i.d., particle size 5 μm, maintained at ambient temperature) by a mobile phase consisted of acetonitrile and 50 mM potassium dihydrogen phosphate buffer (10:90, v/v) with apparent pH of 3.5 ± 0.1 and a flow rate of 1.0 ml/min. The detection wavelength was set at 235 nm. VRC was subjected to different accelerated stress conditions. The degradation products, when any, were well resolved from the pure drug with significantly different retention time values. The method was linear (r = 0.9998) at a concentration range of 2 - 14 μg/ml. The limit of detection and limit of quantitation were 0.38 and 1.11 μg/ml, respectively. The intra- and inter-assay precisions were satisfactory; the relative standard deviations did not exceed 2%. The accuracy of the method was proved; the mean recovery of VRC was 100.10 ± 1.08%. The proposed method has high throughput as the analysis involved short run-time (~ 6 min). The method met the ICH/FDA regulatory requirements. The proposed method was successfully applied for the determination of VRC in bulk and tablets with acceptable accuracy and precisions; the label claim percentages were 99.65 ± 0.32%. The results demonstrated that the method would have a great value when applied in quality control and stability studies for VRC. PMID:21672253

Simultaneous serum nicotine, cotinine, and trans-3'-hydroxycotinine quantitation with minimal sample volume for tobacco exposure status of solid organ transplant patients.

PubMed

Shu, Irene; Wang, Ping

2013-06-01

Concentrations of nicotine and its metabolites in blood are indicative of patients' current tobacco exposure, and their quantifications have been clinically applied to multiple assessments including demonstration of abstinence prior to heart-lung transplantation. For the purpose of transplant evaluation, the laboratory work up is extensive; thereby an assay with minimal sample volume is preferred. We developed and validated a rapid LC-MS/MS assay to simultaneously quantitate nicotine and its major metabolites, Cotinine and trans-3'-OH-cotinine (3-OH-Cot), in serum. 100μL of serum was spiked with deuterated internal standards and extracted by Oasis HLB solid phase extraction cartridge. Nicotine and metabolites in the reconstituted serum extract were separated by Agilent Eclipse XDB-C8 3.5μm 2.1mm×50mm HPLC column within 4.7min, and quantified by MS/MS with positive mode electrospray ionization and multiple reaction monitoring. Ion suppression was insignificant, and extraction efficiency was 79-110% at 50ng/mL for all compounds. Limit of detection was 1.0ng/mL for nicotine and 3-OH-Cot, and <0.5ng/mL for Cotinine. Linearity ranges for nicotine, cotinine and 3-OH-Cot were 2-100, 2-1000, and 5-1000ng/mL with recoveries of 86-115%. Within-day and twenty-day imprecision at nicotine/cotinine/3-OH-Cot levels of 22/150/90, 37/250/150, and 50/800/500ng/mL were all 1.1-6.5%. The reconstituted serum extracts were stable for at least 7 days stored in the HPLC autosampler at 5°C. Our method correlates well with alternative LC-MS/MS methods. We successfully developed and validated an LC-MS/MS assay to quantitate concentrations of nicotine and its metabolites in serum with minimal sample volume to assess tobacco exposure of heart-lung transplant patients. Copyright © 2013 Elsevier B.V. All rights reserved.

Modeling the Effects of Asynchronous Rotation on Secondary Eclipse Timings in HW VIr Binaries

NASA Astrophysics Data System (ADS)

Clancy, Padraig

2018-01-01

HW Vir binaries are post common envelope binaries consisting of a hot subdwarf and red dwarf, with light curves dominated by primary eclipses, a strong reflection effect, and secondary eclipses. They have orbital periods ranging from a few hours to half a day and are generally thought to be tidally locked; most studies assume both synchronous rotation and zero eccentricity when modeling HW Vir light curves and radial velocities. Their stable eclipse timings are frequently used in O-C studies to look for the presence of circumbinary objects, measure evolutionary changes in the orbital period, and even constrain the component masses through Roemer delay measurements of the secondary eclipse. While most systems are probably tidally locked or close to it, even slightly asynchronous rotation could theoretically shift the orbital phase of the reflection effect. Here we investigate how asynchronous rotation might affect measurements of secondary eclipse timings by generating thousands of synthetic light curves with a range of reflection effect phases, fitting eclipse timings, and creating O-C diagrams.

How Accurately Can We Predict Eclipses for Algol? (Poster abstract)

NASA Astrophysics Data System (ADS)

Turner, D.

2016-06-01

(Abstract only) beta Persei, or Algol, is a very well known eclipsing binary system consisting of a late B-type dwarf that is regularly eclipsed by a GK subgiant every 2.867 days. Eclipses, which last about 8 hours, are regular enough that predictions for times of minima are published in various places, Sky & Telescope magazine and The Observer's Handbook, for example. But eclipse minimum lasts for less than a half hour, whereas subtle mistakes in the current ephemeris for the star can result in predictions that are off by a few hours or more. The Algol system is fairly complex, with the Algol A and Algol B eclipsing system also orbited by Algol C with an orbital period of nearly 2 years. Added to that are complex long-term O-C variations with a periodicity of almost two centuries that, although suggested by Hoffmeister to be spurious, fit the type of light travel time variations expected for a fourth star also belonging to the system. The AB sub-system also undergoes mass transfer events that add complexities to its O-C behavior. Is it actually possible to predict precise times of eclipse minima for Algol months in advance given such complications, or is it better to encourage ongoing observations of the star so that O-C variations can be tracked in real time?

A Case Study in High Contrast Coronagraph for Planet Discovery: The Eclipse Concept and Support Laboratory Experience

NASA Technical Reports Server (NTRS)

Trauger, John T.

2005-01-01

Eclipse is a proposed NASA Discovery mission to perform a sensitive imaging survey of nearby planetary systems, including a survey for jovian-sized planets orbiting Sun-like stars to distances of 15 pc. We outline the science objectives of the Eclipse mission and review recent developments in the key enabling technologies. Eclipse is a space telescope concept for high-contrast visible-wavelength imaging and spectrophotometry. Its design incorporates a telescope with an unobscured aperture of 1.8 meters, a coronographic camera for suppression of diffracted light, and precise active wavefront correction for the suppression of scattered background light. For reference, Eclipse is designed to reduce the diffracted and scattered starlight between 0.33 and 1.5 arcseconds from the star by three orders of magnitude compared to any HST instrument. The Eclipse mission provides precursor science exploration and technology experience in support of NASA's Terrestrial Planet Finder (TPF) program.

Eclipse project closeup of QF-106 under tow on takeoff on first flight December 20, 1997

NASA Technical Reports Server (NTRS)

1997-01-01

OFF THE GROUND - The Kelly Space & Technology (KST)/USAF/NASA Eclipse project's modified QF-106 lifts off under tow on the project's first tethered flight on December 20, 1997. The successful 18-minute-long flight reached an altitude of 10,000 feet. NASA's Dryden Flight Research Center, Edwards, California, hosted the project, providing engineering and facility support as well as the project pilot. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

Eclipse project closeup of QF-106 under tow on first tethered flight December 20, 1997

NASA Technical Reports Server (NTRS)

1997-01-01

The Kelly Space and Technology (KST)/USAF/NASA Eclipse project's modified QF-106 is shown under tow on the project's first tethered flight on December 20, 1997. The successful 18-minute-long flight reached an altitude of 10,000 feet. NASA's Dryden Flight Research Center, Edwards, California, is hosting the project, providing engineering and facility support as well as the project pilot, Mark Stucky. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

The Mount Logan (Yukon) Ice Cores: Preliminary Results

NASA Astrophysics Data System (ADS)

Fisher, D. A.

2004-05-01

Three ice cores were taken at different elevations on or near My Logan in the years 2001 and 2002. The summit core (PRCol) comes from the summit plateau ( 5340 masl, length 187 m to bedrock, mean temperature -29 C ) and was done by the Geological Survey of Canada. The NIPR group cored 210m on the flanks of the mountain at King Col (4200 masl mean temperature -16C) and the UNH group cored 20 km from the mountain at Eclipse "Dome" (3015 masl,length 345 m mean temperature -5C) . The three cores were done cooperatively by GSC, NIPR and UNH and cover nominally 30 ka, 1 ka and 2ka respectively . Located very close to the Gulf of Alaska these core records are thought to reflect the climate history of the Pacific Ocean and having three widely spaced elevations, the sites "see" different distances to different sources. The lowest site (Eclipse) has excellent seasonals but a very muted δ 18O history with no obvious little ice age, whereas the most recent 1ka of the PRCol summit sites contains two very large and sudden δ 18O and d (deuterium excess) shifts at 1850 AD and ~ 800 AD. The δ 18O shifts which happen from one year to the next are about 4 o/oo . The summit site (PRCol) δ 18O response is "backwards", ie the Little Ice Age δ 18O values are 4 o/oo more positive than recent ones. The PRCol δ 18O and d suggest that the source water can either be ëlocalí (Gulf of Alaska) or very distant (tropics) . The Eclipse site seems only to get the local water . A massive dust storm originating in central Asia (Gobi) in April 2001 dumped a visible layer all over the St Elias Mountains and this layer was sampled, to provide a calibration "Asian dust event". The satellite and isotoic signatures both agreed that Gobi was the source. The PRCol record covers the Holocene and well back into the ice age. The transition is defined by a sudden ECM shift on the flanks of a more gradual O18 shift. Acknowledgements. Logan consortium consists of : Geological Survey of Canada : Jocelyne Bourgeois, Mike Demuth, David Fisher, Roy Koerner,Chris Zdanowicz, James Zheng. University of Ottawa: Ian Clarke,Raphaelle Cardyn. National Institute of Polar Research (Japan): Kumiko Goto-Azuma University of New Hampshire: Cam Wake, Kaplan Yalcin. University of Maine: Karl Kreutz, Paul Mayewski, Erich Osterberg. Arctic Institute of North America: Gerald Holdsworth. University of Washington: Eric J. Steig, Summer B. Rupper. University of Copenhagen: Dorthe Dahl-Jensen. David Fisher is the presenter but many contributed to what is a joint preliminary offering.

Living matter: the "lunar eclipse" phenomena.

PubMed

Korpan, Nikolai N

2010-01-01

The present investigations describe a unique phenomenon, namely the phenomenon of the "lunar eclipse", which has been observed and discovered by the author in living substance during the freeze-thawing processes in vivo using temperatures of various intensities and its cryosurgical response in animal experiment. Similar phenomena author has observed in nature, namely the total lunar eclipse and total solar eclipse. In this experimental study 76 animals (mongrel dogs) were investigated. A disc cryogenic probe was placed on the pancreas after the laparotomy. For cryosurgical exposure a temperature range of -40 degrees C, -80 degrees C, -120 degrees C and -180 degrees C was selected in contact with pancreas parenchyma. The freeze-thaw cycle was monitored by intraoperative ultrasound before, during and after cryosurgery. Each cryolesion was observed for one hour after thawing intraoperatively. Immediately after freezing, during the thawing process, the snow-white pancreas parenchyma, frozen hard to an ice block and resembling a full moon with a sharp demarcation line, gradually assumed a ruby-red shade and a hemispherical shape as it grew in size depend on reconstruction vascular circulation from the periphery to the center. This snow-white cryogenic lesion dissolved in the same manner in all animal tissues. The "lunar eclipse" phenomenon contributes to a fundamental understanding of the mechanisms of biological tissue damage during low temperature exposure in cryoscience and cryomedicine. Properties of the pancreas parenchyma response during the phenomenon of the "lunar eclipse" provide important insights into the mechanisms of damage and the formation of cryogenic lesion immediately after thawing in cryosurgery. Vascular changes and circulatory stagnation are commonly considered to be the main mechanism of biological tissue injury during low temperature exposure. The phenomenon of the "lunar eclipse" suggests that cryosurgery is the first surgical technique to use anti-angiogenesis with an immediately following cryoaponecrosis and cryoapoptosis in the treatment of malignant tumor. Both the "lunar eclipse" in vivo as well as the similar phenomena, namely the total moon and total solar lunar eclipses, are is part of living nature.

GSC 4232.2850, a new eclipsing binary with elliptical orbit

NASA Astrophysics Data System (ADS)

Goranskij, V.; Shugarov, S.; Kroll, P.; Golovin, A.

2005-04-01

GSC 4232.2830 (20h 01m 28s.407, +61? 10' 17".18, 2000.0, v=12m.1) was suspected to be an eclipsing binary by VPG in the routine overview of photographical plates taken with 40-cm astrograph of SAI Crimean station. To define orbital elements of the binary, we searched for observations in Sonneberg Observatory plate collection, NSVS database (Wozniak et al., 2004), and carried out visual monitoring with a small telescope equipped with an electronic image tube, an analogue of a night vision device. Later, when we had found a preliminary solution, we carried out accurate CCD photometry to improve the orbital elements. We should note, that the depths of eclipses in the NSVS database do not exceed 0m.2, what contradicts to other observations. We suppose that NSVS measurements concern to integral light of two stars, a variable star, and a nearby brighter star, GSC 4232.2395, due to low resolution of this survey, 72". Using all the available observations we found the single orbital solution with an elliptical orbit and the period of 11,6 day. The center of the secondary minimum occurs at the orbital phase 0.69835 or 8.1 day after the primary minimum. The improved ephemeris derived using accurate CCD observations is following: HJD Min I = 2453278,3185(2) + 11.628188 (5) x E. O-C analysis does not show orbital period variations during the time interval of observations, or any evidence of apsidal motion. The observations show that both eclipses have about equal depth 0m.60, but essentially different duration, 0p.028 (7 h.8) for Min I, and 0 p.0175 (4 h.9) for Min II. The eclipses are partial. CCD photometry gives mean colors U-B = -0 m.06, B-V = 0 m.57, and V-R = 0 m.50 without notable color variations in the eclipse phases. Old Sonneberg photographic observations indicate that the eclipses were shallower in the middle of the past century than in the present time! Such contradictions may suggest that the depth of eclipses varied, as in the well-known system SSLac (Mossakovskaja, 1993; Milone et al, 2000; Torres and Stefanic, 2001). The eclipse depth variations should be verified with more precise observations taken during the longer time interval.

The extraneous eclipses on binary light curves: KIC 5255552, KIC 10091110, and KIC 11495766

NASA Astrophysics Data System (ADS)

Zhang, J.; Qian, S. B.; Wang, S. M.; Sun, L. L.; Wu, Y.; Jiang, L. Q.

2018-03-01

Aims: We aim to find more eclipsing multiple systems and obtain their parameters, thus increasing our understanding of multiple systems. Methods: The extraneous eclipses on the Kepler binary light curves indicating extraneous bodies were searched. The binary light curves were analyzed using the binary model, and the extraneous eclipses were studied on their periodicity and shape changes. Results: Three binaries with extraneous eclipses on the binary light curves were found and studied based on the Kepler observations. The object KIC 5255552 is an eclipsing triple system with a fast changing inner binary and an outer companion uncovered by three groups of extraneous eclipses of 862.1(±0.1) d period. The KIC 10091110 is suggested to be a double eclipsing binary system with several possible extraordinary coincidences: the two binaries share similar extremely small mass ratios (0.060(13) and 0.0564(18)), similar mean primary densities (0.3264(42) ρ⊙ and 0.3019(28) ρ⊙), and, most notably, the ratio of the two binaries' periods is very close to integer 2 (8.5303353/4.2185174 = 2.022). The KIC 11495766 is a probable triple system with a 120.73 d period binary and (at least) one non-eclipse companion. Furthermore, very close to it in the celestial sphere, there is a blended background stellar binary of 8.3404432 d period. A first list of 25 eclipsing multiple candidates is presented, with the hope that it will be beneficial for study of eclipsing multiples.

Geospatial Analysis of Low-frequency Radio Signals Collected During the 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Liles, W. C.; Nelson, J.; Kerby, K. C.; Lukes, L.; Henry, J.; Oputa, J.; Lemaster, G.

2017-12-01

The total solar eclipse of 2017, with a path that crosses the continental United States, offers a unique opportunity to gather geospatially diverse data. The EclipseMob project has been designed to crowdsource this data by building a network of citizen scientists across the country. The project focuses on gathering low-frequency radio wave data before, during, and after the eclipse. WWVB, a 60 KHz transmitter in Ft. Collins, CO operated by the National Institutes of Standard and Technology, will provide the transmit signal that will be observed by project participants. Participating citizen scientists are building simple antennas and receivers designed by the EclipseMob team and provided to participants in the form of "receiver kits." The EclipseMob receiver downsamples the 60 KHz signal to 18 KHz and supplies the downsampled signal to the audio jack of a smartphone. A dedicated app is used to collect data and upload it to the EclipseMob server. By studying the variations in WWVB amplitude observed during the eclipse at over 150 locations across the country, we aim to understand how the ionization of the D layer of the ionosphere is impacted by the eclipse as a function of both time and space (location). The diverse locations of the EclipseMob participants will provide data from a wide variety of propagation paths - some crossing the path of the total eclipse, and some remaining on the same side of the eclipse path as the transmitter. Our initial data analysis will involve identifying characteristics that define geospatial relationships in the behavior of observed WWVB signal amplitudes.

Optimization and validation of high-performance liquid chromatography method for analyzing 25-desacetyl rifampicin in human urine

NASA Astrophysics Data System (ADS)

Lily; Laila, L.; Prasetyo, B. E.

2018-03-01

A selective, reproducibility, effective, sensitive, simple and fast High-Performance Liquid Chromatography (HPLC) was developed, optimized and validated to analyze 25-Desacetyl Rifampicin (25-DR) in human urine which is from tuberculosis patient. The separation was performed by HPLC Agilent Technologies with column Agilent Eclipse XDB- Ci8 and amobile phase of 65:35 v/v methanol: 0.01 M sodium phosphate buffer pH 5.2, at 254 nm and flow rate of 0.8ml/min. The mean retention time was 3.016minutes. The method was linear from 2–10μg/ml 25-DR with a correlation coefficient of 0.9978. Standard deviation, relative standard deviation and coefficient variation of 2, 6, 10μg/ml 25-DR were 0-0.0829, 03.1752, 0-0.0317%, respectively. The recovery of 5, 7, 9μg/ml25-DR was 80.8661, 91.3480 and 111.1457%, respectively. Limits of detection (LoD) and quantification (LoQ) were 0.51 and 1.7μg/ml, respectively. The method has fulfilled the validity guidelines of the International Conference on Harmonization (ICH) bioanalytical method which includes parameters of specificity, linearity, precision, accuracy, LoD, and LoQ. The developed method is suitable for pharmacokinetic analysis of various concentrations of 25-DR in human urine.

Simultaneous determination of triptolide, tripdiolide and tripterine in human urine by high-performance liquid chromatography coupled with ion trap atmospheric-pressure chemical ionization mass spectrometry.

PubMed

Jin, Mi-cong; Chen, Xiao-hong; OuYang, Xiao-kun

2009-03-01

An accurate and selective method for the simultaneous determination of triptolide, tripdiolide and tripterine in human urine using hydrocortisone as an internal standard (IS) by high-performance liquid chromatography coupled with atmospheric-pressure chemical ionization mass spectrometry in negative ion mode has been developed. After triptolide, tripdiolide and tripterine in human urine were extracted with ethyl acetate and cleaned by solid-phase extraction with C(18) cartridges, a satisfactory separation was achieved on an XDB C(18) short column (30 x 2.1 mm i.d., 3 microm) using the mobile phase of acetic acid-ammonium acetate (5 mmol/L, pH = 4.5)-acetonitrile-methanol in gradient elution. Detection was operated by APCI in selected ion monitoring mode. The target ions m/z 359, m/z 375, m/z 449 and m/z 419 were selected for the quantification of triptolide, tripdiolide, tripterine and IS, respectively. The linear range was 1.0-100.0 ng mL(-1), and the limits of quantification in human urine were found to be 0.1-0.5 ng mL(-1) for the three compounds. The precisions (CV%) and accuracies were 6.6-12.9 and 85.1-97.0%, respectively. The developed method could be applied to the determination of triptolide, tripdiolide and tripterine in human urine for diagnosis of the intoxication and for forensic purposes. 2008 John Wiley & Sons, Ltd.

The Astronomical Almanac Online - Welcome

Science.gov Websites

(incl. eclipses) Time-Scales and Coordinate Systems Sun Moon Planets Natural Satellites Dwarf Planets version contains precise ephemerides of the Sun, Moon, planets, and satellites, data for eclipses and : Phenomena (incl. eclipses) Section B: Time-Scales and Coordinate Systems Section C: Sun Section D: Moon

Ferrocene Orientation Determined Intramolecular Interactions Using Energy Decomposition Analysis.

PubMed

Wang, Feng; Islam, Shawkat; Vasilyev, Vladislav

2015-11-16

Two very different quantum mechanically based energy decomposition analyses (EDA) schemes are employed to study the dominant energy differences between the eclipsed and staggered ferrocene conformers. One is the extended transition state (ETS) based on the Amsterdam Density Functional (ADF) package and the other is natural EDA (NEDA) based in the General Atomic and Molecular Electronic Structure System (GAMESS) package. It reveals that in addition to the model (theory and basis set), the fragmentation channels more significantly affect the interaction energy terms (Δ E ) between the conformers. It is discovered that such an interaction energy can be absorbed into the pre-partitioned fragment channels so that to affect the interaction energies in a particular conformer of Fc. To avoid this, the present study employs a complete fragment channel-the fragments of ferrocene are individual neutral atoms. It therefore discovers that the major difference between the ferrocene conformers is due to the quantum mechanical Pauli repulsive energy and orbital attractive energy, leading to the eclipsed ferrocene the energy preferred structure. The NEDA scheme further indicates that the sum of attractive (negative) polarization (POL) and charge transfer (CL) energies prefers the eclipsed ferrocene. The repulsive (positive) deformation (DEF) energy, which is dominated by the cyclopentadienyle (Cp) rings, prefers the staggered ferrocene. Again, the cancellation results in a small energy residue in favour of the eclipsed ferrocene, in agreement with the ETS scheme. Further Natural Bond Orbital (NBO) analysis indicates that all NBO energies, total Lewis (no Fe) and lone pair (LP) deletion all prefer the eclipsed Fc conformer. The most significant energy preferring the eclipsed ferrocene without cancellation is the interactions between the donor lone pairs (LP) of the Fe atom and the acceptor antibond (BD*) NBOs of all C-C and C-H bonds in the ligand, LP(Fe)-BD*(C-C & C-H), which strongly stabilizes the eclipsed (D 5h ) conformation by -457.6 kcal·mol -1 .

The earliest known solar eclipse record redated

NASA Astrophysics Data System (ADS)

de Jong, T.; van Soldt, W. H.

1989-03-01

An astronomical event recorded on a clay tablet found in 1948 among the ruins of the acient city of Ugarit, in what is now Syria, was identified 20 years ago as a description of a total solar eclipse that occurred on May 3, 1375 B.C. A new historical dating of the tablet, and mention in the text of the visibility of the planet Mars during the eclipse as well as the month it which it occurred, are used here to show that the recorded eclipse in fact occurred on March 5, 1223 B.C. This new date implies that the secular deceleration of the earth's rotation has changed very little during the past 3000 years.

Spectral irradiance curve calculations for any type of solar eclipse

NASA Technical Reports Server (NTRS)

Deepak, A.; Merrill, J. E.

1974-01-01

A simple procedure is described for calculating the eclipse function (EF), alpha, and hence the spectral irradiance curve (SIC), (1-alpha), for any type of solar eclipse: namely, the occultation (partial/total) eclipse and the transit (partial/annular) eclipse. The SIC (or the EF) gives the variation of the amount (or the loss) of solar radiation of a given wavelength reaching a distant observer for various positions of the moon across the sun. The scheme is based on the theory of light curves of eclipsing binaries, the results of which are tabulated in Merrill's Tables, and is valid for all wavelengths for which the solar limb-darkening obeys the cosine law: J = sub c (1 - X + X cost gamma). As an example of computing the SIC for an occultation eclipse which may be total, the calculations for the March 7, 1970, eclipse are described in detail.

Campaign Photometry During The 2010 Eclipse Of Epsilon Aurigae

NASA Astrophysics Data System (ADS)

Hopkins, Jeff; Stencel, R. E.

2011-01-01

Epsilon Aurigae is a long period (27.1 years) eclipsing binary star system with an eclipse that lasts nearly 2 years, but with severe ambiguities about component masses and shape. The current eclipse began on schedule in August of 2009. During the previous, 1982-1984 eclipse, an International Campaign was formed to coordinate a detailed study of the system. While that Campaign was deemed successful, the evolutionary status of the star system remained unclear. Epsilon Aurigae has been observed nearly continuously since the 1982 eclipse. The current Campaign was officially started in 2006. In addition to a Yahoo forum we have a dedicated web site and more than 18 online newsletters reporting photometry, spectroscopy, interferometry and polarimetry data. High quality UBVRIJH band photometric data since before the start of the current eclipse has been submitted. We explore the color differences among the light curves in terms of eclipse phases and archival data. At least one new model of the star system has been proposed since the current Campaign began: a low mass but very high luminosity F star plus a B star surrounded by a debris disk. The current eclipse and in particular the interferometry and spectroscopic data have caused new thoughts on defining eclipsing variable star contact points and phases of an eclipse. Second contact may not be the same point as start of totality and third contact may not be the same point as the start of egress and end of totality. In addition, the much awaited mid-eclipse brightening may or may not have appeared. This paper identifies the current Campaign contributors and the photometric data. This work was supported in part by the bequest of William Herschel Womble in support of astronomy at the University of Denver, by NSF grant 1016678 to the University of Denver.

KSC-00pp0091

NASA Image and Video Library

2000-01-20

Traveling west to east, the full moon, viewed from Merritt Island, Fla., at 10:18 p.m. EST, begins moving into the Earth's shadow, at the start of a lunar eclipse. Eclipses occur when the Sun, Earth and Moon line up. They are rare because the Moon usually passes above or below the imaginary line connecting Earth and the Sun. The Earth casts a shadow that the Moon can pass through -when it does, it is called a lunar eclipse. They can only occur when the moon is "full." During a total lunar eclipse the Moon takes on a dark red color because it is being lighted slightly by sunlight passing through the Earth's atmosphere and this light has the blue component preferentially scattered out (this is also why the sky appears blue from the surface of the Earth), leaving faint reddish light to illuminate the Moon during the eclipse

MM Herculis - An eclipsing binary of the RS CVn

NASA Technical Reports Server (NTRS)

Sowell, J. R.; Hall, D. S.; Henry, G. W.; Burke, E. W., Jr.; Milone, E. F.

1983-01-01

V, B and U differential photoelectric photometry has been obtained for the RS Canum Venaticorum-class eclipsing binary star MM Her, with the light outside the eclipse being Fourier-analyzed to study wave migration and amplitude. These, together with the mean light level of the system, have been monitored from 1976 through 1980. Observations within the eclipse have revealed eclipses to be partial, rather than total as previously thought. The geometric elements of the presently rectified light curve are forced on the pre-1980 light curves and found to be compatible. With these elements, and previously obtained double line radial velocity curves, new absolute dimensions of 1.18 solar masses and 1.58 solar radii are calculated for the hotter star and 1.27 solar masses and 2.83 solar radii for the cooler star. The plotting of color indices on the color-color curve indicates G2V and K2IV spectral types.

A new astronomical dating of the Trojan war's end.

NASA Astrophysics Data System (ADS)

Papamarinopoulos, S.; Preka-Papadema, P.; Mitropetros, P.; Antonopoulos, P.; Mitropetrou, E.; Saranditis, G.

A solar eclipse's evolution was described in the Iliad in a stepwise mode manifested in increasing gradual darkness, during a warm day at late noon; from Sarpedon's death time to few later from Patroclus' death time. We examined the solar eclipses within the time span 1400-1130 B.C. and we found that only the annular solar eclipse on 6th June 1218 yr B.C. observable in Troy with significant obscuration 75.2 % fits fully with the Homeric descriptions.

The August 21, 2017 American total solar eclipse through the eyes of GPS

NASA Astrophysics Data System (ADS)

Kundu, Bhaskar; Panda, Dibyashakti; Gahalaut, Vineet K.; Catherine, J. K.

2018-04-01

We explored spatio-temporal variation in Total Electron Contents (TEC) in the ionosphere caused by the recent August 21, 2017 total solar eclipse, which was observed over the United States of America. The path of total solar eclipse passes through the continental parts of the United States of America, starting in the northwestern state of Oregon and ending in the southeastern state of South Carolina, approximately covering 4000 km length. Across this length EarthScope Plate Boundary Observatory (PBO) has been operating a dense cGPS/GNSS networks. During the course of passage of the solar eclipse, the sudden decline in solar radiation by temporarily obscuration by the Moon caused a drop of ˜6-9 × 1016 electrons/m2in the ionosphere with time-delay at the cGPS sites. The significant drop in TEC at cGPS sites captured the average migration velocity of shadow along the eclipse path (0.74 km/s), from which we estimated the Moon's orbital velocity (˜1 km/s). Further, this event also caused some marginal increase in TEC during the eclipse in the Earth's ionosphere in the magnetically conjugate region at the tip of South America and Antarctica, consistent with the model predictions of SAMI3 by Naval Research Laboratory.

Searching Planets Around Some Selected Eclipsing Close Binary Stars Systems

NASA Astrophysics Data System (ADS)

Nasiroglu, Ilham; Slowikowska, Agnieszka; Krzeszowski, Krzysztof; Zejmo, M. Michal; Er, Hüseyin; Goździewski, Krzysztof; Zola, Stanislaw; Koziel-Wierzbowska, Dorota; Debski, Bartholomew; Ogloza, Waldemar; Drozdz, Marek

2016-07-01

We present updated O-C diagrams of selected short period eclipsing binaries observed since 2009 with the T100 Telescope at the TUBITAK National Observatory (Antalya, Turkey), the T60 Telescope at the Adiyaman University Observatory (Adiyaman, Turkey), the 60cm at the Mt. Suhora Observatory of the Pedagogical University (Poland) and the 50cm Cassegrain telescope at the Fort Skala Astronomical Observatory of the Jagiellonian University in Krakow, Poland. All four telescopes are equipped with sensitive, back-illuminated CCD cameras and sets of wide band filters. One of the targets in our sample is a post-common envelope eclipsing binary NSVS 14256825. We collected more than 50 new eclipses for this system that together with the literature data gives more than 120 eclipse timings over the time span of 8.5 years. The obtained O-C diagram shows quasi-periodic variations that can be well explained by the existence of the third body on Jupiter-like orbit. We also present new results indicating a possible light time travel effect inferred from the O-C diagrams of two other binary systems: HU Aqr and V470 Cam.

Line Identifications in the Far Ultraviolet Spectrum of the Eclipsing Binary System 31 Cygni

NASA Astrophysics Data System (ADS)

Hagen Bauer, Wendy; Bennett, P. D.

2011-05-01

The eclipsing binary system 31 Cygni (K4 Ib + B3 V) was observed at several phases with the Far Ultraviolet Spectrosocopic Explorer (FUSE) satellite. During total eclipse, a rich emission spectrum was observed, produced by scattering of hot star photons in the extended wind of the K supergiant. The system was observed during deep chromospheric eclipse, and 2.5 months after total eclipse ended. We present an atlas of line identifications in these spectra. During total eclipse, emission features from C II , C III, N I, N II, N III, O I, Si II, P II, P III, S II, S III, Ar I, Cr III, Fe II, Fe III, and Ni II were detected. The strongest emission features arise from N II. These lines appear strongly in absorption during chromospheric eclipse, and even 2.5 months after total eclipse, the absorption bottoms out on the underlying emission seen during total eclipse. The second strongest features in the emission spectrum arise from Fe III. Any chromospheric Fe III absorption is buried within strong chromospheric absorption from other species, mainly Fe II. The emission profiles of most of the doubly-ionized species are red-shifted relative to the systemic velocity, with asymmetric profiles with a steeper long-wavelength edge. Emission profiles from singly-ionized species tend to be more symmetric and centered near the systemic velocity. In deep chromospheric eclipse, absorption features are seen from neutral and singly-ionized species, arising from lower levels up to 3 eV. Many strong chromospheric features are doubled in the observation obtained during egress from eclipse. The 31 Cygni spectrum taken 2.5 months after total eclipse ended ws compared to single-star B spectra from the FUSE archives. There was still some additional chromospheric absorption from strong low-excitation Fe II, O I and Ar I.

Gapped Spin-1/2 Spinon Excitations in a New Kagome Quantum Spin Liquid Compound Cu3Zn(OH)6FBr

NASA Astrophysics Data System (ADS)

Feng, Zili; Li, Zheng; Meng, Xin; Yi, Wei; Wei, Yuan; Zhang, Jun; Wang, Yan-Cheng; Jiang, Wei; Liu, Zheng; Li, Shiyan; Liu, Feng; Luo, Jianlin; Li, Shiliang; Zheng, Guo-qing; Meng, Zi Yang; Mei, Jia-Wei; Shi, Youguo

2017-06-01

We report a new kagome quantum spin liquid candidate Cu3Zn(OH)6FBr, which does not experience any phase transition down to 50 mK, more than three orders lower than the antiferromagnetic Curie-Weiss temperature (∼200 K). A clear gap opening at low temperature is observed in the uniform spin susceptibility obtained from 19F nuclear magnetic resonance measurements. We observe the characteristic magnetic field dependence of the gap as expected for fractionalized spin-1/2 spinon excitations. Our experimental results provide firm evidence for spin fractionalization in a topologically ordered spin system, resembling charge fractionalization in the fractional quantum Hall state. Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0300502, 2016YFA0300503, 2016YFA0300604, 2016YF0300300 and 2016YFA0300802, the National Natural Science Foundation of China under Grant Nos 11421092, 11474330, 11574359, 11674406, 11374346 and 11674375, the National Basic Research Program of China (973 Program) under Grant No 2015CB921304, the National Thousand-Young-Talents Program of China, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences under Grant Nos XDB07020000, XDB07020200 and XDB07020300. The work in Utah is supported by DOE-BES under Grant No DE-FG02-04ER46148.

Updated O-C Diagrams for Several Bright HW Vir Binaries Observed with the Evryscope

NASA Astrophysics Data System (ADS)

Corcoran, Kyle A.; Barlow, Brad; Corbett, Hank; Fors, Octavi; Howard, Ward S.; Law, Nicholas; Ratzloff, Jeff

2018-01-01

HW Vir systems are eclipsing, post-common-envelope binaries consisting of a hot subdwarf star and a cooler M dwarf or brown dwarf companion. They show a strong reflection effect and have characteristically short orbital periods of only a few hours, allowing observers to detect multiple eclipses per night. Observed minus calculated (O-C) studies allow one to measure miniscule variations in the orbital periods of these systems by comparing observed eclipse timings to a calculated ephemeris. This technique is useful for detecting period changes due to secular evolution of the binary, gravitational wave emission, or reflex motion from an orbiting circumbinary object. Numerous eclipse timings obtained over several years are vital to the proper interpretation and analysis of O-C diagrams. The Evryscope – an array of twenty-four individual telescopes built by UNC and deployed on Cerro Tololo – images the entire Southern sky once every two minutes, producing an insurmountable amount of data for objects brighter than 16th magnitude. The cadence with which Evryscope exposes makes it an unparalleled tool for O-C analyses of HW Vir binaries; it will catalogue thousands of eclipses over the next several years. Here we present updated O-C diagrams for several HW Vir binaries using recent measurements from the Evryscope. We also use observations of AA Dor, an incredibly stable astrophysical clock, to characterize the accuracy of the Evryscope’s timestamps.

Safety assessment of continuous glass filaments used in eclipse.

PubMed

Swauger, J E; Foy, J W

2000-11-01

Eclipse is a cigarette that produces smoke by primarily heating, rather than burning, tobacco. The Eclipse heat source assembly employs a continuous filament glass mat jacket to insulate the heat source. The glass mat insulator is composed of continuous glass filaments and a binder. The purpose of this article is to address the potential toxicological significance of the continuous glass filaments under the conditions of intended use. Transfer data and the unique physical characteristics of the filaments demonstrate that significant exposure of the smoker will not occur. The available environmental survey data clearly demonstrate that Eclipse smokers are extremely unlikely to be exposed to continuous glass filaments at a level that represents a biologically significant increase over background exposure to glass fibers. The chemical composition of the continuous glass filaments used in Eclipse is generally similar to C-glass fiber compositions such as MMVF 11 that have failed to produce either tumors or fibrosis in chronic inhalation studies conducted in rats. In vitro dissolution data demonstrate that the continuous glass filaments used in Eclipse are more soluble than biologically active fibers such as rock wool (MMVF 21) or asbestos. However, the continuous glass filaments used in Eclipse were not as soluble in simulated extracellular lung fluid as representative C-glass fibers (MMVF 10 and MMVF 11). In brief, exposure of Eclipse smokers to continuous glass filaments is extremely unlikely to occur at a level that may be construed to be of biological significance.

Determination of aflatoxins in food samples by automated on-line in-tube solid-phase microextraction coupled with liquid chromatography-mass spectrometry.

PubMed

Nonaka, Y; Saito, K; Hanioka, N; Narimatsu, S; Kataoka, H

2009-05-15

A simple and sensitive automated method for determination of aflatoxins (B1, B2, G1, and G2) in nuts, cereals, dried fruits, and spices was developed consisting of in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-mass spectrometry (LC-MS). Aflatoxins were separated within 8 min by high-performance liquid chromatography using a Zorbax Eclipse XDB-C8 column with methanol/acetonitrile (60/40, v/v): 5mM ammonium formate (45:55) as the mobile phase. Electrospray ionization conditions in the positive ion mode were optimized for MS detection of aflatoxins. The pseudo-molecular ions [M+H](+) were used to detect aflatoxins in selected ion monitoring (SIM) mode. The optimum in-tube SPME conditions were 25draw/eject cycles of 40 microL of sample using a Supel-Q PLOT capillary column as an extraction device. The extracted aflatoxins were readily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. Using the in-tube SPME LC-MS with SIM method, good linearity of the calibration curve (r>0.9994) was obtained in the concentration range of 0.05-2.0 ng/mL using aflatoxin M1 as an internal standard, and the detection limits (S/N=3) of aflatoxins were 2.1-2.8 pg/mL. The in-tube SPME method showed >23-fold higher sensitivity than the direct injection method (10 microL injection volume). The within-day and between-day precision (relative standard deviations) at the concentration of 1 ng/mL aflatoxin mixture were below 3.3% and 7.7% (n=5), respectively. This method was applied successfully to analysis of food samples without interference peaks. The recoveries of aflatoxins spiked into nuts and cereals were >80%, and the relative standard deviations were <11.2%. Aflatoxins were detected at <10 ng/g in several commercial food samples.

Development of anion-exchange/reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry methods for the speciation of bio-available iodine and bromine from edible seaweed.

PubMed

Romarís-Hortas, Vanessa; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2012-05-04

Anion exchange high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry has been novelly applied to assess inorganic (iodide and iodate) and organic (3-iodotyrosine - MIT, and 3,5-diiodotyrosine - DIT) iodine species in a single chromatographic run. The optimized operating conditions (Dionex IonPac AS7, gradient elution with 175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase and flow rates within the 0.5-1.5 mL min(-1) range) have also been used to perform inorganic bromine speciation analysis (bromide and bromate). The developed method has been applied for determining the bio-available contents of iodine and bromine species in dialyzates from edible seaweed. Reverse phase high performance liquid chromatography (Zorbax Eclipse XDB-C8, gradient elution with 0.2% (m/m) acetic acid, and 0.2% (m/m) acetic acid in methanol, as mobile phases, and a constant flow rate of 0.75 mL min(-1)) also hyphenated with inductively coupled plasma-mass spectrometry was used to confirm the presence of organic iodine species (MIT and DIT) in the dialyzates. The verification of the presence of iodinated amino acids (MIT and DIT) in the extracts was also performed by reverse phase high performance liquid chromatography-electrospray ionization-mass spectrometry (LTQ Orbitrap). The developed methods have provided good repeatability (RSD values lower than 10% for both anion exchange and reverse phase separations) and analytical recoveries within the 90-105% range for all cases. The in vitro bio-availability method consisted of a simulated gastric and an intestinal digestion/dialysis (10 kDa molecular weight cut-off - MWCO) two-stage procedure. Iodide and MIT were the main bio-available species quantified, whereas bromide was the major bromine species found in the extracts. Copyright © 2012 Elsevier B.V. All rights reserved.

Observation and Analysis of Secondary Eclipses of WASP-32b

NASA Astrophysics Data System (ADS)

Garland, Justin; Harrington, Joesph; Cubillos, Patricio; Blecic, Jasmina; Foster, Andrew S.; Bowman, Matthew O.; Maxted, Pierre F. L.

2014-11-01

We report two Spitzer secondary eclipses of the exoplanet WASP-32b. Discovered by Maxted et al. (2010), this hot-Jupiter planet has a mass of 3.6 +/- 0.07 Mj, a radius of 1.18 +/- 0.07 Rj, and an orbital period of 2.71865 +/- 0.00008 days around a G-type star. We observed two secondary eclipses in the 3.6 micron and 4.5 micron channels using the Spitzer Space Telescope in 2010 as a part of the Spitzer Exoplanet Target of Opportunity program (program 60003). We present eclipse-depth measurements, estimates of infrared brightness temperatures, and refinements of orbital parameters for WASP-32b from our eclipse measurements as well as amatuer and professional data. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

Chemical characterization of Centaurium erythrea L. and its effects on carbohydrate and lipid metabolism in experimental diabetes.

PubMed

Stefkov, Gjoshe; Miova, Biljana; Dinevska-Kjovkarovska, Suzana; Stanoeva, Jasmina Petreska; Stefova, Marina; Petrusevska, Gordana; Kulevanova, Svetlana

2014-02-27

Centaurium erythrea L. fam. Gentianaceae (CE) has been traditionally used for centuries in folk medicine of Balkans as a bitter medicinal herb for digestive complications and for treating febrile conditions and diabetes. The aim of this study was to gain insight into the chemical composition and underlying biochemical mechanism of action of the antihyperglycemic and antilipidemic activities of the dry extract of Centaurium erythrea L., wildly growing and traditionally used medicinal plant in the Republic of Macedonia. An ultrasonic methanol maceration of the aerial parts of the dried plant was performed and the extract was freeze-dried. HPLC-DAD-ESI-MS(n) was carried out on 150 mm × 4.6mm, 5 μm RP-18 Eclipse XDB column, at 40 °C. Mobile phase: water with 1% formic acid (A) and methanol (B) with linear gradient starting with 10% B was used to reach 15% at 5 min, 40% B at 25 min, 55% of B at 50 min and 100% at 60 min, with flow rate of 0.4 mL min(-1). Normal and streptozotocin (STZ) hyperglycemic Wistar rats were used for assessment of the antihyperglycemic and antilipidemic activity by measurement of the key carbohydrate-related enzymes and substrates, as well as lipid state of the organism. HPLC-DAD-ESI-MS(n) analyses revealed presence of four different secoiridoids, seven flavonoid glycosides and seven xanthones in the freeze-dried extract of CE representing 53%, 25% and 22% of all compounds, respectively. The short-term (12 days) treatment of the STZ-diabetic rats with CE-extracts resulted in a 74% reduction of the produced hyperglycemia, which is only 6% less than the reduction caused by glibeclamide (GLB, positive control). The CE-extract had a significant impact on the hepatic carbohydrate metabolism enhancing the direct synthesis of glycogen, normalizing phosphorylase a activity and reducing the activity of glucose-6-phosphatase, which further causes reduction in production of blood glucose level. The long-term (45 days) treatment showed that the HbA1c in CE-treated group of animals was even lower than in the GLB-treated groups. The antilipidemic assessment of the CE-extract revealed decrease of total cholesterol, triglycerides, HDL and LDL level in the blood of the normal and STZ-hyperglycemic rats. The obtained results indicate that treatment with CE extract in STZ-diabetic rats regulates the elevated level of blood glucose and carbohydrate-related disturbances slightly better than the effect of glibenclamide. There was also regulation of the serum lipid status in diabetic rats. Identified groups of bitter compounds in the extract (flavonoides, iridoids and xanthones) probably have influence on the expressed antihyperglycaemic effect. © 2013 Published by Elsevier Ireland Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brewer, Lauren N.; Sandquist, Eric L.; Jeffries, Mark W. Jr.

As part of our study of the old (∼2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVR{sub C}I{sub C}) and spectroscopic observations of the detached eclipsing binary WOCS 24009 (Auner 665; KIC 5023948) with a short orbital period of 3.6 days. WOCS 24009 is a triple-lined system, and we verify that the brightest star is physically orbiting the eclipsing binary using radial velocities and eclipse timing variations. The eclipsing binary components have masses M{sub B} = 1.090 ± 0.010 M{sub ⊙} and M{sub C} = 1.075 ± 0.013 M{sub ⊙}, and radii R{sub B} = 1.099 ± 0.006 ± 0.005 R{sub ⊙} and R{sub C} = 1.069 ± 0.006 ± 0.013 R{submore » ⊙}. The bright non-eclipsing star resides at the cluster turnoff, and ultimately its mass will directly constrain the turnoff mass: our preliminary determination is M{sub A} = 1.251 ± 0.057 M{sub ⊙}. A careful examination of the light curves indicates that the fainter star in the eclipsing binary undergoes a very brief period of total eclipse, which enables us to precisely decompose the light of the three stars and place them in the color–magnitude diagram (CMD). We also present improved analysis of two previously discussed detached eclipsing stars in NGC 6819 (WOCS 40007 and WOCS 23009) en route to a combined determination of the cluster’s distance modulus (m − M){sub V} = 12.38 ± 0.04. Because this paper significantly increases the number of measured stars in the cluster, we can better constrain the age of the CMD to be 2.21 ± 0.10 ± 0.20 Gyr. Additionally, using all measured eclipsing binary star masses and radii, we constrain the age to 2.38 ± 0.05 ± 0.22 Gyr. The quoted uncertainties are estimates of measurement and systematic uncertainties (due to model physics differences and metal content), respectively.« less

Fraction of free-base nicotine in fresh smoke particulate matter from the Eclipse "cigarette" by 1H NMR spectroscopy.

PubMed

Pankow, James F; Barsanti, Kelley C; Peyton, David H

2003-01-01

Solution 1H NMR (proton-NMR) spectroscopy was used to measure the distribution of nicotine between its free-base and protonated forms at 20 degrees C in (a) water; (b) glycerin/water mixtures; and (c) puff-averaged "smoke" particulate matter (PM) produced by the Eclipse cigarette, a so-called "harm reduction" cigarette manufactured by R. J. Reynolds (RJR) Tobacco Co. Smoke PM from the Eclipse contains glycerin, water, nicotine, and numerous other components. Smoke PM from the Eclipse yielded a signal for the three N-methyl protons on nicotine at a chemical shift of delta (ppm) = 2.79 relative to a trimethylsilane standard. With alpha fb = fraction of the total liquid nicotine in free-base form, and alpha a = fraction in the acidic, monoprotonated NicH+ form, then alpha a + alpha fb approximately 1. (The diprotonated form of nicotine was assumed negligible.) When the three types of solutions were adjusted so that alpha a approximately 1, the N-methyl protons yielded delta a = 2.82 (Eclipse smoke PM); 2.79 (35% water/65% glycerin); and 2.74 (water). When the solutions were adjusted so that alpha fb approximately 1, the N-methyl protons yielded delta fb = 2.16 (Eclipse smoke PM); 2.13 (35% water/65% glycerin); and 2.10 (water). In all of the solutions, the rate of proton exchange between NicH+ and Nic was fast relative to the 1H-NMR chemical shift difference in hertz. Each solution containing both NicH+ and Nic thus yielded a single N-methyl peak at a delta given by delta = alpha a delta a + alpha fb delta fb so that delta varied linearly between delta a and delta fb. Since alpha fb = (delta a-delta)/(delta a-delta fb), then delta = 2.79 for the unadjusted Eclipse smoke PM indicates alpha fb approximately 0.04. The effective pH of the Eclipse smoke PM at 20 degrees C may then be calculated as pHeff = 8.06 + log[alpha fb/(1-alpha fb)] = 6.69, where 8.06 is the pKa of NicH+ in water at 20 degrees C. The measurements obtained for the puff-averaged Eclipse smoke PM pertain to the chemistry of the smoke PM as it might be initially inhaled at 20 degrees C. Upon inhalation, the volatilization of nicotine and other acid/base active compounds (as well as a warming toward a body temperature of 37 degrees C) will alter the pHeff value of the smoke PM during the time that it resides and ages in the respiratory tract.

Evidence for a planetary mass third body orbiting the binary star KIC 5095269

NASA Astrophysics Data System (ADS)

Getley, A. K.; Carter, B.; King, R.; O'Toole, S.

2017-07-01

In this paper, we report the evidence for a planetary mass body orbiting the close binary star KIC 5095269. This detection arose from a search for eclipse timing variations amongst the more than 2000 eclipsing binaries observed by Kepler. Light curve and periodic eclipse time variations have been analysed using systemic and a custom Binary Eclipse Timings code based on the Transit Analysis Package which indicates a 7.70 ± 0.08MJup object orbiting every 237.7 ± 0.1 d around a 1.2 M⊙ primary and a 0.51 M⊙ secondary in an 18.6 d orbit. A dynamical integration over 107 yr suggests a stable orbital configuration. Radial velocity observations are recommended to confirm the properties of the binary star components and the planetary mass of the companion.

Eclipses of the inner satellites of Jupiter observed in 2015

NASA Astrophysics Data System (ADS)

Saquet, E.; Emelyanov, N.; Colas, F.; Arlot, J.-E.; Robert, V.; Christophe, B.; Dechambre, O.

2016-06-01

Aims: During the 2014-2015 campaign of mutual events, we recorded ground-based photometric observations of eclipses of Amalthea (JV) and, for the first time, Thebe (JXIV) by the Galilean moons. We focused on estimating whether the positioning accuracy of the inner satellites determined with photometry is sufficient for dynamical studies. Methods: We observed two eclipses of Amalthea and one of Thebe with the 1 m telescope at Pic du Midi Observatory using an IR filter and a mask placed over the planetary image to avoid blooming features. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60 cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. After background removal, we computed a differential aperture photometry to obtain the light flux, and followed with an astrometric reduction. Results: We provide astrometric results with an external precision of 53 mas for the eclipse of Thebe, and 20 mas for that of Amalthea. These observation accuracies largely override standard astrometric measurements. The (O - C)s for the eclipse of Thebe are 75 mas on the X-axis and 120 mas on the Y-axis. The (O - C)s for the total eclipses of Amalthea are 95 mas and 22 mas, along the orbit, for two of the three events. Taking into account the ratio of (O - C) to precision of the astrometric results, we show a significant discrepancy with the theory established by Avdyushev and Ban'shikova in 2008, and the JPL JUP 310 ephemeris. Three of the four eclipse observations where recorded at the 1 m telescope of Pic du Midi Observatory (S2P), the other at Saint-Sulpice Observatory.

Navigating the Path of Totality - Results and Lessons Learned from the 2017 Eclipse Broadcast, Webcast, Mobile App and Online Production

NASA Astrophysics Data System (ADS)

Semper, R.; Higdon, R.

2017-12-01

The 2017 total solar eclipse provided unique opportunity to provide public outreach about astronomy, heliophysics, and scientific discovery. The Navigating the Path of Totality project was designed to produce eclipse related educational resources including live video feeds and distribute them to museums, schools, libraries and the public through online and broadcast media. Using special telescope video camera setups, five feeds were produced including a live one hour English program and in parallel a live one hour Spanish program from Casper, WY with a cutaway to Madras, OR, complete (C1-C4) telescope only feeds from both Madras, OR and Casper, Wy, and a complete (C1-C4) telescope only feed with live musical sonification and accompaniment by the Kronos Quartet. Images from the live feeds were made available on the NASA Website, NASA TV, Exploratorium website, Exploratorium Solar Eclipse mobile app, local television and in museums, libraries and schools worldwide. Associated educational video material including images from the 2016 total eclipse from Micronesia was produced and disseminated. In this talk we will discuss the evaluation results including an examination of the effectiveness of the digital strategy of many mobile channels and mobile apps using different analytics including IBM Watson social media analytics services. We will also present the lessons learned from the project.

Meteorological effects of the solar eclipse of 20 March 2015: analysis of UK Met Office automatic weather station data and comparison with automatic weather station data from the Faroes and Iceland

PubMed Central

Penman, John; Jónsson, Trausti; Bigg, Grant R.; Björnsson, Halldór; Sjúrðarson, Sølvi; Hansen, Mads A.; Cappelen, John; Bryant, Robert G.

2016-01-01

Here, we analyse high-frequency (1 min) surface air temperature, mean sea-level pressure (MSLP), wind speed and direction and cloud-cover data acquired during the solar eclipse of 20 March 2015 from 76 UK Met Office weather stations, and compare the results with those from 30 weather stations in the Faroe Islands and 148 stations in Iceland. There was a statistically significant mean UK temperature drop of 0.83±0.63°C, which occurred over 39 min on average, and the minimum temperature lagged the peak of the eclipse by about 10 min. For a subset of 14 (16) relatively clear (cloudy) stations, the mean temperature drop was 0.91±0.78 (0.31±0.40)°C but the mean temperature drops for relatively calm and windy stations were almost identical. Mean wind speed dropped significantly by 9% on average during the first half of the eclipse. There was no discernible effect of the eclipse on the wind-direction or MSLP time series, and therefore we can discount any localized eclipse cyclone effect over Britain during this event. Similar changes in air temperature and wind speed are observed for Iceland, where conditions were generally clearer, but here too there was no evidence of an eclipse cyclone; in the Faroes, there was a much more muted meteorological signature. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550769

Multi-color light curves and orbital period research of eclipsing binary V1073 Cyg

NASA Astrophysics Data System (ADS)

Tian, Xiao-Man; Zhu, Li-Ying; Qian, Sheng-Bang; Li, Lin-Jia; Jiang, Lin-Qiao

2018-02-01

New multi-color BV RcIc photometric observations are presented for the W UMa type eclipsing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124(±0.011). We collected all available times of light minima spanning 119 yr, including CCD data to construct the O ‑ C curve, and performed detailed O ‑ C analysis. The O ‑ C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic variation exist. The period is decreasing at a rate of Ṗ = ‑1.04(±0.18) × 10‑10 d cycle‑1 and, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P 3 = 82.7(±3.6) yr and an amplitude of A = 0.028(±0.002)d may be explained by magnetic activity of one or both components or the light travel time effect caused by a distant third companion with M 3(i‧ = 90°) = 0.511 M⊙.

Eclipse-Like Events on This Week @NASA – August 18, 2017

NASA Image and Video Library

2017-08-18

ena such as the Aug. 21, 2017 solar eclipse can inspire awe, but scientists can also use eclipse-like events to learn more about the universe. For instance, a total eclipse, or an occultation in scientific terms – happens when a celestial body completely blocks light from a star, like our sun. This type of event can help astronomers learn more about an object’s atmosphere, including whether it might be surrounded by rings or other planetary matter. During a similar event, called a transit, variations in light that result when a closer object passes in front of a star, but only blocks a small part of the star, have been used by missions such as our Kepler space telescope, to discover new planets outside our solar system. Also, SpaceX Launches Science, Supplies to Space Station, New Communications Satellite Launched, Cassini Begins Final Five Orbits around Saturn and Spacewalk aboard the Space Station!

An outstanding researcher of the solar eclipses- Nicolas Donitch

NASA Astrophysics Data System (ADS)

Gaina, Alex

1998-09-01

Nicolae Donitch (1874, Chisinau-1958, Nice, France?) worked in Russia (until 1917), Romania (1918-1944) and France (1945-1958?). His observatory was placed in Dubossary-Vechi (where he worked with some intervals between 1908 and 1944. He was designated by the Russian Academy of Sciences for the observations of the total Solar eclipse in Elche (Spain) on 28 May 1900. Other solar eclipses observed by N. Donitch: 17-18 may 1901, Padong (Sumatra); 1904 - the annular eclipse of the Sun in Pnom-Penh (Cambodge); august 1905, Alcala de Chisvert (Spain) and Assuan (Upper Egypt); 16/17 April 1912, Portugal; 21 august 1914, Crimea; 1925, USA; 1929 Indochina and Philipines; 1930, Egypt; 1932 Egypt and cape Porpoise,Maine USA; 1936, Inneboli, Turkey. Other solar investigations by N. Donitch; Solar cromosphere (Odessa, 1902; Mount- Blanch, 1902-1903); The passage of the planet Mercury through the solar disk (November, 1907, Egypt; October 1914, Algeria).

Amazonia Introduced to General Relativity: The May 29, 1919, Solar Eclipse from a North-Brazilian Point of View

NASA Astrophysics Data System (ADS)

Crispino, Luís C. B.; de Lima, Marcelo C.

2016-12-01

In 1919, A. C. D. Crommelin and C. R. Davidson, British astronomers from the Greenwich Observatory in England, passed by Amazonia on their Brazilian journey aiming to measure the bending of stars' light rays during the total solar eclipse of May 29, 1919, and thereby put the theory of general relativity to the test. In the context of Crommelin's and Davidson's visit, we discuss how Amazonia was introduced to Einstein's theory of gravitation, and also the observations and repercussions of the May 29, 1919, solar eclipse in Belém, capital city of the North-Brazilian Pará state.

Analysis of Free Amino Acids in Different Extracts of Orthosiphon stamineus Leaves by High-Performance Liquid Chromatography Combined with Solid-Phase Extraction.

PubMed

Shafaei, Armaghan; Halim, Nor Hidayah Ab; Zakaria, Norhidayah; Ismail, Zhari

2017-10-01

Orthosiphon stamineus (OS) Benth is a medicinal plant and native in Southeast Asia. Previous studies have shown that OS leaves possess antioxidant, cytotoxic, diuretic, antihypertensive, and uricosuric effects. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids, and flavonoids. To develop and validate an high-performance liquid chromatography (HPLC)-diode array detector (DAD) method combined with solid-phase extraction that involves precolumn derivatization with O -phthaladehyde for simultaneous analysis of free amino acids in OS leaves extracts. OS leaves were extracted with water (OS-W), ethanol (OS-E), methanol (OS-M), 50% ethanol (OS-EW), and 50% methanol (OS-MW). The extracts were treated by C18 cartridge before derivatization, resulting in great improvement of separation by Zorbox Eclipse XDB-C 18 column. The HPLC-DAD method was successfully developed and validated for analyzing the contents of free amino acids in OS extracts. The results showed that l-aspartic acid with 0.93 ± 0.01 nmol/mg was the major free amino acid in OS-W extract. However, in OS-E, OS-M, OS-EW, and OS-MW, l-glutamic acid with 3.53 ± 0.16, 2.17 ± 0.10, 4.01 ± 0.12, and 2.49 ± 0.12 nmol/mg, respectively, was the major free amino acid. Subsequently, l-serine, which was detected in OS-W, OS-E, and OS-M, was the minor free amino acid with 0.33 ± 0.02, 0.12 ± 0.01, and 0.06 ± 0.01 nmol/mg, respectively. However, l-threonine with 0.26 ± 0.02 and 0.19 ± 0.08 nmol/mL in OS-EW and OS-MW, respectively, had the lowest concentration compared with other amino acid components. All validation parameters of the developed method indicate that the method is reliable and efficient to simultaneously determine the free amino acids content for routine analysis of OS extracts. The HPLC-DAD method combined with solid phase extraction was successfully developed and validated for simultaneous determination and quantification of 17 free amino acids in Orthosiphon stamineus (OS) Benth extractsOS extracts were found to be rich in free amino acid contentL-aspartic acid was the major free amino acid in OS water extract while, in OS ethanol, methanol, 50% ethanol and 50% methanol extracts, L-glutamic acid was the major free amino acidL-serine was the minor free amino acid in OS water, ethanol and methanol extracts while, in OS 50% ethanol and 50% methanol extracts, L-threonine had the lowest concentration compared to other amino acid components. Abbreviations used: HPLC-DAD: High-Performance Liquid Chromatography with Diode-Array Detection, OS: Orthosiphon stamineus , OS-W: Orthosiphon stamineus water extract, OS-E: Orthosiphon stamineus ethanol extract, OS-M: Orthosiphon stamineus methanol extract, OS-EW: Orthosiphon stamineus 50% ethanol extract, OS-MW: Orthosiphon stamineus 50% methanol extract, OPA: O-phthaladehyde , SPE: Solid Phase Extraction, UV: Ultraviolet, LOD: Limit of Detection, LOQ: Limit of Quantification, RSD: Relative Standard Deviation.

Serum PARC/CCL-18 concentrations and health outcomes in chronic obstructive pulmonary disease.

PubMed

Sin, Don D; Miller, Bruce E; Duvoix, Annelyse; Man, S F Paul; Zhang, Xuekui; Silverman, Edwin K; Connett, John E; Anthonisen, Nicholas A; Wise, Robert A; Tashkin, Donald; Celli, Bartolome R; Edwards, Lisa D; Locantore, Nicholas; Macnee, William; Tal-Singer, Ruth; Lomas, David A

2011-05-01

There are no accepted blood-based biomarkers in chronic obstructive pulmonary disease (COPD). Pulmonary and activation-regulated chemokine (PARC/CCL-18) is a lung-predominant inflammatory protein that is found in serum. To determine whether PARC/CCL-18 levels are elevated and modifiable in COPD and to determine their relationship to clinical end points of hospitalization and mortality. PARC/CCL-18 was measured in serum samples from individuals who participated in the ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) and LHS (Lung Health Study) studies and a prednisolone intervention study. Serum PARC/CCL-18 levels were higher in subjects with COPD than in smokers or lifetime nonsmokers without COPD (105 vs. 81 vs. 80 ng/ml, respectively; P < 0.0001). Elevated PARC/CCL-18 levels were associated with increased risk of cardiovascular hospitalization or mortality in the LHS cohort and with total mortality in the ECLIPSE cohort. Serum PARC/CCL-18 levels are elevated in COPD and track clinical outcomes. PARC/CCL-18, a lung-predominant chemokine, could be a useful blood biomarker in COPD.

Stability of an ophthalmic formulation of polyhexamethylene biguanide in gamma-sterilized and ethylene oxide sterilized low density polyethylene multidose eyedroppers

PubMed Central

Wasiak, Mathieu; Jouannet, Mireille; Sautou, Valérie

2018-01-01

Background Polyhexamethylene biguanide (PHMB) eye drops are a frequently used medication to treat Acanthamoeba keratitis. In the absence of marketed PHMB eye drops, pharmacy-compounding units are needed to prepare this much needed treatment, but the lack of validated PHMB stability data severely limits their conservation by imposing short expiration dates after preparation. In this study we aim to assess the physicochemical and microbiological stability of a 0.2 mg/mL PHMB eye drop formulation stored in two kinds of polyethylene bottles at two different temperatures. Methods A liquid chromatography coupled with diode array detector stability-indicating method was validated to quantify PHMB, using a cyanopropyl bonded phase (Agilent Zorbax Eclipse XDB-CN column 4.6 × 75 mm with particle size of 3.5 μm) and isocratic elution consisting of acetonitrile/deionized water (3/97 v/v) at a flow rate of 1.3 mL/min. PHMB eye drops stability was assessed for 90 days of storage at 5 and 25 °C in ethylene oxide sterilized low density polyethylene (EOS-LDPE) and gamma sterilized low density polyethylene (GS-LDPE) bottles. The following analyses were performed: visual inspection, PHMB quantification and breakdown products (BPs) screening, osmolality and pH measurements, and sterility assessment. PHMB quantification and BP screening was also performed on the drops emitted from the multidose eyedroppers to simulate in-use condition. Results The analytical method developed meets all the qualitative and quantitative criteria for validation with an acceptable accuracy and good linearity, and is stability indicating. During 90 days of storage, no significant decrease of PHMB concentration was found compared to initial concentration in all stored PHMB eye drops. However, BP were found at day 30 and at day 90 of monitoring in both kind of bottles, stored at 5 and 25 °C, respectively. Although no significant variation of osmolality was found and sterility was maintained during 90 days of monitoring, a significant decrease of pH in GS-LDPE PHMB eye drops was noticed reaching 4 and 4.6 at 25 °C and 5 °C respectively, compared to initial pH of 6.16. Discussion Although no significant decrease in PHMB concentration was found during 90 days of monitoring in all conditions, the appearance of BPs and their unknown toxicities let us believe that 0.2 mg/mL PHMB solution should be conserved for no longer than 60 days in EOS-LDPE bottles at 25 °C. PMID:29682408

GMRT DISCOVERY OF PSR J1544+4937: AN ECLIPSING BLACK-WIDOW PULSAR IDENTIFIED WITH A FERMI-LAT SOURCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, B.; Roy, J.; Gupta, Y.

2013-08-10

Using the Giant Metrewave Radio Telescope, we performed deep observations to search for radio pulsations in the directions of unidentified Fermi-Large Area Telescope {gamma}-ray sources. We report the discovery of an eclipsing black-widow millisecond pulsar, PSR J1544+4937, identified with the uncataloged {gamma}-ray source FERMI J1544.2+4941. This 2.16 ms pulsar is in a 2.9 hr compact circular orbit with a very low mass companion (M{sub c} > 0.017M{sub Sun }). At 322 MHz this pulsar is found to be eclipsing for 13% of its orbit, whereas at 607 MHz the pulsar is detected throughout the low-frequency eclipse phase. Variations in themore » eclipse ingress phase are observed, indicating a clumpy and variable eclipsing medium. Moreover, additional short-duration absorption events are observed around the eclipse boundaries. Using the radio timing ephemeris we were able to detect {gamma}-ray pulsations from this pulsar, confirming it as the source powering the {gamma}-ray emission.« less

Ultraviolet spectral variations of symbiotic nova PU Vul during and after second eclipse

NASA Astrophysics Data System (ADS)

Sanad, M. R.

2016-12-01

I have analyzed spectral data of the symbiotic nova PU Vul observed with the International Ultraviolet Explorer (IUE) during the period 1993-1996. The study concentrated on the two sources of nebular emitting regions, the first is a nebula around the white dwarf partially eclipsed by a cool giant star and the second is a very extended nebular region not affected by the eclipse of the giant star. I concentrated on the N IV] 1486 Å and C IV 1550 Å emission lines produced in the first region and N III] 1750 Å and C III] 1909 Å emission lines produced in the second region very far from the giant star.

The Emergent 1.1-1.7 μm Spectrum of the Exoplanet CoRoT-2b as Measured Using the Hubble Space Telescope

NASA Astrophysics Data System (ADS)

Wilkins, Ashlee N.; Deming, Drake; Madhusudhan, Nikku; Burrows, Adam; Knutson, Heather; McCullough, Peter; Ranjan, Sukrit

2014-03-01

We have used Hubble/WFC3 and the G141 grism to measure the secondary eclipse of the transiting, very hot Jupiter CoRoT-2b in the 1.1-1.7 μm spectral region. We find an eclipse depth averaged over this band equal to 395^{+69}_{-45} parts per million, equivalent to a blackbody temperature of 1788 ± 18 K. We study and characterize several WFC3 instrumental effects, especially the "hook" phenomenon described by Deming et al. We use data from several transiting exoplanet systems to find a quantitative relation between the amplitude of the hook and the exposure level of a given pixel. Although the uncertainties in this relation are too large to allow us to develop an empirical correction for our data, our study provides a useful guide for optimizing exposure levels in future WFC3 observations. We derive the planet's spectrum using a differential method. The planet-to-star contrast increases to longer wavelength within the WFC3 bandpass, but without water absorption or emission to a 3σ limit of 85 ppm. The slope of the WFC3 spectrum is significantly less than the slope of the best-fit blackbody. We compare all existing eclipse data for this planet to a blackbody spectrum, and to spectra from both solar abundance and carbon-rich (C/O = 1) models. A blackbody spectrum is an acceptable fit to the full data set. Extra continuous opacity due to clouds or haze, and flattened temperature profiles, are strong candidates to produce quasi-blackbody spectra, and to account for the amplitude of the optical eclipses. Our results show ambiguous evidence for a temperature inversion in this planet.

The emergent 1.1-1.7 μm spectrum of the exoplanet COROT-2B as measured using the Hubble space telescope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkins, Ashlee N.; Deming, Drake; Madhusudhan, Nikku

2014-03-10

We have used Hubble/WFC3 and the G141 grism to measure the secondary eclipse of the transiting, very hot Jupiter CoRoT-2b in the 1.1-1.7 μm spectral region. We find an eclipse depth averaged over this band equal to 395{sub −45}{sup +69} parts per million, equivalent to a blackbody temperature of 1788 ± 18 K. We study and characterize several WFC3 instrumental effects, especially the 'hook' phenomenon described by Deming et al. We use data from several transiting exoplanet systems to find a quantitative relation between the amplitude of the hook and the exposure level of a given pixel. Although the uncertaintiesmore » in this relation are too large to allow us to develop an empirical correction for our data, our study provides a useful guide for optimizing exposure levels in future WFC3 observations. We derive the planet's spectrum using a differential method. The planet-to-star contrast increases to longer wavelength within the WFC3 bandpass, but without water absorption or emission to a 3σ limit of 85 ppm. The slope of the WFC3 spectrum is significantly less than the slope of the best-fit blackbody. We compare all existing eclipse data for this planet to a blackbody spectrum, and to spectra from both solar abundance and carbon-rich (C/O = 1) models. A blackbody spectrum is an acceptable fit to the full data set. Extra continuous opacity due to clouds or haze, and flattened temperature profiles, are strong candidates to produce quasi-blackbody spectra, and to account for the amplitude of the optical eclipses. Our results show ambiguous evidence for a temperature inversion in this planet.« less

Timing of fluid seepage on summits of Quaker and Conical serpentine mud volcanoes, Mariana forearc: Evidence from U/Th dating of carbonate chimneys

NASA Astrophysics Data System (ADS)

Tong, Hongpeng; Fryer, Patricia; Feng, Dong; Chen, Duofu

2017-04-01

Serpetinization of forearc mantle along deep faults in the Mariana convergent plate margin permits formation of large active serpentinite mud volcanoes on the overiding plate within 90 km of the trench. Fluid seepage on summits of the mud volcanoes lead to the formation of authigenic carbonate chimneys close to the seafloor. Such carbonate chimneys are unique archives of past fluid seepage and assciated envrionemtnal parameters. Here, we report U/Th dating and stable carbon and oxygen isotopes of the chimneys from Quaker and Conical serpentine mud volcanoes. The resulting U/Th ages of samples from Quaker Seamount show three time intervals of 11,081 to10,542 yBP, 5,857 to 5,583 yBP, and 781 to 164 yBP, respectively. By comparison, carbonates from Conical Seamount have U/Th ages between 3,070 yBP and 1,623 yBP. Our results suggest that fluid seepage on the summits of serpentine mud volcanoes are episodic and probably locally controlled. Samples from Quaker seamount show depletion of 13C (δ13C=-7.0-0.4‰ V-PDB), indicating contribution of carbon from anoxic oxidation of abiogenic methane. By contrast, samples from Conical seamount have positive δ18O values (0.6-6.3), suggesting enrichment of 18O in the seepage fluid. The data obtained provide time integrated variation of seepage fluids and seepage dynamics that are archived in authigenic carbonates. This finding adds to the ongoing multidisciplinary effort to better constrain the environment in the Mariana forearc region and to determine the locally dominant biogeochemical processes. Acknowlegment: This study was funded by the CAS (Grant No. XDB06030102).

Oregon Wildfire in Eclipse Zone Imaged by NASA Satellite

NASA Image and Video Library

2017-08-21

The Whitewater Fire in the Mount Jefferson Wilderness in Oregon was started by a lightning strike. As of Aug. 18, 2017, more than 117,000 acres and 30 miles (48 kilometers) of the Pacific Crest Trail are closed to the public in an area that had been expected to be popular with people there to view the August 21 solar eclipse. The smoke clouds sit over the burned area, just west-northwest of Mount Jefferson. The image was acquired Aug. 18, 2017, covers an area of 16 by 17 miles (26.1 by 27.2 kilometers), and is located at 44.7 degrees north, 121.8 degrees west. https://photojournal.jpl.nasa.gov/catalog/PIA21877

V380 Dra: New short-period totally eclipsing active binary

NASA Astrophysics Data System (ADS)

Özdarcan, O.

2014-02-01

In this study, first complete and standard BVR light curves and photometric analysis of the eclipsing binary system V380 Dra are presented. Photometric analysis result indicates that the system has components which are cool main sequence stars. In light and color curves, remarkable asymmetry is observed, especially after secondary minimum, which is believed to be a result of chromospheric activity in one or both components. O-C diagram of available small number of eclipse times, together with new eclipse timings in this work, exhibits no significant variation. Preliminary light curve solution shows that the secondary minimum is total eclipse. By using the advantage of total eclipse and mass-luminosity relation, it is found that the system has a possible mass ratio of q = 0.81. First estimation of masses and radii of primary and secondary components are M1 = 0.77 M⊙,M2 = 0.62 M⊙ and R1 = 0.93 R⊙,R2 = 0.77 R⊙, respectively.

Mechanism of adsorption and eclipse of bacteriophage phi X174. I. In vitro conformational change under conditions of eclipse.

PubMed

Incardona, N L; Blonski, R; Feeney, W

1972-01-01

Bacteriophage phiX174 undergoes a conformational change during viral eclipse when virus-host cell complexes are incubated briefly at 37 C in a complex starvation buffer at pH 8. In this report, basically the same transition is demonstrated in vitro. Incubation of phiX alone for 2 to 3 hr at 35 C in 0.1 m CaCl(2) (pH 7.2) results in an irreversible decrease in S(20,w) because of an increase in the frictional coefficient that occurs during the change in conformation. The slower sedimenting conformation is noninfectious. These properties are remarkably similar to those of the eclipsed particles characterized by Newbold and Sinsheimer. Therefore, the key structural requirements for the molecular mechanism must reside within the architecture of the virus itself. This extremely simplified system uncovered the calcium ion requirement and pronounced dependence on pH between 6 and 7, both inherent properties of adsorption. This and the more than 10-fold greater rate of the in vivo conformational transition allude to the cooperative nature of attachment and eclipse for phiX.

FIRST DAUGHTER IVANKA TRUMP PARTICIPATES IN SOLAR ECLIPSE ACTIVITIES AT NATIONAL AIR AND SPACE MUSEUM

NASA Image and Video Library

2017-08-21

On Monday, Aug. 21, First Daughter, Ivanka Trump participated in solar eclipse viewing and STEM (Science, Technology, Engineering, and Mathematics) educational activities hosted by the Smithsonian National Air and Space Museum in Washington, D.C.

Eclipse program C-141A aircraft

NASA Technical Reports Server (NTRS)

1997-01-01

This photograph shows the Air Force C-141A that was used in the Eclipse project as a tow vehicle. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wind loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

LC-MS/MS method for the determination of the prodrug aripiprazole lauroxil and its three metabolites in plasma and its application to in vitro biotransformation and animal pharmacokinetic studies.

PubMed

Sun, Yiying; Lu, Xiaoyan; Gai, Yunyun; Sha, Chunjie; Leng, Guangyi; Yang, Xiucheng; Liu, Wanhui

2018-04-01

A sensitive and selective LC-MS/MS method for determination of the prodrug aripiprazole lauroxil (AL) and the three metabolites (N-hydroxymethyl aripiprazole [NHA], aripiprazole [ARP], and dehydro aripiprazole [DHA]) in plasma was developed using ARP-d 8 as an internal standard. The analytes were determined on an AB Sciex Triple Quad™ 4500 system using positive ion electrospray ionization and selected multiple reaction monitoring mode. Solid phase extraction was applied for sample preparation for AL, ARP, and DHA, and protein precipitation for NHA. Chromatographic separation was performed on an Agilent Eclipse XDB-CN column (100 × 2.1 mm i.d., 3.5 μm) using the mobile phase of water and acetonitrile (25:75, v/v) containing 0.1% formic acid with a flow rate of 0.5 mL/min. The linear ranges for AL, NHA, ARP, and DHA were 0.5-50 ng/mL, 1.0-50 ng/mL, 0.5-50 ng/mL, and 0.05-5.0 ng/mL, respectively. The average recovery in the plasma sample was stable and reproducible. The precision and accuracy of the intra- and inter-run were within assay variability criteria limits. The developed method was suitable for in vitro biotransformation studies in plasma and animal pharmacokinetic studies after intramuscular injection of AL formulations. Copyright © 2018. Published by Elsevier B.V.

Ionospheric response to the total solar eclipse in India on 22 July, 2009

NASA Astrophysics Data System (ADS)

Chauhan, Vishal; Agrawal, Shikah; Singh, O. P.; Singh, Birbal

2010-05-01

The variations in total electron content (TEC) and amplitude of the fixed frequency VLF transmitter signals (f =19.8 kHz, NWC, Australia) are studied at Agra (Geographic lat. 27.20N, long. 780E), India during the total solar eclipse of 22 July, 2009 which was longest seen in India ever since 18 August, 1968. The equipments used for the study are a dual frequency GPS receiver (GSV 4004V). The data for a period of fifteen days (±7 days from the date of the event) are analysed and it is found that the TEC decreased by about 30% from normal days during the total solar eclipse. The period of the data analysis is characterised by a low level of geomagnetic activity, hence the decrease in TEC s is unlikely to be influenced by geomagnetic disturbances. The results are interpreted in terms of depression in electron densities at all ionospheric heights and are consistent with those obtained by earlier workers during similar eclipse events.

Tidally Induced Pulsations in Kepler Eclipsing Binary KIC 3230227

NASA Astrophysics Data System (ADS)

Guo, Zhao; Gies, Douglas R.; Fuller, Jim

2017-01-01

KIC 3230227 is a short period (P ≈ 7.0 days) eclipsing binary with a very eccentric orbit (e = 0.6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M1 = 1.84 ± 0.18 M⊙, M2 = 1.73 ± 0.17 M⊙ and radii of R1 = 2.01 ± 0.09 R⊙, R2 = 1.68 ± 0.08 R⊙ for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system. After removing the binary light curve model, more than 10 pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l = 2, m = -2 prograde modes.

Serum PARC/CCL-18 Concentrations and Health Outcomes in Chronic Obstructive Pulmonary Disease

PubMed Central

Sin, Don D.; Miller, Bruce E.; Duvoix, Annelyse; Man, S. F. Paul; Zhang, Xuekui; Silverman, Edwin K.; Connett, John E.; Anthonisen, Nicholas A.; Wise, Robert A.; Tashkin, Donald; Celli, Bartolome R.; Edwards, Lisa D.; Locantore, Nicholas; MacNee, William; Tal-Singer, Ruth; Lomas, David A.

2011-01-01

Rationale: There are no accepted blood-based biomarkers in chronic obstructive pulmonary disease (COPD). Pulmonary and activation-regulated chemokine (PARC/CCL-18) is a lung-predominant inflammatory protein that is found in serum. Objectives: To determine whether PARC/CCL-18 levels are elevated and modifiable in COPD and to determine their relationship to clinical end points of hospitalization and mortality. Methods: PARC/CCL-18 was measured in serum samples from individuals who participated in the ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) and LHS (Lung Health Study) studies and a prednisolone intervention study. Measurements and Main Results: Serum PARC/CCL-18 levels were higher in subjects with COPD than in smokers or lifetime nonsmokers without COPD (105 vs. 81 vs. 80 ng/ml, respectively; P < 0.0001). Elevated PARC/CCL-18 levels were associated with increased risk of cardiovascular hospitalization or mortality in the LHS cohort and with total mortality in the ECLIPSE cohort. Conclusions: Serum PARC/CCL-18 levels are elevated in COPD and track clinical outcomes. PARC/CCL-18, a lung-predominant chemokine, could be a useful blood biomarker in COPD. Clinical trial registered with www.clinicaltrials.gov (NCT 00292552). PMID:21216880

The Role of Solar Eclipses in El Nino/La Nina Events

NASA Astrophysics Data System (ADS)

Chiu, B. C.

2005-08-01

The first hint of the fact that solar eclipses mark the enhanced storms called El Nino or La Nina, came from the article by Robert Allan on analysis of frequencies of these events (2001, perhaps Fourier analysis). One mystery was the cause of a cycle with period 15 to 20 years. But the Saros Series of solar eclipses has a period of 18+ years. Then we had the data from Galapagos Islands for the whole 20th century (Philander 2004). The graph of high and low temperatures indicates El Ninos and La Ninas. A search through charts of solar eclipses for those with good locations for bringing high tides at the Tropics, gave a good picture: those at the eastern coast of the pacific Ocean gave El Ninos, and those at the west gave La Ninas. More than half of the peaks and troughs on the temperature graph can be identified with solar eclipses. We looked more closely at a few events that caused great storms. They are described in J. M. Nash's book, ``El Nino" (2002). The most striking case is that of the 1998 Feb. 22 solar eclipse, which corresponds to the so-called El Nino of 1997-98. In conclusion, I would say that the annual El nino effect is due to the sun's travel between the Tropic of Cancer and Tropic of Capricorn. But the enhanced El Niino/La Nina is due to the coming together of sun and moon in the solar eclipses, which seem to come irregularly.

A Handbook of Descriptive and Practical Astronomy

NASA Astrophysics Data System (ADS)

Chambers, George Frederick

2010-06-01

Book I. A Sketch of the Solar System: 1. The sun; 2. The planets; 3. Vulcan; 4. Mercury; 5. Venus; 6. The earth; 7. The moon; 8. Mars; 9. The minor planets; 10. Jupiter; 11. Saturn; 12. Uranus; 13. Neptune; Book II. Eclipses and their Associated Phenomena: 1. General outlines; 2. Eclipses of the sun; 3. The total eclipse of the sun of July 28, 1851; 4. The annular eclipse of the sun of March 14-15, 1858; 5. The total eclipse of the sun of July 18, 1860; 6. Historical notices; 7. Eclipses of the moon; 8. Suggestions for observing annular eclipses of the sun; 9. Transits of the inferior planets; 10. Occultations; Book III. The Tides: 1. Introduction; 2. Local disturbing influences; Book IV. Miscellaneous Astronomical Phenomena: 1. Variation in the obliquity of the ecliptic; 2. Aberration; 3. Refraction; Book V. Comets: 1. General remarks; 2. Periodic comets; 3. Remarkable comets; 4. Cometary statistics; 5. Historical notices; Book VI. Chronological Astronomy: 1. What time is; 2. Hours; 3. Means of measuring time; 4. The Dominical or Sunday letter; 5. Tables for the conversion of time; Book VII. The Starry Heavens: 1. The Pole-Star; 2. Double stars; 3. Variable stars; 4. Clusters and nebulae; 5. The Milky Way; 6. The constellations; Book VIII. Astronomical Instruments: 1. Telescopes; 2. Telescope stands; 3. The equatorial; 4. The transit instrument; 5. Other astronomical instruments; 6. History of the telescope; Book IX. A Sketch of the History of Astronomy; Book X. Meteoric Astronomy: 1. Classification of the subject; 2. The origin of aërolites; 3. Shooting stars; Appendices; Index.

Modeling of the Ionospheric Scintillation and Total Electron Content Observations during the 21 August 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Datta-Barua, S.; Gachancipa, J. N.; Deshpande, K.; Herrera, J. A.; Lehmacher, G. A.; Su, Y.; Gyuk, G.; Bust, G. S.; Hampton, D. L.

2017-12-01

High concentration of free electrons in the ionosphere can cause fluctuations in incoming electromagnetic waves, such as those from the different Global Navigation Satellite Systems (GNSS). The behavior of the ionosphere depends on time and location, and it is highly influenced by solar activity. The purpose of this study is to determine the impact of a total solar eclipse on the local ionosphere in terms of ionospheric scintillations, and on the global ionosphere in terms of TEC (Total Electron Content). The studied eclipse occurred on 21 August 2017 across the continental United States. During the eclipse, we expected to see a decrease in the scintillation strength, as well as in the TEC values. As a broader impact part of our recently funded NSF proposal, we temporarily deployed two GNSS receivers on the eclipse's totality path. One GNSS receiver was placed in Clemson, SC. This is a multi-frequency GNSS receiver (NovAtel GPStation-6) capable of measuring high and low rate scintillation data as well as TEC values from four different GNSS systems. We had the receiver operating before, during, and after the solar eclipse to enable the comparison between eclipse and non-eclipse periods. A twin receiver collected data at Daytona Beach, FL during the same time, where an 85% partial solar eclipse was observed. Additionally, we set up a ground receiver onsite in the path of totality in Perryville, Missouri, from which the Adler Planetarium of Chicago launched a high-altitude balloon to capture a 360-degree video of the eclipse from the stratosphere. By analyzing the collected data, this study looks at the effects of partial and total solar eclipse periods on high rate GNSS scintillation data at mid-latitudes, which had not been explored in detail. This study also explores the impact of solar eclipses on signals from different satellite constellations (GPS, GLONASS, and Galileo). Throughout the eclipse, the scintillation values did not appear to have dramatic changes. However, we observed lower scintillation activity on several satellites from different constellations. For example, between 16 UTC and 22 UTC, there was a slight drop in the S4 scintillation Index (amplitude) values, reaching a local minimum during the time of eclipse totality ( 18:30 UTC). Regarding the Total Electron Content (TEC), which measures the quantity of electrons in the ionosphere, there was a more drastic decrease in the values throughout the partial and total solar eclipse. Additionally, σφ (sigma-phi) values for phase scintillation showed the similar behavior compared to previous few days. This reveals that the solar eclipse did not have a major effect on the phase scintillation. In any case, the totality path was entirely in mid-latitude regions, where phase scintillations are expected to be lower compared to high latitudes.

The early-type multiple system QZ Carinae

NASA Astrophysics Data System (ADS)

Mayer, P.; Lorenz, R.; Drechsel, H.; Abseim, A.

2001-02-01

We present an analysis of the early-type quadruple system QZ Car, consisting of an eclipsing and a non-eclipsing binary. The spectroscopic investigation is based on new high dispersion echelle and CAT/CES spectra of H and He lines. The elements for the orbit of the non-eclipsing pair could be refined. Lines of the brighter component of the eclipsing binary were detected in near-quadrature spectra, while signatures of the fainter component could be identified in only few spectra. Lines of the primary component of the non-eclipsing pair and of both components of the eclipsing pair were found to be variable in position and strength; in particular, the He ii 4686 emission line of the brighter eclipsing component is strongly variable. An ephemeris for the eclipsing binary QZ Car valid at present was derived Prim. Min. = hel. JD 2448687.16 + 5fd9991 * E. The relative orbit of the two binary constituents of the multiple system is discussed. In contrast to earlier investigations we found radial velocity changes of the systemic velocities of both binaries, which were used - together with an O-C analysis of the expected light-time effect - to derive approximate parameters of the mutual orbit of the two pairs. It is shown that this orbit and the distance to QZ Car can be further refined by minima timing and interferometry. Based on observations collected at the European Southern Observatory, La Silla, Chile.

Precise calibration of zero-crossing temperature and drift of an ultralow expansion cavity with a clock transition spectrum

NASA Astrophysics Data System (ADS)

Liu, Hui; Jiang, Kun-Liang; Wang, Jin-Qi; Xiong, Zhuan-Xian; He, Ling-Xiang; Lü, Bao-Long

2018-05-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 61227805, 11574352, 91536104, and 91636215) and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB21030100).

Suzaku Observation of the Dwarf Nova V893 Scorpii: The Discovery of a Partial X-Ray Eclipse

NASA Technical Reports Server (NTRS)

Mukai, Koji; Zietsman, E.; Still, M.

2008-01-01

V893 Sco is an eclipsing dwarf nova that had attracted little attention from X-ray astronomers until it was proposed as the identification of an RXTE all-sky slew survey (XSS) source. Here we report on the po inted X-ray observations of this object using Suzaku. We confirm V893 Sco to be X-ray bright, whose spectrum is highly absorbed for a dwar f nova. We have also discovered a partial X-ray eclipse in V893 Sco. This is the first time that a partial eclipse is seen in Xray light c urves of a dwarf nova. We have successfully modeled the gross features of the optical and X-ray eclipse light curves using a boundary layer geometry of the X-ray emission region. Future observations may lead to confirmation of this basic picture, and allow us to place tight co nstraints on the size of the X-ray emission region. The partial X-ray eclipse therefore should make V893 Sco a key object in understanding the physics of accretion in quiescent dwarf nova.

New O-C Observations for 150 Algols: Insight to the Origins of Period Shifts

NASA Astrophysics Data System (ADS)

Hoffman, D. I.; Harrison, T. E.; McNamara, B. J.; Vestrand, W. T.

2005-12-01

Many eclipsing binaries of type Algol, RS CVn, and W UMa have observed orbital period shifts. Of these, many show both increasing and decreasing period shifts. Two leading explanations for these shifts are third body effects and magnetic activity changing the oblateness of the secondary, though neither one can explain all of the observed period oscillations. The first-generation Robotic Optical Transient Search Experiment (ROTSE-I) based in Los Alamos, NM, was primarily designed to look for the optical counterparts to gamma-ray bursts as well as searching for other optical transients not detected in gamma-rays. The telescope, consisting of four 200mm camera lenses, can image the entire northern sky twice in a night, which is a very useful tool in monitoring relatively bright eclipsing binaries for period shifts. The public data release from ROTSE-I, the Northern Sky Variability Survey (NSVS), spans one year of data stating in April, 1999. O-C data for 150 eclipsing binaries are presented using the NSVS data. We revisit work by Borkovits and Hegedüs on some third body candidates in several eclipsing binary systems using recent AAVSO and NSVS data. Some unusual light curves of eclipsing binaries produced from NSVS data is presented and discussed.

Eclipse program C-141A aircraft

NASA Technical Reports Server (NTRS)

1997-01-01

This photograph shows the Air Force C-141A that was used in the Eclipse project as a tow vehicle. The project used a QF-106 interceptor aircraft to simulate a future orbiter, which would be towed to a high altitude and released to fire its own engines and carry a payload into space. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

Super Blood Moon Lunar Eclipse

NASA Image and Video Library

2017-12-08

A preview animation of the Super Moon Lunar Eclipse On the evening of September 27, 2015 in the Americas (early morning on September 28 in Europe and most of Africa), the Moon enters the Earth’s shadow, creating a total lunar eclipse, the last of four visible in the Western Hemisphere in a span of 18 months. This animation shows the changing appearance of the Moon as it travels into and out of the Earth’s shadow. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The EBLM project. I. Physical and orbital parameters, including spin-orbit angles, of two low-mass eclipsing binaries on opposite sides of the brown dwarf limit

NASA Astrophysics Data System (ADS)

Triaud, A. H. M. J.; Hebb, L.; Anderson, D. R.; Cargile, P.; Collier Cameron, A.; Doyle, A. P.; Faedi, F.; Gillon, M.; Gomez Maqueo Chew, Y.; Hellier, C.; Jehin, E.; Maxted, P.; Naef, D.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Smalley, B.; Stassun, K.; Udry, S.; West, R. G.

2013-01-01

This paper introduces a series of papers aiming to study the dozens of low-mass eclipsing binaries (EBLM), with F, G, K primaries, that have been discovered in the course of the WASP survey. Our objects are mostly single-line binaries whose eclipses have been detected by WASP and were initially followed up as potential planetary transit candidates. These have bright primaries, which facilitates spectroscopic observations during transit and allows the study of the spin-orbit distribution of F, G, K+M eclipsing binaries through the Rossiter-McLaughlin effect. Here we report on the spin-orbit angle of WASP-30b, a transiting brown dwarf, and improve its orbital parameters. We also present the mass, radius, spin-orbit angle and orbital parameters of a new eclipsing binary, J1219-39b (1SWAPJ121921.03-395125.6, TYC 7760-484-1), which, with a mass of 95 ± 2 Mjup, is close to the limit between brown dwarfs and stars. We find that both objects have projected spin-orbit angles aligned with their primaries' rotation. Neither primaries are synchronous. J1219-39b has a modestly eccentric orbit and is in agreement with the theoretical mass-radius relationship, whereas WASP-30b lies above it. Using WASP-South photometric observations (Sutherland, South Africa) confirmed with radial velocity measurement from the CORALIE spectrograph, photometry from the EulerCam camera (both mounted on the Swiss 1.2 m Euler Telescope), radial velocities from the HARPS spectrograph on the ESO's 3.6 m Telescope (prog ID 085.C-0393), and photometry from the robotic 60 cm TRAPPIST telescope, all located at ESO, La Silla, Chile. The data is publicly available at the CDS Strasbourg and on demand to the main author.Tables A.1-A.3 are available in electronic form at http://www.aanda.orgPhotometry tables are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A18

Changes of atmospheric properties over Belgrade, observed using remote sensing and in situ methods during the partial solar eclipse of 20 March 2015

NASA Astrophysics Data System (ADS)

Ilić, L.; Kuzmanoski, M.; Kolarž, P.; Nina, A.; Srećković, V.; Mijić, Z.; Bajčetić, J.; Andrić, M.

2018-06-01

Measurements of atmospheric parameters were carried out during the partial solar eclipse (51% coverage of solar disc) observed in Belgrade on 20 March 2015. The measured parameters included height of the planetary boundary layer (PBL), meteorological parameters, solar radiation, surface ozone and air ions, as well as Very Low Frequency (VLF, 3-30 kHz) and Low Frequency (LF, 30-300 kHz) signals to detect low-ionospheric plasma perturbations. The observed decrease of global solar and UV-B radiation was 48%, similar to the solar disc coverage. Meteorological parameters showed similar behavior at two measurement sites, with different elevations and different measurement heights. Air temperature change due to solar eclipse was more pronounced at the lower measurement height, showing a decrease of 2.6 °C, with 15-min time delay relative to the eclipse maximum. However, at the other site temperature did not decrease; its morning increase ceased with the start of the eclipse, and continued after the eclipse maximum. Relative humidity at both sites remained almost constant until the eclipse maximum and then decreased as the temperature increased. The wind speed decreased and reached minimum 35 min after the last contact. The eclipse-induced decrease of PBL height was about 200 m, with minimum reached 20 min after the eclipse maximum. Although dependent on UV radiation, surface ozone concentration did not show the expected decrease, possibly due to less significant influence of photochemical reactions at the measurement site and decline of PBL height. Air-ion concentration decreased during the solar eclipse, with minimum almost coinciding with the eclipse maximum. Additionally, the referential Line-of-Sight (LOS) radio link was set in the area of Belgrade, using the carrier frequency of 3 GHz. Perturbation of the receiving signal level (RSL) was observed on March 20, probably induced by the solar eclipse. Eclipse-related perturbations in ionospheric D-region were detected based on the VLF/LF signal variations, as a consequence of Lyα radiation decrease.

False Positives in Exoplanet Detection

NASA Astrophysics Data System (ADS)

Leuquire, Jacob; Kasper, David; Jang-Condell, Hannah; Kar, Aman; Sorber, Rebecca; Suhaimi, Afiq; KELT (Kilodegree Extremely Little Telescope)

2018-06-01

Our team at the University of Wyoming uses a 0.6 m telescope at RBO (Red Buttes Observatory) to help confirm results on potential exoplanet candidates from low resolution, wide field surveys shared by the KELT (Kilodegree Extremely Little Telescope) team. False positives are common in this work. We carry out transit photometry, and this method comes with special types of false positives. The most common false positive seen at the confirmation level is an EB (eclipsing binary). Low resolution images are great in detecting multiple sources for photometric dips in light curves, but they lack the precision to decipher single targets at an accurate level. For example, target star KC18C030621 needed RBO’s photometric precision to determine there was a nearby EB causing exoplanet type light curves. Identifying false positives with our telescope is important work because it helps eliminate the waste of time taken by more expensive telescopes trying to rule out negative candidate stars. It also furthers the identification of other types of photometric events, like eclipsing binaries, so they can be studied on their own.

The Araucaria project. The distance to the small Magellanic Cloud from late-type eclipsing binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graczyk, Dariusz; Pietrzyński, Grzegorz; Gieren, Wolfgang

2014-01-01

We present a distance determination to the Small Magellanic Cloud (SMC) based on an analysis of four detached, long-period, late-type eclipsing binaries discovered by the Optical Gravitational Lensing Experiment (OGLE) survey. The components of the binaries show negligible intrinsic variability. A consistent set of stellar parameters was derived with low statistical and systematic uncertainty. The absolute dimensions of the stars are calculated with a precision of better than 3%. The surface brightness-infrared color relation was used to derive the distance to each binary. The four systems clump around a distance modulus of (m – M) = 18.99 with a dispersionmore » of only 0.05 mag. Combining these results with the distance published by Graczyk et al. for the eclipsing binary OGLE SMC113.3 4007, we obtain a mean distance modulus to the SMC of 18.965 ± 0.025 (stat.) ± 0.048 (syst.) mag. This corresponds to a distance of 62.1 ± 1.9 kpc, where the error includes both uncertainties. Taking into account other recent published determinations of the SMC distance we calculated the distance modulus difference between the SMC and the Large Magellanic Cloud equal to 0.458 ± 0.068 mag. Finally, we advocate μ{sub SMC} = 18.95 ± 0.07 as a new 'canonical' value of the distance modulus to this galaxy.« less

Observation and Analysis of Secondary Eclipses of WASP-32b

NASA Astrophysics Data System (ADS)

Garland, Justin; Harrington, Joseph; Cubillos, Patricio E.; Blecic, Jasmina; Foster, Andrew S.; Bowman, Oliver; Maxted, Pierre F. L.

2015-11-01

We report two Spitzer secondary eclipses of the exoplanet WASP-32b. Discovered in 2010 by Maxted et al, this hot-Jupiter planet has a mass of 3.6 ± 0.07 Mj, a radius of 1.18 ± 0.07 Rj, an equilibrium temperature of 1560 ± 50 K, and an orbital period of 2.71865 ± 0.00008 days around a G-type star. We observed two secondary eclipses in the 3.6 µm and 4.5 µm channels using the Spitzer Space Telescope in 2010 as a part of the Spitzer Exoplanet Target of Opportunity program (program 60003). We present eclipse depth estimates of 0.0013 ± 0.00023 in the 4.5 µm band and inconclusive results in the 3.6 µm band. We also report an infrared brightness temperature of 1538 ± 110 in the 4.5 µm channel and refinements of orbital parameters for WASP-32b from our eclipse measurement as well as amatuer and professional data that closely match previous results. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

Secondary Eclipse Observations and Orbital Analysis of WASP-32b

NASA Astrophysics Data System (ADS)

Garland, Justin; Harrington, Joseph; Cubillos, Patricio; Blecic, Jasmina; Foster, Andrew S.; Bowman, Oliver; Maxted, Pierre F. L.

2016-01-01

We report two Spitzer secondary eclipses of the exoplanet WASP-32b. Discovered by Maxted et al. (2010), this hot-Jupiter planet has a mass of 3.6 ± 0.07 MJ a radius of 1.18 ± 0.07 RJ and an orbital period of 2.71865 ± 0.00008 days around a G-type star. We observed two secondary eclipses in the 3.6 μm and 4.5 μm channels using the Spitzer Space Telescope in 2010 as a part of the Spitzer Exoplanet Target of Opportunity program (program 60003). We present eclipse depth estimates of 0.0013 ± 0.00023 in the 4.5 μm band and inconclusive results in the 3.6 μm band. We also report an infrared brightness temperature of 1538 ± 110 in the 4.5 μm channel and refinements of orbital parameters for WASP-32b from our eclipse measurement as well as amatuer and professional data that closely match previous results. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

HD 66051, an eclipsing binary hosting a highly peculiar, HgMn-related star.

PubMed

Niemczura, Ewa; Hümmerich, Stefan; Castelli, Fiorella; Paunzen, Ernst; Bernhard, Klaus; Hambsch, Franz-Josef; Hełminiak, Krzysztof

2017-07-19

HD 66051 is an eclipsing system with an orbital period of about 4.75 d that exhibits out-of-eclipse variability with the same period. New multicolour photometric observations confirm the longevity of the secondary variations, which we interpret as a signature of surface inhomogeneities on one of the components. Using archival and newly acquired high-resolution spectra, we have performed a detailed abundance analysis. The primary component is a slowly rotating late B-type star (T eff  = 12500 ± 200 K; log g = 4.0, v sin i = 27 ± 2 km s -1 ) with a highly peculiar composition reminiscent of the singular HgMn-related star HD 65949, which seems to be its closest analogue. Some light elements as He, C, Mg, Al are depleted, while Si and P are enhanced. Except for Ni, all the iron-group elements, as well as most of the heavy elements, and in particular the REE elements, are overabundant. The secondary component was estimated to be a slowly rotating A-type star (T eff  ~ 8000 K; log g = 4.0, v sin i ~ 18 km s -1 ). The unique configuration of HD 66051 opens up intriguing possibilities for future research, which might eventually and significantly contribute to the understanding of such diverse phenomena as atmospheric structure, mass transfer, magnetic fields, photometric variability and the origin of chemical anomalies observed in HgMn stars and related objects.

Analysis of penumbral eclipse data

NASA Technical Reports Server (NTRS)

Garrett, H. B.

1977-01-01

Two days of data from the ATS-6 1976 eclipse season were analyzed to determine the effects of varying photoelectron flux on spacecraft potential. Particular emphasis was placed on the variation in potential as the satellite entered the earth's penumbra. Measurements from the AE-C satellite of the solar UV radiation were used to construct a model of atmospheric attenuation. This model was found to be consistent with direct measurements of the variations in photoelectron flux as Injun 5 passed into eclipse. Applying the model to the ATS-6 data gave the time dependency of the solar illumination/photoelectron flux as the satellite was eclipsed. This relationship, when combined with the ATS-6 measurements of satellite potential, revealed a nearly linear relation between the solar illumination/photoelectron flux and the logarithm of the satellite potential.

Application programming in C# environment with recorded user software interactions and its application in autopilot of VMAT/IMRT treatment planning.

PubMed

Wang, Henry; Xing, Lei

2016-11-08

An autopilot scheme of volumetric-modulated arc therapy (VMAT)/intensity-modulated radiation therapy (IMRT) planning with the guidance of prior knowl-edge is established with recorded interactions between a planner and a commercial treatment planning system (TPS). Microsoft (MS) Visual Studio Coded UI is applied to record some common planner-TPS interactions as subroutines. The TPS used in this study is a Windows-based Eclipse system. The interactions of our application program with Eclipse TPS are realized through a series of subrou-tines obtained by prerecording the mouse clicks or keyboard strokes of a planner in operating the TPS. A strategy to autopilot Eclipse VMAT/IMRT plan selection process is developed as a specific example of the proposed "scripting" method. The autopiloted planning is navigated by a decision function constructed with a reference plan that has the same prescription and similar anatomy with the case at hand. The calculation proceeds by alternating between the Eclipse optimization and the outer-loop optimization independent of the Eclipse. In the C# program, the dosimetric characteristics of a reference treatment plan are used to assess and modify the Eclipse planning parameters and to guide the search for a clinically sensible treatment plan. The approach is applied to plan a head and neck (HN) VMAT case and a prostate IMRT case. Our study demonstrated the feasibility of application programming method in C# environment with recorded interactions of planner-TPS. The process mimics a planner's planning process and automatically provides clinically sensible treatment plans that would otherwise require a large amount of manual trial and error of a planner. The proposed technique enables us to harness a commercial TPS by application programming via the use of recorded human computer interactions and provides an effective tool to greatly facilitate the treatment planning process. © 2016 The Authors.

Application programming in C# environment with recorded user software interactions and its application in autopilot of VMAT/IMRT treatment planning

PubMed Central

Wang, Henry

2016-01-01

An autopilot scheme of volumetric‐modulated arc therapy (VMAT)/intensity‐modulated radiation therapy (IMRT) planning with the guidance of prior knowledge is established with recorded interactions between a planner and a commercial treatment planning system (TPS). Microsoft (MS) Visual Studio Coded UI is applied to record some common planner‐TPS interactions as subroutines. The TPS used in this study is a Windows‐based Eclipse system. The interactions of our application program with Eclipse TPS are realized through a series of subroutines obtained by prerecording the mouse clicks or keyboard strokes of a planner in operating the TPS. A strategy to autopilot Eclipse VMAT/IMRT plan selection process is developed as a specific example of the proposed “scripting” method. The autopiloted planning is navigated by a decision function constructed with a reference plan that has the same prescription and similar anatomy with the case at hand. The calculation proceeds by alternating between the Eclipse optimization and the outer‐loop optimization independent of the Eclipse. In the C# program, the dosimetric characteristics of a reference treatment plan are used to assess and modify the Eclipse planning parameters and to guide the search for a clinically sensible treatment plan. The approach is applied to plan a head and neck (HN) VMAT case and a prostate IMRT case. Our study demonstrated the feasibility of application programming method in C# environment with recorded interactions of planner‐TPS. The process mimics a planner's planning process and automatically provides clinically sensible treatment plans that would otherwise require a large amount of manual trial and error of a planner. The proposed technique enables us to harness a commercial TPS by application programming via the use of recorded human computer interactions and provides an effective tool to greatly facilitate the treatment planning process. PACS number(s): 87.55.D‐, 87.55.kd, 87.55.de PMID:27929493

Analysis of Free Amino Acids in Different Extracts of Orthosiphon stamineus Leaves by High-Performance Liquid Chromatography Combined with Solid-Phase Extraction

PubMed Central

Shafaei, Armaghan; Halim, Nor Hidayah Ab; Zakaria, Norhidayah; Ismail, Zhari

2017-01-01

Background: Orthosiphon stamineus (OS) Benth is a medicinal plant and native in Southeast Asia. Previous studies have shown that OS leaves possess antioxidant, cytotoxic, diuretic, antihypertensive, and uricosuric effects. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids, and flavonoids. Objective: To develop and validate an high-performance liquid chromatography (HPLC)-diode array detector (DAD) method combined with solid-phase extraction that involves precolumn derivatization with O-phthaladehyde for simultaneous analysis of free amino acids in OS leaves extracts. Materials and Methods: OS leaves were extracted with water (OS-W), ethanol (OS-E), methanol (OS-M), 50% ethanol (OS-EW), and 50% methanol (OS-MW). The extracts were treated by C18 cartridge before derivatization, resulting in great improvement of separation by Zorbox Eclipse XDB-C18 column. Results: The HPLC–DAD method was successfully developed and validated for analyzing the contents of free amino acids in OS extracts. The results showed that l-aspartic acid with 0.93 ± 0.01 nmol/mg was the major free amino acid in OS-W extract. However, in OS-E, OS-M, OS-EW, and OS-MW, l-glutamic acid with 3.53 ± 0.16, 2.17 ± 0.10, 4.01 ± 0.12, and 2.49 ± 0.12 nmol/mg, respectively, was the major free amino acid. Subsequently, l-serine, which was detected in OS-W, OS-E, and OS-M, was the minor free amino acid with 0.33 ± 0.02, 0.12 ± 0.01, and 0.06 ± 0.01 nmol/mg, respectively. However, l-threonine with 0.26 ± 0.02 and 0.19 ± 0.08 nmol/mL in OS-EW and OS-MW, respectively, had the lowest concentration compared with other amino acid components. Conclusion: All validation parameters of the developed method indicate that the method is reliable and efficient to simultaneously determine the free amino acids content for routine analysis of OS extracts. SUMMARY The HPLC-DAD method combined with solid phase extraction was successfully developed and validated for simultaneous determination and quantification of 17 free amino acids in Orthosiphon stamineus (OS) Benth extractsOS extracts were found to be rich in free amino acid contentL-aspartic acid was the major free amino acid in OS water extract while, in OS ethanol, methanol, 50% ethanol and 50% methanol extracts, L-glutamic acid was the major free amino acidL-serine was the minor free amino acid in OS water, ethanol and methanol extracts while, in OS 50% ethanol and 50% methanol extracts, L-threonine had the lowest concentration compared to other amino acid components. Abbreviations used: HPLC-DAD: High-Performance Liquid Chromatography with Diode-Array Detection, OS: Orthosiphon stamineus, OS-W: Orthosiphon stamineus water extract, OS-E: Orthosiphon stamineus ethanol extract, OS-M: Orthosiphon stamineus methanol extract, OS-EW: Orthosiphon stamineus 50% ethanol extract, OS-MW: Orthosiphon stamineus 50% methanol extract, OPA: O-phthaladehyde, SPE: Solid Phase Extraction, UV: Ultraviolet, LOD: Limit of Detection, LOQ: Limit of Quantification, RSD: Relative Standard Deviation. PMID:29142388

Performance study of aluminum shielded room for ultra-low-field magnetic resonance imaging based on SQUID: Simulations and experiments

NASA Astrophysics Data System (ADS)

Li, Bo; Dong, Hui; Huang, Xiao-Lei; Qiu, Yang; Tao, Quan; Zhu, Jian-Ming

2018-02-01

Not Available Project supported in part by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB04020200) and in part by the National Natural Science Foundation of China (Grant No. 11204339).

Superconductivity in Undoped CaFe2As2 Single Crystals

NASA Astrophysics Data System (ADS)

Dong-Yun, Chen; Jia, Yu; Bin-Bin, Ruan; Qi, Guo; Lei, Zhang; Qing-Ge, Mu; Xiao-Chuan, Wang; Bo-Jin, Pan; Gen-Fu, Chen; Zhi-An, Ren

2016-06-01

Not Available Supported by the National Natural Science Foundation of China under Grant No 11474339, the National Basic Research Program of China under Grant Nos 2010CB923000 and 2011CBA00100, and the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB07020100.

GNSS Observations of Ionospheric Variations During the 21 August 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Coster, Anthea J.; Goncharenko, Larisa; Zhang, Shun-Rong; Erickson, Philip J.; Rideout, William; Vierinen, Juha

2017-12-01

On 21 August 2017, during daytime hours, a total solar eclipse with a narrow ˜160 km wide umbral shadow occurred across the continental United States. Totality was observed from the Oregon coast at ˜9:15 local standard time (LST) (17:20 UT) to the South Carolina coast at ˜13:27 LST (18:47 UT). A dense network of Global Navigation Satellite Systems (GNSS) receivers was utilized to produce total electron content (TEC) and differential TEC. These data were analyzed for the latitudinal and longitudinal response of the TEC and for the presence of traveling ionospheric disturbances (TIDs) during eclipse passage. A significant TEC depletion, in some cases greater than 60%, was observed associated with the eclipse shadow, exceeding initial model predictions of 35%. Evidence of enhanced large-scale TID activity was detected over the United States prior to and following the large TEC depletion observed near the time of totality. Signatures of enhanced TEC structures were observed over the Rocky Mountain chain during the main period of TEC depletion.

Transits in our Solar System for educational activities: Mercury Transit 2016 and Total Solar Eclipse 2017

NASA Astrophysics Data System (ADS)

Pérez-Ayúcar, M.; Breitfelner, M.

2017-09-01

Solar transits are rare astronomical event of profound historical importance and with an enormous potential to engage nowadays students and general public into Planetary Sciences and Space. Mercury transits occur only about every 13-14 times per century. Total solar eclipses occur around 18 months apart somewhere on Earth, but they recur only every 3-4 centuries on the same location. Although its historic scientific importance (examples, to measure the distances in the solar system, to observe the solar corona) has diminished since humanity roams our solar system with robotic spacecrafts, transits remain a spectacular astronomical event that is used very effectively to engage general public and students to Science and Space in general. The educational project CESAR (Cooperation through Education in Science and Astronomy Research) has been covering since 2012 such events (Venus transit 2012, live Sun transmissions, solar eclipses, ISS transits ...). We report the outstanding outcome of the two public educational and outreach events since last year: the May 2016 Mercury Transit, and the recent August 2017 Total Eclipse. And the follow up activities expected for future transits.

The apsidal motion of the eccentric eclipsing binary DI Herculis - An apparent discrepancy with general relativity

NASA Technical Reports Server (NTRS)

Guinan, E. F.; Maloney, F. P.

1985-01-01

The apsidal motion of the eccentric eclipsing binary DI Herculis (HD 175227) is determined from an analysis of the available observations and eclipse timings from 1959 to 1984. Least squares solutions to the primary and secondary minima extending over an 84-yr interval yielded a small advance of periastron omega dot of 0.65 deg/100 yr + or - 0.18/100 yr. The observed advance of the periastron is about one seventh of the theoretical value of 4.27 deg/100 yr that is expected from the combined relativistic and classical effects. The discrepancy is about -3.62 deg/100 yr, or a magnitude of about 20 sigma. Classical mechanisms which explain the discrepancy are discussed, together with the possibility that there may be problems with general relativity itself.

UPLC-MS method for quantification of pterostilbene and its application to comparative study of bioavailability and tissue distribution in normal and Lewis lung carcinoma bearing mice.

PubMed

Deng, Li; Li, Yongzhi; Zhang, Xinshi; Chen, Bo; Deng, Yulin; Li, Yujuan

2015-10-10

A UPLC-MS method was developed for determination of pterostilbene (PTS) in plasma and tissues of mice. PTS was separated on Agilent Zorbax XDB-C18 column (50 × 2.1 mm, 1.8 μm) with gradient mobile phase at the flow rate of 0.2 ml/min. The detection was performed by negative ion electrospray ionization in multiple reaction monitoring mode. The linear calibration curve of PTS in mouse plasma and tissues ranged from 1.0 to 5000 and 0.50 to 500 ng/ml (r(2)>0.9979), respectively, with lowest limits of quantification (LLOQ) were between 0.5 and 2.0 ng/ml, respectively. The accuracy and precision of the assay were satisfactory. The validated method was applied to the study of bioavailability and tissue distribution of PTS in normal and Lewis lung carcinoma (LLC) bearing mice. The bioavailability of PTS (dose 14, 28 and 56 mg/kg) in normal mice were 11.9%, 13.9% and 26.4%, respectively; and the maximum level (82.1 ± 14.2 μg/g) was found in stomach (dose 28 mg/kg). The bioavailability, peak concentration (Cmax), time to peak concentration (Tmax) of PTS in LLC mice was increased compared with normal mice. The results indicated the UPLC-MS method is reliable and bioavailability and tissue distribution of PTS in normal and LLC mice were dramatically different. Copyright © 2015 Elsevier B.V. All rights reserved.

Improving spot-scanning proton therapy patient specific quality assurance with HPlusQA, a second-check dose calculation engine.

PubMed

Mackin, Dennis; Li, Yupeng; Taylor, Michael B; Kerr, Matthew; Holmes, Charles; Sahoo, Narayan; Poenisch, Falk; Li, Heng; Lii, Jim; Amos, Richard; Wu, Richard; Suzuki, Kazumichi; Gillin, Michael T; Zhu, X Ronald; Zhang, Xiaodong

2013-12-01

The purpose of this study was to validate the use of HPlusQA, spot-scanning proton therapy (SSPT) dose calculation software developed at The University of Texas MD Anderson Cancer Center, as second-check dose calculation software for patient-specific quality assurance (PSQA). The authors also showed how HPlusQA can be used within the current PSQA framework. The authors compared the dose calculations of HPlusQA and the Eclipse treatment planning system with 106 planar dose measurements made as part of PSQA. To determine the relative performance and the degree of correlation between HPlusQA and Eclipse, the authors compared calculated with measured point doses. Then, to determine how well HPlusQA can predict when the comparisons between Eclipse calculations and the measured dose will exceed tolerance levels, the authors compared gamma index scores for HPlusQA versus Eclipse with those of measured doses versus Eclipse. The authors introduce the αβγ transformation as a way to more easily compare gamma scores. The authors compared measured and calculated dose planes using the relative depth, z∕R × 100%, where z is the depth of the measurement and R is the proton beam range. For relative depths than less than 80%, both Eclipse and HPlusQA calculations were within 2 cGy of dose measurements on average. When the relative depth was greater than 80%, the agreement between the calculations and measurements fell to 4 cGy. For relative depths less than 10%, the Eclipse and HPlusQA dose discrepancies showed a negative correlation, -0.21. Otherwise, the correlation between the dose discrepancies was positive and as large as 0.6. For the dose planes in this study, HPlusQA correctly predicted when Eclipse had and had not calculated the dose to within tolerance 92% and 79% of the time, respectively. In 4 of 106 cases, HPlusQA failed to predict when the comparison between measurement and Eclipse's calculation had exceeded the tolerance levels of 3% for dose and 3 mm for distance-to-agreement. The authors found HPlusQA to be reasonably effective (79% ± 10%) in determining when the comparison between measured dose planes and the dose planes calculated by the Eclipse treatment planning system had exceeded the acceptable tolerance levels. When used as described in this study, HPlusQA can reduce the need for patient specific quality assurance measurements by 64%. The authors believe that the use of HPlusQA as a dose calculation second check can increase the efficiency and effectiveness of the QA process.

Observations of the eclipsing binary b Persei

NASA Astrophysics Data System (ADS)

Templeton, Matthew R.

2015-01-01

Dr. Robert Zavala (USNO-Flagstaff) et al. request V time-series observations of the bright variable star b Persei 7-21 January 2015 UT, in hopes of catching a predicted eclipse on January 15. This is a follow-up to the February 2013 campaign announced in Alert Notice 476, and will be used as a photometric comparison for upcoming interferometric observations with the Navy Precision Optical Interferometer (NPOI) in Arizona. b Per (V=4.598, B-V=0.054) is ideal for photoelectric photometers or DSLR cameras. Telescopic CCD observers may observe by stopping down larger apertures. Comparison and check stars assigned by PI: Comp: SAO 24412, V=4.285, B-V = -0.013; Check: SAO 24512, V=5.19, B-V = -0.05. From the PI: "[W]e wanted to try and involve AAVSO observers in a follow up to our successful detection of the b Persei eclipse of Feb 2013, AAVSO Alert Notice 476 and Special Notice 333. Our goal now is to get good time resolution photometry as the third star passes in front of the close ellipsoidal binary. The potential for multiple eclipses exists. The close binary has a 1.5 day orbital period, and the eclipsing C component requires about 4 days to pass across the close binary pair. The primary eclipse depth is 0.15 magnitude. Photometry to 0.02 or 0.03 mags would be fine to detect this eclipse. Eclipse prediction date (JD 2457033.79 = 2015 01 11 UT, ~+/- 1 day) is based on one orbital period from the 2013 eclipse." More information is available at PI's b Persei eclipse web page: http://inside.warren-wilson.edu/~dcollins/bPersei/. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and information on the targets.

F-106 tow cable attachment and release mechanism for Eclipse program

NASA Technical Reports Server (NTRS)

1997-01-01

View of the tow cable attachment and release mechanism forward of the cockpit on the QF-106 Eclipse aircraft. This mechanism held and then released the Vectran rope used to tow the QF-106 behind an Air Force C-141A. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

Closeup of QF-106 release hook for Eclipse program

NASA Technical Reports Server (NTRS)

1997-01-01

View of the release hook on the QF-106 that allowed the pilot to release the tow rope extending from the C-141A tow plane in the Eclipse project. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

Period Study and Analyses of 2017 Observations of the Totally Eclipsing, Solar Type Binary, MT Camelopardalis

NASA Astrophysics Data System (ADS)

Faulkner, Danny R.; Samec, Ronald G.; Caton, Daniel B.

2018-06-01

We report here on a period study and the analysis of BVRcIc light curves (taken in 2017) of MT Cam (GSC03737-01085), which is a solar type (T ~ 5500K) eclipsing binary. D. Caton observed MT Cam on 05, 14, 15, 16, and 17, December 2017 with the 0.81-m reflector at Dark Sky Observatory. Six times of minimum light were calculated from four primary eclipses and two secondary eclipses:HJD I = 24 58092.4937±0.0002, 2458102.74600±0.0021, 2458104.5769±0.0002, 2458104.9434±0.0029HJD II = 2458103.6610±0.0001, 2458104.7607±0.0020,Six times of minimum light were also calculated from data taken by Terrell, Gross, and Cooney, in their 2016 and 2004 observations (reported in IBVS #6166; TGC, hereafter). In addition, six more times of minimum light were taken from the literature. From all 18 times of minimum light, we determined the following light elements:JD Hel Min I=2458102.7460(4) + 0.36613937(5) EWe found the orbital period was constant over the 14 years spanning all observations. We note that TGC found a slightly increasing period. However, our results were obtained from a period study rather than comparison of observations from only two epochs by the Wilson-Devinney (W-D) Program. A BVRcIc Johnson-Cousins filtered simultaneous W-D Program solution gives a mass ratio (0.3385±0.0014) very nearly the same as TGC’s (0.347±0.003), and a component temperature difference of only ~40 K. As with TGC, no spot was needed in the modeling. Our modeling (beginning with Binary Maker 3.0 fits) was done without prior knowledge of TGC’s. This shows the agreement achieved when independent analyses are done with the W-D code. The present observations were taken 1.8 years later than the last curves by TGC, so some variation is expected.The Roche Lobe fill-out of the binary is ~13% and the inclination is ~83.5 degrees. The system is a shallow contact W-type W UMa Binary, albeit, the amplitudes of the primary and secondary eclipse are very nearly identical. An eclipse duration of ~21 minutes was determined for the secondary eclipse and the light curve solution. Additional and more detailed information is given in the poster paper.

Modeling the temperature-dependent peptide vibrational spectra based on implicit-solvent model and enhance sampling technique

NASA Astrophysics Data System (ADS)

Tianmin, Wu; Tianjun, Wang; Xian, Chen; Bin, Fang; Ruiting, Zhang; Wei, Zhuang

2016-01-01

We herein review our studies on simulating the thermal unfolding Fourier transform infrared and two-dimensional infrared spectra of peptides. The peptide-water configuration ensembles, required forspectrum modeling, aregenerated at a series of temperatures using the GBOBC implicit solvent model and the integrated tempering sampling technique. The fluctuating vibrational Hamiltonians of the amide I vibrational band are constructed using the Frenkel exciton model. The signals are calculated using nonlinear exciton propagation. The simulated spectral features such as the intensity and ellipticity are consistent with the experimental observations. Comparing the signals for two beta-hairpin polypeptides with similar structures suggests that this technique is sensitive to peptide folding landscapes. Project supported by the National Natural Science Foundation of China (Grant No. 21203178), the National Natural Science Foundation of China (Grant No. 21373201), the National Natural Science Foundation of China (Grant No. 21433014), the Science and Technological Ministry of China (Grant No. 2011YQ09000505), and “Strategic Priority Research Program” of the Chinese Academy of Sciences (Grant Nos. XDB10040304 and XDB100202002).

Extrasolar planet detection by binary stellar eclipse timing: evidence for a third body around CM Draconis

NASA Astrophysics Data System (ADS)

Deeg, H. J.; Ocaña, B.; Kozhevnikov, V. P.; Charbonneau, D.; O'Donovan, F. T.; Doyle, L. R.

2008-03-01

Aims:Our objective is to elucidate the physical process that causes the observed observed-minus-calculated (O-C) behavior in the M4.5/M4.5 binary CM Dra and to test for any evidence of a third body around the CM Dra system. Methods: New eclipse minimum timings of CM Dra were obtained between the years 2000 and 2007. The O-C times of the system are fitted against several functions, representing different physical origins of the timing variations. Results: Using our observational data in conjunction with published timings going back to 1977, a clear non-linearity in O-C times is apparent. An analysis using model-selection statistics gives about equal weight to a parabolic and to a sinusoidal fitting function. Attraction from a third body, either at large distance in a quasi-constant constellation across the years of observations or from a body on a shorter orbit generating periodicities in O-C times is the most likely source of the observed O-C times. The white dwarf GJ 630.1B, a proper motion companion of CM Dra, can however be rejected as the responsible third body. Also, no further evidence of the short-periodic planet candidate described by Deeg et al. (2000, A&A, 358, L5) is found, whereas other mechanisms, such as period changes from stellar winds or Applegate's mechanism can be rejected. Conclusions: A third body, being either a few-Jupiter-mass object with a period of 18.5 ± 4.5 years or an object in the mass range of 1.5 M_jup to 0.1 M⊙ with periods of hundreds to thousands of years is the most likely origin of the observed minimum timing behavior.

The Evolution of NR TrA (Nova TrA 2008) from 2008 through 2017

NASA Astrophysics Data System (ADS)

Walter, Frederick M.; Burwitz, Vadim; Kafka, Stella

2018-06-01

The classical nova NR TrA was discovered as an O-type optically-thick classical nova. There is no evidence that it formed dust. Within four years the envelope became sufficiently thin to reveal an eclipsing accretion disk-dominated system with orbitally-modulated permitted lines of C IV, N V, and O VI. XMM observations reveal a non-eclipsing soft X-ray source and a deeply-eclipsing UV continuum. We will present the first ten years of optical spectral evolution of this system accompanied by ten years of BVRIJHK photometry, with an eye to deciphering the current nature of the system.

McDonald 2.1-m and CRTS Photometry of Eclipsing Polars

NASA Astrophysics Data System (ADS)

Wells, Natalie; Mason, Paul

2018-01-01

We present broadband optical photometry of five polars made using the 2.1-m telescope of McDonald Observatory. Four of the polars are eclipsing (EP Dra, FL Cet, V2301 Oph, and a Catalina Sky Survey (CSS) polar candidate). In addition, a pre-polar (MQ Dra) was observed. Typical integration times were 1-3 seconds with no dead time. At this time resolution, eclipse structure can be seen in both one- and two-pole accretors. McDonald 2.1-m data over several years is phased together with CSS photometry covering up to 7 years, in search of indications of period variation. Combining the high-resolution, high-speed photometry obtained using the ProEm camera on the McDonald 2.1-m with the sparse, but high-quality multi-year baseline photometry of the CSS places strong constraints on the time variability of the eclipse periods in these binary systems. In most cases, eclipse variations do not perfectly fit a linear ephemeris. We investigate the source of variations using standard O-C diagram techniques and period search algorithms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barlow, Brad N.; Wade, Richard A.; Liss, Sandra E.

The eclipsing binary system 2M 1938+4603 consists of a pulsating hot subdwarf B star and a cool M dwarf companion in an effectively circular three-hour orbit. The light curve shows both primary and secondary eclipses, along with a strong reflection effect from the cool companion. Here, we present constraints on the component masses and eccentricity derived from the Romer delay of the secondary eclipse. Using six months of publicly available Kepler photometry obtained in short-cadence mode, we fit model profiles to the primary and secondary eclipses to measure their centroid values. We find that the secondary eclipse arrives on averagemore » 2.06 {+-} 0.12 s after the midpoint between primary eclipses. Under the assumption of a circular orbit, we calculate from this time delay a mass ratio of q = 0.2691 {+-} 0.0018 and individual masses of M{sub sd} = 0.372 {+-} 0.024 M{sub Sun} and M{sub c} = 0.1002 {+-} 0.0065 M{sub Sun} for the sdB and M dwarf, respectively. These results differ slightly from those of a previously published light-curve modeling solution; this difference, however, may be reconciled with a very small eccentricity, ecos {omega} Almost-Equal-To 0.00004. We also report a decrease in the orbital period of P-dot = (-1.23 {+-} 0.07) Multiplication-Sign 10{sup -10}.« less

1,1′-Bis[bis­(4-meth­oxy­phen­yl)phosphan­yl]ferrocene

PubMed Central

Ren, Xinfeng; Wang, Le; Li, Ya

2012-01-01

In the crystal structure of the title substituted ferrocene complex, [Fe(C19H18O2P)2], the FeII atom lies on a twofold rotation axis, giving an eclipsed cyclo­penta­dienyl conformation with a ring centroid separation of 3.292 (7) Å and an Fe—C bond-length range of 2.0239 (15)–2.0521 (15) Å. In the ligand, the cyclo­penta­dienyl ring forms dihedral angles of 60.36 (6) and 82.93 (6)° with the two benzene rings of the diphenyl­phosphine group, while the dihedral angle between the benzene rings is 67.4 (5)°. PMID:22807756

Analysis of the monosaccharide composition of water-soluble polysaccharides from Sargassum fusiforme by high performance liquid chromatography/electrospray ionisation mass spectrometry.

PubMed

Wu, Xiaodan; Jiang, Wei; Lu, Jiajia; Yu, Ying; Wu, Bin

2014-02-15

Sargassum fusiforme (hijiki) is the well-known edible algae, whose polysaccharides have been proved to possess interesting bioactivities like antitumor, antioxidant, antimicrobial and immunomodulatory activities. A facile and sensitive method based on high-performance liquid chromatography method of pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone (PMP) coupled with electrospray ionisation mass spectrometry (HPLC/ESI-MS) has been established for the analysis of the monosaccharide composition of polysaccharides in S. fusiforme. Monosaccharides have been converted into PMP-labelled derivatives with aqueous ammonia as a catalyst at 70 °C for 30 min. The optimisation of the pre-column derivatization process was studied. The LODs of the monosaccharides were in the range from 0.01 to 0.02 nmol. PMP-labelled mixture of monosaccharides has been well separated by a reverse-phase HPLC and detected by on-line ESI-MS method under optimised conditions. The mobile phase of elution system was chosen as acetonitrile (solvent A) and 20mM aqueous ammonium acetate (solvent B) (pH 3.0) with Zorbax XDB-C18 column at 30 °C for the separation of the monosaccharide derivatives. Identification of the monosaccharides composition was carried out by analysis with mass spectral behaviour and chromatography characteristics of 1-phenyl-3-methyl-5-pyrazolone (PMP) labelled monosaccharides. All PMP-labelled derivatives display high chemical stabilities, whose regular MS fragmentation is specific for reducing labelled sugars. The result showed that the S. fusiforme polysaccharide consisted of mannose, glucose, galactose, xylose, fucose and glucuronic acid or galacturonic acid, or both uronic acids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Meteorological responses in the atmospheric boundary layer over southern England to the deep partial eclipse of 20 March 2015.

PubMed

Burt, Stephen

2016-09-28

A wide range of surface and near-surface meteorological observations were made at the University of Reading's Atmospheric Observatory in central southern England (latitude 51.441° N, longitude 0.938° W, altitude 66 m above mean sea level) during the deep partial eclipse on the morning of 20 March 2015. Observations of temperature, humidity, radiation, wind speed and direction, and atmospheric pressure were made by computerized logging equipment at 1 Hz, supplemented by an automated cloud base recorder sampling at 1 min intervals and a high-resolution (approx. 10 m vertical interval) atmospheric sounding by radiosonde launched from the same location during the eclipse. Sources and details of each instrumental measurement are described briefly, followed by a summary of observed and derived measurements by meteorological parameter. Atmospheric boundary layer responses to the solar eclipse were muted owing to the heavily overcast conditions which prevailed at the observing location, but instrumental records of the event documented a large (approx. 80%) reduction in global solar radiation, a fall in air temperature of around 0.6°C, a decrease in cloud base height, and a slight increase in atmospheric stability during the eclipse. Changes in surface atmospheric moisture content and barometric pressure were largely insignificant during the event.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

Ionospheric response to the total solar eclipse in India on 22 July, 2009

NASA Astrophysics Data System (ADS)

Chauhan, Vishal; Agrawal, Shikha; Singh, O. P.; Singh, Birbal

2010-10-01

Since The variations of Total Electron Content (TEC) and amplitude of the fixed frequency VLF transmitter signal (f = 19.8 kHz, NWC, Australia) are studied at Agra (Geographic Lat. 27.2°N, Long. 78°E), India during the total solar eclipse of 22 July, 2009 which was longest seen in India ever since 18 August, 1968. The equipment used for the study are a dual frequency GPS receiver (GSV 4004V) and a Soft PAL (Software based phase and amplitude logger) receiver. The data for a period of fifteen days (+/-7 days from the date of the event) are analysed and it is found that the TEC decreased by about 30% from normal days during the total solar eclipse, and the amplitude of the VLF signal also decreased likewise. The period of the data analysis is characterised by a low level of geomagnetic activity, hence the decrease in TEC and amplitude of the VLF signal is unlikely to be influenced by geomagnetic disturbances. The results are interpreted in terms of depression in electron densities at all ionospheric heights and are consistent with those obtained by earlier workers during similar eclipse events.

Modeling of sub-ionospheric VLF signal perturbations associated with total solar eclipse, 2009 in Indian subcontinent

NASA Astrophysics Data System (ADS)

Pal, Sujay; Chakrabarti, Sandip K.; Mondal, Sushanta K.

2012-07-01

During the total solar eclipse of 2009, a week-long campaign was conducted in the Indian sub-continent to study the low-latitude D-region ionosphere using the very low frequency (VLF) signal from the Indian Navy transmitter (call sign: VTX3) operating at 18.2 kHz. It was observed that in several places, the signal amplitude is enhanced while in other places the amplitude is reduced. We simulated the observational results using the well known Long Wavelength Propagation Capability (LWPC) code. As a first order approximation, the ionospheric parameters were assumed to vary according to the degree of solar obscuration on the way to the receivers. This automatically brought in non-uniformity of the ionospheric parameters along the propagation paths. We find that an assumption of 4 km increase of lower ionospheric height for places going through totality in the propagation path simulate the observations very well at Kathmandu and Raiganj. We find an increase of the height parameter by h'=+3.0 km for the VTX-Malda path and h'=+1.8 km for the VTX-Kolkata path. We also present, as an example, the altitude variation of electron number density throughout the eclipse time at Raiganj.

Improving spot-scanning proton therapy patient specific quality assurance with HPlusQA, a second-check dose calculation engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackin, Dennis; Li, Yupeng; Taylor, Michael B.

Purpose: The purpose of this study was to validate the use of HPlusQA, spot-scanning proton therapy (SSPT) dose calculation software developed at The University of Texas MD Anderson Cancer Center, as second-check dose calculation software for patient-specific quality assurance (PSQA). The authors also showed how HPlusQA can be used within the current PSQA framework.Methods: The authors compared the dose calculations of HPlusQA and the Eclipse treatment planning system with 106 planar dose measurements made as part of PSQA. To determine the relative performance and the degree of correlation between HPlusQA and Eclipse, the authors compared calculated with measured point doses.more » Then, to determine how well HPlusQA can predict when the comparisons between Eclipse calculations and the measured dose will exceed tolerance levels, the authors compared gamma index scores for HPlusQA versus Eclipse with those of measured doses versus Eclipse. The authors introduce the αβγ transformation as a way to more easily compare gamma scores.Results: The authors compared measured and calculated dose planes using the relative depth, z/R × 100%, where z is the depth of the measurement and R is the proton beam range. For relative depths than less than 80%, both Eclipse and HPlusQA calculations were within 2 cGy of dose measurements on average. When the relative depth was greater than 80%, the agreement between the calculations and measurements fell to 4 cGy. For relative depths less than 10%, the Eclipse and HPlusQA dose discrepancies showed a negative correlation, −0.21. Otherwise, the correlation between the dose discrepancies was positive and as large as 0.6. For the dose planes in this study, HPlusQA correctly predicted when Eclipse had and had not calculated the dose to within tolerance 92% and 79% of the time, respectively. In 4 of 106 cases, HPlusQA failed to predict when the comparison between measurement and Eclipse's calculation had exceeded the tolerance levels of 3% for dose and 3 mm for distance-to-agreement.Conclusions: The authors found HPlusQA to be reasonably effective (79%± 10%) in determining when the comparison between measured dose planes and the dose planes calculated by the Eclipse treatment planning system had exceeded the acceptable tolerance levels. When used as described in this study, HPlusQA can reduce the need for patient specific quality assurance measurements by 64%. The authors believe that the use of HPlusQA as a dose calculation second check can increase the efficiency and effectiveness of the QA process.« less

Disease Staging and Prognosis in Smokers Using Deep Learning in Chest Computed Tomography.

PubMed

González, Germán; Ash, Samuel Y; Vegas-Sánchez-Ferrero, Gonzalo; Onieva Onieva, Jorge; Rahaghi, Farbod N; Ross, James C; Díaz, Alejandro; San José Estépar, Raúl; Washko, George R

2018-01-15

Deep learning is a powerful tool that may allow for improved outcome prediction. To determine if deep learning, specifically convolutional neural network (CNN) analysis, could detect and stage chronic obstructive pulmonary disease (COPD) and predict acute respiratory disease (ARD) events and mortality in smokers. A CNN was trained using computed tomography scans from 7,983 COPDGene participants and evaluated using 1,000 nonoverlapping COPDGene participants and 1,672 ECLIPSE participants. Logistic regression (C statistic and the Hosmer-Lemeshow test) was used to assess COPD diagnosis and ARD prediction. Cox regression (C index and the Greenwood-Nam-D'Agnostino test) was used to assess mortality. In COPDGene, the C statistic for the detection of COPD was 0.856. A total of 51.1% of participants in COPDGene were accurately staged and 74.95% were within one stage. In ECLIPSE, 29.4% were accurately staged and 74.6% were within one stage. In COPDGene and ECLIPSE, the C statistics for ARD events were 0.64 and 0.55, respectively, and the Hosmer-Lemeshow P values were 0.502 and 0.380, respectively, suggesting no evidence of poor calibration. In COPDGene and ECLIPSE, CNN predicted mortality with fair discrimination (C indices, 0.72 and 0.60, respectively), and without evidence of poor calibration (Greenwood-Nam-D'Agnostino P values, 0.307 and 0.331, respectively). A deep-learning approach that uses only computed tomography imaging data can identify those smokers who have COPD and predict who are most likely to have ARD events and those with the highest mortality. At a population level CNN analysis may be a powerful tool for risk assessment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herrington, J; Price, M; Brindle, J

Purpose: To evaluate the equivalence of spine SBRT treatment plans created in Eclipse for the TrueBeam STx (Varian Medical System, Palo Alto, CA) compared to plans using CyberKnife and MultiPlan (Accuray, Sunnyvale, CA). Methods: CT data and contours for 23 spine SBRT patients previously treated using CyberKnife (CK) were exported from MultiPlan treatment planning system into Eclipse where they were planned using static IMRT 6MV coplanar beams. Plans were created according to the original prescription dose and fractionation schedule while limiting spinal dose according to the RTOG 0631 protocol and maintaining target coverage comparable to the original CK plans. Plansmore » were evaluated using new conformity index (nCI), homogeneity index (HI), dose-volume histogram data, number of MU, and estimated treatment time. To ensure all Eclipse plans were deliverable, standard clinical IMRT QA was performed. The plan results were matched with their complimentary CK plans for paired statistical analysis. Results: Plans generated in Eclipse demonstrated statistically significant (p<0.01) improvements compared to complimentary CK plans in median values of maximum spinal cord dose (17.39 vs. 18.12 Gy), RTOG spinal cord constraint dose (14.50 vs. 16.93 Gy), nCI (1.28 vs. 1.54), HI (1.13 vs. 1.27), MU (3918 vs. 36416), and estimated treatment time (8 vs. 48 min). All Eclipse generated plans passed our clinically used protocols for IMRT QA. Conclusion: CK spine SBRT replanned utilizing Eclipse for LINAC delivery demonstrated dosimetric advantages. We propose improvements in plan quality metrics reviewed in this study may be attributed to dynamic MLCs that facilitate treatment of complicated geometries as well as posterior beams ideal for centrally located and/or posterior targets afforded by gantry-based RT delivery.« less

Magnetocaloric effect in the layered organic-inorganic hybrid (CH3NH3)2CuCl4

NASA Astrophysics Data System (ADS)

Ma, Yinina; Zhai, Kun; Yan, Liqin; Chai, Yisheng; Shang, Dashan; Sun, Young

2018-02-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 51371193 and 11534015), the Youth Innovation Promotion of the Chinese Academy of Sciences (Grant No. 2013004), and the Science Fund from the Chinese Academy of Sciences (Grant Nos. XDB07030200 and KJZD-EW-M05).

Fabrication and characterization of ultra-low noise narrow and wide band Josephson parametric amplifiers

NASA Astrophysics Data System (ADS)

Huang, Keqiang; Guo, Qiujiang; Song, Chao; Zheng, Yarui; Deng, Hui; Wu, Yulin; Jin, Yirong; Zhu, Xiaobo; Zheng, Dongning

2017-08-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 91321208, 11374344, 11404386, 11574380, and 11674376), the Ministry of Science and Technology of China (Grant Nos. 2014CB921401 and 2016YFA0300601), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB07010300).

Nonlinear spectral cleaning effect in cross-polarized wave generation

NASA Astrophysics Data System (ADS)

Yu, Linpeng; Xu, Yi; Wu, Fenxiang; Yang, Xiaojun; Zhang, Zongxin; Wu, Yuanfeng; Leng, Yuxin; Xu, Zhizhan

2018-05-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 11127901, 61521093, and 61505234), the International S&T Cooperation of Program of China (Grant No. 2016YFE0119300), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB160301), and the Youth Innovation Promotion Association, Chinese Academy of Sciences.

31P Nuclear Magnetic Resonance of Charge-Density-Wave Transition in a Single Crystal of RuP

NASA Astrophysics Data System (ADS)

Fan, Guo-Zhi; Chen, Rong-Yan; Wang, Nan-Lin; Luo, Jian-Lin

2015-07-01

Not Available Supported by the National Natural Science Foundation of China under Grant No 11025422, the National Basic Research Program of China under Grant Nos 2011CB921700 and 2015CB921300, and the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB07020200.

Period changes of cataclysmic variables below the period gap: V2051 Oph, OY Car and Z Cha

NASA Astrophysics Data System (ADS)

Pilarčík, L.; Wolf, M.; Zasche, P.; Vraštil, J.

2018-04-01

We present our results of a long-term monitoring of cataclysmic variable stars (CVs). About 40 new eclipses were measured for the three southern SU UMa-type eclipsing CVs: V2051 Oph, OY Car and Z Cha. Based on the current O - C diagrams we confirmed earlier findings that V2051 Oph and OY Car present cyclic changes of their orbital periods lasting 25 and 29 years, respectively. In case of Z Cha we propose the light-time effect caused probably by a presence of the third component orbiting the eclipsing CV with the period of 43.5 years. The minimal mass of this companion results about 15 MJup.

Eclipsing Binaries From the CSTAR Project at Dome A, Antarctica

NASA Astrophysics Data System (ADS)

Yang, Ming; Zhang, Hui; Wang, Songhu; Zhou, Ji-Lin; Zhou, Xu; Wang, Lingzhi; Wang, Lifan; Wittenmyer, R. A.; Liu, Hui-Gen; Meng, Zeyang; Ashley, M. C. B.; Storey, J. W. V.; Bayliss, D.; Tinney, Chris; Wang, Ying; Wu, Donghong; Liang, Ensi; Yu, Zhouyi; Fan, Zhou; Feng, Long-Long; Gong, Xuefei; Lawrence, J. S.; Liu, Qiang; Luong-Van, D. M.; Ma, Jun; Wu, Zhenyu; Yan, Jun; Yang, Huigen; Yang, Ji; Yuan, Xiangyan; Zhang, Tianmeng; Zhu, Zhenxi; Zou, Hu

2015-04-01

The Chinese Small Telescope ARray (CSTAR) has observed an area around the Celestial South Pole at Dome A since 2008. About 20,000 light curves in the i band were obtained during the observation season lasting from 2008 March to July. The photometric precision achieves about 4 mmag at i = 7.5 and 20 mmag at i = 12 within a 30 s exposure time. These light curves are analyzed using Lomb-Scargle, Phase Dispersion Minimization, and Box Least Squares methods to search for periodic signals. False positives may appear as a variable signature caused by contaminating stars and the observation mode of CSTAR. Therefore, the period and position of each variable candidate are checked to eliminate false positives. Eclipsing binaries are removed by visual inspection, frequency spectrum analysis, and a locally linear embedding technique. We identify 53 eclipsing binaries in the field of view of CSTAR, containing 24 detached binaries, 8 semi-detached binaries, 18 contact binaries, and 3 ellipsoidal variables. To derive the parameters of these binaries, we use the Eclipsing Binaries via Artificial Intelligence method. The primary and secondary eclipse timing variations (ETVs) for semi-detached and contact systems are analyzed. Correlated primary and secondary ETVs confirmed by false alarm tests may indicate an unseen perturbing companion. Through ETV analysis, we identify two triple systems (CSTAR J084612.64-883342.9 and CSTAR J220502.55-895206.7). The orbital parameters of the third body in CSTAR J220502.55-895206.7 are derived using a simple dynamical model.

IUE observations of the atmospheric eclipsing binary system Zeta Aurigae

NASA Technical Reports Server (NTRS)

Champman, R. D.

1980-01-01

IUE observations of the eclipsing binary system Zeta Aurigae made prior to and during the eclipse of the relatively small B8 V star by the cool supergiant star (spectral type K2 II) are reported. Spectral lines produced by the absorption of B star radiation in the atmosphere of the K star during eclipse can be used as a probe of the extended K star atmosphere, due to the negligible cool star continuum in the 1200-3200 A region. Spectra taken prior to eclipse are found to be similar to those of the single B8 V star 64 Ori, with the exception of very strong multi-component absorption lines of Si II, Si IV, C IV and the Mg resonance doublet with strong P Cygni profiles, indicating a double shell. Absorption lines including those corresponding to Al II, Al III, Cr II, Mn II, Fe II, Ni II and Ca II are observed to increase in strength and number as the eclipse progresses, with high-ionization-potential lines formed far from the K star, possibly in a shock wave, and low-ionization potential lines, formed in cool plasma, probably a cool wind, nearer to the K star. Finally, an emission-line spectra with lines corresponding to those previously observed in absorption is noted at the time the B-star continuum had disappeared.

Eclipse program QF-106 aircraft in flight

NASA Technical Reports Server (NTRS)

1997-01-01

This photo shows one of the QF-106s used in the Eclipse project in flight. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

A Detailed Survey of Pulsating Variables in Five Globular Clusters (Abstract)

NASA Astrophysics Data System (ADS)

Murphy, B. W.

2016-12-01

(Abstract only) Globular clusters are ideal laboratories for conducting a stellar census. Of particular interest are pulsating variables, which provide astronomers with a tool to probe the properties of the stars and the cluster. We observed each of five globular clusters hundreds to thousands of times over a time span ranging from 2 to 4 years in B, V, and I filters using the SARA 0.6-meter telescope located at Cerro Tololo Interamerican Observatory and the 0.9-meter telescope located at Kitt Peak, Arizona. The images were analyzed using difference image analysis to identify and produce light curves of all variables found in each cluster. In total we identified 377 variables with 140 of these being newly discovered increasing the number of known variables stars in these clusters by 60%. Of the total we have identified 319 RR Lyrae variables (193 RR0, 18 RR01, 101 RR1, 7 RR2), 9 SX Phe stars, 5 Cepheid variables, 11 eclipsing variables, and 33 long period variables. For IC4499 we identified 64 RR0, 18 RR01, 14 RR1, 4 RR2, 1 SX Phe, 1 eclipsing binary, and 2 long period variables. For NGC4833 we identified 10 RR0, 7 RR1, 3 RR2, 6 SX Phe, 5 eclipsing binaries, and 9 long period variables. For NGC6171 (M107) we identified 14 RR0, 7 RR1, and 1 SX Phe. For NGC6402 (M14) we identified 55 RR0, 57 RR1, 1 RR2, 1 SX Phe, 6 Cepheids, 1 eclipsing binary, and 15 long period variables. For NGC6584 we identified 50 RR0, 16 RR1, 4 eclipsing binaries, and 7 long period variables. From our extensive data set we were able to obtain sufficient temporal and complete phase coverage of the RR Lyrae variables. This has allowed us not only to properly classify each of the RR Lyrae variables but also to use Fourier decomposition of the B, V, and I light curves to further analyze the properties of the variable stars and hence the physical properties of each globular cluster.

Period changes of the sample of eclipsing binaries with active chromospheres

NASA Astrophysics Data System (ADS)

Jableka, D.; Zola, S.; Zakrzewski, B.; Szymanski, T.; Kuzmicz, A.; de Villiers, S. N.; Zejda, M.; Koziel-Wierzbowska, D.

2012-11-01

In this work we present results derived from analysis of the O-C behaviour of ten eclipsing binary systems: AR Lac, CG Cyg, HP Aur, MM Her, RS CVn, RT And, SV Cam, V471 Tau, WW Dra and CF Tuc. It was proved on the basis of moments of minima compiled from the literature and new ones determined from recent observations, that these binaries show long term (19-91 years) modulations of their orbital periods, clearly visible in their O-C diagrams. Two possible explanations for this effect are considered: (1) the light-travel time effect due to the presence of a third body orbiting the eclipsing systems; (2) the Applegate mechanism predicting period modulation by changes in the distribution of angular momentum as a star goes through its activity cycles. It was found that in the case of four systems the existence of a third star, orbiting the binary, is a more plausible explanation of observations.

Benchmark Transiting Brown Dwarf LHS 6343 C: Spitzer Secondary Eclipse Observations Yield Brightness Temperature and Mid-T Spectral Class

NASA Astrophysics Data System (ADS)

Montet, Benjamin T.; Johnson, John Asher; Fortney, Jonathan J.; Desert, Jean-Michel

2016-05-01

There are no field brown dwarf analogs with measured masses, radii, and luminosities, precluding our ability to connect the population of transiting brown dwarfs with measurable masses and radii and field brown dwarfs with measurable luminosities and atmospheric properties. LHS 6343 C, a weakly irradiated brown dwarf transiting one member of an M+M binary in the Kepler field, provides the first opportunity to probe the atmosphere of a non-inflated brown dwarf with a measured mass and radius. Here, we analyze four Spitzer observations of secondary eclipses of LHS 6343 C behind LHS 6343 A. Jointly fitting the eclipses with a Gaussian process noise model of the instrumental systematics, we measure eclipse depths of 1.06 ± 0.21 ppt at 3.6 μm and 2.09 ± 0.08 ppt at 4.5 μm, corresponding to brightness temperatures of 1026 ± 57 K and 1249 ± 36 K, respectively. We then apply brown dwarf evolutionary models to infer a bolometric luminosity {log}({L}\\star /{L}⊙ )=-5.16+/- 0.04. Given the known physical properties of the brown dwarf and the two M dwarfs in the LHS 6343 system, these depths are consistent with models of a 1100 K T dwarf at an age of 5 Gyr and empirical observations of field T5-6 dwarfs with temperatures of 1070 ± 130 K. We investigate the possibility that the orbit of LHS 6343 C has been altered by the Kozai-Lidov mechanism and propose additional astrometric or Rossiter-McLaughlin measurements of the system to probe the dynamical history of the system.

Annular and Total Solar Eclipses of 2010

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, J.

2008-01-01

While most NASA eclipse bulletins cover a single eclipse, this publication presents predictions for two solar eclipses during 2010. This has required a different organization of the material into the following sections. Section 1 -- Eclipse Predictions: The section consists of a general discussion about the eclipse path maps, Besselian elements, shadow contacts, eclipse path tables, local circumstances tables, and the lunar limb profile. Section 2 -- Annular Solar Eclipse of 2010 Ja n 15: The section covers predictions and weather prospects for the annular eclipse. Section 3 -- Total Solar Eclipse of 2010 Jul 11: The se ction covers predictions and weather prospects for the total eclipse. Section 4 -- Observing Eclipses: The section provides information on eye safety, solar filters, eclipse photography, and making contact timings from the path limits. Section 5 -- Eclipse Resources: The final section contains a number of resources including information on the IAU Working Group on Eclipses, the Solar Eclipse Mailing List, the NASA eclipse bulletins on the Internet, Web sites for the two 2010 eclipses, and a summary identifying the algorithms, ephemerides, and paramete rs used in the eclipse predictions.

Magneto optical properties of self-assembled InAs quantum dots for quantum information processing

NASA Astrophysics Data System (ADS)

Tang, Jing; Xu, Xiu-Lai

2018-02-01

Not Available Project supported by the National Basic Research Program of China (Grant No. 2014CB921003), the National Natural Science Foundation of China (Grant Nos. 11721404, 51761145104, and 61675228), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos. XDB07030200 and XDPB0803), and the CAS Interdisciplinary Innovation Team.

[Development of a Compared Software for Automatically Generated DVH in Eclipse TPS].

PubMed

Xie, Zhao; Luo, Kelin; Zou, Lian; Hu, Jinyou

2016-03-01

This study is to automatically calculate the dose volume histogram(DVH) for the treatment plan, then to compare it with requirements of doctor's prescriptions. The scripting language Autohotkey and programming language C# were used to develop a compared software for automatically generated DVH in Eclipse TPS. This software is named Show Dose Volume Histogram (ShowDVH), which is composed of prescription documents generation, operation functions of DVH, software visualization and DVH compared report generation. Ten cases in different cancers have been separately selected, in Eclipse TPS 11.0 ShowDVH could not only automatically generate DVH reports but also accurately determine whether treatment plans meet the requirements of doctor’s prescriptions, then reports gave direction for setting optimization parameters of intensity modulated radiated therapy. The ShowDVH is an user-friendly and powerful software, and can automatically generated compared DVH reports fast in Eclipse TPS 11.0. With the help of ShowDVH, it greatly saves plan designing time and improves working efficiency of radiation therapy physicists.

HERCULES X-1: USING ECLIPSE TO MEASURE THE X-RAY CORONA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leahy, D. A.

Observations of HZ Her/Her X-1 by the Rossi X-ray Timing Explorer during High State X-ray eclipses are analyzed. After a sharp ingress caused by the neutron star receding behind the companion star HZ Her, X-ray flux smoothly declines to a minimum at mid-eclipse. It then increases smoothly until egress. The mid-eclipse flux implies an extended emission region around the neutron star that is larger than that of HZ Her. The constancy of the X-ray softness ratio is consistent with electron scattering by an ionized corona. The corona is modeled as spherically symmetric with a power-law density profile. We find amore » best fit of ∝r {sup –1.25} with a normalization of ≅ 10{sup 12} cm{sup –3} at r = 2 × 10{sup 10} cm. The corona could either be in hydrostatic equilibrium, with heating by Compton scattering, a fast outflow, with a high mass-loss rate of ∼10{sup 18} gm s{sup –1}, or a hybrid, with an inner hydrostatic region and outer slow flow with a low mass-loss rate. A brightening at orbital phase 0.94 is suggested to be caused by the impact of the accretion stream with the accretion disk.« less

David Levy's Guide to Eclipses, Transits, and Occultations

NASA Astrophysics Data System (ADS)

Levy, David H.

2010-08-01

Introduction; Part I. The Magic and History of Eclipses: 1. Shakespeare, King Lear, and the Great Eclipse of 1605; 2. Three centuries later: Einstein, relativity, and the solar eclipse of 1919; 3. What causes solar and lunar eclipses; Part II. Observing Solar Eclipses: 4. Safety considerations; 5. What to expect during a partial eclipse; 6. Annular eclipses and what to see in them; 7. Total eclipse of the Sun: introduction to the magic; 8. The onset: temperature drop, Baily's Beads, Diamond Ring; 9. Totality: Corona, Prominences, Chromosphere, and surrounding area; 10. Photographing and imaging a solar eclipse; Part III. Observing Lunar Eclipses: 11. Don't forget the penumbral eclipses!; 12. Partial lunar eclipses; 13. Total lunar eclipses; 14. Photographing and imaging lunar eclipses; Part IV. Occultations: 15. When the Moon occults a star; Part V. Transits: 16. When planets cross the Sun; Part VI. My Favorite Eclipses: 17. A personal canon of eclipses, occultations, and transits I have seen; Appendices; Index.

Evaluation of Oxygen Concentrators and Chemical Oxygen Generators at Altitude and Temperature Extremes.

PubMed

Blakeman, Thomas C; Rodriquez, Dario; Britton, Tyler J; Johannigman, Jay A; Petro, Michael C; Branson, Richard D

2016-05-01

Oxygen cylinders are heavy and present a number of hazards, and liquid oxygen is too heavy and cumbersome to be used in far forward environments. Portable oxygen concentrators (POCs) and chemical oxygen generators (COGs) have been proposed as a solution. We evaluated 3 commercially available POCs and 3 COGs in a laboratory setting. Altitude testing was done at sea level and 8,000, 16,000, and 22,000 ft. Temperature extreme testing was performed after storing devices at 60°C and -35°C for 24 hours. Mean FIO2 decreased after storage at -35°C with Eclipse and iGo POCs and also at the higher volumes after storage at 60°C with the Eclipse. The iGo ceased to operate at 16,000 ft, but the Eclipse and Saros were unaffected by altitude. Oxygen flow, duration of operation, and total oxygen volume varied between COGs and within the same device type. Output decreased after storage at -35°C, but increased at each altitude as compared to sea level. This study showed significant differences in the performance of POCs and COGs after storage at temperature extremes and with the COGs at altitude. Clinicians must understand the performance characteristics of devices in all potential environments. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Educational and Public Outreach Strategies in Anticipation of the 2017 U.S. Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Fulco, C.

2015-12-01

Those who have experienced a total solar eclipse will travel to every corner of the Earth to observe one, such is its spectacular nature. So it is fortunate indeed to have this remarkable event come to the U.S. in less than two years, with its path of totality from Oregon to South Carolina within a day's drive for most of the nation's population. The date of the 21 August 2017 "Great American Eclipse" is rapidly approaching, and with focus on science literacy in U.S. schools greater than ever, educational and public outreach (EPO) must begin in earnest to maximize the scientific and educational benefits from this rare event. As every location in the U.S. will observe at least a partial eclipse, having EPO strategies in place ensures that the greatest number of students and other observers throughout the country will: a) be aware of and prepared for this event, b) observe (and record) it safely and knowledgeably, and c) gain an increased awareness of the natural world. The need for teachers to promote scientific literacy through curriculum is critical for this event. Despite an increased presence of technology in the classroom, more rigorous educational learning standards and virtually instantaneous access to information, data show that science illiteracy in U.S. schools and in the general population is still widespread. In addition, much fear, ignorance and confusion continue to surround eclipses. Many school districts plan to keep students indoors during the eclipse, while the media can be expected to instruct the public to do the same, thus depriving would-be observers of an unforgettable and most likely a once-in-a-lifetime experience. It would be a tragedy on many levels if this eclipse were not viewed, recorded and remembered live and outdoors--not indoors watching on media--by as many persons as possible. Proper EPO strategies performed with ample lead time can ensure that the 2017 U.S. Total Solar Eclipse will be a success from coast-to-coast, and with it, a heightened level of scientific awareness among the educational community and general public alike. (photo: Total Solar Eclipse over Patagonia; copyright 2010 CNF)

Dynamics of Coronal Structures Captured During the 2012 and 2013 Total Solar Eclipses

NASA Astrophysics Data System (ADS)

Alzate, N.; Habbal, S. R.; Druckmuller, M.

2017-12-01

White light eclipse images taken during total solar eclipses provide a very high dynamic range spanning tens of solar radii starting from the solar surface. They capture the instantaneous state of the corona, including dynamic events. We present observations of the 2012 November 13 and 2013 November 3 total solar eclipses, taken by Constantinos Emmanouilidis, in which we captured high latitude tethered prominences accompanied by CMEs, as well as several `atypical' large scale structures, spanning a few solar radii above the solar surface. By complementing the eclipse observations with co-temporaneous SDO/AIA, STEREO/EUVI and SOHO/LASCO observations, we show how the shape of the atypical structures outlines the shape of faint CME shock fronts, driven by flaring activities. The tethered prominences were imaged from their anchor at the solar surface out to several solar radii. The SDO/AIA 30.4, 17.1 and 19.3 nm emission clearly show how a direct link between the cool (104 - 105 K) filamentary emission from prominence material, and the filamentary structures emitting at coronal temperatures (> 106 K), is unmistakably present. The observed survival of these tethered systems out to the field of view of LASCO C3, establishes the likely origin of counter-streaming electrons associated with CMEs observed in interplanetary space (ICMEs). They also provide new insights for CME-initiation models associated with prominence eruptions. Our work highlights the uniqueness of eclipse observations in identifying the impact of transit events on large-scale coronal structures.

Meteorological responses in the atmospheric boundary layer over southern England to the deep partial eclipse of 20 March 2015

PubMed Central

2016-01-01

A wide range of surface and near-surface meteorological observations were made at the University of Reading’s Atmospheric Observatory in central southern England (latitude 51.441° N, longitude 0.938° W, altitude 66 m above mean sea level) during the deep partial eclipse on the morning of 20 March 2015. Observations of temperature, humidity, radiation, wind speed and direction, and atmospheric pressure were made by computerized logging equipment at 1 Hz, supplemented by an automated cloud base recorder sampling at 1 min intervals and a high-resolution (approx. 10 m vertical interval) atmospheric sounding by radiosonde launched from the same location during the eclipse. Sources and details of each instrumental measurement are described briefly, followed by a summary of observed and derived measurements by meteorological parameter. Atmospheric boundary layer responses to the solar eclipse were muted owing to the heavily overcast conditions which prevailed at the observing location, but instrumental records of the event documented a large (approx. 80%) reduction in global solar radiation, a fall in air temperature of around 0.6°C, a decrease in cloud base height, and a slight increase in atmospheric stability during the eclipse. Changes in surface atmospheric moisture content and barometric pressure were largely insignificant during the event. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550762

Reconfigurable Flight Control System for a STOL (Short Take-Off and Landing) Aircraft Using Quantitative Feedback Theory.

DTIC Science & Technology

1984-12-01

XD2, XD3, XD4, XD5, XD6, XD7, XDS, 7M1, MA, MH, M0,MU, MDl,MD2, MD3, MD4, M5, MOS, MD7, MDS REAL CNB, CYB, CL, L, N DIMENSION AMAT(4,4), BMAT (4,S...NO, MU, ND1, MD2, ND3, MD4,ND5, MD6, ND7, NO REAL CNB, CYB, CL, L, N DIMENSION AMAT(4,4), BMAT (4,S)V DIMENSION DIRMAT(5, 5) ,DIRBMAT(5, SJ CHARACTER*3...INPUT MATRIX 8 C BMAT (l,1) - XO1 BMAT (1,2) - X02 BMAT (1,3) = XD3 BMAT (1,4) -XO4 SMAT(1,5) -XD5 BMAT (1,&) - XDG BMQT(1,7) = XD7 EMAT(I,8) - XDB BMAT (,1

Molecular structure and conformational composition of methyl chloroacetate: An electron-diffraction and ab initio molecular orbital investigation

NASA Astrophysics Data System (ADS)

Aarset, Kirsten; Boldermo, Kjell Gunnar; Hagen, Kolbjørn

2010-08-01

The molecular structure and conformational composition of methyl chloroacetate, H 2ClC sbnd C( dbnd O) sbnd O sbnd CH 3, have been determined by gas-phase electron-diffraction (GED), using results from ab initio molecular orbital calculations (HF, MP2 and MP3/6-311+G(d,p)) to obtain constraints on some of the structural parameters. The molecules exist in the gas-phase at 25 °C as a mixture of two stable conformers: syn with C sbnd Cl eclipsing C dbnd O and gauche with C sbnd H approximately eclipsing C dbnd O. In both of these conformers O sbnd CH 3 is also eclipsing C dbnd O. The experimentally observed conformational composition at 25 °C was 36(8)% syn and 64(8)% gauche (parenthesised values are 2 σ), corresponding to a free energy difference between conformers of ΔGexp° = 1.4(9) kJ/mol. The corresponding theoretical values obtained for Δ G° are 1.1 kJ/mol (HF), 2.3 kJ/mol (MP2), and 2.4 kJ/mol (MP3). The results for the principal distances ( rh1) and angles ( ∠h1) for the major gauche conformer obtained from the combined GED/ ab initio study (2 σ uncertainties) are r(CO sbnd CCl) = 1.502(9) Å, r(C sbnd H) = 1.084(6) Å (average value), r(C sbnd Cl) = 1.782(4) Å, r(C dbnd O) = 1.213(4) Å, r(CO sbnd O) = 1.346(4) Å, r(CH 3sbnd O) = 1.468(10) Å, ∠C sbnd C sbnd Cl = 110.0(6)°, ∠C sbnd C dbnd O = 124.7(6)°, ∠C sbnd C sbnd O = 108.3(10)°, ∠C sbnd O sbnd C = 115.9(8)°, ϕ(Cl sbnd C sbnd C dbnd O) = 111(2)°, ϕ(C sbnd O sbnd C dbnd O) = 3(3)°.

Planetary Candidates from K2 Campaign 16

NASA Astrophysics Data System (ADS)

Yu, Liang; Crossfield, Ian J. M.; Schlieder, Joshua E.; Kosiarek, Molly R.; Feinstein, Adina D.; Livingston, John H.; Howard, Andrew W.; Benneke, Björn; Petigura, Erik A.; Bristow, Makennah; Christiansen, Jessie L.; Ciardi, David R.; Crepp, Justin R.; Dressing, Courtney D.; Fulton, Benjamin J.; Gonzales, Erica J.; Hardegree-Ullman, Kevin K.; Henning, Thomas; Isaacson, Howard; Lépine, Sébastien; Martinez, Arturo O.; Morales, Farisa Y.; Sinukoff, Evan

2018-07-01

Given that Campaign 16 of the K2 mission is one of just two K2 campaigns observed so far in “forward-facing” mode, which enables immediate follow-up observations from the ground, we present a catalog of interesting targets identified through photometry alone. Our catalog includes 30 high-quality planet candidates (showing no signs of being non-planetary in nature), 48 more ambiguous events that may be either planets or false positives, 164 eclipsing binaries, and 231 other regularly periodic variable sources. We have released light curves for all targets in C16 and have also released system parameters and transit vetting plots for all interesting candidates identified in this paper. Of particular interest is a candidate planet orbiting the bright F dwarf HD 73344 (V = 6.9, K = 5.6) with an orbital period of 15 days. If confirmed, this object would correspond to a 2.56 ± 0.18 R ⊕ planet and would likely be a favorable target for radial velocity characterization. This paper is intended as a rapid release of planet candidates, eclipsing binaries, and other interesting periodic variables to maximize the scientific yield of this campaign, and as a test run for the upcoming TESS mission, whose frequent data releases call for similarly rapid candidate identification and efficient follow up.

A facile and efficient dry transfer technique for two-dimensional Van derWaals heterostructure

NASA Astrophysics Data System (ADS)

Xie, Li; Du, Luojun; Lu, Xiaobo; Yang, Rong; Shi, Dongxia; Zhang, Guangyu

2017-08-01

Not Available Project supported by the National Basic Research Program of China (Grant Nos. 2013CB934500 and 2013CBA01602), the National Natural Science Foundation of China (Grant Nos. 61325021, 11574361, and 51572289), the Key Research Program of Frontier Sciences, CAS, (Grant No. QYZDB-SSW-SLH004), and the Strategic Priority Research Program (B), CAS (Grant No. XDB07010100).

Sensitive and selective liquid chromatography-tandem mass spectrometry method for the determination of five ganoderic acids in Ganoderma lucidum and its related species.

PubMed

Liu, Yongli; Liu, Youping; Qiu, Feng; Di, Xin

2011-03-25

The present paper describes a novel, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of ganoderic acids C(2), B, A, H, D in Ganoderma lucidum and its related species. Ganoderma samples were prepared using simple ultrasonic extraction. Chromatographic separation was carried out on an Agilent Zorbax XDB C(18) column (250 mm × 4.6 mm i.d., 5μm) with an isocratic mobile phase consisting of acetonitrile, water and formic acid (42:58:0.5, v/v/v). Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization (APCI) interface operating in negative and positive ionization mode via a single within-run polarity switching. Quantitation of five ganoderic acids was performed using selective reaction monitoring (SRM) mode. The intra- and inter-day precision was less than 6.2% and the accuracy ranged from 90.0% to 105.7%. The limit of quantification (LOQ) was 20.0-40.0 ng/mL and the limit of detection (LOD) was 3.0-25.0 ng/mL. With this method, low levels of ganoderic acids in the fruiting bodies of Ganoderma sinense and Ganoderma applanatum were accurately quantified for the first time. Importantly, the method allows unequivocal quantification of the five ganoderic acids in the spores and fruiting bodies of Ganoderma lucidum, whereas the previously published methods have lacked the capability. The method presented will be a powerful tool for quality control of Ganoderma lucidum and its related species. Copyright © 2010 Elsevier B.V. All rights reserved.

New polymorphs of Ru IIIP 3O 9: Cyclo-hexaphosphate Ru 2P 6O 18 and metaphosphate Ru(PO 3) 3 with a novel structure

NASA Astrophysics Data System (ADS)

Fukuoka, Hiroshi; Imoto, Hideo; Saito, Taro

1995-10-01

Two new polymorphs of ruthenium phosphate with RuP 3O 9 composition were prepared and their crystal structures were determined by single-crystal X-ray diffraction. They are cyclo-hexaphosphate Ru 2P 6O 18 and metaphosphate Ru(PO 3) 3. Ru 2P 6O 18 crystallizes in the monoclinic space group P2 1/ c with a = 6.292(2) Å, b = 15.276(2) Å, c = 8.365(2) Å, β = 106.54(2)°, V = 770.6(3) Å 3, Z = 2, R = 0.043, RW = 0.035. The structure contains cyclo-hexaphosphate rings stacking obliquely along the [100] direction and is isotypic with B-form cyclo-phosphates. Ru(PO 3) 3 has a novel structure and crystallizes in the triclinic space group P overline1 with a = 6.957(1) Å, b = 10.324(2) Å, c = 5.030(1) Å, α = 92.45(2)°, β = 92.31(2)°, γ = 98.61(1)°, V = 356.5(1) Å 3, Z = 2, R = 0.030, RW = 0.027. It is built up of a network of infinite [PO 3-] ∞ chains and RuO 6 octahedra. The configuration of the metaphosphate chains is different from that in the C-form Ru(PO 3) 3. While the chains in the C-form consisting of PO 3OPO 3 units are condensed in nearly staggered configurations, the units in the new phosphate are eclipsed.

Management and Performance of APPLE Battery in High Temperature Environment

NASA Technical Reports Server (NTRS)

Suresh, M. S.; Subrahmanyam, A.; Agrawal, B. L.

1984-01-01

India's first experimental communication satellite, APPLE, carried a 12 AH Ni-Cd battery for supplying power during eclipse. Failure to deploy one of the two solar panels resulted in the battery operating in a high temperature environment, around 40 C. This also resulted in the battery being used in diurnal cycles rather than just half yearly eclipse seasons. The management and performance of the battery during its life of two years are described. An attempt to identify the probable degradation mechanisms is also made.

Variable Star and Exoplanet Section of the Czech Astronomical Society

NASA Astrophysics Data System (ADS)

Brát, L.; Zejda, M.

2010-12-01

We present activities of Czech variable star observers organized in the Variable Star and Exoplanet Section of the Czech Astronomical Society. We work in four observing projects: B.R.N.O. - eclipsing binaries, MEDUZA - intrinsic variable stars, TRESCA - transiting exoplanets and candidates, HERO - objects of high energy astrophysics. Detailed information together with O-C gate (database of eclipsing binaries minima timings) and OEJV (Open European Journal on Variable stars) are available on our internet portal http://var.astro.cz.

Determination of 2,4-Dichlorophenoxyacetic acid (2,4-D) in rat serum for pharmacokinetic studies with a simple HPLC method

PubMed Central

Chen, Xiao; Wan, Yanjian; Chen, Xi; Li, Yuanyuan

2018-01-01

2,4-Dichlorophenoxyacetic acid (2,4-D) is a chlorophenoxy herbicide used worldwide. We describe a high-performance liquid chromatography (HPLC) method with UV detection for the determination of 2,4-D in female and male rat serum. This allows to observe the change of serum 2,4-D concentration in rats with time and its pharmacokinetics characteristics with a simple, rapid, optimized and validated method. The serum samples are pretreated and introduced into the HPLC system. The analytes are separated in a XDB-C18 column with a mobile phase of acetonitrile (solvent A) and 0.02 M ammonium acetate (containing 0.1% formic acid) (solvent B) using a gradient elution at a flow rate of 1.0 mL/min. The wavelength for UV detection was set at 230 nm. Calibration curve for 2,4-D was constructed over a range of 0.1–400 mg/L. The method was successfully applied to study the pharmacokinetics of 2,4-D in rats in this study. After oral administration of 300 mg/kg and 60 mg/kg 2,4-D, the mean Cmax values were 601.9 and 218.4 mg/L, the AUC0→∞ values were 23,722 and 4,127 mg×h/L and the clearance (Cl) were 1.10 and 0.02 L/(h×kg), respectively. The developed method was found to be specific, precise, reproducible and rapid. PMID:29342170

Determination of 2,4-Dichlorophenoxyacetic acid (2,4-D) in rat serum for pharmacokinetic studies with a simple HPLC method.

PubMed

Chen, Xiao; Zhang, Hongling; Wan, Yanjian; Chen, Xi; Li, Yuanyuan

2018-01-01

2,4-Dichlorophenoxyacetic acid (2,4-D) is a chlorophenoxy herbicide used worldwide. We describe a high-performance liquid chromatography (HPLC) method with UV detection for the determination of 2,4-D in female and male rat serum. This allows to observe the change of serum 2,4-D concentration in rats with time and its pharmacokinetics characteristics with a simple, rapid, optimized and validated method. The serum samples are pretreated and introduced into the HPLC system. The analytes are separated in a XDB-C18 column with a mobile phase of acetonitrile (solvent A) and 0.02 M ammonium acetate (containing 0.1% formic acid) (solvent B) using a gradient elution at a flow rate of 1.0 mL/min. The wavelength for UV detection was set at 230 nm. Calibration curve for 2,4-D was constructed over a range of 0.1-400 mg/L. The method was successfully applied to study the pharmacokinetics of 2,4-D in rats in this study. After oral administration of 300 mg/kg and 60 mg/kg 2,4-D, the mean Cmax values were 601.9 and 218.4 mg/L, the AUC0→∞ values were 23,722 and 4,127 mg×h/L and the clearance (Cl) were 1.10 and 0.02 L/(h×kg), respectively. The developed method was found to be specific, precise, reproducible and rapid.

A possible giant planet orbiting the cataclysmic variable LX Ser

NASA Astrophysics Data System (ADS)

Li, Kai; Hu, Shaoming; Zhou, Jilin; Wu, Donghong; Guo, Difu; Jiang, Yunguo; Gao, Dongyang; Chen, Xu; Wang, Xianyu

2017-04-01

LX Ser is a deeply eclipsing cataclysmic variable with an orbital period of 0.1584325 d. 62 new eclipse times were determined by our observations and the AAVSO International Data base. Combining all available eclipse times, we analyzed the O - C behavior of LX Ser. We found that the O - C diagram of LX Ser shows a sinusoidal oscillation with a period of 22.8 yr and an amplitude of 0.00035 d. Two mechanisms (i.e., the Applegate mechanism and the light-travel time effect) are applied to explain the cyclic modulation. We found that it is difficult to apply the Applegate mechanism to explain the cyclic oscillation in the orbital period. Therefore, the cyclic period change is most likely to be caused by the light-travel time effect due to the presence of a third body. The mass of the tertiary component was determined to be M3 ∼ 7.5 MJup. We supposed that the tertiary companion is plausibly a giant planet. The stability of the giant planet was checked, and we found that the multiple system is stable.

Periodic Eclipse Variations in Asynchronous Polar V1432 Aql: Evidence of a Shifting Threading Region

NASA Technical Reports Server (NTRS)

Littlefield, Colin; Mukai, Koji; Mumme, Raymond; Cain, Ryan; Magno, Katrina C.; Corpuz, Taylor; Sandefur, Davis; Boyd, David; Cook, Michael; Ulowetz, Joseph;

The O-type eclipsing contact binary LY Aurigae - member of a quadruple system

NASA Astrophysics Data System (ADS)

Mayer, Pavel; Drechsel, Horst; Harmanec, Petr; Yang, Stephenson; Šlechta, Miroslav

2013-11-01

The eclipsing binary LY Aur (O9 II + O9 III) belongs to the rare class of early-type contact systems. We obtained 23 new spectra at the Ondřejov and Dominion Astrophysical Observatories, which were analysed with four older Calar Alto and one ELODIE archive spectra. A new result of this study is that the visual companion of LY Aur - the spectral lines of which are clearly seen in our spectra - is also an SB1 binary having an orbital period of 20.46d, an eccentric orbit, and a radial velocity semi-amplitude of 33 km s-1. The Hα line blend contains an emission component, which shows dependence on the orbital phase of the eclipsing system, with the strongest emission around the secondary eclipse. Revised elements of the eclipsing binary and the orbital solution of the companion binary are determined from our set of spectra and new light-curve solutions of the eclipsing pair. The mass of the primary of 25.5 M⊙ agrees well with its spectral type, whereas the secondary mass of 14 M⊙ is smaller than expected. From an O-C analysis of the minimum times of LY Aur that span more than 40 years, we found that the orbital period is decreasing, indicating the presence of interaction processes. The system is likely in a phase of non-conservative mass exchange. Based on spectral observations collected at the German-Spanish Observatory, Calar Alto, Spain; Dominion Astrophysical Observatory, Canada; Ondřejov Observatory, Czech Republic, and an archival Haute Provence Observatory ELODIE spectrum.

Understanding the Requirements for Open Source Software

DTIC Science & Technology

2009-06-17

GNOME and K Development Environment ( KDE ) for end-user interfaces, the Eclipse and NetBeans interactive development environments for Java-based Web...17 4.1. Informal Post-hoc Assertion of OSS Requirements vs . Requirements Elicitation...18 4.2. Requirements Reading, Sense-making, and Accountability vs . Requirements Analysis

Impact of perioperative blood pressure variability on health resource utilization after cardiac surgery: an analysis of the ECLIPSE trials.

PubMed

Aronson, Solomon; Levy, Jerrold H; Lumb, Philip D; Fontes, Manuel; Wang, Yamei; Crothers, Tracy A; Sulham, Katherine A; Navetta, Marco S

2014-06-01

To examine the impact of blood pressure control on hospital health resource utilization using data from the ECLIPSE trials. Post-hoc analysis of data from 3 prospective, open-label, randomized clinical trials (ECLIPSE trials). Sixty-one medical centers in the United States. Patients 18 years or older undergoing cardiac surgery. Clevidipine was compared with nitroglycerin, sodium nitroprusside, and nicardipine. The ECLIPSE trials included 3 individual randomized open-label studies comparing clevidipine to nitroglycerin, sodium nitroprusside, and nicardipine. Blood pressure control was assessed as the integral of the cumulative area under the curve (AUC) outside specified systolic blood pressure ranges, such that lower AUC represents less variability. This analysis examined surgery duration, time to extubation, as well as intensive care unit (ICU) and hospital length of stay (LOS) in patients with AUC≤10 mmHg×min/h compared to patients with AUC>10 mmHg×min/h. One thousand four hundred ten patients were included for analysis; 736 patients (52%) had an AUC≤10 mmHg×min/h, and 674 (48%) had an AUC>10 mmHg×min/h. The duration of surgery and ICU LOS were similar between groups. Time to extubation and postoperative LOS were both significantly shorter (p = 0.05 and p<0.0001, respectively) in patients with AUC≤10. Multivariate analysis demonstrates AUC≤10 was significantly and independently associated with decreased time to extubation (hazard ratio 1.132, p = 0.0261) and postoperative LOS (hazard ratio 1.221, p = 0.0006). Based on data derived from the ECLIPSE studies, increased perioperative BP variability is associated with delayed time to extubation and increased postoperative LOS. Copyright © 2014 Elsevier Inc. All rights reserved.

Detection of the secondary eclipse of Qatar-1b in the Ks band

NASA Astrophysics Data System (ADS)

Cruz, Patricia; Barrado, David; Lillo-Box, Jorge; Diaz, Marcos; Birkby, Jayne; López-Morales, Mercedes; Fortney, Jonathan J.

2016-10-01

Aims: Qatar-1b is a close-orbiting hot Jupiter (Rp ≃ 1.18 RJ, Mp ≃ 1.33 MJ) around a metal-rich K-dwarf, with orbital separation and period of 0.023 AU and 1.42 days. We have observed the secondary eclipse of this exoplanet in the Ks band with the objective of deriving a brightness temperature for the planet and providing further constraints to the orbital configuration of the system. Methods: We obtained near-infrared photometric data from the ground by using the OMEGA2000 instrument at the 3.5 m telescope at Calar Alto (Spain) in staring mode, with the telescope defocused. We have used principal component analysis (PCA) to identify correlated systematic trends in the data. A Markov chain Monte Carlo analysis was performed to model the correlated systematics and fit for the secondary eclipse of Qatar-1b using a previously developed occultation model. We adopted the prayer bead method to assess the effect of red noise on the derived parameters. Results: We measured a secondary eclipse depth of 0.196%+ 0.071%-0.051%, which indicates a brightness temperature in the Ks band for the planet of 1885+ 212-168 K. We also measured a small deviation in the central phase of the secondary eclipse of -0.0079+ 0.0162-0.0043, which leads to a value for ecosω of -0.0123+ 0.0252-0.0067. However, this last result needs to be confirmed with more data. Based on observations collected at the Calar Alto Observatory, Almería, Spain.Lightcurve data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/595/A61

Synthesis and stereochemical analysis of β-nitromethane substituted γ-amino acids and peptides.

PubMed

Ganesh Kumar, Mothukuri; Mali, Sachitanand M; Gopi, Hosahudya N

2013-02-07

The high diastereoselectivity in the Michael addition of nitromethane to α,β-unsaturated γ-amino esters, crystal conformations of β-nitromethane substituted γ-amino acids and peptides are studied. Results suggest that the N-Boc protected amide NH, conformations of α,β-unsaturated γ-amino esters and alkyl side chains play a crucial role in dictating the high diastereoselectivity of nitromethane addition to E-vinylogous amino esters. Investigation of the crystal conformations of both α,β-unsaturated γ-amino esters and the Michael addition products suggests that an H-C(γ)-C(β)=C(α) eclipsed conformer of the unsaturated amino ester leads to the major (anti) product compared to that of an N-C(γ)-C(β)=C(α) eclipsed conformer. The major diastereomers were separated and subjected to the peptide synthesis. The single crystal analysis of the dipeptide containing β-nitromethane substituted γ-amino acids reveals a helical type of folded conformation with an isolated H-bond involving a nine-atom pseudocycle.

The first comprehensive catalog of γ Dor pulsators and their characteristics

NASA Astrophysics Data System (ADS)

Ibanoglu, C.; Çakırlı, Ö.; Sipahi, E.

2018-07-01

We present the first comprehensive catalog of the γ Doradus type pulsating stars. This catalog covers observational properties of all γ Dor variables obtained until January 2017. The photometric and physical properties of 109 well - known γ Dor pulsators, 18 hybrid stars, 13 anomalous γ Dor stars, and 22 γ Dor stars in eclipsing plus 1 non-eclipsing SB2 binary systems are presented as separate tables. In addition, 291 candidate γ Dor variables discovered by CoRot, 307 candidate γ Dor, 205 hybrid and 11 candidate γ Dor in binaries discovered by Kepler were also presented. Distribution of the genuine single γ Dor pulsators in the Ppuls-Teff, Amplitude-Teff, Amplitude-Ppuls and L-Teff diagrams are presented and discussed. We find following correlations for the γ Dor pulsators in the eclipsing binaries: Ppuls ∝ Porb0.27, Ppuls ∝ Q0.45, and Ppuls ∝ r-0.44, where (Q) is the pulsation constant and r is the fractional radius of the pulsating component in the binary system. The correlation coefficients are not high enough due to limited sample and scattering in the data.

Experimental and Monte Carlo evaluation of Eclipse treatment planning system for effects on dose distribution of the hip prostheses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Çatlı, Serap, E-mail: serapcatli@hotmail.com; Tanır, Güneş

2013-10-01

The present study aimed to investigate the effects of titanium, titanium alloy, and stainless steel hip prostheses on dose distribution based on the Monte Carlo simulation method, as well as the accuracy of the Eclipse treatment planning system (TPS) at 6 and 18 MV photon energies. In the present study the pencil beam convolution (PBC) method implemented in the Eclipse TPS was compared to the Monte Carlo method and ionization chamber measurements. The present findings show that if high-Z material is used in prosthesis, large dose changes can occur due to scattering. The variance in dose observed in the presentmore » study was dependent on material type, density, and atomic number, as well as photon energy; as photon energy increased back scattering decreased. The dose perturbation effect of hip prostheses was significant and could not be predicted accurately by the PBC method for hip prostheses. The findings show that for accurate dose calculation the Monte Carlo-based TPS should be used in patients with hip prostheses.« less

Ginga observations of Centaurus X-3

NASA Technical Reports Server (NTRS)

Nagase, F.; Corbet, R. H. D.; Day, C. S. R.; Inoue, H.; Takeshima, T.; Yoshida, K.; Mihara, T.

1992-01-01

Attention is given to a series of observations of Centaurus X-3 made with Ginga on March 22-24, 1989, over a complete orbital cycle. The data set includes a preeclipse dip, the eclipse ingress and egress, the eclipse itself, and a phase of high steady emission after egress. The mideclipse ephemeris obtained yields an estimate of the rate of change of the orbital period of -(1.738 +/- 0.004) x 10 exp 6/yr, confirming the rate of change reported by Kelley et al. (1983) and improving the precision by a factor of 20. The pulse profiles obtained with Ginga during the high postegress phase are double-peaked at low energies, and show a reversal of phase of 180 deg. No pulsations are detected during the eclipse and at low energies during the preeclipse dip, indicating that X-ray emission at these phases is due to scattering by extended matter. The energy of the iron emission line varies between 6.5 and 6.7 keV during the observation, while its equivalent width varies between 0.18 and 1.5 keV.

LUMINOSITY DISCREPANCY IN THE EQUAL-MASS, PRE-MAIN-SEQUENCE ECLIPSING BINARY PAR 1802: NON-COEVALITY OR TIDAL HEATING?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gomez Maqueo Chew, Yilen; Stassun, Keivan G.; Hebb, Leslie

Parenago 1802, a member of the {approx}1 Myr Orion Nebula Cluster, is a double-lined, detached eclipsing binary in a 4.674 day orbit, with equal-mass components (M{sub 2}/M{sub 1} = 0.985 {+-} 0.029). Here we present extensive VI{sub C} JHK{sub S} light curves (LCs) spanning {approx}15 yr, as well as a Keck/High Resolution Echelle Spectrometer (HIRES) optical spectrum. The LCs evince a third light source that is variable with a period of 0.73 days, and is also manifested in the high-resolution spectrum, strongly indicating the presence of a third star in the system, probably a rapidly rotating Classical T Tauri star.more » We incorporate this third light into our radial velocity and LC modeling of the eclipsing pair, measuring accurate masses (M{sub 1} = 0.391 {+-} 0.032 and M{sub 2} = 0.385 {+-} 0.032 M{sub Sun }), radii (R{sub 1} = 1.73 {+-} 0.02 and R{sub 2} = 1.62 {+-} 0.02 R{sub Sun }), and temperature ratio (T{sub eff,1}/T{sub eff,2} = 1.0924 {+-} 0.0017). Thus, the radii of the eclipsing stars differ by 6.9% {+-} 0.8%, the temperatures differ by 9.2% {+-} 0.2%, and consequently the luminosities differ by 62% {+-} 3%, despite having masses equal to within 3%. This could be indicative of an age difference of {approx}3 Multiplication-Sign 10{sup 5} yr between the two eclipsing stars, perhaps a vestige of the binary formation history. We find that the eclipsing pair is in an orbit that has not yet fully circularized, e = 0.0166 {+-} 0.003. In addition, we measure the rotation rate of the eclipsing stars to be 4.629 {+-} 0.006 days; they rotate slightly faster than their 4.674 day orbit. The non-zero eccentricity and super-synchronous rotation suggest that the eclipsing pair should be tidally interacting, so we calculate the tidal history of the system according to different tidal evolution theories. We find that tidal heating effects can explain the observed luminosity difference of the eclipsing pair, providing an alternative to the previously suggested age difference.« less

Five Millennium Catalog of Lunar Eclipses: -1999 to +3000 (2000 BCE to 3000 CE)

NASA Technical Reports Server (NTRS)

Espenak, Fred; Meeus, Jean

2009-01-01

This catalog is a supplement to the "FiveMillenniumCanonofLunarEclipses." It includes additional information for each eclipse that could not be included in the original publication because of size limits. The data tabulated for each eclipse include the catalog number, canon plate number, calendar date, Terrestrial Dynamical Time of greatest eclipse, (Delta)T, lunation number, Saros number, eclipse type, Quincena Solar Eclipse parameter, gamma, penumbral and umbral eclipse magnitudes, durations of penumbral, partial and total eclipse phases, and geographic coordinates of greatest eclipse (latitude and longitude). The Canon and the Catalog both use the same solar and lunar ephemerides as well as the same values of (Delta)T. This 1-to-1 correspondence between them will enhance the value of each. The researcher may now search, evaluate, and compare eclipses graphically (Canon) or textually (Catalog).

Eclipse program F-106 aircraft in flight, front view

NASA Technical Reports Server (NTRS)

1997-01-01

Shot of the QF-106 aircraft in flight with the landing gear deployed. In 1997 and 1998, the Dryden Flight Research Center at Edwards, California, supported and hosted a Kelly Space & Technology, Inc. project called Eclipse, which sought to demonstrate the feasibility of a reusable tow-launch vehicle concept. The project goal was to successfully tow, inflight, a modified QF-106 delta-wing aircraft with an Air Force C-141A transport aircraft. This would demonstrate the possibility of towing and launching an actual launch vehicle from behind a tow plane. Dryden was the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden provided engineering, instrumentation, simulation, modification, maintenance, range support, and research pilots for the test program. The Air Force Flight Test Center (AFFTC), Edwards, California, supplied the C-141A transport aircraft and crew and configured the aircraft as needed for the tests. The AFFTC also provided the concept and detail design and analysis as well as hardware for the tow system and QF-106 modifications. Dryden performed the modifications to convert the QF-106 drone into the piloted EXD-01 (Eclipse eXperimental Demonstrator-01) experimental aircraft. Kelly Space & Technology hoped to use the results gleaned from the tow test in developing a series of low-cost, reusable launch vehicles. These tests demonstrated the validity of towing a delta-wing aircraft having high wing loading, validated the tow simulation model, and demonstrated various operational procedures, such as ground processing of in-flight maneuvers and emergency abort scenarios.

1SWASP J200503.05-343726.5: A high mass ratio eclipsing binary near the period limit

NASA Astrophysics Data System (ADS)

Bin, Zhang; Shengbang, Qian; Zejda, Miloslav; Liying, Zhu; Nianping, Liu

2017-07-01

First CCD photometric light curves of the eclipsing binary system 1SWASP J200503.05-343726.5 are presented. Our complete light curves in V, R and I bands using the Bessell filter show an out-of-eclipsing distortion, which means that the components of the system may be active. The preliminary photometric solutions with a cool star-spot are derived by using the 2013 version of the Wilson-Devinney (W-D) code. The photometric solutions suggest that 1SWASP J200503.05-343726.5 is a shallow-contact eclipsing binary(f = 9.0 %) with a mass ratio of q = 1.0705 , which is very high for late-type binary systems near the period limit. The primary component is about 230 K hotter than the secondary component. Based on our new CCD eclipse times, the orbital period change was analyzed. According to O - C diagram, the orbital period of the 1SWASP J200503.05-343726.5 shows an increase at a rate of P˙ = + 5.43 ×10-8 days year-1. The period increase may be caused by mass transfer from the less massive component to the more massive one. This shallow-contact system may be formed from a detached short-period binary via orbital shrinkage because of dynamical interactions with a third component or by magnetic braking.

Five Millennium Catalog of Solar Eclipses: -1999 to +3000 (2000 BCE to 3000 CE)

NASA Technical Reports Server (NTRS)

Espenak, Fred; Meeus, Jean

2008-01-01

This catalog is a supplement to the "Five Millennium Canon of Solar Eclipses." It includes additional information for each eclipse that could not be included in the original 648-page publication because of size limits. The data tabulated for each eclipse include the catalog number, canon plate number, calendar date, Terrestrial Dynamical Time of greatest eclipse, (Delta)T, lunation number, Saros number, eclipse type, Quincena Lunar Eclipse parameter, gamma, eclipse magnitude, geographic coordinates of greatest eclipse (latitude and longitude), and the circumstances at greatest eclipse (i.e., Sun altitude and azimuth, path width, and central line duration). The Canon and the Catalog both use the same solar and lunar ephemerides as well as the same values of (Delta)T. This 1-to-1 correspondence between them will enhance the value of each. The researcher may now search, evaluate, and compare eclipses graphically (Canon) or textually (Catalog).

Five Millennium Catalog of Solar Eclipses: -1999 to +3000 (2000 BCE to 3000 CE)-Revised

NASA Technical Reports Server (NTRS)

Espenak, Fred; Meeus, Jean

2009-01-01

This catalog is a supplement to the "Five Millennium Canon of Lunar Eclipses. "It includes additional information for each eclipse that could not be included in the original publication because of size limits. The data tabulated for each eclipse include the catalog number, canon plate number, calendar date, Terrestrial Dynamical Time of greatest eclipse, (Delta)T, lunation number, Saros number, eclipse type, Quincena Solar Eclipse parameter, gamma, penumbral and umbral eclipse magnitudes, durations of penumbral, partial and total eclipse phases, and geographic coordinates of greatest eclipse(latitude and longitude). The Canon and the Catalog both use the same solar and lunar ephemerides as well as the same values of (Delta)T. This 1-to-1 correspondence between them will enhance the value of each. The researcher may now search, evaluate, and compare eclipses graphically (Canon) or textually (Catalog).

NR TrA (Nova TrA 2008) monitoring in support of XMM observations

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2017-03-01

Dr. Fred Walter (Stony Brook University) has requested AAVSO observers' assistance in monitoring NR TrA (Nova TrA 2008) in support of upcoming XMM Newton observations. The XMM observations will take place 2017 March 13 06:21 through March 14 10:34 UT. Walter writes: "NR TrA (Nova TrA 2008) is a compact eclipsing system with a 5.5 hour period. It was a normal Fe II nova that, upon reaching quiescence, took on the appearance of a super-soft source in the optical high state, which suggests an extremely high mass accretion rate. The optical spectrum is dominated by hot permitted lines of O VI, N V, C IV, and He II. Some nova-like variables have similar spectra, though generally without the hot emission lines. Primary eclipse is broad - nearly 40% of the orbit - and deeper at shorter wavelengths, which suggests the eclipse of a hot accretion disk. Primary eclipse depth is about 1 mag at V. There appears to be a shallow secondary eclipse.The primary aim [of the XMM observations] is to detect and characterize the eclipse at X-ray and UV wavelengths. We will obtain low cadence BVRI/JHK observations with SMARTS/Andicam. We request AAVSO support to obtain continuous photometric time series simultaneous with the XMM observation. Any filters are acceptable, but standard Johnson B, V or Cousins R, I are preferred. Clear filters are acceptable. Time resolution better than 5 minutes and uncertainties (outside of eclipse) <0.02 mag are preferred. The best ephemeris I have is: minimum light at JD 55956.822 + 0.219109E. This is based on data from 2013-2015." Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

A Dosimetric Evaluation of The Eclipse and Pinnacle Treatment Planning Systems in Treatment of Vertebral Bodies Using IMRT and VMAT with Modeled and Commissioned Flattening Filter Free (FFF) Fields

NASA Astrophysics Data System (ADS)

Ajo, Ramzi, Jr.

Modern treatment planning systems (TPS's) utilize different algorithms in computing dose within the patient medium. The algorithms rely on properly modeled clinical setups in order to perform optimally. Aside from various parameters of the beam, modifiers, such as multileaf collimators (MLC's), must also be modeled properly. That could not be more true today, where dynamic delivery such as intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) are being increasingly utilized due to their ability to deliver higher dose precisely to the target while sparing more surrounding normal tissue. Two of the most popular TPS's, Pinnacle (Philips) and Eclipse (Varian), were compared, with special emphasis placed on parameterization of the dosimetric leaf gap (DLG) in Eclipse. The DLG is a parameter that accounts for Varian's rounded MLC leaf ends. While Pinnacle accounts for the rounded leaf end by modeling the MLC's, Eclipse uses a measured parameter. This study investigated whether a single value measured DLG is sufficient for dynamic delivery. Using five planning volumes for vertebral body SBRT treatments, each prescribed for 3000 cGy in 5 fractions, an array of 20 treatment plans was generated using varying energies of 6MV-FFF and 10MV-FFF. Treatment techniques consisted of 9-field Step-and-shoot IMRT, and dual-arc VMAT using patient specific optimization criteria in the Pinnacle TPS v9.8. Each plan was normalized to ensure coverage of 3000cGy to 95% of the target volume. The dose was computed in Pinnacle v9.8, with the Collapsed Cone Convolution Superposition algorithm and Eclipse v11, with the Acuros XB algorithm, using a dose grid resolution of 2 mm in both systems. Dose volume histograms (DVH's) were generated for a comparison of max and mean dose to the targets and spinal cord, as well as 95% coverage of the targets and the volume of the spinal cord receiving 14.5 Gy (V14.5). Patient specific quality assurance (PSQA) fields were generated and then delivered, using a Varian Edge linear accelerator, to a 4D QA phantom for a gamma analysis and distance to agreement (DTA) comparison. All Eclipse calculations were made for both measured and optimized DLG parameters. Calculated vs. measured point dose for the Pinnacle TPS had an average difference of 2.79 +/- 2.00%. Gamma analysis using a 3% and 3 mm DTA had 99/100 fields passing at > 95%. Using measured values of the DLG in Eclipse, calculated vs. measured point dose was -4.44 +/- 1.97%, and DTA had 33/110 fields passing at > 95%. After an optimization of the DLG in Eclipse, calculated vs. measured point dose had an average difference of 2.20 +/- 2.23%, and DTA with 95/110 fields passing at > 95%. This study looked at the performance of the Pinnacle and Eclipse TPS's, with special consideration given to the DLG parameterization used by Eclipse. The results support the idea that a single valued DLG is not sufficient for dynamic delivery. An optimization of the parameter is necessary to account for the high modulation of IMRT and VMAT techniques.

Five Millennium Canon of Solar Eclipses: -1999 to +3000 (2000 BCE to 3000 CE)

NASA Technical Reports Server (NTRS)

Espenak, Fred; Meeus, Jean

2006-01-01

During 5,000-year period from -1999 to +3000 (2000BCE to 3000CE), Earth will experience 11,898 eclipses of the Sun. The statistical distribution of eclipse types for this interval is as follows: 4,200 partial eclipses, 3956 annular eclipses, 3173 total eclipses,and 569 hybrid eclipses. Detailed global maps for each of the 11,898 eclipses delineate the geographic regions of visibility for both the penumbral (partial) and umbral or antumbral (total, annular, or hybrid) phases of every event. Modern political borders are plotted to assist in the determination of eclipse visibility. The uncertainty in Earth's rotational period expressed in the parameter (delta)T and its impact on the geographic visibility of eclipses in the past and future is discussed.

Profiling LC-DAD-ESI-TOF MS method for the determination of phenolic metabolites from avocado (Persea americana).

PubMed

Hurtado-Fernández, Elena; Carrasco-Pancorbo, Alegría; Fernández-Gutiérrez, Alberto

2011-03-23

A powerful HPLC-DAD-ESI-TOF MS method was established for the efficient identification of the chemical constituents in the methanolic extracts of avocado (Persea americana). Separation and detection conditions were optimized by using a standard mix containing 39 compounds belonging to phenolic acids and different categories of flavonoids, analytes that could be potentially present in the avocado extracts. Optimum LC separation was achieved on a Zorbax Eclipse Plus C18 analytical column (4.6×150 mm, 1.8 μm particle size) by gradient elution with water+acetic acid (0.5%) and acetonitrile as mobile phases, at a flow rate of 1.6 mL/min. The detection was carried out by ultraviolet-visible absorption and ESI-TOF MS. The developed method was applied to the study of 3 different varieties of avocado, and 17 compounds were unequivocally identified with standards. Moreover, around 25 analytes were tentatively identified by taking into account the accuracy and isotopic information provided by TOF MS.

There's An App For That: Planning Ahead for the Solar Eclipse in August 2017

NASA Astrophysics Data System (ADS)

Chizek Frouard, Malynda R.; Lesniak, Michael V.; Bell, Steve

2017-01-01

With the total solar eclipse of 2017 August 21 over the continental United States approaching, the U.S. Naval Observatory (USNO) on-line Solar Eclipse Computer can now be accessed via an Android application, available on Google Play.Over the course of the eclipse, as viewed from a specific site, several events may be visible: the beginning and ending of the eclipse (first and fourth contacts), the beginning and ending of totality (second and third contacts), the moment of maximum eclipse, sunrise, or sunset. For each of these events, the USNO Solar Eclipse 2017 Android application reports the time, Sun's altitude and azimuth, and the event's position and vertex angles. The app also lists the duration of the total phase, the duration of the eclipse, the magnitude of the eclipse, and the percent of the Sun obscured for a particular eclipse site.All of the data available in the app comes from the flexible USNO Solar Eclipse Computer Application Programming Interface (API), which produces JavaScript Object Notation (JSON) that can be incorporated into third-party Web sites or custom applications. Additional information is available in the on-line documentation (http://aa.usno.navy.mil/data/docs/api.php).For those who prefer using a traditional data input form, the local circumstances can still be requested at http://aa.usno.navy.mil/data/docs/SolarEclipses.php.In addition the 2017 August 21 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) consolidates all of the USNO resources for this event, including a Google Map view of the eclipse track designed by Her Majesty's Nautical Almanac Office (HMNAO).Looking further ahead, a 2024 April 8 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2024.php) is also available.

The ultraviolet spectrum of the eclipsing binary IM Aurigae

NASA Technical Reports Server (NTRS)

Bruhweiler, F. C.; Feibelman, W. A.; Kondo, Y.

1986-01-01

Low dispersion IUE spectra have been obtained at primary and secondary minima, together with a high dispersion spectrum near maximum, for the eclipsing Algol-type IM Aurigae system. The weak, sharp absorption features noted at two distinct velocities in the high dispersion data are attributed to circumbinary gaseous shells and/or gas streams between the stellar components. The implications of these results for the recently observed increase in O-C values of the primary minimum, which prompted this UV spectral search for evidence of a recent mass-loss event, are discussed.

A Catalog of Eclipsing Binaries and Variable Stars Observed with ASTEP 400 from Dome C, Antarctica

NASA Astrophysics Data System (ADS)

Chapellier, E.; Mékarnia, D.; Abe, L.; Guillot, T.; Agabi, K.; Rivet, J.-P.; Schmider, F.-X.; Crouzet, N.; Aristidi, E.

2016-10-01

We used the large photometric database of the ASTEP program, whose primary goal was to detect exoplanets in the southern hemisphere from Antarctica, to search for eclipsing binaries (EcBs) and variable stars. 673 EcBs and 1166 variable stars were detected, including 31 previously known stars. The resulting online catalogs give the identification, the classification, the period, and the depth or semi-amplitude of each star. Data and light curves for each object are available at http://astep-vo.oca.eu.

Gap plasmon-enhanced photoluminescence of monolayer MoS2 in hybrid nanostructure

NASA Astrophysics Data System (ADS)

Yu, Le; Liu, Di; Qi, Xiao-Zhuo; Xiong, Xiao; Feng, Lan-Tian; Li, Ming; Guo, Guo-Ping; Guo, Guang-Can; Ren, Xi-Feng

2018-04-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 61590932 and 11774333), the Anhui Initiative Project in Quantum Information Technologies, China (Grant No. AHY130300), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB24030600), the National Key Research and Development Program of China (Grant No. 2016YFA0301700), and the Fundamental Research Funds for the Central Universities, China.

Solar Eclipse Computer API: Planning Ahead for August 2017

NASA Astrophysics Data System (ADS)

Bartlett, Jennifer L.; Chizek Frouard, Malynda; Lesniak, Michael V.; Bell, Steve

2016-01-01

With the total solar eclipse of 2017 August 21 over the continental United States approaching, the U.S. Naval Observatory (USNO) on-line Solar Eclipse Computer can now be accessed via an application programming interface (API). This flexible interface returns local circumstances for any solar eclipse in JavaScript Object Notation (JSON) that can be incorporated into third-party Web sites or applications. For a given year, it can also return a list of solar eclipses that can be used to build a more specific request for local circumstances. Over the course of a particular eclipse as viewed from a specific site, several events may be visible: the beginning and ending of the eclipse (first and fourth contacts), the beginning and ending of totality (second and third contacts), the moment of maximum eclipse, sunrise, or sunset. For each of these events, the USNO Solar Eclipse Computer reports the time, Sun's altitude and azimuth, and the event's position and vertex angles. The computer also reports the duration of the total phase, the duration of the eclipse, the magnitude of the eclipse, and the percent of the Sun obscured for a particular eclipse site. On-line documentation for using the API-enabled Solar Eclipse Computer, including sample calls, is available (http://aa.usno.navy.mil/data/docs/api.php). The same Web page also describes how to reach the Complete Sun and Moon Data for One Day, Phases of the Moon, Day and Night Across the Earth, and Apparent Disk of a Solar System Object services using API calls.For those who prefer using a traditional data input form, local circumstances can still be requested that way at http://aa.usno.navy.mil/data/docs/SolarEclipses.php. In addition, the 2017 August 21 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) consolidates all of the USNO resources for this event, including a Google Map view of the eclipse track designed by Her Majesty's Nautical Almanac Office (HMNAO). Looking further ahead, a 2024 April 8 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2024.php) is also available.

On-line Eclipse Resources from the U.S. Naval Observatory: Planning Ahead for April 2024

NASA Astrophysics Data System (ADS)

Fredericks, Amy C.; Bartlett, J. L.; Bell, S.; Stapleton, J. C.

2014-01-01

On 8 April 2024, “…night from mid-day…” (Archilochus, 648 BCE) will appear to fortunate observers along a narrow band, approximately 115 mi (185 km) wide, that crosses fifteen states from Texas to Maine. In response to growing interest in the two total solar eclipses that will sweep the continental United States in the next 11 years, the U.S. Naval Observatory has developed an on-line resource center with direct links to 2024-specific services: the 2024 April 8 Total Solar Eclipse page (http://aa.usno.navy.mil/data/docs/Eclipse2024.php). The Solar Eclipse Computer (http://aa.usno.navy.mil/data/docs/SolarEclipses.php) calculates tables of local circumstances for events visible throughout the world. A similar service is available for lunar eclipses, Lunar Eclipse Computer (http://aa.usno.navy.mil/data/docs/LunarEclipse.php). The USNO Eclipse Portal (http://astro.ukho.gov.uk/eclbin/query_usno.cgi) provides diagrams and animations showing the global circumstances for events visible throughout the world and local circumstances for events visible at selected locations. The Web site, which includes both solar and lunar eclipses, is a joint effort with Her Majesty’s Nautical Almanac Office. The Eclipses of the Sun and Moon page (http://aa.usno.navy.mil/data/docs/UpcomingEclipses.php) links to electronic copies of the visibility maps from The Astronomical Almanac. The Eclipse Reference List (http://aa.usno.navy.mil/faq/docs/eclipse_ref.php) is a representative survey of the available literature for those interested in delving into these phenomena, either technically or historically. As exciting as the 2024 total solar eclipse, another spectacular event will precede it; a total solar eclipse will cross a different swath of the continent on August 21, 2017. The U.S. Naval Observatory has a resource center for that event as well (http://aa.usno.navy.mil/data/docs/Eclipse2017.php) . If your plans for 2024 are not yet made, visit the 2024 April 8 Total Solar Eclipse page to prepare for up to 4 minutes 31 seconds of “unexampled beauty, grandeur, and impressiveness” (Newcomb 1890) and of darkness.

Practicing for 2023 and 2024: What the AAS Solar Eclipse Task Force Learned from the "Great American Eclipse" of 2017

NASA Astrophysics Data System (ADS)

Fienberg, R. T.; Speck, A. K.; Habbal, S. R.

2017-12-01

More than three years ahead of the "Great American Eclipse" of August 2017, the American Astronomical Society formed the AAS Solar Eclipse Task Force to function as a think tank, coordinating body, and communication gateway to the vast resources available about the 2017 eclipse and solar eclipses more generally. The task force included professional and amateur astronomers, formal and informal educators, and science journalists; many had experienced total solar eclipses before, and others would experience their first totality in August 2017. The AAS task force secured funding from the AAS Council, the National Science Foundation, and NASA. These resources were used mainly for three purposes: (1) to build a website that contains basic information about solar eclipses, safe viewing practices, and eclipse imaging and video, along with resources for educators and the media and a searchable map of eclipse-related events and activities, with links to other authoritative websites with more detailed information; (2) to solicit, receive, evaluate, and fund proposals for mini-grants to support eclipse-related education and public outreach to underrepresented groups both inside and outside the path of totality; and (3) to organize a series of multidisciplinary workshops across the country to prepare communities for the eclipse and to facilitate collaborations between astronomers, meteorologists, school administrators, and transporation and emergency-management professionals. Most importantly, the AAS Solar Eclipse Task Force focused on developing and disseminating appropriate eclipse safety information. The AAS and NASA jointly developed safety messaging that won the endorsement of the American Academies of Opthalmology and Optometry. In the weeks immediately preceding the eclipse, it became clear that the marketplace was being flooded by counterfeit eclipse glasses and solar viewers, leading to a last minute change in our communication strategy. In this talk, we'll review the task force's activities, take stock of what went right and what went wrong, and consider how to do an even better job preparing the nation for the next two "Great American" solar eclipses: the annular eclipse of October 14, 2023, and the total eclipse of April 8, 2024.

Photometric Analysis of Eclipsing Binary Az Vir

NASA Astrophysics Data System (ADS)

Neugarten, Andrew; Akiba, Tatsuya; Gokhale, Vayujeet

2018-06-01

We present photometric analysis of the eclipsing binary star system Az Vir. Standard BVR filter data were obtained using the 17-inch PlaneWave Instruments CDK telescope at the Truman State University Observatory in Kirksville, Mo and the 31-inch NURO telescope at the Lowell Observatory complex in Flagstaff, AZ. We apply an eight-term truncated Fourier fit to the light curves generated from these data to confirm the classification of Az Vir as a W Ursae Majoris-type eclipsing variable, using criteria specified by Rucinski (1997). We also calculate the values for the O’Connell Effect Ratio (OER) and the Light Curve Asymmetry (LCA) to quantify the asymmetry in the BVR light curves. In addition, we use data provided by the SuperWASP mission to perform long term O-C (observed minus calculated) analysis on the system to determine if and how its period is changing.

Photometric Study of the Pulsating, Eclipsing Binary OO Dra

NASA Astrophysics Data System (ADS)

Zhang, X. B.; Deng, L. C.; Tian, J. F.; Wang, K.; Sun, J. J.; Liu, Q. L.; Xin, H. Q.; Zhou, Q.; Yan, Z. Z.; Luo, Z. Q.; Luo, C. Q.

2014-12-01

We present a comprehensive photometric study of the pulsating, eclipsing binary OO Dra. Simultaneous B- and V-band photometry of the star was carried out on 14 nights. A revised orbital period and a new ephemeris were derived from the data. The first photometric solution of the binary system and the physical parameters of the component stars are determined. They reveal that OO Dra could be a detached system with a less-massive secondary component nearly filling its Roche lobe. By subtracting the eclipsing light changes from the data, we obtained the intrinsic pulsating light curves of the hotter, massive primary component. A frequency analysis of the residual light yields two confident pulsation modes in both B- and V-band data with the dominant frequency detected at 41.865 c/d. A brief discussion concerning the evolutionary status and the pulsation nature of the binary system is finally given.

Photometric study of the pulsating, eclipsing binary OO DRA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, X. B.; Deng, L. C.; Tian, J. F.

We present a comprehensive photometric study of the pulsating, eclipsing binary OO Dra. Simultaneous B- and V-band photometry of the star was carried out on 14 nights. A revised orbital period and a new ephemeris were derived from the data. The first photometric solution of the binary system and the physical parameters of the component stars are determined. They reveal that OO Dra could be a detached system with a less-massive secondary component nearly filling its Roche lobe. By subtracting the eclipsing light changes from the data, we obtained the intrinsic pulsating light curves of the hotter, massive primary component.more » A frequency analysis of the residual light yields two confident pulsation modes in both B- and V-band data with the dominant frequency detected at 41.865 c/d. A brief discussion concerning the evolutionary status and the pulsation nature of the binary system is finally given.« less

A YOUNG ECLIPSING BINARY AND ITS LUMINOUS NEIGHBORS IN THE EMBEDDED STAR CLUSTER Sh 2-252E

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lester, Kathryn V.; Gies, Douglas R.; Guo, Zhao, E-mail: lester@chara.gsu.edu, E-mail: gies@chara.gsu.edu, E-mail: guo@chara.gsu.edu

We present a photometric and light curve analysis of an eccentric eclipsing binary in the K2 Campaign 0 field, which resides in Sh 2-252E, a young star cluster embedded in an H ii region. We describe a spectroscopic investigation of the three brightest stars in the crowded aperture to identify which is the binary system. We find that none of these stars are components of the eclipsing binary system, which must be one of the fainter nearby stars. These bright cluster members all have remarkable spectra: Sh 2-252a (EPIC 202062176) is a B0.5 V star with razor sharp absorption lines, Sh 2-252b is amore » Herbig A0 star with disk-like emission lines, and Sh 2-252c is a pre-main-sequence star with very red color.« less

BEER ANALYSIS OF KEPLER AND CoRoT LIGHT CURVES. IV. DISCOVERY OF FOUR NEW LOW-MASS WHITE DWARF COMPANIONS IN THE KEPLER DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faigler, S.; Kull, I.; Mazeh, T.

We report the discovery of four short-period eclipsing systems in the Kepler light curves, consisting of an A-star primary and a low-mass white dwarf (WD) secondary (dA+WD)—KIC 4169521, KOI-3818, KIC 2851474, and KIC 9285587. The systems show BEaming, Ellipsoidal and Reflection (BEER) phase modulations together with primary and secondary eclipses. These add to the 6 Kepler and 18 WASP short-period eclipsing dA+WD binaries that were previously known. The light curves, together with follow-up spectroscopic observations, allow us to derive the masses, radii, and effective temperatures of the two components of the four systems. The orbital periods, of 1.17–3.82 days, andmore » WD masses, of 0.19–0.22 M{sub ⊙}, are similar to those of the previously known systems. The WD radii of KOI-3818, KIC 2851474, and KIC 9285587 are 0.026, 0.035, and 0.026 R{sub ⊙}, respectively, the smallest WD radii derived so far for short-period eclipsing dA+WD binaries. These three binaries extend the previously known population to older systems with cooler and smaller WD secondaries. KOI-3818 displays evidence for a fast-rotating primary and a minute but significant eccentricity, ∼1.5 × 10{sup −3}. These features are probably the outcome of the mass-transfer process.« less

Ferrocene/fullerene hybrids showing large second-order nonlinear optical activities: impact of the cage unit size.

PubMed

Wang, Wen-Yong; Wang, Li; Ma, Na-Na; Zhu, Chang-Li; Qiu, Yong-Qing

2015-06-07

The electron donor-acceptor complexes, which undergo intramolecular charge transfer under external stimulus, are an emerging class of materials showing important application in nonlinear optics. Synthesizing ferrocene/fullerene complexes through face-to-face fusion would enjoy the merits of both ferrocene and fullerene due to their strong donor-acceptor interactions. Four ferrocene/fullerene hybrid complexes with the gradual extension of fullerene cage size, including CpFe(C60H5), CpFe(C66H5), CpFe(C70H5), and CpFe(C80H5) (Cp is cyclopentadienyl), have been investigated by density functional theory. These hybrid molecules give eclipsed and staggered isomers. The main reason that the eclipsed isomer is stable is that the eclipsed structure possesses large CpFefullerene bonding energy. The CpFefullerene interaction is smaller than that of CpFefullerene, which must come from two different interfaces. The presence of covalent bond character between CpFe and fullerene is supported by the localized orbital locator, deformation of electron density distribution and energy decomposition analysis. Significantly, the absorption bands and first hyperpolarizabilities of these hybrid complexes are strongly sensitive to the fullerene cage size, which is ascribed to a change in the charge transfer pattern, especially for CpFe(C80H5), which displays reverse π → π* charge transfer from bottom to top cage, leading to notable hyperpolarizability. Investigation of the structure-property relationship at the molecular level can benefit the design and preparation of such hybrid complexes in chemistry and materials science.

Eclipse Megamovie 2017: How did we do?

NASA Astrophysics Data System (ADS)

Hudson, Hugh; Bender, Mark; Collier, Braxton; Johnson, Calvin; Koh, Justin; Konerding, David; Martinez Oliveros, Juan Carlos; Peticolas, Laura; White, Vivian; Zevin, Dan

2018-01-01

The Eclipse Megamovie program, as set up for the Great American Eclipse of 21 August 2017, achived a massive volunteer participation, making maximal use existing equipment but with coordinated training. Everything worked fine, and the archive entered the public domain on Friday, October 6. It comprises about 800 GB of data from DSLR cameras and telescopes. An additional 200 GB of data were obtained by smartphone cameras operating a dedicated free app. The massive oversampling made possible by the many (about 2500) volunteer observers has opened new parameter space for tracking coronal and chromospheric time development. Fortuitously some solar activity appeared during the 90-minute period of totality, including a C-class flare and an ongoing CME. At the smartphone level, with the advantage of precise GPS timing, we have data on solar structure via the timing of Baily's Beads at the 2nd and 3rd contacts. The Megamovie archive is an historical first, and we hope that it has already been a springboard for citizen-science projects. We discuss the execution of the program, presenting some of the 2017 science plans and results. We expect that the eclipse of 2024 will be better still.

The PHEMU15 catalogue and astrometric results of the Jupiter's Galilean satellite mutual occultation and eclipse observations made in 2014-2015

NASA Astrophysics Data System (ADS)

Saquet, E.; Emelyanov, N.; Robert, V.; Arlot, J.-E.; Anbazhagan, P.; Baillié, K.; Bardecker, J.; Berezhnoy, A. A.; Bretton, M.; Campos, F.; Capannoli, L.; Carry, B.; Castet, M.; Charbonnier, Y.; Chernikov, M. M.; Christou, A.; Colas, F.; Coliac, J.-F.; Dangl, G.; Dechambre, O.; Delcroix, M.; Dias-Oliveira, A.; Drillaud, C.; Duchemin, Y.; Dunford, R.; Dupouy, P.; Ellington, C.; Fabre, P.; Filippov, V. A.; Finnegan, J.; Foglia, S.; Font, D.; Gaillard, B.; Galli, G.; Garlitz, J.; Gasmi, A.; Gaspar, H. S.; Gault, D.; Gazeas, K.; George, T.; Gorda, S. Y.; Gorshanov, D. L.; Gualdoni, C.; Guhl, K.; Halir, K.; Hanna, W.; Henry, X.; Herald, D.; Houdin, G.; Ito, Y.; Izmailov, I. S.; Jacobsen, J.; Jones, A.; Kamoun, S.; Kardasis, E.; Karimov, A. M.; Khovritchev, M. Y.; Kulikova, A. M.; Laborde, J.; Lainey, V.; Lavayssiere, M.; Le Guen, P.; Leroy, A.; Loader, B.; Lopez, O. C.; Lyashenko, A. Y.; Lyssenko, P. G.; Machado, D. I.; Maigurova, N.; Manek, J.; Marchini, A.; Midavaine, T.; Montier, J.; Morgado, B. E.; Naumov, K. N.; Nedelcu, A.; Newman, J.; Ohlert, J. M.; Oksanen, A.; Pavlov, H.; Petrescu, E.; Pomazan, A.; Popescu, M.; Pratt, A.; Raskhozhev, V. N.; Resch, J.-M.; Robilliard, D.; Roschina, E.; Rothenberg, E.; Rottenborn, M.; Rusov, S. A.; Saby, F.; Saya, L. F.; Selvakumar, G.; Signoret, F.; Slesarenko, V. Y.; Sokov, E. N.; Soldateschi, J.; Sonka, A.; Soulie, G.; Talbot, J.; Tejfel, V. G.; Thuillot, W.; Timerson, B.; Toma, R.; Torsellini, S.; Trabuco, L. L.; Traverse, P.; Tsamis, V.; Unwin, M.; Abbeel, F. Van Den; Vandenbruaene, H.; Vasundhara, R.; Velikodsky, Y. I.; Vienne, A.; Vilar, J.; Vugnon, J.-M.; Wuensche, N.; Zeleny, P.

2018-03-01

During the 2014-2015 mutual events season, the Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE), Paris, France, and the Sternberg Astronomical Institute (SAI), Moscow, Russia, led an international observation campaign to record ground-based photometric observations of Galilean moon mutual occultations and eclipses. We focused on processing the complete photometric observations data base to compute new accurate astrometric positions. We used our method to derive astrometric positions from the light curves of the events. We developed an accurate photometric model of mutual occultations and eclipses, while correcting for the satellite albedos, Hapke's light scattering law, the phase effect, and the limb darkening. We processed 609 light curves, and we compared the observed positions of the satellites with the theoretical positions from IMCCE NOE-5-2010-GAL satellite ephemerides and INPOP13c planetary ephemeris. The standard deviation after fitting the light curve in equatorial positions is ±24 mas, or 75 km at Jupiter. The rms (O-C) in equatorial positions is ±50 mas, or 150 km at Jupiter.

A NEW CLASS OF NASCENT ECLIPSING BINARIES WITH EXTREME MASS RATIOS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moe, Maxwell; Stefano, Rosanne Di, E-mail: mmoe@cfa.harvard.edu

2015-03-10

Early B-type main-sequence (MS) stars (M {sub 1} ≈ 5-16 M {sub ☉}) with closely orbiting low-mass stellar companions (q = M {sub 2}/M {sub 1} < 0.25) can evolve to produce Type Ia supernovae, low-mass X-ray binaries, and millisecond pulsars. However, the formation mechanism and intrinsic frequency of such close extreme mass-ratio binaries have been debated, especially considering none have hitherto been detected. Utilizing observations of the Large Magellanic Cloud galaxy conducted by the Optical Gravitational Lensing Experiment, we have discovered a new class of eclipsing binaries in which a luminous B-type MS star irradiates a closely orbiting low-massmore » pre-MS companion that has not yet fully formed. The primordial pre-MS companions have large radii and discernibly reflect much of the light they intercept from the B-type MS primaries (ΔI {sub refl} ≈ 0.02-0.14 mag). For the 18 definitive MS + pre-MS eclipsing binaries in our sample with good model fits to the observed light-curves, we measure short orbital periods P = 3.0-8.5 days, young ages τ ≈ 0.6-8 Myr, and small secondary masses M {sub 2} ≈ 0.8-2.4 M {sub ☉} (q ≈ 0.07-0.36). The majority of these nascent eclipsing binaries are still associated with stellar nurseries, e.g., the system with the deepest eclipse ΔI {sub 1} = 2.8 mag and youngest age τ = 0.6 ± 0.4 Myr is embedded in the bright H II region 30 Doradus. After correcting for selection effects, we find that (2.0 ± 0.6)% of B-type MS stars have companions with short orbital periods P = 3.0-8.5 days and extreme mass ratios q ≈ 0.06-0.25. This is ≈10 times greater than that observed for solar-type MS primaries. We discuss how these new eclipsing binaries provide invaluable insights, diagnostics, and challenges for the formation and evolution of stars, binaries, and H II regions.« less

PREDICTING GAIA’S PARALLAX DISTANCE TO THE CYGNUS OB2 ASSOCIATION WITH ECLIPSING BINARIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiminki, Daniel C.; Kobulnicky, Henry A.; Álvarez, Carlos A. Vargas

2015-10-01

The Cygnus OB2 Association is one of the nearest and largest collections of massive stars in the Galaxy. Situated at the heart of the “Cygnus X” complex of star-forming regions and molecular clouds, its distance has proven elusive owing to the ambiguous nature of kinematic distances along this ℓ ≃ 80° sightline and the heavy, patchy extinction. In an effort to refine the three-dimensional geometry of key Cygnus X constituents, we have measured distances to four eclipsing double-lined OB-type spectroscopic binaries that are probable members of Cyg OB2. We find distances of 1.33 ± 0.17, 1.32 ± 0.07, 1.44 ±more » 0.18, and 1.32 ± 0.13 kpc toward MT91 372, MT91 696, CPR2002 A36, and Schulte 3, respectively. We adopt a weighted average distance of 1.33 ± 0.06 kpc. This agrees well with spectrophotometric estimates for the Association as a whole and with parallax measurements of protostellar masers in the surrounding interstellar clouds, thereby linking the ongoing star formation in these clouds with Cyg OB2. We also identify Schulte 3C (O9.5V), a 4″ visual companion to the 4.75 day binary Schulte 3(A+B), as a previously unrecognized Association member.« less

Books and Other Resources for Education about the August 21, 2017, Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Fraknoi, Andrew; Kentrianakis, Michael

2017-06-01

As part of our work to reach and educate the 300+ million Americans of all ages about observing the August 21 solar eclipse, especially by being outdoors in the path of totality but also for those who will see only partial phases, we have compiled annotated lists of books, pamphlets, travel guides, websites, and other information useful for teachers, students, and the general public and made them available on the web, at conferences, and through webinars. Our list includes new eclipse books by David Barron, Anthony Aveni, Frank Close, Tyler Nordgren, John Dvorak, Michael Bakich, and others. We list websites accessible to the general public including those of the International Astronomical Union Working Group on Eclipses (http://eclipses.info, which has links to all the sites listed below); the AAS Eclipse 2017 Task Force (http://eclipse2017.aas.org); NASA Heliophysics (http://eclipse.nasa.gov); Fred Espenak (the updated successor to his authoritative "NASA website": http://EclipseWise.com); Michael Zeiler (http://GreatAmericanEclipse.com); Xavier Jubier (http://xjubier.free.fr/en/site_pages/solar_eclipses/); Jay Anderson (meteorology: http://eclipsophile.com); NASA's Eyes (http://eyes.nasa.gov/eyes-on-eclipse.html and its related app); the Astronomical Society of the Pacific (http://www.astrosociety.org/eclipse); Dan McGlaun (http://eclipse2017.org/); Bill Kramer (http://eclipse-chasers.com). Specialized guides include Dennis Schatz and Andrew Fraknoi's Solar Science for teachers (from the National Science Teachers Association:http://www.nsta.org/publications/press/extras/files/solarscience/SolarScienceInsert.pdf), and a printing with expanded eclipse coverage of Jay Pasachoff's, Peterson Field Guide to the Stars and Planets (14th printing of the fourth edition, 2016: http://solarcorona.com).A version of our joint list is to be published in the July issue of the American Journal of Physics as a Resource Letter on Eclipses, adding to JMP's 2010, "Resource Letter SP-1 on Solar Physics," AJP, 78, September, 890-901.

Preparing for and Observing the 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, J.

2015-11-01

I discuss ongoing plans and discussions for EPO and scientific observing of the 21 August 2017 total solar eclipse. I discuss aspects of EPO based on my experiences at the 60 solar eclipses I have seen. I share cloud statistics along the eclipse path compiled by Jay Anderson, the foremost eclipse meteorologist. I show some sample observations of composite imagery, of spectra, and of terrestrial temperature changes based on observations of recent eclipses, including 2012 from Australia and 2013 from Gabon. Links to various mapping sites of totality, partial phases, and other eclipse-related information, including that provided by Michael Zeiler, Fred Espenak (retired from NASA) and Xavier Jubier can be found on the website I run for the International Astronomical Union's Working Group on Eclipses at http://www.eclipses.info.

Fifty year canon of solar eclipses: 1986 - 2035

NASA Technical Reports Server (NTRS)

Espenak, Fred

1987-01-01

A complete catalog is presented, listing the general characteristics of every solar eclipse from 1901 through 2100. To complement this catalog, a detailed set of cylindrical projection world maps shows the umbral paths of every solar eclipse over the 200 year interval. Focusing in on the next 50 years, accurate geodetic path coordinates and local circumstances for the 71 central eclipses from 1987 through 2035 are tabulated. Finally, the geodetic paths of the umbral and penumbral shadows of all 109 solar eclipses in this period are plotted on orthographic projection maps of the Earth. Appendices are included which discuss eclipse geometry, eclipse frequency and occurrence, modern eclipse prediction and time determination. Finally, code for a simple Fortran program is given to predict the occurrence and characteristics of solar eclipses.

Is There a Circumbinary Planet around NSVS 14256825?

NASA Astrophysics Data System (ADS)

Nasiroglu, Ilham; Goździewski, Krzysztof; Słowikowska, Aga; Krzeszowski, Krzysztof; Żejmo, Michał; Zola, Staszek; Er, Huseyin; Ogłoza, Waldemar; Dróżdż, Marek; Koziel-Wierzbowska, Dorota; Debski, Bartlomiej; Karaman, Nazli

2017-03-01

The cyclic behavior of (O-C) residuals of eclipse timings in the sdB+M eclipsing binary NSVS 14256825 was previously attributed to one or two Jovian-type circumbinary planets. We report 83 new eclipse timings that not only fill in the gaps in those already published but also extend the time span of the (O-C) diagram by three years. Based on the archival and our new data spanning over more than 17 years, we re-examined the up-to-date system (O-C). The data revealed a systematic, quasi-sinusoidal variation deviating from an older linear ephemeris by about 100 s. It also exhibits a maximum in the (O-C) near JD 2,456,400 that was previously unknown. We consider two most credible explanations of the (O-C) variability: the light propagation time due to the presence of an invisible companion in a distant circumbinary orbit, and magnetic cycles reshaping one of the binary components, known as the Applegate or Lanza-Rodonó effect. We found that the latter mechanism is unlikely due to the insufficient energy budget of the M-dwarf secondary. In the framework of the third-body hypothesis, we obtained meaningful constraints on the Keplerian parameters of a putative companion and its mass. Our best-fitting model indicates that the observed quasi-periodic (O-C) variability can be explained by the presence of a brown dwarf with the minimal mass of 15 Jupiter masses rather than a planet, orbiting the binary in a moderately elliptical orbit (e≃ 0.175) with a period of ˜10 years. Our analysis rules out the two-planet model proposed earlier.

The beginnings of German governmental sponsorship in astronomy: the solar eclipse expeditions of 1868 as a prelude to the Venus transit expeditions of 1874 and 1882

NASA Astrophysics Data System (ADS)

Duerbeck, Hilmar W.

The origins of the North German expeditions to observe the total solar eclipse of August 18, 1868, are outlined. The incentive was made by politician and science writer Aaron Bernstein, the financing was provided by the North German Federation, and the project was handled by members of the Astronomische Gesellschaft. The astronomical expeditions to Mulwar in India and Aden in South Arabia are summarized, the following archaeological expedition to upper Egypt is also considered. The activities of the participating scientists, also with respect to the preparation of popular accounts, are described. Finally, the impact of these expeditions on the planning of the large-scale project to observe the Venus transits of 1874 and 1882 is investigated.

Astronomy Teaching and Teachers Continuing Education: the Interdisciplinarity during a Total Lunar Eclipse. (Spanish Title: Enseñanza de la Astronomía y la Formación Continua de Profesores: la Interdisciplinariedad Durante un Eclipse Total de Luna.) Educação EM Astronomia E Formação Continuada de Professores: a Interdisciplinaridade Durante um Eclipse Lunar TOTAL

NASA Astrophysics Data System (ADS)

Langhi, Rodolfo

2009-07-01

This paper describes how 67 teachers from 23 cities, could awaken, in students, the scientific interest, using a natural astronomical phenomenon: a total lunar eclipse. Before and after of eclipse, meetings for continuing education were characterized by interdisciplinarity of astronomy and the importance of these observations. Working groups were formed by teachers and students, who organized the survey data, mobilizing the people in their cities. The results point ways about how to provide the scientific culture and the motivation to learn science in students, using approaches between the following communities: scientific, amateur and school. En este artículo se describe cómo 67 profesores de 23 ciudades, despertó el interés científico en los estudiantes mediante un fenómeno astronómico: un eclipse total de Luna. Antes y después del eclipse, reuniones para la formación continua se centraron en la interdisciplinariedad de la astronomía, y la importancia de las observaciones de este tipo de fenómeno. Profesores y estudiantes formaron grupos de trabajo para investigar datos durante el eclipse, con el participación de la comunidad en sus ciudades. Los resultados apuntan a las opciones que conducen a la cultura científica y la motivación para aprender la ciencia, utilizando las relaciones de los siguientes grupos: científicos, aficionados y la escuela. Este texto relata como 67 professores, provenientes de 23 cidades, puderam despertar, nos alunos, o interesse científico utilizando um fenômeno natural astronômico: um eclipse lunar total. O evento foi precedido e procedido por encontros de formação continuada, onde se caracterizou a interdisciplinaridade da astronomia e a importância das observações de fenômenos como estes. Grupos de trabalho foram formados por professores e alunos, que se organizaram para o levantamento conjunto de dados durante o fenômeno, além do envolvimento da comunidade em suas respectivas cidades. Os resultados apontam para caminhos que podem proporcionar a motivação e a cultura científica, através de aproximações entre as comunidades científica, amadora e escolar.

Report of the IAU Working Group on Solar Eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2015-08-01

The Working Group on Solar Eclipses coordinates scientists and information in the study of the Sun and the heliosphere at solar eclipses. Our Website at http://eclipses.info has a wide variety of information, including links to maps and other websites dealing with solar eclipses, as well as information on how to observe the partial-phases of solar eclipses safely and why it is interesting for not only scientists but also for the public to observe eclipses and to see how we work to uncover the mysteries of the sun's upper atmosphere. In the last triennium, there were total eclipses in Australia and the Pacific in 2012; in an arc across Africa from Gabon to Uganda and Kenya in 2013; and in the Arctic, including Svalbard and the Faeroes plus many airplanes aloft, in 2015. In the coming triennium, there will be total solar eclipses in Indonesia and the Pacific in 2016 and then, on 21 August 2017, a total solar eclipse that will sweep across the Continental United States from northwest to southeast. Mapping websites, all linked to http://eclipses.info, include Fred Espenak's http://EclipseWise.com; Michael Zeiler's http://GreatAmericanEclipse.com and http://eclipse-maps.com; Xavier Jubier's http://xjubier.free.fr; and (with weather and cloudiness analysis) Jay Anderson's http://eclipser.ca. Members of the Working Group, chaired by Jay Pasachoff (U.S.), include Iraida Kim (Russia), Kiroki Kurokawa (Japan), Jagdev Singh (India), Vojtech Rusin (Slovakia), Zhongquan Qu (China), Fred Espenak (U.S.), Jay Anderson (Canada), Glenn Schneider (U.S.), Michael Gill (U.K.), Xavier Jubier (France), Michael Zeiler (U.S.), and Bill Kramer (U.S.).

Gravitation is Retarded:Theory and Evidence

NASA Astrophysics Data System (ADS)

Tang, K.

2009-12-01

Gravitation is Retarded:Theory and Evidence There were more than twenty times of observations about gravity anomalies during the solar eclipses since Maurice Allais’s pendulum test during the total solar eclipse of 1954 in Paris. All the theoretical modes are calculated according to Newton’s gravitation law. But due to the observation environments and conditions during above observations were not quite well, the platform for mounting the gravimeters were quite simple, so that the environment and human’s disturbance were unavoidable, therefore the data obtained from above observation where questionable. It is very hard to give a conclusion to say the gravity anomalies during the eclipses were really existing or not. The more important issue is that none of the suggested external factors could account for the magnitude and timing of observed anomalies, according to Chris Duif of University of Technology of Netherland. Since the total solar eclipse of Mohe, 1997, I have been working on a theory to explain the gravity anomalies. At Mohe, I was watching the image of the eclipse, and led a scientific term to conduct a comprehensive geophysical observation, including the gravity observation. The two kinds of observations were conducted at same location and same time. We noticed that solar light of the eclipse was emitted 500 seconds before the image reached to our eyes and cameras. It was reasonable to have similar idea that the gravitation emitted from the sun is also 500 seconds before our gravimeter received and recorded it; it means that gravitation is retarded. Based on either the Special Relativity or Leinard-Wiechert retarded potential, I have deduced the expressions for retarded gravitation; it is vector modification on Newton’s universal gravitation law. The retarded gravitation is gRT=-GM(R-Rβ)(1-β2)/R3(1-βr)3 For common cases, bodies move in a weak gravitation field along a quasi-straight light or with a slow speed, such as planets move around the sun or the moon/satellites moves around the earth, I have deduced a very useful expression gRT=gNT[1+(βθ2-2βr2)/2c2] where,β=v/c,βr=vr/c,βθ=vθ/c, gNT=-GMr/r3. I would like to stress that the approximate solution from the general relativity is only of a scalar modification, as a comparison. The Great Total Soar Eclipse along Yangzi River of July 22 of 2009 provided us a great opportunity to clean up the doubts for last 50 years. Consider that solar gravitation is retarded and the earth’s response is delayed, moon’s retarded factor is negligible, all the theoretical amplitudes and the frequencies for each components of solar tide and moon tide can be calculated, the amplitudes and delay factor of earth tide, the frequencies for each components of solar tide, moon tide and earth tide can been separated and measured from the observation data: AsinωS(t-tS+tE)+BsinωM(t+tE)=Csinωtot(t+ttot). Taking t=t1 and t=t2, we can get two equations with only two variables, solve the two equations, we can get the retarded factor of the solar gravitation and the delay factor of earth response for each compoenets. The retarded factor obtained will be strong evidence that gravitation is retarded.

Mapping the 2017 Eclipse: Education, Navigation, Inspiration

NASA Astrophysics Data System (ADS)

Zeiler, M.

2015-12-01

Eclipse maps are a unique vessel of knowledge. At a glance, they communicate the essential knowledge of where and when to successfully view a total eclipse of the sun. An eclipse map also provides detailed knowledge of eclipse circumstances superimposed on the highway system for optimal navigation, especially in the event that weather forces relocation. Eclipse maps are also a vital planning tool for solar physicists and astrophotographers capturing high-resolution imagery of the solar corona. Michael Zeiler will speak to the role of eclipse maps in educating the American public and inspiring people to make the effort to reach the path of totality for the sight of a lifetime. Michael will review the role of eclipse maps in astronomical research and discuss a project under development, the 2017 Eclipse Atlas for smartphones, tablets, and desktop computers.

Photometric and Spectroscopic Study of the Delta Scuti Stars FH Cam, CU CVn and CC Lyn

NASA Astrophysics Data System (ADS)

Conidis, G. J.; Gazeas, K. D.; Capobianco, C. C.; Ogloza, W.

2010-06-01

Three short period (P ˜ 1 day) variable stars from the Hipparcos catalogue targets were observed after suspected misclassification as Beta Lyr eclipsing systems (Perryman et al. 1997), as no secondary component had been noticed in the inspection of their Broadening Functions (BFs) (Rucinski 2002). FH Cam is found to be a multiple star system with a member exhibiting Delta Scuti behaviour. The dominant pulsation frequency is found to be 7.3411 ± 0.0002 c/d, which corresponds to a pulsation mode of l ≤ 1. We confirmed the pulsations of CU CVn using photometric observations and found a pulsation frequency of 14.7626 ± 0.0250 c/d, which is in agreement with the period given in literature. CC Lyn is a non-eclipsing visual binary (CCDM J07359+4302AB), the brighter component (A) is found to be a multi-mode Delta Scuti pulsator, with pulsation frequencies of 5.6402 ± 0.0004 c/d and 7.3368 ± 0.0005 c/d.

The rotational barrier in ethane: a molecular orbital study.

PubMed

Quijano-Quiñones, Ramiro F; Quesadas-Rojas, Mariana; Cuevas, Gabriel; Mena-Rejón, Gonzalo J

2012-04-20

The energy change on each Occupied Molecular Orbital as a function of rotation about the C-C bond in ethane was studied using the B3LYP, mPWB95 functional and MP2 methods with different basis sets. Also, the effect of the ZPE on rotational barrier was analyzed. We have found that σ and π energies contribution stabilize a staggered conformation. The σ(s) molecular orbital stabilizes the staggered conformation while the stabilizes the eclipsed conformation and destabilize the staggered conformation. The π(z) and molecular orbitals stabilize both the eclipsed and staggered conformations, which are destabilized by the π(v) and molecular orbitals. The results show that the method of calculation has the effect of changing the behavior of the energy change in each Occupied Molecular Orbital energy as a function of the angle of rotation about the C-C bond in ethane. Finally, we found that if the molecular orbital energy contribution is deleted from the rotational energy, an inversion in conformational preference occurs.

THE CHANGE OF THE ORBITAL PERIODS ACROSS ERUPTIONS AND THE EJECTED MASS FOR RECURRENT NOVAE CI AQUILAE AND U SCORPII

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaefer, Bradley E.

2011-12-01

I report on the cumulative results from a program started 24 years ago designed to measure the orbital period change of recurrent novae (RNe) across an eruption. The goal is to use the orbital period change to measure the mass ejected during each eruption as the key part of trying to measure whether the RNe white dwarfs are gaining or losing mass over an entire eruption cycle, and hence whether they can be progenitors for Type Ia supernovae. This program has now been completed for two eclipsing RNe: CI Aquilae (CI Aql) across its eruption in 2000 and U Scorpiimore » (U Sco) across its eruption in 1999. For CI Aql, I present 78 eclipse times from 1991 to 2009 (including four during the tail of the 2000 eruption) plus two eclipses from 1926 and 1935. For U Sco, I present 67 eclipse times, including 46 times during quiescence from 1989 to 2009, plus 21 eclipse times in the tails of the 1945, 1999, and 2010 eruptions. The eclipse times during the tails of eruptions are systematically and substantially shifted with respect to the ephemerides from the eclipses in quiescence, with this being caused by shifts of the center of light during the eruption. These eclipse times are plotted on an O - C diagram and fitted to models with a steady period change ( P-dot ) between eruptions (caused by, for example, conservative mass transfer) plus an abrupt period change ({Delta}P) at the time of eruption. The primary uncertainty arises from the correlation between {Delta}P with P-dot , such that a more negative P-dot makes for a more positive {Delta}P. For CI Aql, the best fit is {Delta}P = -3.7{sup +9.2}{sub -7.3} Multiplication-Sign 10{sup -7}. For U Sco, the best fit is {Delta}P = (+ 43 {+-} 69) Multiplication-Sign 10{sup -7} days. These period changes can directly give a dynamical measure of the mass ejected (M{sub ejecta}) during each eruption with negligible sensitivity to the stellar masses and no uncertainty from distances. For CI Aql, the 1{sigma} upper limit is M{sub ejecta} < 10 Multiplication-Sign 10{sup -7} M{sub Sun }. For U Sco, I derive M{sub ejecta} = (43 {+-} 67) Multiplication-Sign 10{sup -7} M{sub Sun }.« less

Fifty Year Canon of Lunar Eclipses: 1986-2035

NASA Technical Reports Server (NTRS)

Espenak, Fred

1989-01-01

A complete catalog is presented, listing the general circumstances of every lunar eclipse from 1901 through 2100. To compliment this catalog, a set of figures illustrate the basic Moon-shadow geometry and global visibility for every lunar eclipse over the 200 year interval. Focusing in on the next fifty years, 114 detailed diagrams show the Moon's path through Earth's shadow during every eclipse, including contact times at each phase. The accompanying cylindrical projection maps of Earth show regions of hemispheric visibility for all phases. The appendices discuss eclipse geometry, eclipse frequency and recurrence, enlargement of Earth's shadow, crater timings, eclipse brightness and time determination. Finally, a simple FORTRAN program is provided which can be used to predict the occurrence and general characteristics of lunar eclipses. This work is a companion volume to NASA Reference Publication 1178: Fifty Year Canon of Solar Eclipses: 1986-2035.

Outreach to Scientists and to the Public about the Scientific Value of Solar Eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, J.

2017-12-01

The Great American Eclipse of August 21, 2017, provided an unprecedented opportunity for outreach among American audiences on a giant scale in the age of social media. Professonal scientists and other educators, however, were not exempt from ignorance of the remaining scientific value of observing solar eclipses, often mistakenly thinking that space satellites or mountaintop observatories could make artificial eclipses as good as natural ones, which they can't. Further, as Chair of the Working Group on Eclipses of the International Astronomical Union and as a frequent observer of solar eclipses in other countries, I felt an obligation to provide at-least-equal hospitality in our country. Here I discuss our welcome to and interaction with eclipse scientists from Greece, Slovakia, Australia, Bulgaria, Iran, China, and Japan and their participation in the eclipse observations. I describe my own outreach about the still-vital solar-eclipse observations through my August 2017 articles in Nature Astronomy and Scientific American as well as through book reviews in Nature and Phi Beta Kappa's Key Reporter and co-authorship of a Resource Letter on Observing Solar Eclipses in the July issue og the American Journal of Physics. I describe my eclipse-day Academic Minute on National Public Radio via WAMC and on http://365daysofastronomy.org, a website started during the International Year of Astronomy. I discuss my blog post on lecturing to pre-school through elementary-school students for the National Geographic Society's Education Blog. I show my Op-Ed pre-eclipse in the Washington Post. I discuss our eclipse-night broadcast of an eclipse program on PBS's NOVA, and its preparation over many months, back as far and farther than the February 26, 2017, annular solar eclipse observed from Argentinian Patagonia, with images from prior eclipses including 2013 in Gabon and 2015 in Svalbard. My work at the 2017 total solar eclipse was supported in large part with grants from the Committee for Research and Exploration of the National Geographic Society and from the Solar Terrestrial Program of the Division of Atmospheric and Geospace Sciences of the National Science Foundation.

A Detailed Study of the Variable Stars in Five Galactic Globular Clusters: IC4499, NGC4833, NGC6171 (M107), NGC6402 (M14), and NGC6584

NASA Astrophysics Data System (ADS)

Murphy, Brian W.; Darragh, Andrew; Hettinger, Paul; Hibshman, Adam; Johnson, Elliott W.; Liu, Z. J.; Pajkos, Michael A.; Stephenson, Hunter R.; Vondersaar, John R.; Conroy, Kyle E.; McCombs, Thayne A.; Reinhardt, Erik D.; Toddy, Joseph

2015-08-01

We present the results of an extensive study intended to search for and properly classify the variable stars in five galactic globular clusters. Each of the five clusters was observed hundreds to thousands of times over a time span ranging from 2 to 4 years using the SARA 0.6m located at Cerro Tololo Interamerican Observatory. The images were analyzed using the image subtract method of Alard (2000) to identify and produce light curves of all variables found in each cluster. In total we identified 373 variables with 140 of these being newly discovered increasing the number of known variables stars in these clusters by 60%. Of the total we have identified 312 RR Lyrae variables (187 RR0, 18 RR01, 99 RR1, 8 RR2), 9 SX Phe stars, 6 Cepheid variables, 11 eclipsing variables, and 35 long period variables. For IC4499 we identified 64 RR0, 18 RR01, 14 RR1, 4 RR2, 1 SX Phe, 1 eclipsing binary, and 2 long period variables. For NGC4833 we identified 10 RR0, 7 RR1, 2 RR2, 6 SX Phe, 5 eclipsing binaries, and 9 long period variables. For NGC6171 (M107) we identified 13 RR0, 7 RR1, and 1 SX Phe. For NGC6402 (M14) we identified 52 RR0, 56 RR1, 1 RR2, 1 SX Phe, 6 Cepheids, 1 eclipsing binary, and 15 long period variables. For NGC6584 we identified 48 RR0, 15 RR1, 1 RR2, 5 eclipsing binaries, and 9 long period variables. Using the RR Lyrae variables we found the mean V magnitude of the horizontal branch to be VHB = ⟨V ⟩RR = 17.63, 15.51, 15.72, 17.13, and 16.37 magnitudes for IC4499, NGC4833, NGC6171 (M107), NGC6402 (M14), and NGC6584, respectively. From our extensive data set we were able to obtain sufficient temporal and complete phase coverage of the RR Lyrae variables. This has allowed us not only to properly classify each of the RR Lyrae variables but also to use Fourier decomposition of the light curves to further analyze the properties of the variable stars and hence physical properties of each clusters. In this poster we will give the temperature, radius, stellar mass, metallicity, and helium abundance of the set of RR Lyrae variable stars found in each of the five globular clusters.

Simultaneous determination of ten Aconitum alkaloids in rat tissues by UHPLC-MS/MS and its application to a tissue distribution study on the compatibility of Heishunpian and Fritillariae thunbergii Bulbus.

PubMed

Yang, Bin; Xu, Yanyan; Wu, Yuanyuan; Wu, Huanyu; Wang, Yuan; Yuan, Lei; Xie, Jiabin; Li, Yubo; Zhang, Yanjun

2016-10-15

A rapid, sensitive and selective ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous determination of ten Aconitum alkaloids in rat tissues. The tissue samples were prepared by a simple procedure protein precipitation with acetonitrile containing 0.1% acetic acid and separated on an Agilent XDB C18 column (4.6 mm×50mm, 1.8μm) using gradient elution with a mobile phase consisting of water and acetonitrile (both containing 0.1% formic acid) at a flow rate of 0.3mL/min. The quantitive determination was performed on an electrospray ionization (ESI) triple quadrupole tandem mass spectrometer using selective reaction monitoring (SRM) under positive ionization mode. The established method was fully validated according to the USA Food and Drug Administration (FDA) bioanalytical method validation guidance and the results demonstrated that the method was sensitive and selective with the lowest limits of quantification (LLOQ) at 0.025ng/mL in rat tissue homogenates. Meanwhile, the linearity, precision, accuracy, extraction recovery, matrix effect and stability were all within the required limits of biological sample analysis. After method validation, the validated method was successfully applied to the tissue distribution study on the compatibility of Heishunpian (HSP, the processed product of Aconitum carmichaelii Debx) and Fritillariae thunbergii Bulbus (Zhebeimu, ZBM). The results indicated that the distribution feature of monoester diterpenoid aconitines (MDAs), diester diterpenoid aconitines (DDAs) and non-ester alkaloids (NEAs) were inconsistency, and the compatibility of HSP and ZBM resulted in the distribution amount of DDAs increased in tissues. What's more, the results could provide the reliable basis for systematic research on the substance foundation of the compatibility of the herbal pair. Copyright © 2016 Elsevier B.V. All rights reserved.

Massive companions of binary systems

NASA Astrophysics Data System (ADS)

Jableka, D.; Zola, S.; Zakrzewski, B.; Kreiner, J. M.; Ogloza, W.

2018-04-01

We examined the O-C diagrams of eclipsing binary systems and selected these exhibiting cyclic shape, either sinusoidal or quasi sinusoidal. Assuming these variations being due to the Light Time Travel effect (LTE), we estimated the parameters of companions with the Monte Carlo method. As a result, we identified nearly two dozen of eclipsing systems that might have companions with a minimum mass larger than that of a neutron star. Their masses fall into the range between 1.7 and 34 solar masses. This sample of triples with high mass companions can be confirmed with the help of observations gathered by Gaia: parallaxes and astrometric measurements.

Determination of aflatoxins in medicinal plants by high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Siddique, Nadeem A; Mujeeb, Mohd; Ahmad, Sayeed; Panda, Bibhu P; Makhmoor, Mohd

2013-01-01

The intention of the proposed work is to study the presence of the aflatoxins B1, B2, G1 and G2 in medicinal plants, namely Mucuna pruriens, Delphinium denudatum and Portulaca oleraceae. The aflatoxins were extracted, purified by immunoaffinity column chromatography and analysed by high-performance liquid chromatography-tandem quadrupole mass spectrometry with electrospray ionisation (HPLC-MS/MS). Fungal count was carried out in PDA media. A good linear relationship was found for AFB1, AFB2, AFG1 and AFG2 at 1-10 ppb (r>0.9995). The analyte accuracy under three different spiking levels was 86.7-108.1 %, with low per cent relative standard deviations in each case. The aflatoxins can be separated within 5 to7 min using an Agilent XDB C18-column. We found that AFB1 and AFB2 were in trace amounts below the detection limit in M. pruriens whilst they were not detected in D. denudatum. P. oleraceae was found to be contaminated with AFB1 and AFB2. AFG1 and AFG2 were not detected in M. pruriens, P. oleraceae and were below the detection limit in D. denudatum. This was consistent with very low numbers of fungal colonies observed after 6 hr of incubation. The analytical method developed is simple, precise, accurate, economical and can be effectively used to determine the aflatoxins in medicinal plants and therefore to control the quality of products. The aflatoxin levels in the plant extracts examined were related to the minimal fungal load in the medicinal plants examined.

Satellite observations of surface temperature during the March 2015 total solar eclipse.

PubMed

Good, Elizabeth

2016-09-28

The behaviour of remotely sensed land surface temperatures (LSTs) from the spinning-enhanced visible and infrared imager (SEVIRI) during the total solar eclipse of 20 March 2015 is analysed over Europe. LST is found to drop by up to several degrees Celcius during the eclipse, with the minimum LST occurring just after the eclipse mid-point (median=+1.5 min). The drop in LST is typically larger than the drop in near-surface air temperatures reported elsewhere, and correlates with solar obscuration (r=-0.47; larger obscuration = larger LST drop), eclipse duration (r=-0.62; longer duration = larger LST drop) and time (r=+0.37; earlier eclipse = larger LST drop). Locally, the LST drop is also correlated with vegetation (up to r=+0.6), with smaller LST drops occurring over more vegetated surfaces. The LSTs at locations near the coast and at higher elevation are also less affected by the eclipse. This study covers the largest area and uses the most observations of eclipse-induced surface temperature drops to date, and is the first full characterization of satellite LST during an eclipse (known to the author). The methods described could be applied to Geostationary Operational Environmental Satellite (GOES) LST data over North America during the August 2017 total solar eclipse.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

Eclipses and dust formation by WC9 type Wolf-Rayet stars

NASA Astrophysics Data System (ADS)

Williams, P. M.

2014-12-01

Visual photometry of 16 WC8-9 dust-making Wolf-Rayet (WR) stars during 2001-2009 was extracted from the All-Sky Automated Survey All Star Catalogue (ASAS-3) to search for eclipses attributable to extinction by dust formed in clumps in our line of sight. Data for a comparable number of dust-free WC6-9 stars were also examined to help characterize the data set. Frequent eclipses were observed from WR 104, and several from WR 106, extending the 1994-2001 studies by Kato et al., but not supporting their phasing the variations in WR 104 with its `pinwheel' rotation period. Only four other stars showed eclipses, WR 50 (one of the dust-free stars), WR 69, WR 95 and WR 117, and there may have been an eclipse by WR 121, which had shown two eclipses in the past. No dust eclipses were shown by the `historic' eclipsers WR 103 and WR 113. The atmospheric eclipses of the latter were observed but the suggestion by David-Uraz et al. that dust may be partly responsible for these is not supported. Despite its frequent eclipses, there is no evidence in the infrared images of WR 104 for dust made in its eclipses, demonstrating that any dust formed in this process is not a significant contributor to its circumstellar dust cloud and suggesting that the same applies to the other stars showing fewer eclipses.

The Secondary Eclipse and Transit of HD 209458b at 24 micron

NASA Astrophysics Data System (ADS)

Harrington, J.; Luszcz, S.; Deming, D.; Richardson, L. J.; Seager, S.

2005-08-01

We used the Multiband Imaging Photometer on the Spitzer Space Telescope to obtain 24-micron lightcurves for one secondary eclipse and half a transit of extrasolar planet HD 209458b behind/in front of its star. Optimal photometric extraction of the total system brightness gives S/N of ˜100 per 10-sec exposure. We measure the deficit of planetary flux in secondary eclipse at 55 ± 10 μ Jy, or 0.260 ± 0.046% of the stellar flux, giving a brightness temperature of 1130 ± 150 K. The secondary eclipse occurs within 7 min (1σ ) of the mid-time between transits, essentially eliminating the hypothesis that HD 209458b's radius is inflated by tidal dissipation due to an elliptical orbit. Such an orbit would have required a second planet in a resonant orbit. This measurement and a similar, simultaneously-submitted result for TrES-1 by Charbonneau et al. (2005) are the first direct measurements of radiation from confirmed extrasolar planets. We measure a preliminary transit depth of 1.559 ± 0.065% of the stellar flux. The stellar limb-darkening curve is flat to within the errors, as expected for this wavelength. Adopting a stellar radius of 1.18 ± 0.10 R⊙ (Cody and Sasselov 2002) gives a planetary radius of 1.43 ± 0.13 RJ, consistent with that derived from optical measurements. The large error bar prevents us from ruling out a significant wavelength dependence of the eclipsing radius, as might be be expected if a particulate coma were responsible for the inflated optical radius. Spitzer has acquired an additional complete transit; updated results will be presented at the conference. This work was supported by the NASA Origins of Solar Systems program and the Spitzer Space Telescope. LJR is an NRC research associate.

Addressing Students' Misconceptions about Eclipses

ERIC Educational Resources Information Center

Slater, Timothy F.; Gelderman, Richard

2017-01-01

The upcoming Aug. 21, 2017, total solar eclipse, with its 70-mile wide path of totality stretching across much of North America, provides us with a unique opportunity to teach students about eclipses. One might naturally assume that students have little difficulty understanding the nature of eclipses. After all, the notion that eclipses occur when…

Public outreach and education during the 2016 total solar eclipse in Palu and Malang

NASA Astrophysics Data System (ADS)

Rachmadian, A. P.; Kunjaya, C.; Wahono, W.; Anugrah, A. A.

2016-11-01

MAGIC (Ma Chung Galactic Club) of Ma Chung University, Malang, is one of the amateur astronomers club who did public outreach and education during the Total Solar Eclipse March 9, 2016. The motivation for doing this was the bad experience during Total Solar Eclipse 1983. At that time the Indonesian government forbid the people to observe the Total Solar Eclipse in a way to avoid blindness. We try to fix this misunderstanding by educating people the safe way to enjoy the partial and total solar eclipse. MAGIC team was divided into two teams, one team went to Palu and did the solar eclipse related education in six high schools before and during the eclipse. The other team did the observation on Ma Chung University campus, Malang, to accompany people who want to see the partial solar eclipse through filtered telescopes. The sky during the solar eclipse was clear both in Malang and Palu. People were very excited and satisfied with the solar eclipse, and their interest to astronomy is increased.

The X-ray eclipse of the LMC binary CAL 87

NASA Technical Reports Server (NTRS)

Schmidtke, P. C.; Mcgrath, T. K.; Cowley, A. P.; Frattare, L. M.

1993-01-01

ROSAT-PSPC observations of the LMC eclipsing binary CAL 87 show a short-duration, shallow X-ray eclipse which coincides in phase with the primary optical minimum. Characteristics of the eclipse suggest the X-ray emitting region is only partially occulted. Similarities with the eclipse of the accretion-disk corona in X 1822-37 are discussed. However, no temperature variation through eclipse is found for CAL 87. A revised orbital period, combining published data and recent optical photometry, is given.

Kepler eclipsing binary stars. IV. Precise eclipse times for close binaries and identification of candidate three-body systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conroy, Kyle E.; Stassun, Keivan G.; Prša, Andrej

2014-02-01

We present a catalog of precise eclipse times and analysis of third-body signals among 1279 close binaries in the latest Kepler Eclipsing Binary Catalog. For these short-period binaries, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the eclipse timings. We present a method to measure precise eclipse times in the presence of distorted light curves, such as in contact and near-contact binaries which exhibit continuously changing light levelsmore » in and out of eclipse. We identify 236 systems for which we find a timing variation signal compatible with the presence of a third body. These are modeled for the light travel time effect and the basic properties of the third body are derived. This study complements J. A. Orosz et al. (in preparation), which focuses on eclipse timing variations of longer period binaries with flat out-of-eclipse regions. Together, these two papers provide comprehensive eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an ongoing resource freely accessible online to the community.« less

Candidates of eclipsing multiples based on extraneous eclipses on binary light curves: KIC 7622486, KIC 7668648, KIC 7670485 and KIC 8938628

NASA Astrophysics Data System (ADS)

Zhang, Jia; Qian, Sheng-Bang; He, Jian-Duo

2017-02-01

Four candidates of eclipsing multiples, based on new extraneous eclipses found on Kepler binary light curves, are presented and studied. KIC 7622486 is a double eclipsing binary candidate with orbital periods of 2.2799960 d and 40.246503 d. The two binary systems do not eclipse each other in the line of sight, but there is mutual gravitational influence between them which leads to the small but definite eccentricity of 0.0035(0.0022) associated with the short 2.2799960 d period orbit. KIC 7668648 is a hierarchical quadruple system candidate, with two sets of solid 203 ± 5 d period extraneous eclipses and another independent set of extraneous eclipses. A clear and credible extraneous eclipse is found on the binary light curve of KIC 7670485 which makes it a triple system candidate. Two sets of extraneous eclipses with periods of about 390 d and 220 d are found on KIC 8938628 binary curves, which not only confirm the previous conclusion of the 388.5 ± 0.3 triple system, but also indicate new additional objects that make KIC 8938628 a hierarchical quadruple system candidate. The results from these four candidates will contribute to the field of eclipsing multiples.

Poster 16: Eclipse-induced changes of Titan's meteorology at equinox

NASA Astrophysics Data System (ADS)

Tokano, Tetsuya

2016-06-01

Titan experiences solar eclipses by Saturn on ˜20 consecutive orbits around equinox for durations of up to ˜6 hours. The impact of these eclipses on Titan's surface, lower atmosphere and middle atmosphere is investigated by a global climate model. When an eclipse commences, the surface temperature on the subsaturnian side drops by up to 0.3 K, so that the diurnal maximum surface temperature remains lower than on the antisaturnian side, which is never eclipsed. By contrast, the tropospheric air temperature does not abruptly decrease during the eclipses because of the large thermal inertia, but the diurnal mean temperature slightly decreases. The surface wind at low latitudes becomes less gusty in the presence of eclipse due to damping of turbulence. The troposphere outside the planetary boundary layer is not sensitive to eclipses. In most parts of the stratosphere and mesosphere the temperature decreases by up to 2 K due to eclipses, but there are also layers, which experience relative warming due to thermal contraction of the underlying layers. The temperature in the middle atmosphere rapidly recovers after the end of the eclipse season. Eclipse-induced cooling and warming changes the zonal wind speed by a few m/s due to thermal wind adjustment to changing latitudinal temperature gradients.

The Great American Eclipse: Lessons Learned from Public Education

NASA Astrophysics Data System (ADS)

Edson, Shauna Elizabeth; Phoebe Waterman Haas Public Observatory

2018-01-01

The total solar eclipse of 2017 was a high-profile opportunity for nationwide public education. Astronomy experts suddenly became vital sources of information for a lay population whose interest in the eclipse greatly surpassed expectations. At the National Air and Space Museum, we leveraged our relatively accessible location and particularly diverse audience to help thousands of people, from novices to enthusiasts, prepare to view the eclipse safely. The goal was to empower all people so they could experience this unique astronomical event, understand what was happening, and observe the Sun safely. Over the course of two years spent talking with the public about the eclipse, we encountered common misconceptions, worries about safety or liability, and people experiencing confusion or information overload. We developed guidelines for handling these challenges, from correcting misinformation to managing the sudden spike in demand for glasses just before August 21.In particular, we helped people understand the following essential points:- The total phase of the eclipse is only visible from a limited path.- The partial eclipse is visible from a large area outside the path of totality.- The eclipse takes up to three hours from start to finish, providing ample time for viewing.- The Sun can be observed safely using several methods, including but not limited to eclipse glasses.- The eclipse happens because the Moon’s orbit is taking it directly between the Sun and the Earth.- Eclipses do not happen every month because the Moon’s orbit is tilted with respect to the Earth's orbital plane.- Students in schools can safely view the eclipse, with proper protection and supervision, to prevent eye damage and minimize liability.Public education about the eclipse appears to have been successful, as evidenced by the large number of people who saw their first total solar eclipse and the absence of reported eye damage cases. Amidst the excitement, photographs, and stories that emerged from the eclipse, there are valuable lessons that will be useful in helping the public prepare for future eclipses, in 2024 and beyond.

2016 SPD: Day 3

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-06-01

Editors note:This week were in Boulder, Colorado at the47th meeting of the AAS Solar Physics Division (SPD). Follow along to catch some of the latest news from the field of solar physics!Yesterdayspress conference was titled Preparing for the 2017 Great American Eclipse. Four speakers highlighted both outreach and research projects that are planned for the eclipse that will cross the continental United States on August 21st next year.Eclipse from High AltitudeFirst up, Angela Des Jardins (Montana Space Grant Consortium) introduced us to the nationwide Eclipse Ballooning Project.An eclipse as seen from the ISS. Being up high gives you a very different perspective on eclipses! [NASA]The last total solar eclipse in the continental United States was in 1979, and people were told to stay inside and watch from their TVs! For the next total solar eclipse in the US, we want the opposite: for everyone to be outdoors and in the path of totality to watch (with eclipse glasses lets be safe)! This eclipse is a fantastic educational opportunity, and a way to reach an enormous audience.And what better way to experience the eclipse than to be involved? The Eclipse Ballooning Project is involving more than 50 student teams from 30 states to fly high-altitude balloons at 20 locations along the total eclipse path. These balloons will send live videos and images from the edge of space to the NASA website.Why? Being someplace high up provides an entirely different view for an eclipse! Instead of looking up to watch the Moon slide in front of the Sun, you can look down to watch the Moons shadow race across the Earths surface at thousands of miles per hour. This unique perspective is rare, and has certainly never been covered live. This will be an awesome addition to other coverage of the eclipse!At Maximum TotalityThe next speaker, Gordon Emslie, described the outreach efforts planned at his institution, Western Kentucky University (WKU). The location where the eclipse totality will last the longest 2 minutes and 40 seconds is the small town of Hopkinsville, KY. WKU is located a little over an hour away, and both locations are prepared for a large influx of people on eclipse day!Partial solar eclipse as viewed by the space-based Solar Dynamics Observatory. [NASA/SDO]WKU is located just off the centerline of eclipse path, which has some advantages: this provides better viewing of some of the chromospheric features of the Sun during the eclipse, like priminences and solar loops. WKU is setting up a variety of educational and public outreach activities at their football stadium and the WKU farm, and they encourage you to come visit for the eclipse!In addition, they are participating in a nationwide experiment called Citizen CATE, short for the Continental American Telescopic Eclipse. This project will use 60 telescopes spanning the 2500 mile path of totality to record continuous data of the eclipse as it travels across the US. The result will be data of a remarkable 90 minutes of totality, revealing the activity of the solar corona and providing an extended view of the eclipse as has never been seen before.Science During the EclipseNext up was Shadia Habbal (University of Hawaii), who is a co-leader of the AAS 2017 Eclipse Task Force. In addition to her education and outreach efforts associated with the eclipse, however, Habbal is a solar eclipse researcher. She and her collaborators are known as the Solar Wind Sherpas, due to the fact that they hand-carry their science equipment around the world for solar eclipses!Solar corona during a 2008 eclipse, with color overlay indicating emission from highly ionized iron lines. [Habbal et al. 2010]The primary science done during solar eclipses is the study of the solar corona, the region that extends from the solar surface out to several solar radii. This region is too faint to observe normally, but when the light from the Suns disk is blocked out, we can examine it.Unfortunately, the space telescopes that observe the Sun all have relatively narrow fields of view. But during an eclipse, we can gain the larger context for the corona with ground-based observations, with the Moon conveniently blocking the light from the Suns disk! The cover photo is a spectacular example of this.Observations of the corona during eclipses can provide information on both enormous events, like coronal mass ejections, and faint dynamical features, like plasma instabilities and expanding loops. In addition, we can learn about the plasma properties by examining emission from highly charged ions. The upcoming eclipse should provide a great opportunity to do some coronal science!A Unique OpportunityThe final press-conference speaker for the meeting was Jay Pasachoff (Williams College and Caltech), a veteran solar eclipse observer who was able to speak to what we could expect if we make it into the path of totality next year.Path of totality across the continental US for the August 2017 eclipse. [Fred Espenak/NASA GSFC]Pasachoff pointed out that there are nearly 12 million people located within the band of totality. There are probably another 200 million within a days drive! He strongly encouraged anyone able to make it to the path of totality to do so, pointing out that the experience in person is completely unlike the experience of watching a video. The process of watching the world around you go dark, he says, is something that simply isnt captured when you watch an eclipse on TV.If you plan to travel for the eclipse, Pasachoffs recommendation is to aim for the northwest end of the path of totality, rather than the southeast end surprisingly, weather statistics suggest you have a better chance of not getting clouded out in the northwest.We now have a year left to educate everyone likely to view the eclipse on when and how to view it safely! Accordingly, Pasachoff concluded the conference by providing a series of links on where to find more information:eclipses.infototalsolareclipse.orgGreatAmericanEclipse.comeclipsophile.com

HATS-36b and 24 Other Transiting/Eclipsing Systems from the HATSouth-K2 Campaign 7 Program

NASA Astrophysics Data System (ADS)

Bayliss, D.; Hartman, J. D.; Zhou, G.; Bakos, G. Á.; Vanderburg, A.; Bento, J.; Mancini, L.; Ciceri, S.; Brahm, R.; Jordán, A.; Espinoza, N.; Rabus, M.; Tan, T. G.; Penev, K.; Bhatti, W.; de Val-Borro, M.; Suc, V.; Csubry, Z.; Henning, Th.; Sarkis, P.; Lázár, J.; Papp, I.; Sári, P.

2018-03-01

We report on the result of a campaign to monitor 25 HATSouth candidates using the Kepler space telescope during Campaign 7 of the K2 mission. We discover HATS-36b (EPIC 215969174b, K2-145b), an eccentric (e=0.105+/- 0.028) hot Jupiter with a mass of 3.216+/- 0.062 {M}{{J}} and a radius of 1.235+/- 0.043 {R}{{J}}, which transits a solar-type G0V star (V = 14.386) in a 4.1752-day period. We also refine the properties of three previously discovered HATSouth transiting planets (HATS-9b, HATS-11b, and HATS-12b) and search the K2 data for TTVs and additional transiting planets in these systems. In addition, we also report on a further three systems that remain as Jupiter-radius transiting exoplanet candidates. These candidates do not have determined masses, however pass all of our other vetting observations. Finally, we report on the 18 candidates that we are now able to classify as eclipsing binary or blended eclipsing binary systems based on a combination of the HATSouth data, the K2 data, and follow-up ground-based photometry and spectroscopy. These range in periods from 0.7 day to 16.7 days, and down to 1.5 mmag in eclipse depths. Our results show the power of combining ground-based imaging and spectroscopy with higher precision space-based photometry, and serve as an illustration as to what will be possible when combining ground-based observations with TESS data.

Discovery of two eclipsing X-ray binaries in M 51

NASA Astrophysics Data System (ADS)

Wang, Song; Soria, Roberto; Urquhart, Ryan; Liu, Jifeng

2018-04-01

We discovered eclipses and dips in two luminous (and highly variable) X-ray sources in M 51. One (CXOM51 J132943.3+471135) is an ultraluminous supersoft source, with a thermal spectrum at a temperature of about 0.1 keV and characteristic blackbody radius of about 104 km. The other (CXOM51 J132946.1+471042) has a two-component spectrum with additional thermal-plasma emission; it approached an X-ray luminosity of 1039erg s-1 during outbursts in 2005 and 2012. From the timing of three eclipses in a series of Chandra observations, we determine the binary period (52.75 ± 0.63 hr) and eclipse fraction (22% ± 0.1%) of CXOM51 J132946.1+471042. We also identify a blue optical counterpart in archival Hubble Space Telescope images, consistent with a massive donor star (mass of ˜20-35M⊙). By combining the X-ray lightcurve parameters with the optical constraints on the donor star, we show that the mass ratio in the system must be M_2/M_1 ≳ 18, and therefore the compact object is most likely a neutron star (exceeding its Eddington limit in outburst). The general significance of our result is that we illustrate one method (applicable to high-inclination sources) of identifying luminous neutron star X-ray binaries, in the absence of X-ray pulsations or phase-resolved optical spectroscopy. Finally, we discuss the different X-ray spectral appearance expected from super-Eddington neutron stars and black holes at high viewing angles.

Discovery of two eclipsing X-ray binaries in M 51

NASA Astrophysics Data System (ADS)

Wang, Song; Soria, Roberto; Urquhart, Ryan; Liu, Jifeng

2018-07-01

We discovered eclipses and dips in two luminous (and highly variable) X-ray sources in M 51. One (CXOM51 J132943.3+471135) is an ultraluminous supersoft source, with a thermal spectrum at a temperature of about 0.1 keV and characteristic blackbody radius of about 104 km. The other (CXOM51 J132946.1+471042) has a two-component spectrum with additional thermal-plasma emission; it approached an X-ray luminosity of 1039 erg s-1 during outbursts in 2005 and 2012. From the timing of three eclipses in a series of Chandra observations, we determine the binary period (52.75 ± 0.63 h) and eclipse fraction (22 ± 0.1 per cent) of CXOM51 J132946.1+471042. We also identify a blue optical counterpart in archival Hubble Space Telescope images, consistent with a massive donor star (mass of ˜20-35 M⊙). By combining the X-ray light-curve parameters with the optical constraints on the donor star, we show that the mass ratio in the system must be M_2/M_1 ≳ 18 and therefore the compact object is most likely a neutron star (exceeding its Eddington limit in outburst). The general significance of our result is that we illustrate one method (applicable to high-inclination sources) of identifying luminous neutron star X-ray binaries, in the absence of X-ray pulsations or phase-resolved optical spectroscopy. Finally, we discuss the different X-ray spectral appearance expected from super-Eddington neutron stars and black holes at high viewing angles.

Eclipse Soundscapes Project: Making the August 21, 2017 Total Solar Eclipse Accessible to Everyone

NASA Astrophysics Data System (ADS)

Winter, H. D., III

2017-12-01

The Eclipse Soundscapes Project delivered a multisensory experience that allowed the blind and visually impaired to engage with the August 21, 2017 total solar eclipse along with their sighted peers in a way that would not have been possible otherwise. The project, from the Smithsonian Astrophysical Observatory and NASA's Heliophysics Education Consortium, includes illustrative audio descriptions of the eclipse in real time, recordings of the changing environmental sounds during the eclipse, and an interactive "rumble map" app that allows users to experience the eclipse through touch and sound. The Eclipse Soundscapes Project is working with organizations such as the National Parks Service (NPS), Science Friday, and Brigham Young University and by WGBH's National Center for Accessible Media (NCAM) to bring the awe and wonder of the total solar eclipse and other astronomical phenomena to a segment of the population that has been excluded from and astronomy and astrophysics for far too long, while engaging all learners in new and exciting ways.

N-(ferrocenecarbonyl)-N'-(quinolin-8-yl)thiourea.

PubMed

Yang, Jia-Xiang; Tian, Yu-Peng; Liu, Qing-Liang; Xie, Yong-Shu; Fun, Hoong-Kun; Chantrapromma, Suchada; Razak, Ibrahim Abdul

2002-01-01

In the title compound, [Fe(C5H5)(C16H12N3OS)], the 8-aminoquinoline and acylthiourea moieties are almost planar. There are two perpendicular arrangements of the molecules in the crystal with slightly different conformations. The two cyclopentadienyl rings in each molecule are parallel and eclipsed.

Educating the Public about the 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2017-01-01

On behalf of the International Astronomical Union's Working Group on Solar Eclipses, I have long worked to bring knowledge about eclipses and how to observe the safely to the people of the various countries from which partial, annular, or total solar eclipses are visible. In 2017, we have first a chance to educate the people of South America on the occasion of the February 26 annular eclipse through southern Chile and Argentina that is partial throughout almost the entire continent (and an eclipse workshop will be held February 22-24 in Esquel, Argentina: http://sion.frm.utn.edu.ar/WDEAII) and then a chance to educate the 300 million people of the United States and others in adjacent countries as far south as northern South America about the glories of totality and how to observe partial phases. Our website, a compendium of links to information about maps, safe observing, science, and more is at http://eclipses.info. We link to important mapping sites at EclipseWise.com, GreatAmericanEclipse.com, and http://xjubier.free.fr/en/site_pages/solar_eclipses/xSE_GoogleMap3.php?Ecl=+20170821&Acc=2&Umb=1&Lmt=1&Mag=1&Max=1, and information about cloudiness statistics at http://eclipsophile.com, as well as simulation sites at https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4314 and http://eyes.jpl.nasa.gov. The American Astronomical Society's task force on the 2017 eclipse has a website at http://eclipse.aas.org. We are working to disseminate accurate information about how and why to observe the total solar eclipse, trying among other things to head off common misinformation about the hazards of looking at the sun at eclipses or otherwise. About 12 million Americans live within the 70-mile-wide band of totality, and we encourage others to travel into it, trying to make clear the difference between even a 99% partial eclipse and a total eclipse, with its glorious Baily's beads, diamond rings, and totality that on this occasion lasts between 2 minutes and 2 minutes 40 seconds on the centerline. Our research on the 2017 total solar eclipse is supported by grants from the Committee for Research and Exploration of the National Geographic Society and from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation.

The Architecture of the GW Ori Young Triple-star System and Its Disk: Dynamical Masses, Mutual Inclinations, and Recurrent Eclipses

NASA Astrophysics Data System (ADS)

Czekala, Ian; Andrews, Sean M.; Torres, Guillermo; Rodriguez, Joseph E.; Jensen, Eric L. N.; Stassun, Keivan G.; Latham, David W.; Wilner, David J.; Gully-Santiago, Michael A.; Grankin, Konstantin N.; Lund, Michael B.; Kuhn, Rudolf B.; Stevens, Daniel J.; Siverd, Robert J.; James, David; Gaudi, B. Scott; Shappee, Benjamin J.; Holoien, Thomas W.-S.

2017-12-01

We present spatially and spectrally resolved Atacama Large Millimeter/submillimeter Array (ALMA) observations of gas and dust orbiting the pre-main-sequence hierarchical triple-star system GW Ori. A forward modeling of the 13CO and C18O J = 2–1 transitions permits a measurement of the total stellar mass in this system, 5.29+/- 0.09 {M}ȯ , and the circumtriple disk inclination, 137\\buildrel{\\circ}\\over{.} 6+/- 2\\buildrel{\\circ}\\over{.} 0. Optical spectra spanning a 35 yr period were used to derive new radial velocities and, coupled with a spectroscopic disentangling technique, revealed that the A and B components of GW Ori form a double-lined spectroscopic binary with a period of 241.50 ± 0.05 days; a tertiary companion orbits that inner pair with a period of 4218 ± 50 days. Combining the results from the ALMA data and the optical spectra with three epochs of astrometry in the literature, we constrain the individual stellar masses in the system ({M}{{A}}≈ 2.7 {M}ȯ , {M}{{B}}≈ 1.7 {M}ȯ , {M}{{C}}≈ 0.9 {M}ȯ ) and find strong evidence that at least one of the stellar orbital planes (and likely both) is misaligned with the disk plane by as much as 45°. A V-band light curve spanning 30 yr reveals several new ∼30-day eclipse events 0.1–0.7 mag in depth and a 0.2 mag sinusoidal oscillation that is clearly phased with the AB–C orbital period. Taken together, these features suggest that the A–B pair may be partially obscured by material in the inner disk as the pair approaches apoastron in the hierarchical orbit. Lastly, we conclude that stellar evolutionary models are consistent with our measurements of the masses and basic photospheric properties if the GW Ori system is ∼1 Myr old.

Eclipsing the Light...Fantastic! Teaching Science.

ERIC Educational Resources Information Center

Leyden, Michael B.

1995-01-01

Features the concepts of optics and geometry of eclipses. Presents the "eclipse rule," suggesting classroom activities in which students derive this rule. Includes some triangles activities for outdoors that illustrate eclipsing and sighting phenomena. (ET)

Bringing the Great American Solar Eclipse to West Virginia

NASA Astrophysics Data System (ADS)

Keesee, A. M.; Williamson, K.; Robertson-Honecker, J.

2017-12-01

West Virginia experienced up to 90% coverage during the Great American Solar Eclipse on August 21st. To reach the greatest number of West Virginians, we targeted educators and the 4-H program to provide those community leaders with the tools to help students learn about and safely view the eclipse. We developed a website that consolodated relevant eclipse activities, fact sheets, and outreach videos to train educators and others in the public about the science of the eclipse and how to view a partial eclipse safely. The 4-H Summer Experiement used at all 4-H summer camps and events was designed to focus on the eclipse. We distributed over 20,000 custom designed eclipse glasses. These were distributed to teachers through an online request system and to 4-H members involved in summer activities. We hosted a pre-eclipse event on the campus of West Virginia University for the public to learn about the science of the eclipse, relevant research being conducted at the university, and provide tips for safe viewing. Student volunteers were available on campus during the day of the eclipse to hand out glasses and answer questions. We will present the results of our outreach and events as well as lessons learned for the 2024 eclipse. Support for this project was provided by the WVU Department of Physics and Astronomy, WVU Extension, the WV Space Grant Consortium, a WVU internal grant, the Green Bank Observatory, and individual supporters of a crowdfunding campaign.

Superconductivity in Sm-doped CaFe2As2 single crystals

NASA Astrophysics Data System (ADS)

Dong-Yun, Chen; Bin-Bin, Ruan; Jia, Yu; Qi, Guo; Xiao-Chuan, Wang; Qing-Ge, Mu; Bo-Jin, Pan; Tong, Liu; Gen-Fu, Chen; Zhi-An, Ren

2016-06-01

In this article, the Sm-doping single crystals Ca1 - x Sm x Fe2As2 (x = 0 ˜ 0.2) were prepared by the CaAs flux method, and followed by a rapid quenching treatment after the high temperature growth. The samples were characterized by structural, resistive, and magnetic measurements. The successful Sm-substitution was revealed by the reduction of the lattice parameter c, due to the smaller ionic radius of Sm3+ than Ca2+. Superconductivity was observed in all samples with onset T c varying from 27 K to 44 K upon Sm-doping. The coexistence of a collapsed phase transition and the superconducting transition was found for the lower Sm-doping samples. Zero resistivity and substantial superconducting volume fraction only happen in higher Sm-doping crystals with the nominal x > 0.10. The doping dependences of the c-axis length and onset T c were summarized. The high-T c observed in these quenched crystals may be attributed to simultaneous tuning of electron carriers doping and strain effect caused by lattice reduction of Sm-substitution. Project supported by the National Natural Science Foundation of China (Grant No. 11474339), the National Basic Research Program of China (Grant Nos. 2010CB923000 and 2011CBA00100), and the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB07020100).

The Solar Eclipse Predictions of Chiljeongsam-Oepyeon in Early Choseon

NASA Astrophysics Data System (ADS)

Ahn, Young Sook; Lee, Yong Sam

2004-12-01

The history books of East Asia about astronomical phenomena have the more records of the solar eclipse frequently than any other ones. It is because traditionally, the solar eclipse meaned the fate of dynasty and the king's rule. The Sun, the biggest thing in the heaven symbolized the king, and the solar eclipse foresaw that the king had the problem in private including the body, and the country might suffer from difficulties in a great scale. So the king and all of the ministers used to gather to hold a ceremony named Gusikrye which solar eclipse may pass safely. Consequently, kings always had concernments on collecting informations of solar eclipse. Inspite of importance of solar eclipse predictions, but at the beginning of the Choseon, the predictions of the solar eclipse didn't fit. King Sejong compiled the Chiljeongsan-naepion and the Chiljeongsan-oepyeon to calculate the celestial phenomena including the solar eclipse. By the publications of these two books, the calendar making system of Choseon was firmly established. The Chiljeongsan-oepyeon adopted Huihui calendar of Arabia. The Solar eclipse predictions of Chiljeongsan-oepyeon were relative correct compared to modern method in early Choseon dynasty.

Changes in Latitude, Changes in Attitude: U.S. Naval Observatory Observations of Solar Eclipses 1869 to the Present

NASA Astrophysics Data System (ADS)

Chizek Frouard, Malynda R.; Towne, Linda; Kaplan, George H.

2017-01-01

In anticipation of the 2017 August 21 total solar eclipse over the continental United States, the history of U.S. Naval Observatory eclipse observations illustrates the changes in science, technology, and policy over the past 148 years.USNO eclipse observations began in 1869, when staff traveled to Des Moines, Iowa and the Bering Strait to look for intra-mercurial planets and to observe the solar corona. During the golden age of eclipse expeditions, the USNO officially participated in a dozen expeditions between 1869 and 1929. Seven of these expeditions were to US locations: 1869 in Iowa; 1878 in Colorado, Wyoming, and Texas; 1880 in California; 1900 in Georgia and North Carolina; 1918 in Oregon; 1923 in California; and 1925 in New York. A total solar eclipse has not traced a path across the width of the continental US since 1918 although several eclipses have passed over parts of the US since then.A few official expeditions occurred later in the 20th century to measure the solar diameter, including a total eclipse in the northwest US in 1979 and an annular eclipse across the southeast in 1984. However, observations began transitioning to mostly personal adventures as individual astronomers arranged unofficial trips.Historians can use the USNO Multi-year Interactive Computer Almanac (MICA) to compute local circumstances for solar eclipses world-wide starting with the annual eclipse of 1800 April 24, which was visible from Alaska. Those looking to make history in 2017 may consult the USNO 2017 August 21 Solar Eclipse Resource page (http://aa.usno.navy.mil/data/docs/Eclipse2017.php).

Quantitative evaluation of space charge effects of laser-cooled three-dimensional ion system on a secular motion period scale

NASA Astrophysics Data System (ADS)

Du, Li-Jun; Song, Hong-Fang; Chen, Shao-Long; Huang, Yao; Tong, Xin; Guan, Hua; Gao, Ke-Lin

2018-04-01

Not Available Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0304401), the National Natural Science Foundation of China (Grant Nos. 11622434, 11474318, 91336211, and 11634013), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB21030100), Hubei Province Science Fund for Distinguished Young Scholars (Grant No. 2017CFA040), and the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2015274).

Influence of anisotropy on the electrical conductivity and diffusion coefficient of dry K-feldspar: Implications of the mechanism of conduction

NASA Astrophysics Data System (ADS)

Dai, Li-Dong; Hu, Hai-Ying; Li, He-Ping; Sun, Wen-Qing; Jiang, Jian-Jun

2018-02-01

Not Available Project supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (CAS) (Grant No. XDB 18010401), the Key Research Program of Frontier Sciences of CAS (Grant No. QYZDB-SSW-DQC009), the “135” Program of the Institute of Geochemistry of CAS, the Hundred-Talent Program of CAS, and the National Natural Science Foundation of China (Grant Nos. 41474078, 41774099, and 41772042).

Popular Berkeley Lab X-ray Data Booklet reissued

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, Art

2001-03-02

X-ray scientists and synchrotron-radiation users who have been patiently waiting for an updated version of the popular X-Ray Data Booklet last published in 1986 by the Center for X-Ray Optics at the Lawrence Berkeley National Laboratory can breathe a sigh of relief. The venerable ''little orange book'' has now been reissued under the auspices of CXRO and the Advanced Light Source (ALS) with an April printing of 10,000 paper copies and the posting of a Web edition at http://xdb.lbl.gov.

Experimental Determination of the Landé g-Factors for 5s 2 1 S and 5s5p 3 P States of the 87Sr Atom

NASA Astrophysics Data System (ADS)

Lu, Ben-quan; Wang, Yebing; Guo, Yang; Xu, Qinfang; Yin, Mojuan; Li, Jiguang; Chang, Hong

2018-04-01

Not Available Supported by the National Natural Science Foundation of China under Grant Nos 61127901, 11404025 and 91536106, the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB21030700, the Key Research Project of Frontier Science of Chinese Academy of Sciences under Grant No QYZDB-SSW-JSC004, and the China Postdoctoral Science Foundation under Grant No 2014M560061.

NASA Videofile of Solar Eclipse from Jefferson City, Missouri

NASA Image and Video Library

2017-08-21

During the eclipse, 14 states across the U.S. were in the path of totality and experienced more than two minutes of darkness in the middle of the day – with a partial eclipse viewable all across North America. The broadcast – Eclipse Across America: Through the Eyes of NASA – covered locations along the path of totality, from Oregon to South Carolina including public reactions from all ages. During this event, NASA Glenn Research Center celebrates the eclipse at the capital eclipse event in Jefferson City, MO

solar eclipse 2016

NASA Image and Video Library

2017-12-08

NASA TV video from yesterday's total solar eclipse, when the moon pass directly in front of the sun. It happened from 8:38 to 8:42 p.m. EST March 8. As the moon passed precisely between the sun and Earth – a relatively rare occurrence that happens only about once a year because of the fact that the moon and the sun do not orbit in the exact same plane – it blocked the sun’s bright face, revealing the tenuous and comparatively faint solar atmosphere, the corona. The total eclipse was only visible in parts of Southeast Asia Learn more about this event: youtu.be/MQjPFwcjh9c ‪ NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram ‬

KIC 4150611: a rare multi-eclipsing quintuple with a hybrid pulsator

NASA Astrophysics Data System (ADS)

Hełminiak, K. G.; Ukita, N.; Kambe, E.; Kozłowski, S. K.; Pawłaszek, R.; Maehara, H.; Baranec, C.; Konacki, M.

2017-06-01

Aims: We aim to analyse KIC 4150611 (HD 181469) - an interesting, bright quintuple system that includes a hybrid δ Sct/γ Dor pulsator. Four periods of eclipses - 94.2, 8.65, 1.52 and 1.43 d - have been observed by the Kepler satellite, and three point sources (A, B, and C) are seen in high angular resolution images. Methods: From spectroscopic observations made with the HIDES spectrograph attached to the 1.88-m telescope of the Okayama Astrophysical Observatory (OAO), we have calculated for the first time radial velocities (RVs) of the component B - a pair of G-type stars - and combined them with Kepler photometry in order to obtain absolute physical parameters of this pair. We also managed to directly measure RVs of the pulsator, for the first time. Additionally, we modelled the light curves of the 1.52 and 1.43-day pairs, and measured their eclipse timing variations (ETVs). We also performed relative astrometry and photometry of three sources seen on the images taken with the NIRC2 camera of the Keck II telescope. Finally, we compared our results with theoretical isochrones. Results: The brightest component Aa is the hybrid pulsator, transited every 94.2 days by a pair of K/M-type stars (Ab1+Ab2), which themselves form a 1.52-day eclipsing binary. The components Ba and Bb are late G-type stars, forming another eclipsing pair with a 8.65 day period. Their masses and radii are MBa = 0.894 ± 0.010 M⊙, RBa = 0.802 ± 0.044 R⊙ for the primary, and MBb = 0.888 ± 0.010 M⊙, RBb = 0.856 ± 0.038 R⊙ for the secondary. The remaining period of 1.43 days is possibly related to a faint third star C, which itself is most likely a background object. The system's properties are well-represented by a 35 Myr isochrone, basing on which the masses of the pulsator and the 1.52-day pair are MAa = 1.64(6) M⊙, and MAb,tot = 0.90(13) M⊙, respectively. There are also suggestions of additional bodies in the system.

Building on the US Eclipse Experience in Schools, with the Public, and Beyond the US

NASA Astrophysics Data System (ADS)

Simmons, Mike; Chee, Zoe; Bartolone, Lindsay

2018-01-01

Astronomers Without Borders (AWB) organized several programs for the August 21, 2017 total solar eclipse, both before and after the event, to increase participation, build on the inspiration of the eclipse, share the eclipse experience, and prepare for the eclipse in 2024.AWB focused on preparing institutions that were least likely to receive resources despite extensive nationwide efforts. AWB distributed more than 100,000 donated glasses, to isolated schools, children's cancer hospitals, abused women’s shelters, and other institutions without access to other resource providers.AWB’s Building on the Eclipse Education Program builds on the inspiration of the eclipse for STEM education. The program uses a small, personal spectroscope kit to study sunlight in different scientific fields and includes free classroom activities that meet NGSS standards.A program to collect eclipse observing glasses for schools in developing countries for future eclipses was announced around the time of the eclipse and quickly went viral, with coverage by national and innumerable local media outlets. This effort builds on AWB’s earlier programs for schools in Africa and in South America for past eclipses. Well over one million pairs are expected, as compared to the tens of thousands AWB provided through crowdfunding for previous efforts. Nearly 1000 glasses collection centers were created spontaneously, without a public call. Factors leading to widespread and diverse public participation will be presented.A program calling for first-time eclipse observers to share their experiences addresses a major issue in encouraging people to travel to the path of totality. Expert and eclipse-enthusiast testimony often fails to convince people of the value of the experience of totality as “a few minutes of darkness.” This program will share the disconnect between expectation and experience from first-time “ordinary” observers to encourage others to travel to the path of totality for the total solar eclipse in 2024.Analysis and planned follow-up and expanded programs will also be described.

Satellite observations of surface temperature during the March 2015 total solar eclipse

PubMed Central

2016-01-01

The behaviour of remotely sensed land surface temperatures (LSTs) from the spinning-enhanced visible and infrared imager (SEVIRI) during the total solar eclipse of 20 March 2015 is analysed over Europe. LST is found to drop by up to several degrees Celcius during the eclipse, with the minimum LST occurring just after the eclipse mid-point (median=+1.5 min). The drop in LST is typically larger than the drop in near-surface air temperatures reported elsewhere, and correlates with solar obscuration (r=−0.47; larger obscuration = larger LST drop), eclipse duration (r=−0.62; longer duration = larger LST drop) and time (r=+0.37; earlier eclipse = larger LST drop). Locally, the LST drop is also correlated with vegetation (up to r=+0.6), with smaller LST drops occurring over more vegetated surfaces. The LSTs at locations near the coast and at higher elevation are also less affected by the eclipse. This study covers the largest area and uses the most observations of eclipse-induced surface temperature drops to date, and is the first full characterization of satellite LST during an eclipse (known to the author). The methods described could be applied to Geostationary Operational Environmental Satellite (GOES) LST data over North America during the August 2017 total solar eclipse. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550764

Glorious Eclipses

NASA Astrophysics Data System (ADS)

Brunier, Serge; Luminet, Jean-Pierre

2000-12-01

Stargazers who may have missed the last total solar eclipse of the 20th century this past summer have just been given another chance to observe this "once in a lifetime" occurrence. Inside Glorious Eclipses they will find startling images and rich personal accounts that fully capture this event and other recent eclipses. The book will also insure that readers will not miss another eclipse in the next 60 years! Specially designed in a beautiful, large format, the volume portrays eclipses of all kinds--lunar, solar, and those occurring elsewhere in the Solar System and beyond. Brunier and Luminet have gathered together all aspects of eclipses, and carefully selected a host of lavish images. The authors detail the history of eclipses, the celestial mechanics involved, their observation, and scientific interest. Personal accounts of recent eclipses are also included as well as all relevant information about forthcoming eclipses up to 2060. Complete with NASA maps and data, Glorious Eclipses is the ultimate source for all those interested in these remarkable (and rare) celestial events. Serge Brunier is chief editor of the journal Ciel et Espace, a photo-journalist, and the author of many nonfiction books aimed at both specialists and the general public. Jean-Pierre Luminet is an astrophysicist at the Paris-Meudon Observatory and director of research at the Centre pour la Recherche Scientifique. He is the author of many popular astronomy books, including Black Holes (Cambridge University Press, 1992).

Symbolism and discovery: eclipses in art.

PubMed

Blatchford, Ian

2016-09-28

There is a fascinating tradition of depicting solar eclipses in Western art, although these representations have changed over time. Eclipses have often been an important feature of Christian iconography, but valued as much for their biblical significance as for the splendour of the physical event. However, as Western culture passed through the Renaissance and Enlightenment the depictions of eclipses came to reflect new astronomical knowledge and a thirst for rational learning well beyond the confines of the church and other elites. Artists also played a surprisingly important role in helping scientists in the nineteenth century understand and record the full phenomena of an eclipse, even as the advent of photography also came to solve a number of scientific puzzles. In the most recent century, artists have responded to eclipses with symbolism, abstraction and playfulness.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

On the Importance of Solar Eclipse Geometry in the Interpretation of Ionospheric Observations

NASA Astrophysics Data System (ADS)

Stankov, S.; Verhulst, T. G. W.

2017-12-01

A reliable interpretation of solar eclipse effects on the geospace environment, and on the ionosphere in particular, necessitates a careful consideration of the so-called eclipse geometry. A solar eclipse is a relatively rare astronomical phenomenon, which geometry is rather complex, specific for each event, and fast changing in time. The standard, most popular way to look at the eclipse geometry is via the two-dimensional representation (map) of the solar obscuration on the Earth's surface, in which the path of eclipse totality is drawn together with isolines of the gradually-decreasing eclipse magnitude farther away from this path. Such "surface maps" are widely used to readily explain some of the solar eclipse effects including, for example, the well-known decrease in total ionisation (due to the substantial decrease in solar irradiation), usually presented by the popular and easy to understand ionospheric characteristic of Total Electron Content (TEC). However, many other effects, especially those taking place at higher altitudes, cannot be explained in this fashion. Instead, a complete, four-dimensional (4D) description of the umbra (and penumbra), would be required. This presentation will address the issue of eclipse geometry effects on various ionospheric observations carried out during the total solar eclipse of August 21, 2017. In particular, GPS-based TEC and ionosonde measurements will be analysed and the eclipse effects on the ionosphere will be interpreted with respect to the actual eclipse geometry at ionospheric heights. Whenever possible, a comparison will be made with results from previous events, such as the ones from March 20, 2015 and October 3, 2005.

Eclipse prediction on the ancient Greek astronomical calculating machine known as the Antikythera Mechanism.

PubMed

Freeth, Tony

2014-01-01

The ancient Greek astronomical calculating machine, known as the Antikythera Mechanism, predicted eclipses, based on the 223-lunar month Saros cycle. Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, referring to solar eclipse inscriptions. These include Index Letter Groups, describing shared eclipse characteristics. The grouping and ordering of the index letters, the organization of the inscriptions and the eclipse times have previously been unsolved. A new reading and interpretation of data from the back plate of the Antikythera Mechanism, including the glyphs, the index letters and the eclipse inscriptions, has resulted in substantial changes to previously published work. Based on these new readings, two arithmetical models are presented here that explain the complete eclipse prediction scheme. The first model solves the glyph distribution, the grouping and anomalous ordering of the index letters and the structure of the inscriptions. It also implies the existence of lost lunar eclipse inscriptions. The second model closely matches the glyph times and explains the four-turn spiral of the Saros Dial. Together, these models imply a surprisingly early epoch for the Antikythera Mechanism. The ancient Greeks built a machine that can predict, for many years ahead, not only eclipses but also a remarkable array of their characteristics, such as directions of obscuration, magnitude, colour, angular diameter of the Moon, relationship with the Moon's node and eclipse time. It was not entirely accurate, but it was an astonishing achievement for its era.

Eclipse Prediction on the Ancient Greek Astronomical Calculating Machine Known as the Antikythera Mechanism

PubMed Central

Freeth, Tony

2014-01-01

The ancient Greek astronomical calculating machine, known as the Antikythera Mechanism, predicted eclipses, based on the 223-lunar month Saros cycle. Eclipses are indicated on a four-turn spiral Saros Dial by glyphs, which describe type and time of eclipse and include alphabetical index letters, referring to solar eclipse inscriptions. These include Index Letter Groups, describing shared eclipse characteristics. The grouping and ordering of the index letters, the organization of the inscriptions and the eclipse times have previously been unsolved. A new reading and interpretation of data from the back plate of the Antikythera Mechanism, including the glyphs, the index letters and the eclipse inscriptions, has resulted in substantial changes to previously published work. Based on these new readings, two arithmetical models are presented here that explain the complete eclipse prediction scheme. The first model solves the glyph distribution, the grouping and anomalous ordering of the index letters and the structure of the inscriptions. It also implies the existence of lost lunar eclipse inscriptions. The second model closely matches the glyph times and explains the four-turn spiral of the Saros Dial. Together, these models imply a surprisingly early epoch for the Antikythera Mechanism. The ancient Greeks built a machine that can predict, for many years ahead, not only eclipses but also a remarkable array of their characteristics, such as directions of obscuration, magnitude, colour, angular diameter of the Moon, relationship with the Moon’s node and eclipse time. It was not entirely accurate, but it was an astonishing achievement for its era. PMID:25075747

Eclipse takeoff and flight

NASA Technical Reports Server (NTRS)

1998-01-01

This 25-second clip shows the QF-106 'Delta Dart' tethered to the USAF C-141A during takeoff and in flight. NASA Dryden Flight Research Center, Edwards, California, supported a Kelly Space and Technology, Inc. (KST)/U.S. Air Force project known as Eclipse, which demonstrated a reusable tow launch vehicle concept. The purpose of the project was to demonstrate a reusable tow launch vehicle concept that had been conceived and patented by KST. Kelly Space obtained a contract with the USAF Research Laboratory for the tow launch demonstration project under the Small Business Innovation Research (SBIR) program. The USAF SBIR contract included the modifications to turn the QF-106 into the Experimental Demonstrator #1 (EXD-01), and the C141A aircraft to incorporate the tow provisions to link the two aircraft, as well as conducting flight tests. The demonstration consisted of ground and flight tests. These tests included a Combined Systems Test of both airplanes joined by a tow rope, a towed taxi test, and six towed flights. The primary goal of the project was demonstrating the tow phase of the Eclipse concept using a scaled-down tow aircraft (C-141A) and a representative aerodynamically-shaped aircraft (QF-106A) as a launch vehicle. This was successfully accomplished. On December 20, 1997, NASA research pilot Mark Stucky flew a QF-106 on the first towed flight behind an Air Force C-141 in the joint Eclipse project with KST to demonstrate the reusable tow launch vehicle concept developed by KST. Kelly hoped to use the data from the tow tests to validate a tow-to-launch procedure for reusable space launch vehicles. Stucky flew six successful tow tests between December 1997 and February 6, 1998. On February 6, 1998, the sixth and final towed flight brought the project to a successful completion. Preliminary flight results determined that the handling qualities of the QF-106 on tow were very stable; actual flight measured values of tow rope tension were well within predictions made by the simulation, aerodynamic characteristics and elastic properties of the tow rope were a significant component of the towing system; and the Dryden high-fidelity simulation provided a representative model of the performance of the QF-106 and C-141A airplanes in tow configuration. Total time on tow for the entire project was 5 hours, 34 minutes, and 29 seconds. All six flights were highly productive, and all project objectives were achieved. All three of the project objectives were successfully accomplished. The objectives were: demonstration of towed takeoff, climb-out, and separation of the EXD-01 from the towing aircraft; validation of simulation models of the towed aircraft systems; and development of ground and flight procedures for towing and launching a delta-winged airplane configuration safely behind a transport-type aircraft. NASA Dryden served as the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden also supplied engineering, simulation, instrumentation, range support, research pilots, and chase aircraft for the test series. Dryden personnel also performed the modifications to convert the QF-106 into the piloted EXD-01 aircraft. During the early flight phase of the project, Tracor, Inc. provided maintenance and ground support for the two QF-106 airplanes. The Air Force Flight Test Center (AFFTC), Edwards, California, provided the C-141A transport aircraft for the project, its flight and engineering support, and the aircrew. Kelly Space and Technology provided the modification design and fabrication of the hardware that was installed on the EXD-01 aircraft. Kelly Space and Technology hopes to use the data gleaned from the tow tests to develop a series of low-cost reusable launch vehicles, in particular to gain experience towing delta-wing aircraft having high wing loading, and in general to demonstrate various operational procedures such as ground processing and abort scenarios. The first successful towed flight occurred on December 20, 1997. Prior to this first tow test flight, the C-141A and EXD-01 were used to conduct a series of tethered taxi tests that would validate the tow procedures. Before these tethered taxi tests, a successful joint flight test was conducted in late October 1996, by Dryden, AFFTC, and KST, in which one of the Dryden F-18 chase aircraft flew at various ranges and locations behind the C-141A to define the wake turbulence and wingtip vortex environment. This flight test was replicated in July 1997, with an unmodified QF-106 flight proficiency aircraft.

Period variations of Algol-type eclipsing binaries AD And, TWCas and IV Cas

NASA Astrophysics Data System (ADS)

Parimucha, Štefan; Gajdoš, Pavol; Kudak, Viktor; Fedurco, Miroslav; Vaňko, Martin

2018-04-01

We present new analyses of variations in O – C diagrams of three Algol-type eclipsing binary stars: AD And, TW Cas and IV Cas. We have used all published minima times (including visual and photographic) as well as newly determined ones from our and SuperWasp observations. We determined orbital parameters of 3rd bodies in the systems with statistically significant errors, using our code based on genetic algorithms and Markov chain Monte Carlo simulations. We confirmed the multiple nature of AD And and the triple-star model of TW Cas, and we proposed a quadruple-star model of IV Cas.

A connection between long-term luminosity variations and orbital period changes in chromospherically active binaries

NASA Technical Reports Server (NTRS)

Hall, Douglas S.

1991-01-01

The eclipsing binary CG Cyg provides observational confirmation of three predictions made by Applegate's (1991) improvement on the theory that magnetic cycles cause the quasi-periodic orbital period changes in binaries containing a convective star. The mean brightness outside eclipse and the period vary with the same cycle length of about 50 yr. The light curve and O - C curve are in phase, with maximum light and period increase occurring in early 1980. The chromospherically active star becomes bluer in phase with the brightening. Because a period increase occurs at maximum brightness, the sense of the star's differential rotation is specified: outside rotating faster.

Proton acceleration measurements using fs laser irradiation of foils in the target normal sheath acceleration regime

NASA Astrophysics Data System (ADS)

Batani, D.; Boutoux, G.; Burgy, F.; Jakubowska, K.; Ducret, J. E.

2018-05-01

We present experimental results obtained at the CELIA laboratory using the laser ECLIPSE to study proton acceleration from ultra-intense laser pulses. Several types of targets were irradiated with different laser conditions (focusing and prepulse level). Proton emission was characterized using time-of-flight detectors (SiC and diamond) and a Thomson parabola spectrometer. In all cases, the maximum energy of observed protons was of the order of 260 keV with a large energy spectrum. Such characteristics are typical of protons emitted following the target normal sheath acceleration mechanism for low-energy short-pulse lasers like ECLIPSE.

Hybrid crystals of cuprates and iron-based superconductors

NASA Astrophysics Data System (ADS)

Xia, Dai; Cong-Cong, Le; Xian-Xin, Wu; Jiang-Ping, Hu

2016-07-01

We propose two possible new compounds, Ba2CuO2Fe2As2 and K2CuO2Fe2Se2, which hybridize the building blocks of two high temperature superconductors, cuprates and iron-based superconductors. These compounds consist of square CuO2 layers and antifluorite-type Fe2 X 2 (X = As, Se) layers separated by Ba/K. The calculations of binding energies and phonon spectra indicate that they are dynamically stable, which ensures that they may be experimentally synthesized. The Fermi surfaces and electronic structures of the two compounds inherit the characteristics of both cuprates and iron-based superconductors. These compounds can be superconductors with intriguing physical properties to help to determine the pairing mechanisms of high T c superconductivity. Project supported by the National Basic Research Program of China (Grant No. 2015CB921300), the National Natural Science Foundation of China (Grant Nos. 1190020 and 11334012), and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB07000000).

Cognitive aspects of ancient Maya eclipse theory.

NASA Astrophysics Data System (ADS)

Closs, M. P.

This paper is concerned with determining the nature of eclipse phenomena as it was perceived by the ancient Maya. It approaches the problem by considering the linguistic information pertaining to eclipses and by exploring the traditional beliefs associated with the occurrence of eclipses among the postconquest Maya. These data yield a model of a native eclipse theory which is compatible with hieroglyphic and iconographic materials pertaining to the ancient Maya.

Notable Images of the 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Wilson, Teresa; Dahiwale, Aishwarya; Nemiroff, Robert; Bonnell, Jerry

2018-01-01

The "Great American Eclipse" – the total solar eclipse visible across the USA on 21 August 2017 – resulted in some notable eclipse images and videos high in educational and scientific value. Some of the images that were selected to appear on the Astronomy Picture of the Day (APOD) website are shown in high resolution accompanied by educational descriptions. The questions of whether this eclipse was the most viewed and the most photographed event of any type in human history will be discussed. People are invited to come by and share their own eclipse images and stories.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Zhao; Gies, Douglas R.; Fuller, Jim, E-mail: guo@astro.gsu.edu, E-mail: gies@chara.gsu.edu, E-mail: jfuller@caltech.edu

KIC 3230227 is a short period (P  ≈ 7.0 days) eclipsing binary with a very eccentric orbit ( e  = 0.6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M {sub 1} = 1.84 ± 0.18  M {sub ⊙}, M {sub 2} = 1.73 ± 0.17  M {sub ⊙} and radii of R {sub 1} = 2.01 ± 0.09  R {sub ⊙}, R {sub 2} = 1.68 ± 0.08 R {sub ⊙} for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system.more » After removing the binary light curve model, more than 10 pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l  = 2, m  = −2 prograde modes.« less

Using the ionospheric response to the solar eclipse on 20 March 2015 to detect spatial structure in the solar corona.

PubMed

Scott, C J; Bradford, J; Bell, S A; Wilkinson, J; Barnard, L; Smith, D; Tudor, S

2016-09-28

The total solar eclipse that occurred over the Arctic region on 20 March 2015 was seen as a partial eclipse over much of Europe. Observations of this eclipse were used to investigate the high time resolution (1 min) decay and recovery of the Earth's ionospheric E-region above the ionospheric monitoring station in Chilton, UK. At the altitude of this region (100 km), the maximum phase of the eclipse was 88.88% obscuration of the photosphere occurring at 9:29:41.5 UT. In comparison, the ionospheric response revealed a maximum obscuration of 66% (leaving a fraction, Φ, of uneclipsed radiation of 34±4%) occurring at 9:29 UT. The eclipse was re-created using data from the Solar Dynamics Observatory to estimate the fraction of radiation incident on the Earth's atmosphere throughout the eclipse from nine different emission wavelengths in the extreme ultraviolet (EUV) and X-ray spectrum. These emissions, having varying spatial distributions, were each obscured differently during the eclipse. Those wavelengths associated with coronal emissions (94, 211 and 335 Å) most closely reproduced the time varying fraction of unobscured radiation observed in the ionosphere. These results could enable historic ionospheric eclipse measurements to be interpreted in terms of the distribution of EUV and X-ray emissions on the solar disc.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

78 FR 49908 - Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-16

... Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: We are adopting a new airworthiness directive (AD) for all Eclipse Aerospace... Eclipse Aerospace, Inc., 26 East Palatine Road, Wheeling, Illinois 60090; telephone: (877) 373-7978...

Public Education and Outreach for Observing Solar Eclipses and Transits

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2015-08-01

The general public is often very interested in observing solar eclipses, with widespread attention from newspapers and other sources often available only days before the events. Recently, the 2012 eclipse's partial phases in Australia and the 2015 eclipse's partial phases throughout Europe as well as western Asia and northern Africa, were widely viewed. The 21 August 2017 eclipse, whose totality will sweep across the Continental United States from northwest to southeast, will have partial phases visible throughout the U.S., Canada, Mexico, Central America, and into South America. The 2019 and 2020 partial phases of total eclipses will be visible throughout South America, and partial phases from annular eclipses will be visible from other parts of the world. The 9 May 2016 transit of Mercury will be best visible from the Western Hemisphere, Europe, and Africa. Many myths and misunderstandings exist about the safety of observing partial phases, and it is our responsibility as astronomers and educators to transmit accurate information and to attempt the widest possible distribution of such information. The Working Group on Public Education at Eclipses and Transits, formerly of Commission 46 on Education and Development and now of New Commission 11, tries to coordinate the distribution of information. In collaboration with the Solar Division's Working Group on Solar Eclipses, their website at http://eclipses.info is a one-stop shop for accurate information on how to observe eclipses, why it is interesting to do so, where they will be visible (with links to online maps and weather statistics), and how encouraging students to observe eclipses can be inspirational for them, perhaps even leading them to realize that the Universe can be understood and therefore renewing the strength of their studies. Links to information about transits of Mercury and Venus are also included.

Solar Eclipses and the International Year of Astronomy

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2009-05-01

Solar eclipses capture the attention of millions of people in the countries from which they are visible and provide a major opportunity for public education, in addition to the scientific research and student training that they provide. The 2009 International Year of Astronomy began with an annular eclipse visible from Indonesia on 26 January, with partial phases visible also in other parts of southeast Asia. On 22 July, a major and unusually long total solar eclipse will begin at dawn in India and travel across China, with almost six minutes of totality visible near Shanghai and somewhat more visible from Japanese islands and from ships at sea in the Pacific. Partial phases will be visible from most of eastern Asia, from mid-Sumatra and Borneo northward to mid-Siberia. Eclipse activities include many scientific expeditions and much ecotourism to Shanghai, Hangzhou, and vicinity. My review article on "Eclipses as an Astrophysical Laboratory" will appear in Nature as part of their IYA coverage. Our planetarium presented teacher workshops and we made a film about solar research. Several new books about the corona or eclipses are appearing or have appeared. Many articles are appearing in astronomy magazines and other outlets. Eclipse interviews are appearing on the Planetary Society's podcast "365 Days of Astronomy" and on National Geographic Radio. Information about the eclipse and safe observation of the partial phases are available at http://www.eclipses.info, the Website of the International Astronomical Union's Working Group on Solar Eclipses and of its Program Group on Public Education at the Times of Eclipses of its Commission on Education and Development. The Williams College Expedition to the 2009 Eclipse in the mountains near Hangzhou, China, is supported in part by a grant from the Committee for Research and Exploration of the National Geographic Society. E/PO workshops were supported by NASA.

The eclipse of the Sun from 20 May 2015

NASA Astrophysics Data System (ADS)

Tiron, S. D.

2015-04-01

The interview of the Radio Moldova with astronomer about the coming Eclipse of the Sun, included the following topics: 1) The circumstances of the Total eclipse 2) The circumstances of the Partial Eclipse in the Republic of Moldova 3) Protection of eyes during Observations

Suppression of the Polar Tongue of Ionization During the 21 August 2017 Solar Eclipse

NASA Astrophysics Data System (ADS)

Dang, Tong; Lei, Jiuhou; Wang, Wenbin; Burns, Alan; Zhang, Binzheng; Zhang, Shun-Rong

2018-04-01

It has long been recognized that during solar eclipses, the ionosphere-thermosphere system changes greatly within the eclipse shadow, due to the rapid reduction of solar irradiation. However, the concept that a solar eclipse impacts polar ionosphere behavior and dynamics as well as magnetosphere-ionosphere coupling has not been appreciated. In this study, we investigate the potential impact of the 21 August 2017 solar eclipse on the polar tongue of ionization (TOI) using a high-resolution, coupled ionosphere-thermosphere-electrodynamics model. The reduction of electron densities by the eclipse in the middle latitude TOI source region leads to a suppressed TOI in the polar region. The TOI suppression occurred when the solar eclipse moved into the afternoon sector. The Global Positioning System total electron content observations show similar tendency of polar region total electron content suppression. This study reveals that a solar eclipse occurring at middle latitudes may have significant influences on the polar ionosphere and magnetosphere-ionosphere coupling.

Outreach activities in anticipation of the 2016 solar eclipse in Sorong

NASA Astrophysics Data System (ADS)

Putra Raharja, Endra; Pramudya, Yudhiakto

2016-11-01

Sorong is located outside the narrow path of total solar eclipse on March 9th, 2016. The predicted obscuration of the sun was 94.2%. The public outreach to anticipate the solar eclipse was intended to educate students in junior and senior high school in Sorong Regency. Some of them are located in the remote area where the educational materials are difficult to find. The public outreach is unique, since it was run by the local person who is student of physics education. The student has both the ability to explain the solar eclipse phenomenon and able to adapt to knowledge level of students. The materials that were given to the schools are brochure and the eclipse glasses. Beside solar eclipse lectures in class, the pinhole workshop and observation practice were held. The limited materials and resources were faced during the public outreach. However, the enthusiasm was shown by the students and teachers. At least one of the schools held the solar eclipse observation on the day of the eclipse.

Low-Tc direct current superconducting quantum interference device magnetometer-based 36-channel magnetocardiography system in a magnetically shielded room

NASA Astrophysics Data System (ADS)

Qiu, Yang; Li, Hua; Zhang, Shu-Lin; Wang, Yong-Liang; Kong, Xiang-Yan; Zhang, Chao-Xiang; Zhang, Yong-Sheng; Xu, Xiao-Feng; Yang, Kang; Xie, Xiao-Ming

2015-07-01

We constructed a 36-channel magnetocardiography (MCG) system based on low-Tc direct current (DC) superconducting quantum interference device (SQUID) magnetometers operated inside a magnetically shielded room (MSR). Weakly damped SQUID magnetometers with large Steward-McCumber parameter βc (βc ≈ 5), which could directly connect to the operational amplifier without any additional feedback circuit, were used to simplify the readout electronics. With a flux-to-voltage transfer coefficient ∂ V/∂ Φ larger than 420 μV/Φ 0, the SQUID magnetometers had a white noise level of about 5.5 fT·Hz-1/2 when operated in MSR. 36 sensing magnetometers and 15 reference magnetometers were employed to realize software gradiometer configurations. The coverage area of the 36 sensing magnetometers is 210×210 mm2. MCG measurements with a high signal-to-noise ratio of 40 dB were done successfully using the developed system. Project supported by “One Hundred Persons Project” of the Chinese Academy of Sciences and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB04020200).

Green and simple analytical method to determine benzimidazoles in milk samples by using salting-out assisted liquid-liquid extraction and capillary liquid chromatography.

PubMed

Tejada-Casado, Carmen; Del Olmo-Iruela, Monsalud; García-Campaña, Ana M; Lara, Francisco J

2018-08-01

A green and simple multiresidue method using capillary liquid chromatography (CLC) with UV-diode array detection (DAD) has been developed for the determination of sixteen benzimidazoles (BZs) and its metabolites in milk samples. The separation was achieved in <32 min, using a Zorbax XDB-C18 column (150 mm × 0.5 mm I.D, 5 μm), with a mobile phase consisting of 50 mM ammonium acetate (solvent A) and a mixture of acetonitrile/methanol (1:1 v/v) (solvent B), at a flow rate of 9 μL min -1 . The temperature of the column was 20 °C and 6 μL of sample were injected. In spite of the complexity of milk samples, an effective, simple and fast sample preparation method called salting out-assisted liquid-liquid extraction (SALLE) was developed for the analysis of these compounds in cow milk samples. To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized including the amount of sample, type and volume of the extraction solvent, and the nature and amount of the salt. Good linearity was obtained (R 2  > 0.9985 for all BZs) with limits of detection (LOD) between 1.0 and 2.8 μg kg -1 . Relative standard deviations of repeatability and intermediate precision were below 1.6 and 14.2%, respectively. Satisfactory recoveries between 79.1 and 99.6% were also obtained for three types of milk samples (cow, sheep and goat). The advantages of a miniaturized technique such as CLC in terms of better efficiencies and reduced solvent consumption, combined with the simplicity of the SALLE procedure, make this method a useful alternative for the monitoring of these residues at trace level. Copyright © 2018 Elsevier B.V. All rights reserved.

Selected results from the epsilon Aurigae eclipse campaign, and what lies ahead

NASA Astrophysics Data System (ADS)

Stencel, Robert E.

2013-07-01

The torrent of data generated during the 2009-2011 eclipse of the enigmatic binary, epsilon Aurigae, has provided abundant opportunity to test and refine the many ideas associated with this system. The UBVRIJH photometric light curves established times of ingress and egress, and also revealed that the differential color of the disk varied, relative to pre- or post- mid-eclipse phase. Inter-eclipse monitoring indicated secular variations suggestive of a rapidly evolving F supergiant star. Interferometric imaging decisively identified the eclipse-causing agent to be an opaque disk (CHARA+MIRC). Spectroscopy has shown that a hot source occupies the center of this disk (He I 10830A, Far-UV excess), that the disk exhibits substructure (K I 7699A) and may have an extended atmosphere (CHARA+VEGA), and that the disk is isotopically-enhanced in 13C (GNIRS) and in rare-earth elements during a third contact "still-stand" in the light curve, suggestive of a mass transfer stream. Polarimetry and spectro-polarimetry provided additional constraints on the F star atmospheric variation and the nature of the dust scattering in the disk. Numerical models of the disk are exploring its relationship to the wider class of transitional and debris-type disks, and how differential heating of the dust may reveal properties not otherwise detected spectroscopically. As the system moves to quadrature in coming years, continued observing opportunities will continue to exist. I am grateful for support from the estate of William Herschel Womble for astronomy at the University of Denver, which has made possible two decades of research on this star that otherwise has revealed its secrets only very slowly.

The Guilford-Carleton Eclipse Expedition of 1900

NASA Astrophysics Data System (ADS)

English, Thomas R., III

2006-12-01

The solar eclipse of 1900 May 28 provided an opportunity for American astronomers to make observations from home soil, as the shadow tracked across the southeastern United States from New Orleans to Norfolk. Eclipse parties were scattered throughout the southern states, including large-scale scientific teams traveling to sites in Georgia and North Carolina. These major operations, staffed by groups from Yerkes, Princeton, USNO, and Lick, featured multiple observing programs and all the modern techniques they could manage. In addition to the major astrophysical endeavors, there were many smaller parties in the field in 1900 that resembled the more casual eclipse expeditions that were characteristic of a few decades before. In these efforts, relatively small groups of observers used modest instruments and made mostly visual observations, and the expedition was as much a social event as it was a scientific venture. One such group was the party from Carleton College and Guilford College that observed from a fruit farm in Southern Pines, NC. At the turn of the century, the Goodsell Observatory at Carleton College in Minnesota was an important regional astronomical facility that had provided weather and time data for over 20 years, and was the site of publication of Popular Astronomy, a widely circulated astronomical journal. At Guilford College, on the other hand, the astronomy course was taught by the school’s Treasurer, and there were no significant astronomical facilities. The presentation will explain how these two schools came to combine efforts to study the 1900 solar eclipse, and will summarize the events of the trip and the observations made. This research was supported in part by the Herbert C. Pollock Award of the Dudley Observatory.

The 1982 ultraviolet eclipse of the symbiotic binary AR Pav

NASA Technical Reports Server (NTRS)

Hutchings, J. B.; Cowley, A. P.; Ake, T. B.; Imhoff, C. L.

1983-01-01

Observations with the International Ultraviolet Explorer (IUE) of the symbiotic binary AR Pav through its 1982 eclipse show that the hot star is not eclipsed. The hot star is associated with an extended region of continuum emission which is partially eclipsed. The eclipsed radiation is hotter near to its center, with a maximum temperature of about 9000 K. The uneclipsed flux is hotter than this. UV emission lines are not measurably eclipsed and presumably arise in a much larger region than the continuum. These data provide new constraints on models of the system but also are apparently in contradiction to those based on ground-based data.

On the detection and attribution of gravity waves generated by the 20 March 2015 solar eclipse.

PubMed

Marlton, G J; Williams, P D; Nicoll, K A

2016-09-28

Internal gravity waves are generated as adjustment radiation whenever a sudden change in forcing causes the atmosphere to depart from its large-scale balanced state. Such a forcing anomaly occurs during a solar eclipse, when the Moon's shadow cools part of the Earth's surface. The resulting atmospheric gravity waves are associated with pressure and temperature perturbations, which in principle are detectable both at the surface and aloft. In this study, surface pressure and temperature data from two UK sites at Reading and Lerwick are examined for eclipse-driven gravity wave perturbations during the 20 March 2015 solar eclipse over northwest Europe. Radiosonde wind data from the same two sites are also analysed using a moving parcel analysis method, to determine the periodicities of the waves aloft. On this occasion, the perturbations both at the surface and aloft are found not to be confidently attributable to eclipse-driven gravity waves. We conclude that the complex synoptic weather conditions over the UK at the time of this particular eclipse helped to mask any eclipse-driven gravity waves.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Authors.

An Outreach Project to Provide 2.1 Million Eclipse Glasses and Eclipse Information through 7,100 Libraries Nationwide

NASA Astrophysics Data System (ADS)

Fraknoi, Andrew; Schatz, Dennis; Dusenbery, Paul; Duncan, Douglas; Holland, Anne; Laconte, Keliann

2018-01-01

With support from the Moore Foundation, Google, the Research Corporation, and NASA, we were able to distribute about 2.1 million eclipse glasses and an extensive booklet of eclipse information and outreach suggestions to 7,100 public libraries throughout the nation. It appears that this project was the single largest program to provide glasses and eclipse information to the public in the U.S. The project using (and significantly enlarged) the existing STARNet network of libraries set up and maintained by the Space Science Institute. We were able to get glasses to a diverse set of institutions, including urban, rural, Native American, small town and large city libraries. In this poster, we will summarize the history of the project, the various components and how they worked together, and the results of a post survey of the librarians, which provided numbers, photographs, and impressions from the many libraries and their patrons. A map of the libraries involved is at www.starnetlibraries.org/2017eclipse/. The booklet of information that was sent to help train librarians in eclipse science and eclipse outreach can still be downloaded free at: http://www.starnetlibraries.org/EclipseGuide/.”

78 FR 30243 - Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-22

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Dosimetric quality control of Eclipse treatment planning system using pelvic digital test object

NASA Astrophysics Data System (ADS)

Benhdech, Yassine; Beaumont, Stéphane; Guédon, Jeanpierre; Crespin, Sylvain

2011-03-01

Last year, we demonstrated the feasibility of a new method to perform dosimetric quality control of Treatment Planning Systems in radiotherapy, this method is based on Monte-Carlo simulations and uses anatomical Digital Test Objects (DTOs). The pelvic DTO was used in order to assess this new method on an ECLIPSE VARIAN Treatment Planning System. Large dose variations were observed particularly in air and bone equivalent material. In this current work, we discuss the results of the previous paper and provide an explanation for observed dose differences, the VARIAN Eclipse (Anisotropic Analytical) algorithm was investigated. Monte Carlo simulations (MC) were performed with a PENELOPE code version 2003. To increase efficiency of MC simulations, we have used our parallelized version based on the standard MPI (Message Passing Interface). The parallel code has been run on a 32- processor SGI cluster. The study was carried out using pelvic DTOs and was performed for low- and high-energy photon beams (6 and 18MV) on 2100CD VARIAN linear accelerator. A square field (10x10 cm2) was used. Assuming the MC data as reference, χ index analyze was carried out. For this study, a distance to agreement (DTA) was set to 7mm while the dose difference was set to 5% as recommended in the TRS-430 and TG-53 (on the beam axis in 3-D inhomogeneities). When using Monte Carlo PENELOPE, the absorbed dose is computed to the medium, however the TPS computes dose to water. We have used the method described by Siebers et al. based on Bragg-Gray cavity theory to convert MC simulated dose to medium to dose to water. Results show a strong consistency between ECLIPSE and MC calculations on the beam axis.

Establishing the accuracy of asteroseismic mass and radius estimates of giant stars - I. Three eclipsing systems at [Fe/H] ˜ -0.3 and the need for a large high-precision sample

NASA Astrophysics Data System (ADS)

Brogaard, K.; Hansen, C. J.; Miglio, A.; Slumstrup, D.; Frandsen, S.; Jessen-Hansen, J.; Lund, M. N.; Bossini, D.; Thygesen, A.; Davies, G. R.; Chaplin, W. J.; Arentoft, T.; Bruntt, H.; Grundahl, F.; Handberg, R.

2018-05-01

We aim to establish and improve the accuracy level of asteroseismic estimates of mass, radius, and age of giant stars. This can be achieved by measuring independent, accurate, and precise masses, radii, effective temperatures and metallicities of long period eclipsing binary stars with a red giant component that displays solar-like oscillations. We measured precise properties of the three eclipsing binary systems KIC 7037405, KIC 9540226, and KIC 9970396 and estimated their ages be 5.3 ± 0.5, 3.1 ± 0.6, and 4.8 ± 0.5 Gyr. The measurements of the giant stars were compared to corresponding measurements of mass, radius, and age using asteroseismic scaling relations and grid modelling. We found that asteroseismic scaling relations without corrections to Δν systematically overestimate the masses of the three red giants by 11.7 per cent, 13.7 per cent, and 18.9 per cent, respectively. However, by applying theoretical correction factors fΔν according to Rodrigues et al. (2017), we reached general agreement between dynamical and asteroseismic mass estimates, and no indications of systematic differences at the precision level of the asteroseismic measurements. The larger sample investigated by Gaulme et al. (2016) showed a much more complicated situation, where some stars show agreement between the dynamical and corrected asteroseismic measures while others suggest significant overestimates of the asteroseismic measures. We found no simple explanation for this, but indications of several potential problems, some theoretical, others observational. Therefore, an extension of the present precision study to a larger sample of eclipsing systems is crucial for establishing and improving the accuracy of asteroseismology of giant stars.

Optical Photometry and X-Ray Monitoring of the ``Cool Algol'' BD +05°706: Determination of the Physical Properties

NASA Astrophysics Data System (ADS)

Torres, Guillermo; Mader, Jeff A.; Marschall, Laurence A.; Neuhäuser, Ralph; Duffy, Alaine S.

2003-06-01

We present new photometric observations in the BVRI bands of the double-lined eclipsing binary BD +05°706 conducted over three observing seasons, as well as new X-ray observations obtained with ROSAT covering a full orbital cycle (P=18.9 days). A detailed light-curve analysis of the optical data shows the system to be semidetached, confirming indications from an earlier analysis by Torres et al. (published in 1998), with the less massive and cooler star filling its Roche lobe. The system is a member of the rare class of cool Algol systems, which are different from the ``classical'' Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the new photometry with a reanalysis of the spectroscopic observations reported by Torres et al., we derive accurate absolute masses for the components of M1=2.633+/-0.028 Msolar and M2=0.5412+/-0.0093 Msolar, radii of R1=7.55+/-0.20 Rsolar and R2=11.02+/-0.21 Rsolar, as well as effective temperatures of 5000+/-100 and 4640+/-150 K, for the primary and secondary, respectively. There are obvious signs of activity (spottedness) in the optical light curve of the binary. Our X-ray light curve clearly shows the primary eclipse but not the secondary eclipse, suggesting that the primary star is the dominant source of the activity in the system. The depth and duration of the eclipse allow us to infer some of the properties of the X-ray-emitting region around that star.

Effects of the March 2015 solar eclipse on near-surface atmospheric electricity.

PubMed

Bennett, A J

2016-09-28

Measurements of atmospheric electrical and standard meteorological parameters were made at coastal and inland sites in southern England during the 20 March 2015 partial solar eclipse. Clear evidence of a reduction in air temperature resulting from the eclipse was found at both locations, despite one of them being overcast during the entire eclipse. The reduction in temperature was expected to affect the near-surface electric field (potential gradient (PG)) through a reduction in turbulent transfer of space charge. No such effect could be unambiguously confirmed, however, with variability in PG and air-Earth current during the eclipse being comparable to pre- and post-eclipse conditions. The already low solar radiation for this latitude, season and time of day was likely to have contributed to the reduced effect of the eclipse on atmospheric electricity through boundary layer stability. The absence of a reduction in mean PG shortly after time of maximum solar obscuration, as observed during eclipses at lower geomagnetic latitude, implied that there was no significant change in atmospheric ionization from cosmic rays above background variability. This finding was suggested to be due to the relative importance of cosmic rays of solar and galactic origin at geomagnetic mid-latitudes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Author(s).

Solar Eclipses Observed from Antarctica

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2013-01-01

Aspects of the solar corona are still best observed during totality of solar eclipses, and other high-resolution observations of coronal active regions can be observed with radio telescopes by differentiation of occultation observations, as we did with the Jansky Very Large Array for the annular solar eclipse of 2012 May 20 in the US. Totality crossing Antarctica included the eclipse of 2003 November 23, and will next occur on 2021 December 4; annularity crossing Antarctica included the eclipse of 2008 February 7, and will next occur on 2014 April 29. Partial phases as high as 87% coverage were visible and were imaged in Antarctica on 2011 November 25, and in addition to partial phases of the total and annular eclipses listed above, partial phases were visible in Antarctica on 2001 July 2011, 2002 December 4, 2004 April 19, 2006 September 22, 2007 September 11, and 2009 January 26, and will be visible on 2015 September 13, 2016 September 1, 2017 February 26, 2018 February 15, and 2020 December 14. On behalf of the Working Group on Solar Eclipses of the IAU, the poster showed the solar eclipses visible from Antarctica and this article shows a subset (see www.eclipses.info for the full set). A variety of investigations of the Sun and of the response of the terrestrial atmosphere and ionosphere to the abrupt solar cutoff can be carried out at the future eclipses, making the Antarctic observations scientifically useful.

Ionospheric effects over Europe during the solar eclipse on 20 March 2015

NASA Astrophysics Data System (ADS)

Hoque, Mainul; Jakowski, Norbert; Berdermann, Jens

2017-04-01

A total solar eclipse occurred on March 20, 2015 moving from the North-West Europe towards the North-East. Due to strong solar radiation changes dynamic processes were initiated in the atmosphere and ionosphere causing a measurable impact e.g. on the temperature and ionization during the eclipse. We analyzed the 20 March 2015 solar eclipse effects on the ionospheric structure over Europe using multi-sensor observations such as vertical sounding (VS) and Global Positioning System (GPS) measurements. Whereas the VS measurements are used to provide peak electron density information at the ionospheric F2, F1 and E layers over selected ionosonde stations, a dense network of GPS stations is used to provide high spatial resolution of the total electron content (TEC) estimates over Europe. We reconstructed the TEC maps with 5 minutes time resolution and thus investigated the original TEC maps and differential TEC maps obtained by subtracting 27 days medians from the actual TEC map values on 20 March 2015. By combining VS and GPS measurements the equivalent slab thickness has been estimated over several ionosonde stations to get information how the shape of the vertical electron density profile changes during the eclipse. The analysis of the solar eclipse on 20 March 2015 presented here will contribute to understand the ionospheric response on solar eclipses occurring at different latitudes. The observations indicate that a number of competitive processes initiated by an eclipse are often enhanced by dynamic forces associated with large scale geophysical conditions not directly impacted by the solar eclipse. Our TEC estimation shows that the total ionization reduces up to 60% (after bias correction 40%) as a function of obscuration. Since the 20 March 2015 eclipse occurred during the negative phase of a severe geomagnetic storm on 17 March 2015, the observed TEC depletion is higher than those reported earlier for 1999 and 2005 eclipses. Thus, a negative bias of up to 20% was observed over Northern Europe already before the eclipse occurred. Moreover, the eclipse path of the solar eclipse in 2015 is traced at higher latitudes compared with eclipses observed in the years 1999 and 2005. The ionospheric response to the obscuration function is delayed up to 40 minutes decreasing with growing distance from the totality zone and increasing with altitude. The increasing delay with altitude is in agreement with earlier findings for other eclipses. The equivalent slab thickness was found to increase by approximately 80 -100 km during the solar eclipse on 20 March 2015 showing evidence for a pronounced loss in the bottomside ionosphere causing a delayed depletion of the topside ionosphere.

Public education in developing countries on the occasions of eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

Total solar eclipses will cross southern Africa on June 21, 2001, and on December 4, 2002. Most of Africa will see partial phases. The total phase of the 2001 eclipse will be visible from parts of Angola, Zambia, Zimbabwe, Mozambique and Madagascar. The total phase of the 2002 eclipse will be visible from parts of Angola, Botswana, Zimbabwe, South Africa and Mozambique. Public education must be undertaken to tell the people how to look at the eclipse safely. We can take advantage of having the attention of the people and of news media to teach about not only eclipses but also the rest of astronomy. I am Chair of a "Public Education at Eclipses" subcommission of IAU Commission 46 on the Teaching of Astronomy, and we are able to advise educators and others about materials, procedures and information releases.

Spitzer Secondary Eclipses of HAT-P-13b

NASA Astrophysics Data System (ADS)

Hardy, Ryan A.; Harrington, J.; Hardin, M. R.; Madhusudhan, N.; Cubillos, P.; Blecic, J.; Bakos, G.; Hartman, J. D.

2013-10-01

HAT-P-13 b is a transiting hot Jupiter with a slightly eccentric orbit (e = 0.010) inhabiting a two-planet system. The two-planet arrangement provides an opportunity to probe the interior structure of HAT-P-13b. Under equilibrium-tide theory and confirmation that the apsides of planets b and c are in alignment, a measurement of the planet's eccentricity can be related to the planet's tidal Love number k2, which describes the central condensation of the planet's mass and its deformation under tidal effects. A measurement of k2 could constrain interior models of HAT-P-13b. HAT-P-13b's orbit is configured favorably for refinement of the eccentricity by secondary eclipse timing observations, which provide direct measurements of ecosω. In 2010, Spitzer observed two secondary eclipses of HAT-P-13b in the 3.6- and 4.5-μm IRAC bandpasses. We present secondary eclipse times and depths; joint models of the HAT-P-13 system that incorporate transit photometry and radial velocity data; and constraints on the atmospheric chemistry of HAT-P-13b that suggest solar-abundance composition without a thermal inversion. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA, which provided support for this work. This work was supported in part by NASA Planetary Atmospheres Grant NNX13AF38G.

Double cyclic variations in orbital period of the eclipsing cataclysmic variable EX Dra

NASA Astrophysics Data System (ADS)

Han, Zhong-tao; Qian, Sheng-bang; Voloshina, Irina; Zhu, Li-Ying

2017-06-01

EX Dra is a long-period eclipsing dwarf nova with ˜2-3 mag amplitude outbursts. This star has been monitored photometrically from November, 2009 to March, 2016 and 29 new mid-eclipse times were obtained. By using new data together with the published data, the best fit to the O-C curve indicate that the orbital period of EX Dra have an upward parabolic change while undergoing double-cyclic variations with the periods of 21.4 and 3.99 years, respectively. The upward parabolic change reveals a long-term increase at a rate of \\dot{P}= {+7.46}×10^{-11} s s^{-1}. The evolutionary theory of cataclysmic variables (CVs) predicts that, as a CV evolves, the orbital period should be decreasing rather than increasing. Secular increase can be explained as the mass transfer between the secondary and primary or may be just an observed part of a longer cyclic change. Most plausible explanation for the double-cyclic variations is a pair of light travel-time effect via the presence of two companions. Their masses are determined to be MAsin i'A=29.3(±0.6) M_{Jup} and MBsin i'B=50.8(±0.2) M_{Jup}. When the two companions are coplanar to the orbital plane of the central eclipsing pair, their masses would match to brown dwarfs.

Observing Solar Eclipses in the Developing World

NASA Astrophysics Data System (ADS)

Pasachoff, J. M.

2006-08-01

The paths of totality of total solar eclipses cross the world, with each spot receiving such a view about every 300 years. The areas of the world from which partial eclipses are visible are much wider. For the few days prior to a total eclipse, the attention of a given country is often drawn toward the eclipse, providing a teachable moment that we can use to bring astronomy to the public's attention. Also, it is important to describe how to observe the partial phases of the eclipse safely. Further, it is important to describe to those people in the zone of totality that it is not only safe but also interesting to view totality. Those who are misled by false warnings that overstate the hazards of viewing the eclipse, or that fail to distinguish between safe and unsafe times for naked-eye viewing, may well be skeptical when other health warnings--perhaps about AIDS or malaria prevention or polio inoculations--come from the authorities, meaning that the penalties for misunderstanding the astronomical event can be severe. Through the International Astronomical Union's Working Group on Solar Eclipses and through the I.A.U.'s Program Group on Public Education at the Times of Eclipses, part of the Commission on Education and Development, we make available information to national authorities, to colleagues in the relevant countries, and to others, through our Websites at http://www.eclipses.info and http://www.totalsolareclipse.net and through personal communication. Among our successes at the 29 March 2006 total solar eclipse was the distribution through a colleague in Nigeria of 400,000 eye-protection filters.

75 FR 45075 - Airworthiness Directives; Eclipse Aerospace, Inc. Model EA500 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-02

... Airworthiness Directives; Eclipse Aerospace, Inc. Model EA500 Airplanes AGENCY: Federal Aviation Administration... in the Federal Register on July 9, 2010 (75 FR 39472), and applies to certain Eclipse Aerospace, Inc... Federal holidays. For service information identified in this proposed AD, contact Eclipse Aerospace, Inc...

The Totality App — General Lessons and Future Eclipses

NASA Astrophysics Data System (ADS)

Bennett, Jeffrey

2018-06-01

With the excitement around the 2017 eclipse, I worked with an app development company to create the Totality app, which featured eclipse predictions from the code of Xavier Jubier. We have since updated the app for future eclipses, including a Spanish version given the upcoming eclipses in Chile/Argentina. I will briefly discuss the current app, the process through which we developed it, and relevant lessons learned along the way that may be useful to others interested in developing apps for astronomy education.

Survey of conformational isomerism in (E)-2-[(4-bromophenylimino)methyl]-5-(diethylamino)phenol compound from structural and thermochemical points of view.

PubMed

Albayrak, Çiğdem; Kaştaş, Gökhan; Odabaşoğlu, Mustafa; Frank, René

2012-09-01

In this study, (E)-2-[(4-bromophenylimino)methyl]-5-(diethylamino)phenol compound was investigated by mainly focusing on conformational isomerism. For this purpose, molecular structure and spectroscopic properties of the compound were experimentally characterized by X-ray diffraction, FT-IR and UV-Vis spectroscopic techniques, and computationally by DFT method. The X-ray diffraction analysis of the compound shows the formation of two conformers (anti and eclipsed) related to the ethyl groups of the compound. The two conformers are connected to each other by non-covalent C-H⋯Br and C-H⋯π interactions. The combination of these interactions is resulted in fused R(2)(2)(10) and R(2)(4)(20) synthons which are responsible for the tape structure of crystal packing arrangement. The X-ray diffraction and FT-IR analyses also reveal the existence of enol form in the solid state. From thermochemical point of view, the computational investigation of isomerism includes three studies: the calculation of (a) the rate constants for transmission from anti or eclipsed conformations to transition state by using Eyring equation, (b) the activation energy needed for isomerism by using Arrhenius equation, (c) the equilibrium constant from anti conformer to eclipsed conformer by using the equation including the change in Gibbs free energy. The dependence of tautomerism on solvent types was studied on the basis of UV-Vis spectra recorded in different organic solvents. The results showed that the compound exists in enol form in all solvents except ethyl alcohol. Copyright © 2012 Elsevier B.V. All rights reserved.

A spectroscopic investigation of the eclipsing binary Epsilon Aurigae

NASA Technical Reports Server (NTRS)

Balachandran, Suchitra

1991-01-01

The objectives were to examine, in detail, the spectra of the eclipsing binary Epsilon Aurigae taken with the IUE satellite telescope during the 1982 to 1984 eclipse. All of the low resolution spectra were analyzed and UV light curves are presented. The primary findings are as follows: (1) a constant eclipse depth from 1600 A to longer wavelengths and a sharp drop in the eclipse depth from 1600 to 1200 A; (2) the absence of large amplitude fluctuations in the UV as expected from a Cepheid primary; and (3) equal ingress and egress times in contradiction to that interpreted from visible light curves. The effects of these findings on the eclipse geometry are being studied.

Eclipses in Australian Aboriginal Astronomy

NASA Astrophysics Data System (ADS)

Hamacher, Duane W.; Norris, Ray P.

2011-07-01

We explore about fifty different Australian Aboriginal accounts of lunar and solar eclipses to determine how Aboriginal groups understood this phenomenon. We summarize the literature on Aboriginal references to eclipses. We show that many Aboriginal groups viewed eclipses negatively, frequently associating them with bad omens, evil magic, disease, blood and death. In many communities, elders or medicine men claimed to be able to control or avert eclipses by magical means, solidifying their roles as providers and protectors within their communities. We also show that some Aboriginal groups seem to have understood the motions of the Sun-Earth-Moon system, the connection between the lunar phases and tides, and acknowledged that solar eclipses were caused by the Moon blocking the Sun.

Eclipse Across America on This Week @NASA – August 25, 2017

NASA Image and Video Library

2017-08-25

The Aug. 21 eclipse across America generated interest and excitement far and wide. Our coverage of the historic eclipse – the first coast-to-coast total solar eclipse for the U.S. in 99 years – was widespread … Anchored from the College of Charleston, in South Carolina – we showed you views of the eclipse that only NASA could. Views from space, from Earth’s atmosphere and from the ground – with expert observation and analysis provided from many of the 14 states around the country, situated along the path of totality. That’s where thousands of people flocked – for the ultimate eclipse experience – total darkness in the middle of the day!

Physical and metabolic requirements for early interaction of poliovirus and human rhinovirus with HeLa cells.

PubMed Central

Lonberg-Holm, K; Whiteley, N M

1976-01-01

Attachment, ""tight binding'' and eclipse of radioactive poliovirus 2 (P2) and human rhinovirus 2 (HRV 2) were investigated. The activation energy for attachment of both HRV2 and P2 was about 13 kcal/mol. HRV2 differed from P2 in two respects: the Arrhenius plot for attachment of HRV2 showed a break at 15 to 19 degrees C when the cells were first treated several hours at 0 degrees C, and attachment of HRV2 was inhibited by treatment of cells with metabolic poisons able to reduce cellular ATP by more than 90%. Tight binding was determined by isolation of a specific P2-membrane complex or by loss of EDTA dissociability of HRV2. Tight binding of both viruses was slowed by 0.01 M iodoacetamide but not by 0.02 M F-; F- plus 0.002 M CN- slowed tight binding of HRV2 but not of P2. Eclipse, the irreversible alteration of parental virions, was detected by isolation of cell-associated subviral particles or by loss of cell-associated infectious virus. Eclipse of both viruses is slowed by iodoacetamide or F-. It seems likely that the early steps of infection with picornaviruses may be sensitive to alterations in the cell membrane produced by metabolic inhibitors or by treatment at low temperature. PMID:184301

KEPLER ECLIPSING BINARIES WITH STELLAR COMPANIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gies, D. R.; Matson, R. A.; Guo, Z.

2015-12-15

Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars amongmore » this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.« less

Light curve solutions of the eclipsing eccentric binaries KIC 8111622, KIC 10518735, KIC 8196180 and their out-of-eclipse variability

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana P.; Vasileva, Doroteya L.

2018-02-01

We determined the orbits and stellar parameters of three eccentric eclipsing binaries by light curve solutions of their Kepler data. KIC 8111622 and KIC 10518735 undergo total eclipses while KIC 8196180 reveals partial eclipses. The target components are G and K stars, excluding the primary of KIC 8196180 which is early F star. KIC 8196180 reveals well-visible tidally-induced feature at periastron, i.e. it is an eclipsing heartbeat star. The characteristics of the observed periastron feature (shape, width and amplitude) confirm the theoretical predictions. There are additional out-of-eclipse variations of KIC 8196180 with the orbital period which may be explained by spot activity of synchronously rotating component. Besides worse visible periastron feature KIC 811162 exhibits small-amplitude light variations whose period is around 2.3 times shorter than the orbital one. These oscillations were attributed to spot(s) on asynchronously rotating component.

Fall 2011 Eclipse Season Begins

NASA Image and Video Library

2017-12-08

The Fall 2011 eclipse season started on September 11. Here is an AIA 171 image from 0657 UT with the first eclipse! SDO has eclipse seasons twice a year near each equinox. For three weeks near midnight Las Cruces time (about 0700 UT) our orbit has the Earth pass between SDO and the Sun. These eclipses can last up to 72 minutes in the middle of an eclipse season. The current eclipse season started on September 11 and lasts until October 4. To read more about SDO go to: sdo.gsfc.nasa.gov/ Credit: NASA/GSFC/SDO NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

What are the Perspectives of Indonesian Students to Japanese Ritual during Solar Eclipse?

NASA Astrophysics Data System (ADS)

Haristiani, N.; Rusli, A.; Wiryani, A. S.; Nandiyanto, A. B. D.; Purnamasari, A.; Sucahya, T. N.; Permatasari, N.

2018-02-01

In this globalization era, many people still believe the myths about solar eclipse. The myths about solar eclipse are different between one country or are to another. In this context, the aim of this study was to investigate the perspective of Indonesian students in viewing how the Japanese people face their believing myths in solar eclipse. This research also investigated the student belief on several mythical stories in Indonesia, their understanding of the Islamic view, and their knowledge based on science concept relating to the solar eclipse phenomenon. To understand the Indonesian students’ perspective about the solar eclipse myths in Japanese, we took a survey to Indonesian students which are studying Japanese culture and language. Based on the results, the Indonesian student think that there is no significant difference between Indonesian and Japanese people in facing the solar eclipse.

High-speed photometry of the eclipsing dwarf nova OY Carinae

NASA Technical Reports Server (NTRS)

Cook, M. C.

1985-01-01

High-speed photometry of the eclipsing dwarf nova OY Car in the quiescent state is presented. OY Car becomes highly reddened during eclipse, with minimum flux colours inconsistent with optically thick emission in the U and B bandpasses. Mass ratios in the range 6.5 to 12 are required to reconcile the eclipse structure with theoretical gas stream trajectories. Primary eclipse timings reveal a significant decrease in the orbital period and the duration of primary eclipse indicates the presence of a luminous ring about the white dwarf. The hotspot eclipse reveals a hotspot which is elongated along the rim of the accretion disc, with optical emission being non-uniformly distributed along the rim. The location of the hotspot in the accretion disc implies a disc radius larger than that of an inviscid disc, with variation in the position of the hotspot being consistent with a fixed stream trajectory.

Eclipse 2017: Through the eyes of NASA

NASA Astrophysics Data System (ADS)

Mayo, Louis; NASA/GSFC Heliophysics Education Consortium

2016-10-01

The August 21, 2017 eclipse will be the first time a total solar eclipse has traversed the Continental US since June 8th, 1918. Anticipation y for energy for this eclipse is off the charts. Over 500 million in North America alone will catch the eclipse in either partial or total phase. Parts of South America, Africa, and Europe will see a partial eclipse as well. NASA is planning to take full advantage of this unique celestial event as an education and public engagement opportunity by leveraging its extensive networks of partners, numerous social media platforms, broadcast media, and its significant unique space assets and people to bring the eclipse to America and the world as only NASA can. This talk will outline NASA's education plans in some detail replicating our many Big Events successes including the 2012 Transit of Venus and the MSL/Curiosity landing and show how scientists and the public can get involved.

The 2017 Total Solar Eclipse: Through the Eyes of NASA

NASA Astrophysics Data System (ADS)

Young, C. Alex; Mayo, Louis; Ng, Carolyn; Cline, Troy; Lewis, Elaine; Reed, Shannon; Debebe, Asidesach; Stephenson, Bryan; Odenwald, Sten; Hill, Steele; Wright, Ernest

2017-01-01

The August 21, 2017 eclipse will be the first time a total solar eclipse has traversed the Continental US since June 8th, 1918. Anticipation and energy for this eclipse is off the charts! Over 500 million in North America alone will catch the eclipse in either partial or total phase. Parts of South America, Africa, and Europe will see a partial eclipse as well. NASA is planning to take full advantage of this unique celestial event as an education and public engagement opportunity by leveraging its extensive networks of partners, numerous social media platforms, broadcast media, and its significant unique space assets and people to bring the eclipse to America and the world as only NASA can.This talk will outline NASA’s education plans in some detail replicating our many Big Events successes including the 2012 Transit of Venus and the MSL/Curiosity landing and show how scientists and the public can get involved.

Solar Eclipse Engagement and Outreach in Madras and Warm Springs, Oregon

NASA Astrophysics Data System (ADS)

Kirk, M. S.; Pesnell, W. D.; Ahern, S.; Boyle, M.; Gonzales, T.; Leone, C.

2017-12-01

The Central Oregon towns of Madras and Warm Springs were in an ideal location to observe the total solar eclipse of 2017. In anticipation of this event, we embarked on a yearlong partnership to engage and excite these communities. We developed educational events for all students in the school district, grades K-12, as well as two evening keynote addresses during an eclipse week in May. This eclipse week provided resources, learning opportunities, and safety information for all students and families prior to the end of the school year. With the collaboration of graphic design students at Oregon State University, we produced static educational displays as an introduction to the Museum at Warm Springs' exhibit featuring eclipse art. The weekend before the eclipse, we gave away 15,000 pairs of solar viewing glasses to the local community and manned a science booth at the Oregon Solarfest to engage the arriving eclipse tourists. These efforts culminated on Monday, August 21st with tens of thousands of people viewing eclipse totality in Madras and Warm Springs.

Spatiotemporal change of sky polarization during the total solar eclipse on 29 March 2006 in Turkey: polarization patterns of the eclipsed sky observed by full-sky imaging polarimetry.

PubMed

Sipocz, Brigitta; Hegedüs, Ramón; Kriska, György; Horváth, Gábor

2008-12-01

Using 180 degrees field-of-view (full-sky) imaging polarimetry, we measured the spatiotemporal change of the polarization of skylight during the total solar eclipse on 29 March 2006 in Turkey. We present our observations here on the temporal variation of the celestial patterns of the degree p and angle alpha of linear polarization of the eclipsed sky measured in the red (650 nm), green (550 nm), and blue (450 nm) parts of the spectrum. We also report on the temporal and spectral change of the positions of neutral (unpolarized, p = 0) points, and points with local minima or maxima of p of the eclipsed sky. Our results are compared with the observations performed by the same polarimetric technique during the total solar eclipse on 11 August 1999 in Hungary. Practically the same characteristics of celestial polarization were encountered during both eclipses. This shows that the observed polarization phenomena of the eclipsed sky may be general.

Coordinated weather balloon solar radiation measurements during a solar eclipse.

PubMed

Harrison, R G; Marlton, G J; Williams, P D; Nicoll, K A

2016-09-28

Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes.This article is part of the themed issue 'Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse'. © 2016 The Authors.

The National Eclipse Weather Experiment: an assessment of citizen scientist weather observations

PubMed Central

2016-01-01

The National Eclipse Weather Experiment (NEWEx) was a citizen science project designed to assess the effects of the 20 March 2015 partial solar eclipse on the weather over the United Kingdom (UK). NEWEx had two principal objectives: to provide a spatial network of meteorological observations across the UK to aid the investigation of eclipse-induced weather changes, and to develop a nationwide public engagement activity-based participation of citizen scientists. In total, NEWEx collected 15 606 observations of air temperature, cloudiness and wind speed and direction from 309 locations across the UK, over a 3 h window spanning the eclipse period. The headline results were processed in near real time, immediately published online, and featured in UK national press articles on the day of the eclipse. Here, we describe the technical development of NEWEx and how the observations provided by the citizen scientists were analysed. By comparing the results of the NEWEx analyses with results from other investigations of the same eclipse using different observational networks, including measurements from the University of Reading’s Atmospheric Observatory, we demonstrate that NEWEx provided a fair representation of the change in the UK meteorological conditions throughout the eclipse. Despite the simplicity of the approach adopted, robust reductions in both temperature and wind speed during the eclipse were observed. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550767

Using the ionospheric response to the solar eclipse on 20 March 2015 to detect spatial structure in the solar corona

PubMed Central

Bradford, J.; Bell, S. A.; Wilkinson, J.; Smith, D.; Tudor, S.

2016-01-01

The total solar eclipse that occurred over the Arctic region on 20 March 2015 was seen as a partial eclipse over much of Europe. Observations of this eclipse were used to investigate the high time resolution (1 min) decay and recovery of the Earth’s ionospheric E-region above the ionospheric monitoring station in Chilton, UK. At the altitude of this region (100 km), the maximum phase of the eclipse was 88.88% obscuration of the photosphere occurring at 9:29:41.5 UT. In comparison, the ionospheric response revealed a maximum obscuration of 66% (leaving a fraction, Φ, of uneclipsed radiation of 34±4%) occurring at 9:29 UT. The eclipse was re-created using data from the Solar Dynamics Observatory to estimate the fraction of radiation incident on the Earth’s atmosphere throughout the eclipse from nine different emission wavelengths in the extreme ultraviolet (EUV) and X-ray spectrum. These emissions, having varying spatial distributions, were each obscured differently during the eclipse. Those wavelengths associated with coronal emissions (94, 211 and 335 Å) most closely reproduced the time varying fraction of unobscured radiation observed in the ionosphere. These results could enable historic ionospheric eclipse measurements to be interpreted in terms of the distribution of EUV and X-ray emissions on the solar disc. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550766

Student artistry sparks eclipse excitement on Maui: NSO/DKIST EPO for the 2016 Partial Solar Eclipse

NASA Astrophysics Data System (ADS)

Schad, Thomas A.; Penn, Matthew J.; Armstrong, James

2016-05-01

Local creativity and artistry is a powerful resource that enhances education programs and helps us generate excitement for science within our communities. In celebration of the 2016 Solar Eclipse, the National Solar Observatory (NSO) and its Daniel K Inouye Solar Telescope (DKIST) project were pleased to engage with students across Maui County, Hawai`i, via the 2016 Maui Eclipse Art Contest. With the help of the Maui Economic Development Board and the University of Hawai'is Institute for Astronomy, we solicited art entries from all K-12 schools in Maui County approximately 6 months prior to the eclipse. Along with divisional prizes, a grand prize was selected by a panel of local judges, which was subsequently printed on 25,000 solar eclipse viewing glasses and distributed to all Maui students. We found that the impact of a locally-sourced glasses design cannot be understated. Overall, the success of this program relied upon reaching out to individual teachers, supplying educational flyers to all schools, and visiting classrooms. On the day of the eclipse, all of the art entries were prominently displayed during a community eclipse viewing event at Kalama Beach Park in Kihei, HI, that was co-hosted by NSO and the Maui Science Center. This eclipse art contest was integral to making local connections to help promote science education on Maui, and we suggest that it could be adapted to the solar community's EPO activities for the upcoming 2017 Great American Solar Eclipse.

[Determination of arbutin in apple juice concentrate by ultra performance liquid chromatography with electrospray ionization tandem mass spectrometry].

PubMed

Kong, Xianghong; He, Qiang; Yue, Aishan; Wu, Shuangmin; Li, Jianhua

2010-06-01

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was developed for the determination of arbutin in apple juice concentrate. Samples were diluted with water, then cleaned-up with a PS-DVB column. Quantitation was carried out using an external standard method. UPLC was performed on an Eclipse Plus C, column (100 mm x 2.1 mm, 1.8 microm) using a gradient solvent system (methanol-water). MS/MS was performed with multiple reaction monitoring (MRM) mode. The detection limit of arbutin was 0.02 mg/L. The method showed good linear relationship at the range of 0.04-2.0 mg/L. The recoveries ranged from 75.2% to 102.7% with relative standard deviations (RSDs) less than 8.9%. The method is simple, fast and sensitive. It's suitable for quantitative and qualitative analysis of arbutin in apple juice concentrate.

Separation and characterization of chemical constituents in Ginkgo biloba extract by off-line hydrophilic interaction×reversed-phase two-dimensional liquid chromatography coupled with quadrupole-time of flight mass spectrometry.

PubMed

Ji, Shuai; He, Dan-Dan; Wang, Tian-Yun; Han, Jie; Li, Zheng; Du, Yan; Zou, Jia-Hui; Guo, Meng-Zhe; Tang, Dao-Quan

2017-11-30

Ginkgo biloba extract (GBE), derived from the leaves of Ginkgo biloba L., is one of the most widely used traditional Chinese medicines worldwide. Due to high structural diversity and low abundance of chemical constituents in GBE, conventional reversed-phase liquid chromatography has limited power to meet the needs of its quality control. In this study, an off-line hydrophilic interaction×reversed-phase two-dimensional liquid chromatography (HILIC×RP 2D-LC) system coupled with diode array detection (DAD) and quadrupole time-of-flight mass spectrometry (qTOF-MS) was established to comprehensively analyze the chemical constituents of GBE. After optimizing the chromatographic columns and mobile phase of 2D-LC, a Waters XBridge Amide column using acetonitrile/water/formic acid as the mobile phase was selected as the first dimension to fractionate GBE, and the obtained fractions were further separated on an Agilent Zorbax XDB-C18 column with methanol/water/formic acid as the mobile phase. As a result, a total of 125 compounds were detected in GBE. The orthogonality of the 2D-LC system was 69.5%, and the practical peak capacity was 3864 and 2994, respectively, calculated by two different methods. The structures of 104 compounds were tentatively characterized by qTOF-MS analysis, and 21 of them were further confirmed by comparing with reference standards. This established HILIC×RP 2D-LC-qTOF/MS system can greatly improve the separation and characterization of natural products in GBE or other complicated herbal extracts. Copyright © 2017 Elsevier B.V. All rights reserved.

Colliding stellar winds in the eclipsing Wolf-Rayet binary V444 Cygni

NASA Technical Reports Server (NTRS)

Brown, Douglas N.; Shore, Steven N.

1988-01-01

High resolution spectra of V444 Cygni have been obtained using the International Ultraviolet Explorer Satellite. These spectra span both eclipses and include one observation at third quadrature. Together with seven archival spectra, they provide reasonably complete phase coverage for the system. The variations in the P Cygni profiles of the He(II) and N(IV) lines, imply the existence of a low density region in the WR wind. This region occupies a relatively narrow range of orbital phase coinciding with the highest terminal velocities observed in C IV. These data are interpreted to be evidence of an interaction region separating the winds of the O-star and Wolf-Rayet star.

Preparing for the Great American Eclipse of Aug. 21: for Yourself, and for Holding an Event for the Public and Students.

NASA Astrophysics Data System (ADS)

Duncan, D. K.

2016-12-01

On Aug. 21, 2017 a Total Eclipse of the Sun will cross the US. For the first time in 40 years every state will have at least 80% of the sun covered by the moon, and lucky people from Oregon to South Carolina will see the beauty of the total eclipse and remember it all their lives. It is as difficult to convey the impression of a total eclilpse as it is to convey what the Grand Canyon is like. Words cannot do it justice. It looks like the end of the world as the flames of solar prominances rise from the edge of the "black hole" of the eclipsed sun, and silver streamers of the sun's corona stretch across the sky. People scream, applaud, or cry. Animals do strange things. At a total eclipse in the Galapagos dozens of whales and dolphins surfaced at the time of the total elcipse, surrounded our boat, and after the eclipse swam away. At a partial eclipse, even a 99% eclipse, those spectacular aspects are not seen, so it is a good idea to make plans to go to where the eclipse is total. This session will use examples from 10 total eclipses the author has viewed and made available to the public, since March 7, 1970, to suggest practical preparations for the evnt. Advice will be given on how and where to see the eclipse yourself, and how to help the public, teachers, and students where you live enjoy the spectacle and raise their interest in science. It is hoped that by the time of the AGU meeting "Kits" of educational materials and safe eclipse-watching glasses will be available to AGU members. This will be discussed. A Public Service Announcement suitable for use on television, the Internet, or in schools should also be available.

Light Curves and Analyses of the Eclipsing Overcontact Binaries V546 And & V566 And & the Discovery of a New Variable Star

NASA Astrophysics Data System (ADS)

Bradstreet, David H.; Sanders, S. J.; Volpert, C. G.

2013-01-01

New precision V & Rc light curves of the eclipsing binaries V546 And and V566 And have been obtained using the 41-cm telescopes at the Eastern University Observatory equipped with SBIG ST-10XME CCD’s. V546 And (GSC 2828:18, P = 0.3831 days, m = 11.2) has only one published discovery light curve with significant scatter in the data. The system was observed on seven nights from 30 Aug - 20 Sep 2012, accumulating approximately 900 observations in both V and Rc. The light curves show distinctly that the system is totally eclipsing and preliminary analysis indicates that the binary is W-type (the larger, more massive star is the cooler component), has a mass ratio of 0.34, small temperature difference between the stars of 300 K, and a fillout of 0.30. There is also strong evidence of the presence of starspots influencing the slopes of both eclipses. V566 And (GSC 2321:257, P = 0.3897 days, m = 10.9) is a totally eclipsing overcontact system likewise showing obvious O’Connell effects likely due to starspots. V566 And was observed on seven nights from 30 Aug - 25 Sep 2012, accumulating more than 900 observations in both V and Rc. Preliminary light curve models indicate a W-type system with a small temperature difference between the stars of 200 K and a mass ratio of only 0.20. The original comparison star for V566 And, GSC 2321:911 (m = 12.0), turned out to be a previously unknown variable star with a period of approximately 0.466 days and a light amplitude in Rc of 0.15 mag. This new variable has no information concerning it in the online archives and initial analysis seems to indicate that this may be an ellipsoidal variable. The complete light curve analyses will be presented for both systems and the new variable’s light curves will also be discussed.

Changes in the Silicate Dust Features of the Symbiotic Star R Aquarii Prior to the Upcoming 2022 Eclipse and Periastron Events

NASA Astrophysics Data System (ADS)

Omelian, Eric; Sankrit, Ravi; Helton, Andrew; Gorti, Uma; Wagner, R. Mark

2018-01-01

The symbiotic star, R Aquarii (R Aqr) consists of a dusty, pulsating Mira (period 387 days) and a hot white dwarf (WD) that orbit each other with a period of about 44 years. Based on the light curve from ca. 1890 CE onwards, and associated nebular and jet activity, it has been established (with a high degree of confidence) that the WD eclipses the Mira around the time of the periastron passage. One of the phenomena associated with this phase in the orbit is enhanced accretion onto the WD, which in turn energizes the jet outflow. The next eclipse is imminent, and it is estimated that periastron will occur in 2022. Infrared observations of R Aqr have established that the emission consists of a thermal spectrum with an effective temperature of about 2500 K with superposed silicate dust features. These silicate features are known to vary with time, and UKIRT spectra taken within a single Mira phase have shown that some of the variation is correlated with the pulsation of the dust envelope of the AGB star.We have used the FORCAST instrument on SOFIA to observe R Aqr during Cycles 4 and 5 as part of an ongoing monitoring of the system as it goes through eclipse and periastron. Photometry between 6 and 37 μm, and spectra covering the 10 and 18 μm silicate features have shown significant changes in the spectrum compared with earlier data in the same wavelength range obtained by ISO at an epoch closer to apastron. We present our data along with archival data from other IR observatories and use them to characterize the changes in the silicate emission. These data are presented along with model calculations using DUSTY and RADMC-3D that we have used to explore the changes in dust properties that are necessary to explain the differences in the emission profiles. We also present our plans for continued monitoring of R Aqr through the upcoming eclipse, which is required in order to separate the effects of pulsation from the longer-term orbital effects on the dust profiles.

Effect of Hyper-Resistivity on Nonlinear Tearing Modes

NASA Astrophysics Data System (ADS)

Yang, Wen; Li, Ding; Xu, Xue-qiao

2018-06-01

Not Available Supported by the National Natural Science Foundation of China under Grant No 11675257, the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDB16010300, the Key Research Program of Frontier Science of Chinese Academy of Sciences under Grant No QYZDJ-SSW-SYS016, and the External Cooperation Program of Chinese Academy of Sciences under Grant No 112111KYSB20160039. This material is based upon the work supported by the US Department of Energy, Office of Science, Office of Fusion Energy Sciences, LLNL-JRNL-748586.

Short apsidal period of three eccentric eclipsing binaries discovered in the Large Magellanic Cloud

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Kyeongsoo; Lee, Chung-Uk; Kim, Seung-Lee

2014-06-01

We present new elements of apsidal motion in three eccentric eclipsing binaries located in the Large Magellanic Cloud. The apsidal motions of the systems were analyzed using both light curves and eclipse timings. The OGLE-III data obtained during the long period of 8 yr (2002-2009) allowed us to determine the apsidal motion period from their analyses. The existence of third light in all selected systems was investigated by light curve analysis. The O – C diagrams of EROS 1018, EROS 1041, and EROS 1054 were analyzed using the 30, 44, and 26 new times of minimum light, respectively, determined frommore » full light curves constructed from EROS, MACHO, OGLE-II, OGLE-III, and our own observations. This enabled a detailed study of the apsidal motion in these systems for the first time. All of the systems have a significant apsidal motion below 100 yr. In particular, EROS 1018 shows a very fast apsidal period of 19.9 ± 2.2 yr in a detached system.« less

A critical review of period analyses and implications for mass exchange in W UMa eclipsing binaries: Paper 3

NASA Astrophysics Data System (ADS)

Nelson, R. H.; Terrell, D.; Milone, E. F.

2016-02-01

This is the third of a series of four papers, the goal of which is to identify the overcontact eclipsing binary star systems for which a solid case can be made for mass exchange. To reach this goal, it is necessary first to identify those systems for which there is a strong case for period change. We have identified 60 candidate systems; in the first two papers (Nelson et al. 2014, 2016) we discussed 40 individual cases; this paper continues with the last 20. For each system, we present a detailed discussion and evaluation concerning the observational and interpretive material presented in the literature. At least one eclipse timing (ET) diagram, commonly referred to as an "O-C diagram", that includes the latest available data, accompanies each discussion. In paper 4, we will discuss the mechanisms that can cause period change and which of the 60 systems can be reliably concluded to exhibit mass exchange; we will also provide a list of marginal and rejected cases - suitable for future work.

Fifty year canon of solar eclipses: 1986-2035

NASA Technical Reports Server (NTRS)

Espenak, Fred

1986-01-01

A reference of moderately detailed eclipse predictions and maps for use by the professional astronomical community is provided. The general characteristics of every solar eclipse and a detailed set of cylindrical project world maps which show the umbral paths of every solar eclipse from 1901 to 2100 are presented. The geodetic path coordinates and local circumstance on the center line, and a series of orthographic projection maps which show the regions of visibility of both partial and central phases for every eclipse from 1986 through 2035 are also provided.

Resource Letter OSE-1: Observing Solar Eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Fraknoi, Andrew

2017-07-01

This Resource Letter provides a guide to the available literature, listing selected books, articles, and online resources about scientific, cultural, and practical issues related to observing solar eclipses. It is timely, given that a total solar eclipse will cross the continental United States on August 21, 2017. The next total solar eclipse path crossing the U.S. and Canada will be on April 8, 2024. In 2023, the path of annularity of an annular eclipse will cross Mexico, the United States, and Canada, with partial phases visible throughout those countries.

Lunar eclipses: Probing the atmosphere of an inhabited planet

NASA Astrophysics Data System (ADS)

García Muñoz, A.

2013-04-01

The Moon's brightness during a lunar eclipse is indicative of the composition, cloudiness and aerosol loading of the Earth's atmosphere. The idea of using lunar eclipse observations to characterize the Earth's atmosphere is not new, but the interest raised by the prospects of discovering Earth-like exoplanets transiting their host stars has brought renewed attention to the method. We review some recent efforts made in the prediction and interpretation of lunar eclipses. We also comment on the contribution of the lunar eclipse theory to the refractive theory of planetary transits.

Moon eclipse from 21 december 2010 in Romania

NASA Astrophysics Data System (ADS)

Gaina, Alex; Haus, Marian; Conovici, Matei; Vasiliu, Dan

2010-12-01

The authors discuss the Total Moon's eclipse from 21 december 2010, their circumstances for Romania and Central Europe. One notes that the informations from the NASA eclipses website do not inform correctly about the observability of the initial penumbral phase (P1-U1) of the eclipse. The same reffer to the Anuarul Astronomic Roman, published by the Institutul Astronomic Roman for 2010. By contrary the web site by Fred Espenac informed correctly the astronomical community. The Moon setted before the begining of the penumbral phase of the eclipse.

Feasibility study for the use of a YF-12 aircraft as a scientific instrument platform for observing the 1970 solar eclipse

NASA Technical Reports Server (NTRS)

Mercer, R. D.

1973-01-01

The scientific and engineering findings are presented of the feasibility study for the use of a YF-12 aircraft as a scientific instrument platform for observing the 1970 solar eclipse. Included in the report is the computer program documentation of the solar eclipse determination; summary data on SR-71A type aircraft capabilities and limitations as an observing platform for solar eclipses; and the recordings of an informal conference on observations of solar eclipses using SR-71A type aircraft.

Total Solar Eclipse of 2008 August 01

NASA Technical Reports Server (NTRS)

Espenak, F.; Anderson, J.

2007-01-01

On 2008 August 01, a total eclipse of the Sun is visible from within a narrow corridor that traverses half the Earth. The path of the Moon's umbral shadow begins in northern Canada and extends across Greenland, the Arctic, central Russia, Mongolia, and China. A partial eclipse is seen within the much broader path of the Moon's penumbral shadow, which includes northeastern North America, most of Europe and Asia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for 308 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Bio-analytical method development and validation of Rasagiline by high performance liquid chromatography tandem mass spectrometry detection and its application to pharmacokinetic study

PubMed Central

Konda, Ravi Kumar; Chandu, Babu Rao; Challa, B.R.; Kothapalli, Chandrasekhar B.

2012-01-01

The most suitable bio-analytical method based on liquid–liquid extraction has been developed and validated for quantification of Rasagiline in human plasma. Rasagiline-13C3 mesylate was used as an internal standard for Rasagiline. Zorbax Eclipse Plus C18 (2.1 mm×50 mm, 3.5 μm) column provided chromatographic separation of analyte followed by detection with mass spectrometry. The method involved simple isocratic chromatographic condition and mass spectrometric detection in the positive ionization mode using an API-4000 system. The total run time was 3.0 min. The proposed method has been validated with the linear range of 5–12000 pg/mL for Rasagiline. The intra-run and inter-run precision values were within 1.3%–2.9% and 1.6%–2.2% respectively for Rasagiline. The overall recovery for Rasagiline and Rasagiline-13C3 mesylate analog was 96.9% and 96.7% respectively. This validated method was successfully applied to the bioequivalence and pharmacokinetic study of human volunteers under fasting condition. PMID:29403764

Spectral and photometric studies of the polar USNO-A2.0 0825-18396733

NASA Astrophysics Data System (ADS)

Gabdeev, M. M.; Borisov, N. V.; Shimansky, V. V.; Spiridonova, O. I.

2015-03-01

Results of photometric and spectral studies of the new magnetic cataclysmic variable (polar) USNO-A2.0 0825-18396733 are presented. Photometric data in the B, V, and R c filters show that this object exhibits a red excess of R c - V = 1 m . A red continuum with superposed strong single-peaked Balmer emission lines and HeII λ4686 Å emission, weak lines of neutral helium, and lines of heavy elements are observed in the object's spectra. Doppler maps constructed using the hydrogen and ionized-helium lines indicate that these lines form near the inner Lagrangian point, and that their formation is associated with an accretion stream. The spectra and radial-velocity curves indicate the eclipse of the white dwarf in the system to be partial. Radial-velocity curves derived for emission lines are used to estimate the component masses. The mass of the white dwarf is estimated to be 0.71-0.78 M ⊙, and the mass of the red dwarf to be 0.18-0.20 M ⊙.

Public Education Plans for the 2017 August 21 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2016-06-01

A total solar eclipse will cross the continental United States on 2017 August 21, the first such in 99 years and the first whose path of totality on land is entirely in the United States since 1776. People in the rest of the United States-as well as in Canada, Central America, and northern South America-will have a partial solar eclipse. Totality will range up to about 70 km in diameter, and will be visible from a path that extends from Oregon to South Carolina. Cloudiness statistics based on decades on satellite infrared imaging are more favorable for western sites. The sun's diameter will be 80% covered in Miami (south of totality) and New York (north of totality), and 70% covered in Los Angeles (south of totality). For the Working Group on Solar Eclipses of the International Astronomical Union, I maintain a website at http://eclipses.info that provides links to a wide variety of eclipse-related material and to useful websites run by others.Prior to this total eclipse, annular eclipses will cross Africa (from Gabon to Tanzania and Madagascar) and Isle de la Réunion on 2016 September 1, and Chile and Argentina on 2017 February 26, at which time we plan an eclipse workshop in Esquel, Argentina.For the forthcoming 2017 eclipse, we acknowledge grants to JMP and Williams College from the Solar Terrestrial Program of the Atmospheric and Geospace Sciences Division of the National Science Foundation and from the Committee for Research and Exploration of the National Geographic Society.

The 2017 Solar Eclipse Community Impacts through Public Library Engagement

NASA Astrophysics Data System (ADS)

Dusenbery, P.; Holland, A.; LaConte, K.; Mosshammer, G.; Harold, J. B.; Fraknoi, A.; Schatz, D.; Duncan, D. K.

2017-12-01

More than two million pairs of eclipse glasses were distributed free through public libraries in the U.S. for the solar eclipse of the Sun taking place on August 21, 2017. About 7,000 organizations, including public library branches, bookmobiles, tribal libraries, library consortia, and state libraries took part in the celestial event of the century. Many organizations received a package of free safe-viewing glasses, plus a 24-page information booklet about eclipse viewing and suggested program ideas. An educational video was also produced on how best to do public outreach programs about the eclipse. The project was supported, in part, by the Gordon and Betty Moore Foundation, with additional help from Google, NASA, the Research Corporation, and the National Science Foundation (NSF). The program was managed through the Space Science Institute's National Center for Interactive Learning as part of its STAR Library Network (STAR_Net). Resources developed by STAR_Net for this event included an Eclipse Resource Center; a newsletter for participating libraries to learn about eclipses and how to implement an effective and safe eclipse program; eclipse program activities on its STEM Activity Clearinghouse; webinars; and connections to subject matter experts from NASA's and the American Astronomical Society's volunteer networks. This presentation will provide an overview of the extensive collaboration that made this program possible as well as highlight the national impact that public libraries made in their communities.

Eclipse-induced wind changes over the British Isles on the 20 March 2015

PubMed Central

2016-01-01

The British Isles benefits from dense meteorological observation networks, enabling insights into the still-unresolved effects of solar eclipse events on the near-surface wind field. The near-surface effects of the solar eclipse of 20 March 2015 are derived through comparison of output from the Met Office’s operational weather forecast model (which is ignorant of the eclipse) with data from two meteorological networks: the Met Office’s land surface station (MIDAS) network and a roadside measurement network operated by Vaisala. Synoptic-evolution relative calculations reveal the cooling and increase in relative humidity almost universally attributed to eclipse events. In addition, a slackening of wind speeds by up to about 2 knots in already weak winds and backing in wind direction of about 20° under clear skies across middle England are attributed to the eclipse event. The slackening of wind speed is consistent with the previously reported boundary layer stabilization during eclipse events. Wind direction changes have previously been attributed to a large-scale ‘eclipse-induced cold-cored cyclone’, mountain slope flows, and changes in the strength of sea breezes. A new explanation is proposed here by analogy with nocturnal wind changes at sunset and shown to predict direction changes consistent with those observed. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550759

Configuring Eclipse for GMAT Builds: Instructions for Windows Users, Rev. 0.3

NASA Technical Reports Server (NTRS)

Conway, Darrel J.

2007-01-01

This document provides instructions about how to configure the Eclipse IDE to build GMAT on Windows based PCs. The current instructions are preliminary; the Windows builds using Eclipse are currently a bit crude. These instructions are intended to give you enough information to get Eclipse setup to build wxWidgets based executables in general, and GMAT in particular.

Eclipsing cataclysmic variables. Deep eclipses in H0928+501. YY Draconis, the whirling dervish. New x ray pulsar candidates from HEAO-1

NASA Technical Reports Server (NTRS)

Patterson, Joseph

1993-01-01

The status report covering the period from 1 June 1992 to 31 May 1993 is included. Areas of research include: (1) eclipsing cataclysmic variables; (2) deep eclipses in H0928+501; (3) YY Draconis, the Whirling Dervish; and (4) new x ray pulsar candidates from HEAO-1.

The Astrophysics of the Solar Corona at the August 21, 2017, American Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay

2017-01-01

The first total solar eclipse to cross the United States from coast to coast in 99 years will occur on August 21, 2017, with a 70-mile-wide path of totality from Oregon to South Carolina, with cloudiness statistics more favorable in the northwest than in the southeast. I will discuss a series of observations of the solar corona made during recent solar eclipses and related spacecraft observations. I will further discuss plans for using the 2017 eclipse for furthering our studies of the heating of the solar corona to millions of kelvins, of the dynamics of coronal mass ejections and polar plumes, and of the response of the corona to the solar magnetic field. I will conclude by discussing public-education plans for the eclipse, during which the whole U.S., Mexico, Central America, and Canada will enjoy a partial eclipse. My work at solar eclipses has recently been supported by the NSF and the Committee for Research and Exploration of the National Geographic Society, and I thank them both for research grants for our scientific studies of the 2017 total eclipse, including AGS-1602461 from the NSF and 987816 from National Geographic.

On the detection and attribution of gravity waves generated by the 20 March 2015 solar eclipse

PubMed Central

2016-01-01

Internal gravity waves are generated as adjustment radiation whenever a sudden change in forcing causes the atmosphere to depart from its large-scale balanced state. Such a forcing anomaly occurs during a solar eclipse, when the Moon’s shadow cools part of the Earth’s surface. The resulting atmospheric gravity waves are associated with pressure and temperature perturbations, which in principle are detectable both at the surface and aloft. In this study, surface pressure and temperature data from two UK sites at Reading and Lerwick are examined for eclipse-driven gravity wave perturbations during the 20 March 2015 solar eclipse over northwest Europe. Radiosonde wind data from the same two sites are also analysed using a moving parcel analysis method, to determine the periodicities of the waves aloft. On this occasion, the perturbations both at the surface and aloft are found not to be confidently attributable to eclipse-driven gravity waves. We conclude that the complex synoptic weather conditions over the UK at the time of this particular eclipse helped to mask any eclipse-driven gravity waves. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550763

Eclipse timings of the low-mass X-ray binary EXO 0748-676: Statistical arguments against orbital period changes

NASA Technical Reports Server (NTRS)

Hertz, Paul; Wood, Kent S.; Cominsky, Lynn

1995-01-01

EXO 0748-676, an eclipsing low-mass X-ray binary, is one of only about four or five low-mass X-ray binaries for which orbital period evolution has been reported. We observed a single eclipse egress with ROSAT . The time of this egress is consistent with the apparent increase in P(sub orb) previously reported on the basis of EXOSAT and Ginga observations. Standard analysis, in which O-C (observed minus calculated) timing residuals are examined for deviations from a constant period, implicitly assume that the only uncertainty in each residual is measurement error and that these errors are independent. We argue that the variable eclipse durations and profiles observed in EXO 0748-676 imply that there is an additional source of uncertainty in timing measurements, that this uncertainty is intrinsic to the binary system, and that it is correlated from observation to observation with a variance which increases as a function of the number of binary cycles between observations. This intrinsic variability gives rise to spurious trends in O-C residuals which are misinterpreted as changes in the orbital period. We describe several statistics tests which can be used to test for the presence of intrinsic variability. We apply those statistical tests which are suitable to the EXO 0748-676 observations. The apparent changes in the orbital period of EXO 0748-676 can be completely accounted for by intrinsic variability with an rms variability of approximately 0.35 s per orbital cycle. The variability appears to be correlated from cycle-to-cycle on timescales of less than 1 yr. We suggest that the intrinsic variability is related to slow changes in either the source's X-ray luminosity or the structure of the companion star's atmosphere. We note that several other X-ray binaries and cataclysmic variables have previously reported orbital period changes which may also be due to intrinsic variability rather than orbital period evolution.

Confirming Variability in the Secondary Eclipse Depth of the Rocky Super-Earth 55 Cancri e

NASA Astrophysics Data System (ADS)

Tamburo, Patrick; Mandell, Avi; Deming, Drake; Garhart, Emily

2017-01-01

We present a reanalysis of Spitzer transit and secondary eclipse observations of the rocky super Earth 55 Cancri e using Pixel Level Decorrelation (Deming et al. 2015). Secondary eclipses of this planet were found to be significantly variable by Demory et al. (2016), implying a changing brightness temperature which could be evidence of volcanic activity due to tidal forces. If genuine, this result would represent the first evidence for such a process outside of bodies in our own solar system, and would further expand our understanding of the huge variety of planetary systems that can develop in our universe. Spitzer eclipse observations, however, are subject to strong systematic effects which can heavily impact the retrieved eclipse model. A reanalysis of this result with an independent method is therefore needed to confirm eclipse depth variability. We tentatively confirm variability, finding a shallower increase in eclipse depth over the course of observations compared to Demory et al. (2015).

The 1st of April 2470 BC Total Solar Eclipse Seen by the Prophet Ibraheem

NASA Astrophysics Data System (ADS)

Yousef, S. M.

The Holy Quran describes a phenomenon seen by young Abraham that can only fit a solar eclipse. Two criteria were given for this particular eclipse; first only one planet was seen as soon as it got dark and second no corona was seen. In order to justify the first selection rule, examinations of solar and planetary longitudes for total solar eclipses passing over Babel were carried out. Only the eclipse of the 1st of April 2470 BC meets this condition, as it was only Venus that was seen at that eclipse. The second selection rule was also naturally fulfilled, as Babel happened to be on the border of the totality zone hence no corona was seen, however all the time the moon glistened as Baily's beads. There is no doubt that the prophet Abraham witnessed the 1st of April total solar eclipse that passed over Babel. This will put him about 470 years backward than it was previously anticipated.

Preparing for Eclipse 2017 on This Week @NASA – August 11, 2017

NASA Image and Video Library

2017-08-11

The Aug. 21 total solar eclipse across America is generating a lot of interest – and a lot of questions. You’ll find answers to many of your eclipse questions at NASA’s Eclipse 2017 website -- eclipse2017.nasa.gov. The site is full of information to help you prepare for this rare celestial event – including eclipse-related activities, events, viewing safety tips, and other resources. Then, on the day of the eclipse, you can see the event “Through the Eyes of NASA” – during a special NASA TV broadcast that includes coast-to-coast coverage from the ground, from the air and from space. Coverage begins with a special pre-show at noon eastern – followed by in-depth coverage at 1pm. You can also watch on Aug. 21 at www.nasa.gov/eclipselive. Also, TDRS-M Update, Webb’s Sunshield Layers Installed, RS-25 Engine Testing Rolls On, and Chief Technologist Visits Industry Partner!

Two Commemorative Expeditions to Celebrate the Return to Totality

NASA Astrophysics Data System (ADS)

Thompson, Kristen; English, Tom

2018-01-01

Throughout history, total solar eclipses have generated excitement across the scientific community, as they provide a unique opportunity to study the Sun’s corona. Occurrences of such events have prompted many American astronomy programs to organize expeditions aimed at studying and photographing the eclipse. Only two observing stations from any of the major 19th and early 20th century eclipse expeditions were once again found in the path of totality of the 21 August 2017 Great American Eclipse. These stations, one in Newberry, SC and the other in Winnsboro, SC, were located in the shadow of the 28 May 1900 eclipse that passed through the southeastern United States from New Orleans to Norfolk. To celebrate this unique opportunity, we organized two expeditions that travelled to these towns to commemorate their return to totality. In this talk, I will describe the circumstances of the 1900 solar eclipse, our modern expeditions, and our effort to bring this eclipse history to life for the community.

A Vanishing Star Revisited

NASA Astrophysics Data System (ADS)

1999-07-01

VLT Observations of an Unusual Stellar System Reinhold Häfner of the Munich University Observatory (Germany) is a happy astronomer. In 1988, when he was working at a telescope at the ESO La Silla observatory, he came across a strange star that suddenly vanished off the computer screen. He had to wait for more than a decade to get the full explanation of this unusual event. On June 10-11, 1999, he observed the same star with the first VLT 8.2-m Unit Telescope (ANTU) and the FORS1 astronomical instrument at Paranal [1]. With the vast power of this new research facility, he was now able to determine the physical properties of a very strange stellar system in which two planet-size stars orbit each other. One is an exceedingly hot white dwarf star , weighing half as much as the Sun, but only twice as big as the Earth. The other is a much cooler and less massive red dwarf star , one-and-a-half times the size of planet Jupiter. Once every three hours, the hot star disappears behind the other, as seen from the Earth. For a few minutes, the brightness of the system drops by a factor of more than 250 and it "vanishes" from view in telescopes smaller than the VLT. A variable star named NN Serpentis ESO PR Photo 30a/99 ESO PR Photo 30a/99 [Preview - JPEG: 400 x 468 pix - 152k] [Normal - JPEG: 800 x 936 pix - 576k] [High-Res - JPEG: 2304 x 2695 pix - 4.4M] Caption to ESO PR Photo 30a/99 : The sky field around the 17-mag variable stellar system NN Serpentis , as seen in a 5 sec exposure through a V(isual) filter with VLT ANTU and FORS1. It was obtained just before the observation of an eclipse of this unsual object and served to centre the telescope on the corresponding sky position. The field shown here measures 4.5 x 4.5 armin 2 (1365 x 1365 pix 2 ; 0.20 arcsec/pix). The field is somewhat larger than that shown in Photo 30b/99 and has the same orientation to allow comparison: North is about 20° anticlockwise from the top and East is 90° clockwise from that direction. The unsual star in question is designated NN Serpentis , or just NN Ser . As the name indicates, it is located in the constellation of Serpens (The Serpent), about 12° north of the celestial equator. A double letter, here "NN", is used to denote variable stars [2]. It is a rather faint object of magnitude 17, about 25,000 times fainter than what can be perceived with the unaided eye. The distance is about 600 light-years (180 pc). In July 1988, Reinhold Häfner performed observations of NN Ser (at that time still known by its earlier name PG 1550+131 ) with the Danish 1.54-m telescope at La Silla. He was surprised, but also very pleased to discover that it underwent a very deep eclipse every 187 minutes. Within less than 2 minutes, the brightness dropped by a factor of more than 100 (5 magnitudes). During the next 9 minutes, the star completely disappeared from view - it was too faint to be observed with this telescope. It then again reappeared and the entire event was over after just 11 minutes. Why eclipses are so important for stellar studies An eclipse occurs when one of the stars in a binary stellar system moves in front of the other, as seen by the observer. The effect is similar to what happens during a solar eclipse when the Moon moves in front of the Sun. In both cases, the eclipse may be partial or total , depending on whether or not the eclipsed star (or the Sun) is completely hidden from view. The occurence of eclipses in stellar systems, as seen from the Earth, depends on the spatial orientation of the orbital plane and the sizes of the two stars. Two eclipses take place during one orbital revolution, but they may not both be observable. The physical properties of the two stars in a binary system (e.g., the sizes of the stars, the size and shape of the orbit, the distribution of the light on the surfaces of the stars, their temperatures etc.) can be determined from the measured "light-curve" of the system (a plot of brightness vrs. time). The stars are always too close to each other to be seen as anything but a point of light. The light-curve thus describes the way the total brightness of the two stars changes during one orbital revolution, including the variation of the combined light of the two components as they cover each other during the eclipses. Already in 1988, it was concluded that the eclipse observed in NN Ser must be caused by a bright and hot star (a white dwarf ) being hidden by another body, most probably a red dwarf star . Because of the dramatic effect, this object soon became known as the "Vanishing Star" , cf. ESO Press Release 09/88 (8 December 1988). Critical information missing for NN Ser One particularly critical piece of information is needed for a light-curve study to succeed, that is whether the eclipse is "total" or "partial" . If during the eclipse one star is entirely hidden by the other, we only see the light of the star in front. In that case, the measured amount of light does not change during the phase of totality. The light-curve is "flat" at the bottom of the minimum and the measured brightness indicates the intrinsic luminosity of the eclipsing star. Moreover, for a given orbit, the duration of the totality is proportional to the size of that star. This crucial information was not available for NN Ser . The brightness at minimum was simply too faint to allow any measurements of the system with available telescopes during this phase. For this reason, the properties of the eclipsing star could only be guessed. Reaching for the bottom The new VLT observations have overcome this. Thanks to the powerful combination of the 8.2-m ANTU telescope and the multi-mode FORS1 instrument, it was possible to measure the complete lightcurve of NN Ser , also during the darkest phase of the eclipse. This extreme observation demanded most careful preparation. Since there is very little light available, the longest possible integration time must be used in order to collect a sufficient number of photons and to achieve a reasonable photometric accuracy. However, the eclipse only lasts a few minutes and it would only be possible to exposure and read-out a few, normal exposures from the CCD camera, not enough to fully characterize the light curve at minimum. Reinhold Häfner decided to use another method. By having the telescope perform a controlled change of position on the sky ("drift") during the exposure, the light from NN Ser before, during and after the eclipse will not be registered on the same spot of the camera detector, but rather along a line. He carefully chose a direction in which this line would not cross those of other stars in the neighbourhood of NN Ser . This was ensured by rotating FORS1 to a predetermined position angle. The drift rate was fixed as one pixel (0.20 arcsec) per 3 seconds of time, a compromise between the necessary integration time and desired time resolution that would give the best chance to document the exact shape of the light-curve . In theory, this would then allow the measurement of the intensity along the recorded trail of NN Ser and hence its brightness at any given time during the eclipse. But how deep would the eclipse be? Would the resulting exposure on each pixel at minimum light be long enough to register a measurable signal? Seeing the light from the cool star! ESO PR Photo 30b/99 ESO PR Photo 30b/99 [Preview - JPEG: 400 x 464 pix - 156k] [Normal - JPEG: 800 x 927 pix - 584k] [High-Res - JPEG: 2292 x 2662 pix - 4.1M] ESO PR Photo 30c/99 ESO PR Photo 30c/99 [Preview - JPEG: 472 x 400 pix - 48k] [Normal - JPEG: 943 x 800 pix - 96k] Caption to ESO PR Photo 30b/99 : 18.5-min "drift" exposure with VLT ANTU and FORS1 of the sky field around the variable stellar system NN Ser (indicated with an arrow). The telescope moved 1 pixel (0.20 arcsec) every 3 seconds so that the images of the stars in the field are trailed from left to right. After some minutes, the very deep eclipse of NN Ser begins when the brightness drops dramatically during the first partial phase. The star is clearly visible at a constant level all through the total phase at minimum light. It then brightens during the second partial phase and is back to the former level after approximately 10.5 min. The FORS1 instrument was rotated by about 70° to ensure that the trail of NN Ser would not overlap those of the neighbouring stellar images during this special exposure. The field shown measures 2.7 x 2.7 armin 2 and may be compared with that shown in Photo 30a/99; it has the same orientation. Caption to ESO PR Photo 30c/99 : The light-curve of the variable stellar system NN Ser , as extracted from the drift exposure shown in Photo 30b/99 . The count rate is proportional to the brightness of the object; it is about 18,000 counts/pix outside the eclipse and decreases to about 70 counts during the total eclipse (since the full range of the eclipse is shown here, this low level is almost indistinguishable from 0 in this figure). Various properties of the two stars in the NN Ser system may be determined from the shape of the light-curve. The fact that the light-curve is "flat" at the bottom is a clear sign that the eclipse is total , i.e. the hot white dwarf star is completely hidden behind the cool red dwarf star. As ESO PR Photo 30b/99 shows, ANTU and FORS1 did manage this difficult observation! Aided by an excellent seeing of 0.5 arcsec, i.e. a good concentration of the light on each pixel, the recorded signal from NN Ser - although very faint - is well measurable at all times during the eclipse . In the mean, about 70 counts/pixel were registered at the minimum, down from about 18,000 outside the eclipse ( Photo 30c/99 ). The ratio is then about 250, corresponding to just over 6 magnitudes. The measured magnitude during eclipse is 23.0 in the V-band (green-yellow; wavelength 550 nm). Of even greater importance is the fact that the light-curve is found to be perfectly flat at the bottom, i.e. the eclipse is most certainly total . The white dwarf star is therefore being completely hidden as it moves behind the cooler and larger star, and we see only the latter during the eclipse. As explained above, this then allows to determine many of its properties. For instance, the fact that the light-curve has no obvious "soft shoulders" at the beginning and end of the total phase indicates that the white dwarf abruptly disappears from view. Thus the faint star cannot have a very extended atmosphere, otherwise the brightness change would have been more gradual. The total phase was found to last 7 m 37 s and each of the partial phases only 1 m 26 s. This shows that the orbit must be nearly perpendicular to the plane of the sky. This angle is referred to as the orbital inclination ; for NN Ser , it must be in the interval between 84° - 90°. A preliminary analysis indicates that the diameter of the cool star is between 200,000 and 245,000 km, i.e. about 1.5 times that of planet Jupiter. The white dwarf is even smaller; its diameter is between 25,000 and 31,000 km, or about twice the size of the Earth. The distance between the two stars is 660,000 km, or half the size of the Sun. Thus NN Ser is really a very small system - it would easily fit into our central star! The surface temperatures are widely different, about 55,000 and 2,800 degrees, respectively. By adding to this analysis earlier measurements of the orbital velocity of the white dwarf star, it is possible to estimate the mass of the cool star as between 0.10 and 0.14 solar masses. The white dwarf is significantly heavier, about 0.57 solar masses. Stellar objects with masses below approx. 0.08 solar mass are believed to be brown dwarfs , i.e. "still-born" stars in which nuclear fusion did not ignite. Since the mass of the cool star in NN Ser is near this limit, could it perhaps be such an object? A spectrum of the cool star ESO PR Photo 30d/99 ESO PR Photo 30d/99 [Preview - JPEG: 480 x 400 pix - 60k] [Normal - JPEG: 960 x 800 pix - 136k] Caption to ESO PR Photo 30d/99 : The spectrum of the cool dwarf star in the variable stellar system NN Ser . The 5 min exposure was obtained during the total phase of the eclipse, when the magnitude of the system was V = 23.0. Several TiO bands are clearly visible in this slightly smoothed tracing. A few deep and narrow "absorption" features are residuals from sky subtraction. The original resolution is 0.55 nm/pix. A spectral type of M6 or later is deduced for NN Ser . The spectrum of a more nearby (and hence much brighter) M6.5 dwarf star (temperature approx. 2600 degrees) is shown below for comparison. The VLT has already delivered the answer: it turns out to be no . The cool component of NN Ser may be a very small and faint object, but it is a real star that harbours nuclear processes in its interior. The temperature is on the high side for a brown dwarf, but the definite proof can only be obtained from the spectrum. ANTU and FORS1 were able to obtain a spectrum of NN Ser during the total eclipse, i.e. at a time when the visual magnitude was 23.0, cf. Photo 30d/99 . The exposure had to be limited to 5 min only, in order to ensure that there would be no contamination by extra light from the much brighter white dwarf companion star, as this is the case during the partial phases of the eclipse. Despite the difficult circumstances, it was possible to record a faint spectrum in the 600 - 900 nm (red - near-IR) wavelength interval. Although it is quite noisy, several molecular bands of TiO (titanium oxide) are well visible; VO (vanadium oxide) bands may also be present. They allow the classification of the spectrum as that of a very-late-type star, of spectral type M6 or later . This is in reasonable agreement with the mentioned temperature around 2800 degrees. In any case, this spectrum is quite unlike that of a brown dwarf, thus confirming that the cool companion star in NN Ser is a normal hydrogen-burning red dwarf star . NN Ser: a "missing link" in stellar theory The binary system NN Ser is now in an evolutionary stage that is referred to as the pre-cataclysmic phase. It will be followed by the cataclysmic phase , during which a gas stream will flow from the larger star to the smaller one. This phenomenon is characterized by frequent and abrupt increase in brightness. While many stars are known that are now in that unstable phase, only a few stars have ever been found to be in the preceding, transitory phase. Of these, NN Ser is the only one that has such a deep eclipse and for which it has now become possible to determine quite well the properties of the two components. NN Ser thus represents a most welcome example of a "missing link" in the theory of stellar evolution. It is therefore of great interest to perform further observations of such a rare object. They will include attempts to obtain more spectra to define the spectral type of the cool star very accurately. This will allow a critical check of current theories of atmospheres and evolutionary computations for the smallest and lightest stars. But for now, Reinhold Häfner looks forward to further nights at Paranal with the ESO astronomers there. "We worked together in a wonderful way during these demanding observations", he said, "and without their great support all of this would have been next to impossible!" Notes [1] These observations were carried out during "guaranteed observing time", allocated to the three German institutes that built the FORS instrument. More details about this instrument and related issues are available in ESO Press Release 14/98. [2] Astronomers designate variable stars according to the constellation in which they are seen in the sky and the order in which they are recognized as having variable brightness. For historical reasons, the first variable star in a given constellation (that is not already known by a greek letter, e.g. "Delta Cephei") is designated as "R" (e.g. "R Coronae Borealis"), the second as "S", etc. until "Z". Then follow "RR", "RS",..."RZ", "SS"..."SZ" until "ZZ" and only then from the beginning of the alphabet, "AA"..."AZ", "BA".. etc. until "QZ". How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org../ ). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory.

Photometric and spectral studies of the eclipsing polar CRTS CSS081231 J071126+440405

NASA Astrophysics Data System (ADS)

Borisov, N. V.; Gabdeev, M. M.; Shimansky, V. V.; Katysheva, N. A.; Kolbin, A. I.; Shugarov, S. Yu.; Goranskij, V. P.

2016-01-01

We present the results of the study of the eclipsing polar CRTS CSS081231 J071126+440405. Photometric observations allowed us to refine the orbital period of the system P_ circ = 0_ \\cdot ^d 0.08137673. Considerable changes in the appearance of the object's spectra have occurred over the period of September 20-21, 2001: the slope of the continuum changed from "red" to "blue", and the variability of the line profiles over the duration of the orbital period has also changed. Doppler maps have shown a shift of the emission line-forming region along the accretion stream closer to the white dwarf. We measured the duration of the eclipse of the system and imposed constraints on the inclination angle 78_ \\cdot ^ circ 7 < i < 79_ \\cdot ^ circ 3. The derived radial velocity amplitude was used to obtain the basic parameters of the system: M 1 = 0.86 ± 0.08 M ⊙, M 2 = 0.18 ± 0.02 M ⊙, q = 0.21 ± 0.01, R L2 = 0.20 ± 0.03 R ⊙, A = 0.80 ± 0.03 R ⊙. The spectra of the object exhibit cyclotron harmonics. Their comparison with model spectra allowed us to determine the parameters of the accretion column: B = 31-34 MG, T e = 10-12 keV, θ = 80-90°, and Λ = 105.

HF Band Observations and Modeling of the 2017 Eclipse

NASA Astrophysics Data System (ADS)

Earle, G. D.; Kordella, L.; Han, X.; Moses, M. L.; Sweeney, D.; McGwier, R. W.; Lloyd, W.; Ruohoniemi, J. M.

2017-12-01

A nationwide network of observatories has been created to study the effects of the 2017 eclipse on the F-region of the ionosphere. These include the SuperDARN HF radars in Oregon and Kansas, software defined radios in Oregon, Kansas, and South Carolina, and scintillation receivers placed northward of the central eclipse line across the continent. In this talk we will present data obtained by these systems during the eclipse, and interpret these data using a ray-tracing numerical code in conjunction with the SAMI-3 first principles model. Comparisons to results from the CORS network of GPS-TEC receivers will be made, and the F-region density and altitude perturbations observed during the eclipse will be contrasted with ionosonde data from an eclipse that occurred over the United Kingdom in 1999.

Constructing 'Black Sun': the Documentary Film of the 2012 Eclipses

NASA Astrophysics Data System (ADS)

Holbrook, Jarita

2014-06-01

2012 offered an opportunity that was not to be missed: two solar eclipses. Drs Alphonse Sterling and Hakeem Oluseyi began doing collaborative research during total solar eclipses in 2006 in Ghana. Since then they have continued to do eclipse observation when funds and whether permitted. As a filmmaker, the opportunity to film Sterling and Oluseyi during the 2012 eclipses in Tokyo and Cairns fulfilled the goal of showing the excitement of time-sensitive research, the lives of astrophysicists, and diversity within the astronomy community. As an astrophysicist who did not specialize in solar astrophysics, it was an opportunity for me both to learn and to solidify for the audience what we know about the sun and the importance of eclipse observation. Clips of the film will be included.

Preparing a Nation for the Eclipse of a Generation -

NASA Astrophysics Data System (ADS)

Speck, Angela; Habbal, Shadia; Tresch Fienberg, Richard; Kentrianakis, Michael; Fraknoi, Andrew; Nordgren, Tyler; Penn, Matthew; Pasachoff, Jay M.; Bakich, Michael; Winter, Henry; Gay, Pamela; Motta, Mario

2018-01-01

On August 21st 2017, there was a total solar eclipse visible from a vast swath of the US.In preparation for that event, the American Astronomical society created a taskforce charged with planning for the eclipse for the entire nation. The preparations included interfacing with the public, the media, non-profit organizations and governmental organizations. Preliminary data suggests that nearly 90% of American adults watched the eclipse either directly or via live streams. Moreover, there were no major problems associated with the event, in spite of valiant attempts from, e.g. imprope solar viewing materials. The eclipse offered opportunities for many scientific experiments within and ebyond astronomy. Here we present on the work of the taskforce, and the lessons learned as well as lesser known science experiments undertaken during the eclipse.

An Atlas of O-C Diagrams of Eclipsing Binary Stars

NASA Astrophysics Data System (ADS)

Kreiner, Jerzy M.; Kim, Chun-Hwey; Nha, Il-Seong

The Atlas contains data for 1,138 eclipsing binaries represented by 91,798 minima timings, collected from the usual international and local journals, observatory publications and unpublished minima. Among this source material there is a considerable representation of amateur astronomers. Some timings were found in the card-index catalogue of the Astronomical Observatory of the Jagiellonian University, Cracow. Stars were included in the Atlas provided that they satisfied 3 criteria: (1) at least 20 minima had been times; (2) these minima spanned at least 2,500 cycles; and (3) the 2,500 cycles represented no fewer than 40 years. Some additional stars not strictly satisfying these criteria were also included if useful information was available. For each star, the Atlas contains the (O-C) diagram calculated by the authors and a table of general information containing: binary characteristics; assorted catalogue numbers; the statistics of the collected minima timings; the light elements (light ephemeris); comments and literature references. All of the data and diagrams in the Atlas are also available in electronic form on the Internet at http://www.as.ap.krakow.pl/o- c".

First Results from the August 21, 2017, Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2017-08-01

I report on the observations planned and, weather permitting, made from our site in Salem, Oregon, at the August 21, 2017, total solar eclipse. I also give a first report on collaborators' successes, including Megamovie and simultaneous space observations. We also describe our participation in PBS's NOVA on the eclipse that was to be aired on public television on eclipse night. Our eclipse expedition is supported in large part by grants from the Solar Terrestrial Program of the Atmospheric Sciences Division of NSF and by the Committee for Research and Exploration of the National Geographic Society.

Solar diameter measurements from eclipses as a solar variability proxy

NASA Astrophysics Data System (ADS)

Dunham, David W.; Sofia, Sabatino; Guhl, Konrad; Herald, David

The widths of total solar eclipse paths depends on the diameter of the Sun, so if observations are obtained near both the northern and southern limits of the eclipse path, in principle, the angular diameter of the Sun can be measured. Concerted efforts have been made to obtain contact timings from locations near total solar eclipse path edges since the mid 19th century, and Edmund Halley organized a rather successful first effort in 1715. Members of IOTA have been making increasingly sophisticated observations of the Baily's bead phenomena near central solar eclipse path edges since 1970.

The Optical Gravitational Lensing Experiment. Eclipsing Binary Stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2003-03-01

We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive.

Relativistic apsidal motion in eccentric eclipsing binaries

NASA Astrophysics Data System (ADS)

Wolf, M.; Claret, A.; Kotková, L.; Kučáková, H.; Kocián, R.; Brát, L.; Svoboda, P.; Šmelcer, L.

2010-01-01

Context. The study of apsidal motion in detached eclipsing binary systems is known to be an important source of information about stellar internal structure as well as the possibility of verifying of General Relativity outside the Solar System. Aims: As part of the long-term Ondřejov and Ostrava observational projects, we aim to measure precise times of minima for eccentric eclipsing binaries, needed for the accurate determination of apsidal motion, providing a suitable test of the effects of General Relativity. Methods: About seventy new times of minimum light recorded with photoelectric or CCD photometers were obtained for ten eccentric-orbit eclipsing binaries with significant relativistic apsidal motion. Their O-C diagrams were analysed using all reliable timings found in the literature, and new or improved elements of apsidal motion were obtained. Results: We confirm very long periods of apsidal motion for all systems. For BF Dra and V1094 Tau, we present the first apsidal-motion solution. The relativistic effects are dominant, representing up to 100% of the total observable apsidal-motion rate in several systems. The theoretical and observed values of the internal structure constant k 2 were compared for systems with lower relativistic contribution. Using the light-time effect solution, we predict a faint third component for V1094 Tau orbiting with a short period of about 8 years. Partly based on photoelectric observations secured at the Hvar Observatory, Faculty of Geodesy, Zagreb, Croatia, in October 2008.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

NASA employees and contractors use protective glasses to view a partial solar eclipse from NASA Headquarters Monday, Aug. 21, 2017 in Washington. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Gwen Pitman)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-22

NASA employees and contractors use protective glasses to view a partial solar eclipse from NASA Headquarters Tuesday, Aug. 22, 2017 in Washington. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Gwen Pitman)

Solar Eclipse from NASA Goddard

NASA Image and Video Library

2017-08-21

View of the partial solar eclipse from NASA's Goddard Space Flight Center in Greenbelt, Md on Monday, August 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Credit: NASA/Goddard/Rebecca Roth

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

Robert Lightfoot, acting NASA administrator and Thomas Zurbuchen NASA AA for the science mission directorate view a partial eclipse solar eclipse Monday, August 21, 2017, from onboard a NASA Armstrong Flight Research Center’s Gulfstream III 35,000 feet above the Oregon Coast. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. Photo Credit: (NASA/Carla Thomas)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

This composite image of nine pictures shows the progression of a partial solar eclipse near Banner, Wyoming on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Joel Kowsky)

In the Shadow of the Moon, What Type of Solar Eclipse Will We See?

ERIC Educational Resources Information Center

Brown, Todd; Brown, Katrina

2017-01-01

Solar eclipses occur several times a year, but most people will be lucky if they see one total solar eclipse in their lifetime. There are two upcoming total solar eclipses that can be seen from different parts of the United States (August 21, 2017 and April 8, 2024), and they provide teachers with an amazing opportunity to engage students with a…

Lessons from Distributing Eclipse Glasses: Planning Ahead for April 2024

NASA Astrophysics Data System (ADS)

Bartlett, Jennifer Lynn; Wilson, Teresa; Chizek Frouard, Malynda R.; Phlips, Alan

2018-01-01

In preparation for the 2017 August 21 total solar eclipse across the continental United States, a multifaceted effort encouraged safe public observation of this spectacular event. However, we experienced mixed results distributing free ISO 12312-2 compliant eclipse glasses.On the positive side, we successfully dispensed several hundred in Virginia through in-school programs about the eclipse. We created a 2017-eclipse information sheet to accompany a safe-viewing handout. To facilitate sending glasses home in student backpacks, we wrapped each pair in a double-sided flyer and sealed the bundle in an individual envelope. We also passed out glasses during evening and weekend activities at a planetarium. Religious, business, and educational groups were all excited to receive them as were co-workers, family, and friends.On the negative side, planetarium staff declined to give eclipse glasses to students without a parent due to safety and liability concerns. Then, a day camp returned 200 pairs less than 72 hours before the event for the same reasons. However, we also received several requests from groups that had waited until too late to be accommodated easily.During the week before the eclipse, demand for eclipse glasses in New York, Michigan, Indiana, Illinois, Wisconsin, Minnesota, South Dakota, Nebraska, and Missouri was less than anticipated. While many people were well prepared, the recalls and reported counterfeiting made others suspicious. Concurrently, vendors were offering their remaining stock for $1–10 each.The experiences of the 2017 total solar eclipse, both good and bad, will not completely fade before preparations for 2024 begin. We look forward enthusiastically to sharing that event with as many people as possible and hope that the overall distribution of eclipse glasses goes more smoothly.We thank the AAS for providing 1,000+ of the eclipse glasses we shared, which were donated to them by Google to promote the Eclipse Megamovie project; Rainbow Symphony was the manufacturer. The authors supplemented these with a few personal purchases. AAS, NASA, NSF, American Academies of Ophthalmology and Optometry, and the American Optometric Association jointly disseminated the safe-viewing handout.

Solar Eclipse-Induced Changes in the Ionosphere over the Continental US

NASA Astrophysics Data System (ADS)

Erickson, P. J.; Zhang, S.; Goncharenko, L. P.; Coster, A. J.; Hysell, D. L.; Sulzer, M. P.; Vierinen, J.

2017-12-01

For the first time in 26 years, a total solar eclipse occurred over the continental United States on 21 August 2017, between 16:00-20:00 UT. We report on American solar eclipse observations of the upper atmosphere, conducted by a team led by MIT Haystack Observatory. Efforts measured ionospheric and thermospheric eclipse perturbations. Although eclipse effects have been studied for more than 50 years, recent major sensitivity and resolution advances using radio-based techniques are providing new information on the eclipse ionosphere-thermosphere-mesosphere (ITM) system response. Our study was focused on quantifying eclipse effects on (1) traveling ionospheric disturbances (TIDs) and atmospheric gravity waves (AGWs); (2) spatial ionospheric variations associated with the eclipse; and (3) altitudinal and temporal ionospheric profile variations. We present selected early findings on ITM eclipse response including a dense global network of 6000 GNSS total electron content (TEC) receivers (100 million measurements per day; 1x1 degree spatial grid) and the Millstone Hill and Arecibo incoherent scatter radars. TEC depletions of up to 60% in magnitude were associated with the eclipse umbra and penumbra and consistently trailed the eclipse totality center. TEC enhancements associated with prominent orographic features were observed in the western US due to complex interactions as the lower atmosphere cooled in response to decreasing EUV energy inputs. Strong TIDs in the form of bow waves, stern waves, and a stern wake were observed in TEC data. Altitude-resolved plasma parameter profiles from Millstone Hill saw a nearly 50% decrease in F region electron density in vertical profiles, accompanied by a corresponding 200-250 K decrease in electron temperature. Wide field Millstone Hill radar scans showed similar decreases in electron density to the southwest, maximizing along the line of closest approach to totality. Data is available to the research community through the MIT Haystack Madrigal system. Alongside a summary of observations, we will also present preliminary quantitative comparisons with several ongoing modeling efforts.

Effects of interstellar dust scattering on the X-ray eclipses of the LMXB AX J1745.6-2901 in the Galactic Centre

NASA Astrophysics Data System (ADS)

Jin, Chichuan; Ponti, Gabriele; Haberl, Frank; Smith, Randall; Valencic, Lynne

2018-07-01

AX J1745.6-2901 is an eclipsing low-mass X-ray binary in the Galactic Centre (GC). It shows significant X-ray excess emission during the eclipse phase, and its eclipse light curve shows an asymmetric shape. We use archival XMM-Newton and Chandra observations to study the origin of these peculiar X-ray eclipsing phenomena. We find that the shape of the observed X-ray eclipse light curves depends on both photon energy and the shape of the source extraction region, and also shows differences between the two instruments. By performing detailed simulations for the time-dependent X-ray dust-scattering halo, as well as directly modelling the observed eclipse and non-eclipse halo profiles of AX J1745.6-2901, we obtained solid evidence that its peculiar eclipse phenomena are indeed caused by the X-ray dust scattering in multiple foreground dust layers along the line of sight (LOS). The apparent dependence on the instruments is caused by different instrumental point spread functions. Our results can be used to assess the influence of dust-scattering in other eclipsing X-ray sources, and raise the importance of considering the timing effects of dust-scattering halo when studying the variability of other X-ray sources in the GC, such as Sgr A⋆. Moreover, our study of halo eclipse reinforces the existence of a dust layer local to AX J1745.6-2901 as reported by Jin et al. (2017), as well as identifying another dust layer within a few hundred parsecs to the Earth, containing up to several tens of percent LOS dust, which is likely to be associated with the molecular clouds in the Solar neighbourhood. The remaining LOS dust is likely to be associated with the molecular clouds located in the Galactic disc in-between.

Progressive Neuronal Pathology and Synaptic Loss Induced by Prediabetes and Type 2 Diabetes in a Mouse Model of Alzheimer's Disease.

PubMed

Ramos-Rodriguez, Juan Jose; Spires-Jones, Tara; Pooler, Amy M; Lechuga-Sancho, Alfonso Maria; Bacskai, Brian J; Garcia-Alloza, Monica

2017-07-01

Age remains the main risk factor for developing Alzheimer's disease (AD) although certain metabolic alterations, including prediabetes and type 2 diabetes (T2D), may also increase this risk. In order to understand this relationship, we have studied an AD-prediabetes mouse model (APP/PS1) with severe hyperinsulinemia induced by long-term high fat diet (HFD), and an AD-T2D model, generated by crossing APP/PS1 and db/db mice (APP/PS1xdb/db). In both, prediabetic and diabetic AD mice, we have analyzed underlying neuronal pathology and synaptic loss. At 26 weeks of age, when both pathologies were clearly established, we observed severe brain atrophy in APP/PS1xdb/db animals as well as cortical thinning, accompanied by increased caspase activity. Reduced senile plaque burden and elevated soluble Aβ40 and 42 levels were observed in AD-T2D mice. Further assessment revealed a significant increase of neurite curvature in prediabetic-AD mice, and this effect was worsened in AD-T2D animals. Synaptic density loss, analyzed by array tomography, revealed a synergistic effect between T2D and AD, whereas an intermediate state was observed, once more, in prediabetic-AD mice. Altogether, our data suggest that early prediabetic hyperinsulinemia may exacerbate AD pathology, and that fully established T2D clearly worsens these effects. Therefore, it is feasible that early detection of prediabetic state and strict metabolic control could slow or delay progression of AD-associated neuropathological features.

Total Eclipse of the Ballpark: Connecting Space and Sports

NASA Astrophysics Data System (ADS)

Wasser, Molly; Petro, Noah; Jones, Andrea; Bleacher, Lora; Keller, John; Wes Patterson, G.

2018-01-01

The anticipation and excitement surrounding the total solar eclipse of 2017 provided astronomy educators with an incredible platform to share space science with huge audiences. The Public Engagement Team for NASA’s Lunar Reconnaissance Orbiter (LRO) took advantage of this opportunity to share lunar science with the public by highlighting the often-overlooked central player in the eclipse – the Moon. As the sole planetary science representatives on NASA’s Science Mission Directorate eclipse leadership team, the LRO team had limited resources to conduct national public outreach. In order to increase our reach, we found success in partnerships.In early 2017, we began working with Minor League Baseball (MiLB) teams across the path of totality on August eclipse events. These partnerships proved fruitful for both parties. While MiLB is a national organization, each team is deeply rooted in its community. This proved essential as each of our four main MiLB partners handled event logistics, provided facilities, connected NASA Subject Matter Experts (SMEs) with local media, and drew in captive crowds. With this tactic, a handful of NASA representatives were able to reach nearly 30,000 people. In turn, LRO provided engaging educational content relevant to the context, SMEs to guide the eclipse viewing experience, eclipse glasses, and safety information. Our participation drew in an audience who would not typically attend baseball games while we were able to reach individuals who would not normally attend a science event. In addition, the eclipse inspired one team, the Salem-Keizer Volcanoes from Salem, OR, to make baseball history by holding the first ever eclipse delay in professional sports.In this talk, we will present on the benefits of the partnership, offer lessons learned, and suggest ways to get involved for the 2024 eclipse – and all the baseball seasons in between.

Geographically Distributed Citizen Scientist Training for the 2017 Citizen CATE Experiment

NASA Astrophysics Data System (ADS)

Gelderman, Richard; Penn, Matt; Baer, Robert; Isberner, Fred; Pierce, Michael; Walter, Donald K.; Yanamandra-Fisher, Padma; Sheeley, Neil R.

2016-01-01

The solar eclipse of 21 August 2017 will be visible to over a half billion people across the entire North American continent. The roughly 100-mile wide path of totality, stretching from Oregon to South Carolina, will be the destination for tens of millions of people. In the decades since 1979, when the last total solar eclipse was visible from the continental USA, the phenomenon of Internet enabled citizen science has grown to be an accepted mode for science. The Citizen Continental-America Telescopic Eclipse (Citizen CATE) experiment has been funded as one of the three 2017 eclipse related NASA STEM agreements to engage citizen scientists in a unique, cutting-edge solar physics experiment. Teams across the USA will be trained to use standardized refracting telescope and digital imager set-ups to observe the solar corona during the eclipse, acquiring multiple exposures to create one high dynamic range image. After observing during the eclipse, the CATE volunteers will upload the combined image to a cloud-storage site and the CATE team will then work to properly orient and align all the images collected from across the continent to produce a continuous 90-minutes movie. A time-compressed first cut of the entire sequence will be made available to media outlets on the same afternoon of the eclipse, with hope that high quality images will encourage the most accurate coverage of this Great American Eclipse. We discuss overall the project, as well as details of the initial tests of the prototype set-up (including in the Faroe Islands during the March 2015 total solar eclipse) and plans for the future night-time and day-time observing campaigns, and for a handful of observing teams positioned for overlapping observations of the March 2016 total solar eclipse in the South Pacific.

Total Solar Eclipse of 2006 March 29

NASA Technical Reports Server (NTRS)

Espenak, F.; Anderson, J.

2004-01-01

On 2006 March 29, a total eclipse of the Sun will be visible from within a narrow corridor which traverses half the Earth. The path of the Moon's umbral shadow begins in Brazil and extends across the Atlantic, northern Africa, and central Asia where it ends at sunset in western Mongolia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the northern two thirds of Africa, Europe, and central Asia.Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 350 cities, maps of the eclipse path, weather prospects, the lunar limb profile, and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Solar Eclipse: Concept of “Science” and “Language” Literacy

NASA Astrophysics Data System (ADS)

Haristiani, N.; Zaen, R.; Nandiyanto, A. B. D.; Rusmana, A. N.; Azis, F.; Danuwijaya, A. A.; Abdullah, A. G.

2018-02-01

The purpose of this study was to evaluate the concept of science and language literacy of solar eclipse. The study was conducted through a survey to 250 students with different ages (from 17 to 23 years old), grades, and majors in Universitas Pendidikan Indonesia. The survey was completed with a questionnaire consisting of 41 questions. In the case of the language literacy, experimental results showed that various expressions in facing the solar eclipse phenomenon are found. Relating to the science literacy, most students have good science understanding to the solar eclipse phenomenon. In conclusion, the understanding about the solar eclipse is affected by formal science education and religion understanding that they have been accepted since their childhood. These factors have also influenced the belief of Indonesian people to the solar eclipse myth and the way of expressions a language literacy.

Strategies for the public communication of eclipses

NASA Astrophysics Data System (ADS)

Bretones, P. S.

2015-03-01

Eclipses are among the celestial events that draw the attention of the public. This paper discusses strategies for using eclipses as public communication opportunities in the media. It discusses the impact of articles written by the author and analysis of published material for 25 observed eclipses over the last 30 years by mass media in the state of São Paulo, Brazil. On each occasion, a standard article was posted on the Internet and sent to newspapers, radio and TV with information, such as: date, time and local circumstances; type of the eclipse; area of visibility; explanation; diagram of the phenomenon, and the Moon's path through Earth's shadow; eclipses in history; techniques of observation; getting photographs; place and event for public observation. Over the years, direct contact was maintained with the media and jounralists by the press offices of the institutions.

SPECIAL SEMINAR - The NOTTE experiment, or how to become a Total Solar Eclipse chaser

ScienceCinema

None

2017-12-09

The NOTTE experiment (Neutrino Oscillations with Telescope during Total Eclipse) aims at searching for visible photons emitted through a possible radiative decay of solar neutrinos. The experiment and the expeditions organized by a group of physicists and astrophysicists from INFN and INAF Bologna hunting for Total Solar Eclipses from 1998 to 2006 wil be described. The results of observations performed during total solar eclipse expeditions in 2001 (Zambia) and 2006 (Sahara desert, Libya) are presented and a beautiful photo gallery will be shown. Other peculiar observations that can be made during a solar eclipse are also illustrated. The seminar will be followed by a brief presentation of future camps for solar eclipse chasers and scientists organized in 2008 in Russia, Kazakhstan, China and Mongolia, in 2009 in Shanghai and on the Easter Island in 2010.

A study of integrated learning and the value of science in remote education: using the Internet to relay the total solar eclipse of 2001 June 11 in Africa

NASA Astrophysics Data System (ADS)

Takahashi, N.; Agata, H.; Maeda, K.; Okyudo, M..; Yamazaki, Y.

A total solar eclipse was observed on 2001 June 21 in Angola, Zambia, and Zimbabwe in Africa. For the purpose of promotion of science education using a solar eclipse as an educational project, the whole image and an enlarged image of the Sun, that showed the process of an eclipse and how things went in the observation area, were broadcast to the world through the Internet (Live Eclipse). Such images were distributed to four primary schools in Hiroshima and the Science and Technology Museum in Tokyo to give a remote lecture through computers. To find the effectiveness of the lecture, the learning effect on the participating children was examined two times before and after the remote lecture on the solar eclipse.

The Unique Scientific Assets of Multi-Wavelength Total Solar Eclipse Observations

NASA Astrophysics Data System (ADS)

Habbal, S. R.; Druckmuller, M.; Ding, A.

2017-12-01

Total solar eclipses continue to yield new discoveries regarding the dynamics and thermodynamics of the corona, due to the radial span of the field of view available during totality, starting from the solar surface out to several solar radii, and due to the diagnostic potential provided by coronal emission lines. Scientific highlights from past eclipse observations as well as from the 21 August 2017 eclipse, now spanning a solar cycle, will be presented. These include white light and spectral line imaging as well as imaging spectrometry. Emphasis will be placed on the unique insights into the origin of dynamic structures captured in eclipse images, and the temperature distribution in the corona derived from these eclipse observations. Implications of these results for the general problem of coronal heating, as well as for the next generation of space instrumentation will be discussed.

Analysis of ionospheric irregularities during total solar eclipse 2016 based on GNSS observation

NASA Astrophysics Data System (ADS)

Husin, A.; Jiyo; Anggarani, S.; Ekawati, S.; Dear, V.

2016-11-01

A total solar eclipse occurred over Indonesia in the morning hours on 9 March 2016. Ionisations in the ionosphere which is associated with the solar radiation during the total eclipse provided a good opportunity to study the ionospheric irregularities. Using global navigation satellite system (GNSS) data taken from dual-frequency receivers in Manado, we investigated and analysed the total electron content (TEC) perturbations with a time resolution of 60 s to reveal ionospheric irregularities during total eclipse. Result showed that TEC conditions based on IPP were decreased during solar eclipse on March 9, comparing with the neighbour day. The maximum percentage deviation (DTEC) from the average value during eclipse period, 00:00 - 02:40 UT reach -41.5%. The duration of maximum decrement in TEC occurs were around 2-30 minutes after the maximum obscuration.

Total Solar Eclipse of 2002 December 04

NASA Technical Reports Server (NTRS)

Espenak, Fred; Anderson, Jay

2001-01-01

On 2002 December 04, a total eclipse of the Sun will be visible from within a narrow corridor which traverses the Southern Hemisphere. The path of the Moon's umbral shadow begins in the South Atlantic, crosses southern Africa and the Indian Ocean, and ends at sunset in southern Australia. A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes the southern two thirds of Africa, Antarctica, Indian Ocean and Australia. Detailed predictions for this event are presented and include besselian elements, geographic coordinates of the path of totality, physical ephemeris of the umbra, topocentric limb profile corrections, local circumstances for approximately 400 cities, maps of the eclipse path, weather prospects, the lunar limb profile and the sky during totality. Information on safe eclipse viewing and eclipse photography is included.

Coordinated weather balloon solar radiation measurements during a solar eclipse

PubMed Central

2016-01-01

Solar eclipses provide a rapidly changing solar radiation environment. These changes can be studied using simple photodiode sensors, if the radiation reaching the sensors is unaffected by cloud. Transporting the sensors aloft using standard meteorological instrument packages modified to carry extra sensors, provides one promising but hitherto unexploited possibility for making solar eclipse radiation measurements. For the 20 March 2015 solar eclipse, a coordinated campaign of balloon-carried solar radiation measurements was undertaken from Reading (51.44°N, 0.94°W), Lerwick (60.15°N, 1.13°W) and Reykjavik (64.13°N, 21.90°W), straddling the path of the eclipse. The balloons reached sufficient altitude at the eclipse time for eclipse-induced variations in solar radiation and solar limb darkening to be measured above cloud. Because the sensor platforms were free to swing, techniques have been evaluated to correct the measurements for their changing orientation. In the swing-averaged technique, the mean value across a set of swings was used to approximate the radiation falling on a horizontal surface; in the swing-maximum technique, the direct beam was estimated by assuming that the maximum solar radiation during a swing occurs when the photodiode sensing surface becomes normal to the direction of the solar beam. Both approaches, essentially independent, give values that agree with theoretical expectations for the eclipse-induced radiation changes. This article is part of the themed issue ‘Atmospheric effects of solar eclipses stimulated by the 2015 UK eclipse’. PMID:27550757

Evaluating the Eclipse: How good was it?

NASA Astrophysics Data System (ADS)

Noel-Storr, Jacob; InsightSTEM Evaluation Team

2018-01-01

We present findings from the evaluation program carried out of education, public outreach, and communication activities around the "Great American Eclipse" of August 21, 2017. We include findings drawn from the experiences of 30 participants in planning activities prior to the eclipse and 31 recipients of mini-grants for eclipse activities supported by the American Astronomical Society through a grant from the National Science Foundation. We synthesize evaluations gathered by these and other volunteering organizations to provide a multi-site picture of experiences and learning outcomes at eclipse-related events - both in the path of totality and in partial eclipse settings. We make use of qualitative and quantitative responses representing over 30,000 individuals who observed (or tried to observe) the eclipse. We will share findings from across the range of programs included in our evaluation network along with specific highlights. We emphasize a reflection on the motivation and activity behind the 2017 eclipse, and how to leverage the lessons learned for future events on this scale (such as the eclipse of April 8, 2024) along with messages relevant to other events connected with astronomical phenomena, or in multi-site settings.This work was supported in part by the National Science Foundation under Grant No. 1564535 awarded to the American Astronomical Society. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation or the American Astronomical Society.

Statistical analysis of geomagnetic field variations during solar eclipses

NASA Astrophysics Data System (ADS)

Kim, Jung-Hee; Chang, Heon-Young

2018-04-01

We investigate the geomagnetic field variations recorded by INTERMAGNET geomagnetic observatories, which are observed while the Moon's umbra or penumbra passed over them during a solar eclipse event. Though it is generally considered that the geomagnetic field can be modulated during solar eclipses, the effect of the solar eclipse on the observed geomagnetic field has proved subtle to be detected. Instead of exploring the geomagnetic field as a case study, we analyze 207 geomagnetic manifestations acquired by 100 geomagnetic observatories during 39 solar eclipses occurring from 1991 to 2016. As a result of examining a pattern of the geomagnetic field variation on average, we confirm that the effect can be seen over an interval of 180 min centered at the time of maximum eclipse on a site of a geomagnetic observatory. That is, demonstrate an increase in the Y component of the geomagnetic field and decreases in the X component and the total strength of the geomagnetic field. We also find that the effect can be overwhelmed, depending more sensitively on the level of daily geomagnetic events than on the level of solar activity and/or the phase of solar cycle. We have demonstrated it by dividing the whole data set into subsets based on parameters of the geomagnetic field, solar activity, and solar eclipses. It is suggested, therefore, that an evidence of the solar eclipse effect can be revealed even at the solar maximum, as long as the day of the solar eclipse is magnetically quiet.

Heliophysics at total solar eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2017-08-01

Observations during total solar eclipses have revealed many secrets about the solar corona, from its discovery in the 17th century to the measurement of its million-kelvin temperature in the 19th and 20th centuries, to details about its dynamics and its role in the solar-activity cycle in the 21st century. Today's heliophysicists benefit from continued instrumental and theoretical advances, but a solar eclipse still provides a unique occasion to study coronal science. In fact, the region of the corona best observed from the ground at total solar eclipses is not available for view from any space coronagraphs. In addition, eclipse views boast of much higher quality than those obtained with ground-based coronagraphs. On 21 August 2017, the first total solar eclipse visible solely from what is now United States territory since long before George Washington's presidency will occur. This event, which will cross coast-to-coast for the first time in 99 years, will provide an opportunity not only for massive expeditions with state-of-the-art ground-based equipment, but also for observations from aloft in aeroplanes and balloons. This set of eclipse observations will again complement space observations, this time near the minimum of the solar activity cycle. This review explores the past decade of solar eclipse studies, including advances in our understanding of the corona and its coronal mass ejections as well as terrestrial effects. We also discuss some additional bonus effects of eclipse observations, such as recreating the original verification of the general theory of relativity.

Lunar shadow eclipse prediction models for the Earth orbiting spacecraft: Comparison and application to LEO and GEO spacecrafts

NASA Astrophysics Data System (ADS)

Srivastava, Vineet K.; Kumar, Jai; Kulshrestha, Shivali; Srivastava, Ashutosh; Bhaskar, M. K.; Kushvah, Badam Singh; Shiggavi, Prakash; Vallado, David A.

2015-05-01

A solar eclipse occurs when the Sun, Moon and Earth are aligned in such a way that shadow of the Moon falls on the Earth. The Moon's shadow also falls on the Earth orbiting spacecraft. In this case, the alignment of the Sun, Moon, and spacecraft is similar to that of the Sun, Moon, and Earth but this phenomenon is often referred as a lunar eclipse falling on the spacecraft. Lunar eclipse is not as regular in terms of times of occurrence, duration, and depth as the Earth shadow eclipse and number of its occurrence per orbital location per year ranges from zero to four with an average of two per year; a spacecraft may experience two to three lunar eclipses within a twenty-four hour period [2]. These lunar eclipses can cause severe spacecraft operational problems. This paper describes two lunar shadow eclipse prediction models using a projection map approach and a line of intersection method by extending the Earth shadow eclipse models described by Srivastava et al. [10,11] for the Earth orbiting spacecraft. The attractive feature of both models is that they are much easier to implement. Both mathematical models have been simulated for two Indian low Earth orbiting spacecrafts: Oceansat-2, Saral-1, and two geostationary spacecrafts: GSAT-10, INSAT-4CR. Results obtained by the models compare well with lunar shadow model given by Escobal and Robertson [12], and high fidelity commercial software package, Systems Tool Kit (STK) of AGI.

A1540-53, an eclipsing X-ray binary pulsator

NASA Technical Reports Server (NTRS)

Becker, R. H.; Swank, J. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Pravdo, S. H.; Saba, J. R.

1977-01-01

An eclipsing X-ray binary pulsator consistent with the location of A1540-53 has been observed. The source pulse period was 528.93 + or - 0.10 s. The binary nature is confirmed by a Doppler curve for the pulsation period. The eclipse angle of 30.5 + or - 3 deg and the 4-hour transition to and from eclipse suggest an early-type giant or supergiant primary star.

Massive eclipsing binary candidates

NASA Technical Reports Server (NTRS)

Garrison, R. F.; Schild, R. E.; Hiltner, W. A.

1983-01-01

New UBV data are provided for 63 southern OB stars which are either identified in the survey by Garrison, Hiltner, and Schild as having double lines or are known from Wood et al. to be eclipsing binaries. Twenty of the stars are known eclipsing variables. Four stars, not previously known as eclipsing, have both spectroscopic evidence of duplicity and significant photometric variations. Several additional stars have a marginally significant spread in V magnitude.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen passing in front of the Sun during a solar eclipse from Ross Lake, Northern Cascades National Park, Washington on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Sun is seen as it rises behind Jack Mountain head of the solar eclipse, Monday, Aug. 21, 2017, Ross Lake, Northern Cascades National Park, Washington. A total solar eclipse will sweep across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

This composite image shows the progression of a partial solar eclipse over Ross Lake, in Northern Cascades National Park, Washington on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

New Zealand Astronomy and the 9 September 1885 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Orchiston, Wayne; Rowe, Glen

The second half of the nineteenth century saw a blossoming of interest in solar eclipses as astronomers tried to establish whether the corona was a solar, lunar or terrestrial phenomenon, and as they investigated the nature of the corona, the chromosphere and prominences. Critical in these investigations were astronomy's newest allies: photography and spectroscopy. Photography was used with great effectiveness throughout the half century, but spectroscopy was first applied during the `Indian eclipse' of 1868. Thereafter, almost every total solar eclipse was subjected to scrutiny, the intensity of which depended upon the duration of the eclipse and the location of its path of totality. The first total solar eclipse visible from New Zealand following European settlement occurred on 9 September 1885, and attracted the attention of professional scientists and amateur astronomers. The centre of the path of totality extended from West Wanganui Inlet on the far northern reaches of the west coast of the South Island to Castle Point on the Wairarapa Coast, and a total eclipse was visible from population centres like Collingwood, Nelson, Picton, Wellington, Otaki, Palmerston North, Wanganui and throughout the Wairarapa. In this chapter we examine this eclipse, in the context of New Zealand astronomy and the international development of solar physics.

EE Cep observations requested for upcoming eclipse

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2014-07-01

The AAVSO requests observations for the upcoming eclipse of EE Cephei, a long-period eclipsing variable. EE Cep has a period of 2,050 days, and shows strong variations in the eclipse light curve from one event to the next. Observations are needed to study the morphology of the upcoming eclipse, which will be used to better understand the shape of the eclipsing disk and how it precesses. Mid-eclipse is predicted to be August 23, 2014, but the early stages of the eclipse may begin as much as a month earlier. EE Cep is being observed by a number of amateur and professional astronomers using multiple telescopes at multiple wavelengths. Among these is a collaboration (see https://sites.google.com/site/eecep2014campaign/) headed by Cezary Galan at the Nicolaus Copernicus Astronomical Center in Poland; several individual AAVSO observers are already participating in this effort. The AAVSO is not currently a partner in that campaign, but all data submitted to the AAVSO will be publicly available. The AAVSO strongly encourages observers to begin following this star now, and to continue observations into October 2014 at least. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and observations.

Stellar Obliquity and Magnetic Activity of Planet-hosting Stars and Eclipsing Binaries Based on Transit Chord Correlation

NASA Astrophysics Data System (ADS)

Dai, Fei; Winn, Joshua N.; Berta-Thompson, Zachory; Sanchis-Ojeda, Roberto; Albrecht, Simon

2018-04-01

The light curve of an eclipsing system shows anomalies whenever the eclipsing body passes in front of active regions on the eclipsed star. In some cases, the pattern of anomalies can be used to determine the obliquity Ψ of the eclipsed star. Here we present a method for detecting and analyzing these patterns, based on a statistical test for correlations between the anomalies observed in a sequence of eclipses. Compared to previous methods, ours makes fewer assumptions and is easier to automate. We apply it to a sample of 64 stars with transiting planets and 24 eclipsing binaries for which precise space-based data are available, and for which there was either some indication of flux anomalies or a previously reported obliquity measurement. We were able to determine obliquities for 10 stars with hot Jupiters. In particular we found Ψ ≲ 10° for Kepler-45, which is only the second M dwarf with a measured obliquity. The other eight cases are G and K stars with low obliquities. Among the eclipsing binaries, we were able to determine obliquities in eight cases, all of which are consistent with zero. Our results also reveal some common patterns of stellar activity for magnetically active G and K stars, including persistently active longitudes.

Discovery of Eclipses from the Accreting Millisecond X-Ray Pulsar Swift J1749.4-2807

NASA Technical Reports Server (NTRS)

Markwardt, C. B.; Stromhmayer, T. E.

2010-01-01

We report the discovery of X-ray eclipses in the recently discovered accreting millisecond X-ray pulsar SWIFT J1749.4-2807. This is the first detection of X-ray eclipses in a system of this type and should enable a precise neutron star mass measurement once the companion star is identified and studied. We present a combined pulse and eclipse timing solution that enables tight constraints on the orbital parameters and inclination and shows that the companion mass is in the range 0.6-0.8 solar mass for a likely range of neutron star masses, and that it is larger than a main-sequence star of the same mass. We observed two individual eclipse egresses and a single ingress. Our timing model shows that the eclipse features are symmetric about the time of 90 longitude from the ascending node, as expected. Our eclipse timing solution gives an eclipse duration (from the mid-points of ingress to egress) of 2172+/-13 s. This represents 6.85% of the 8.82 hr orbital period. This system also presents a potential measurement of "Shapiro" delay due to general relativity; through this technique alone, we set an upper limit to the companion mass of 2.2 Solar mass .

Atmospheric boundary layer effects induced by the 20 March 2015 solar eclipse

NASA Astrophysics Data System (ADS)

Gray, Suzanne L.; Harrison, R. Giles

2016-04-01

The British Isles benefits from dense meteorological observation networks, enabling insights into the still-unresolved effects of solar eclipse events on the near-surface wind field. The near-surface effects of the solar eclipse of 20 March 2015 are derived through comparison of output from the Met Office's operational weather forecast model (which is ignorant of the eclipse) with data from two meteorological networks: the Met Office's land surface station (MIDAS) network and a roadside measurement network operated by Vaisala. Synoptic-evolution relative calculations reveal the cooling and increase in relative humidity almost universally attributed to eclipse events. In addition, a slackening of wind speeds by up to about 2 knots in already weak winds and backing in wind direction of about 20 degrees under clear skies across middle England are attributed to the eclipse event. The slackening of wind speed is consistent with the previously reported boundary layer stabilisation during eclipse events. Wind direction changes have previously been attributed to a large-scale `eclipse-induced cold-cored cyclone', mountain slope flows, and changes in the strength of sea breezes. A new explanation is proposed here by analogy with nocturnal wind changes at sunset and shown to predict direction changes consistent with those observed.

The Citizen CATE Experiment: High altitude cirrus cloud removal from eclipse data through use of Kalman filters.

NASA Astrophysics Data System (ADS)

Jensen, Logan; Citizen CATE Experiment 2017 Team

2018-01-01

The Citizen Continental America Telescopic Eclipse (CATE) Experiment was designed to fill in the current data gap for the solar corona from approximately 1 to 2.5 solar radii. Using the total solar eclipse, the project took advantage of the unique opportunity to study this region of the corona from 68 identical sites across the United States. Before the 2017 eclipse, image reduction pipelines and advanced processing techniques were researched and implemented using data that had been collected from the 2016 Indonesian eclipse as a test set. This would speed up the turnaround from data to science after the 2017 eclipse.When processing the 2016 eclipse data, cirrus clouds became apparent moving across the field of view. These would interfere with future processing goals for the data such as coronal filament tracing and polar plume measurements. As the clouds moved across the field they did not completely obscure any part of the image, instead they produced variable, moving absorption across the CATE field of view. This had the effect of creating a noisy signal for each pixel. A noise reduction procedure based on a Kalman filter was developed to effectively remove the clouds from the data. Initial results from the 2016 eclipse data are presented.

Rapid quantification of resveratrol in mouse plasma by ultra high pressure liquid chromatography (UPLC) coupled to tandem mass spectrometry.

PubMed

Castillo-Pichardo, Linette; Dharmawardhane, Suranganie; Rodríguez-Orengo, José F

2014-12-01

The objective of this study was to develop a rapid and sensitive method for the quantification of resveratrol, a polyphenolic compound with multiple health beneficial effects, in mouse plasma. We used reversed-phase ultra high pressure-liquid chromatography with tandem mass spectrometry detection for the determination of resveratrol levels in mouse plasma. An Agilent Zorbax Eclipse Plus C18 column (2.1 mm x 50 mm, 1.8 μm) was used as the stationary phase. The mobile phase consisted of a gradient formed using 1 mM ammonium fluoride and methanol. Using this improved method, we obtained a retention time of 2.2 min and a total run time of 5 min, for resveratrol. The calibration curve for resveratrol showed a linear range from 0.5 to 100 ng/mL. The average coefficient of variation was 6% for interday variation and 4% for intraday variation. The recovery for resveratrol in mouse plasma was 85 ± 10% (mean ± standard deviation). The method presented herein allows a rapid and very sensitive quantification of resveratrol in mouse plasma at concentrations as low as 500 ppt.

Physical Properties and Evolution of the Eclipsing Binary System XZ Canis Minoris

NASA Astrophysics Data System (ADS)

Poochaum, R.; Komonjinda, S.; Soonthornthum, B.; Rattanasoon, S.

2010-07-01

This research aims to study the eclipse binary system so that its physical properties and evolution can be determined and used as an example to teach high school astronomy. The study of an eclipsing binary system XZ Canis Minoris (XZ CMi) was done at Sirindhorn Observatory, Chiang Mai University using a 0.5-meter reflecting telescope with CCD photometric system (2184×1417 pixel) in B V and R bands of UVB System. The data obtained were used to construct the light curve for each wavelength band and to compute the times of its light minima. New elements were derived using observations with linear to all available minima. As a result, linear ephemeris is HDJmin I = .578 808 948+/-0.000 000 121+2450 515.321 26+/-0.001 07 E, and the new orbital period of XZ CMi is 0.578 808 948+/-0.000 000 121 day. The values obtained were used with the previously published times of minima to get O-C curve of XZ CMi. The result revealed that the orbital period of XZ CMi is continuously decreased at a rate of 0.007 31+/-0.000 57 sec/year. This result indicates that the binary stars are moving closer continuously. From the O-C residuals, there is significant change to indicate the existence of the third body or magnetic activity cycle on the star. However, further analysis of the physical properties of XZ CMi is required.

Period changes of the long-period cataclysmic binary EX Draconis

NASA Astrophysics Data System (ADS)

Pilarčík, L.; Wolf, M.; Dubovský, P. A.; Hornoch, K.; Kotková, L.

2012-03-01

The cataclysmic variable star EX Dra is a relatively faint but frequently investigated eclipsing dwarf nova. In total 35 new eclipses were measured photometrically as part of our long-term monitoring of interesting eclipsing systems. Using published and new mid-eclipse times obtained between 2004 and 2011 we constructed the observed-minus-calculated diagram. The current data present 21 years of period modulation with a semi-amplitude of 2.5 min. The eclipse timings show significant deviations from the best sinusoidal fit, which indicates that this ephemeris is not a complete description of the data. The fractional period change is roughly ΔP/P = 3 × 10-6.

Light curve solutions of the eccentric binaries KIC 10992733, KIC 5632781, KIC 10026136 and their out-of-eclipse variability

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana; Vasileva, Doroteya

2018-01-01

We determined the orbits and stellar parameters of three eccentric eclipsing binaries by light curve solutions of their Kepler data. KIC 10992733 and KIC 5632781 undergo total eclipses while KIC 10026136 reveals partial eclipses. The components of the targets are G and K stars. KIC 10992733 exhibited variations which were attributed to variable visibility of spot(s) on asynchronously rotating component. KIC 5632781 and KIC 1002613 reveal tidally-induced features at periastron, i.e. they might be considered as eclipsing heartbeat stars. The characteristics of the periastron features (shape, width and amplitude) confirm the theoretical predictions.

VizieR Online Data Catalog: OGLE eclipsing binaries in LMC (Wyrzykowski+, 2003)

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2003-09-01

We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive. (2 data files).

GMRT discovery of PSR J1544+4937: An eclipsing black-widow pulsar identified with a Fermi-LAT source

DOE PAGES

Bhattacharyya, B.; Roy, J.; Ray, P. S.; ...

2013-07-29

Using the Giant Metrewave Radio Telescope, we performed deep observations to search for radio pulsations in the directions of unidentified Fermi-Large Area Telescope γ-ray sources. We report the discovery of an eclipsing black-widow millisecond pulsar, PSR J1544+4937, identified with the uncataloged γ-ray source FERMI J1544.2+4941. This 2.16 ms pulsar is in a 2.9 hr compact circular orbit with a very low mass companion (Mc > 0.017M ⊙). At 322 MHz this pulsar is found to be eclipsing for 13% of its orbit, whereas at 607 MHz the pulsar is detected throughout the low-frequency eclipse phase. Variations in the eclipse ingressmore » phase are observed, indicating a clumpy and variable eclipsing medium. Moreover, additional short-duration absorption events are observed around the eclipse boundaries. Finally, using the radio timing ephemeris we were able to detect γ-ray pulsations from this pulsar, confirming it as the source powering the γ-ray emission.« less

Initial Results of HamSCI Ham Radio 21 August 2017 Eclipse Ionospheric Experiments

NASA Astrophysics Data System (ADS)

Frissell, N. A.; Gerrard, A. J.; Vega, J. S.; Katz, J. D.; West, M. L.; Gunning, S. W.; Moses, M. L.; Miller, E. S.; Erickson, P. J.; Huba, J.; Silver, H. W.; Ceglia, F.; Smith, P.; Williams, R.; Shovkoplyas, A.; Earle, G. D.; Gerzoff, R.; Gladstone, P.; Reyer, S. E.; Ackermann, J. R.; Bern, D.; Rose, S. W.

2017-12-01

On 21 August 2017, a total solar eclipse will cause the shadow of the moon to traverse the United States from Oregon to South Carolina in just over 90 minutes. The sudden absence of sunlight due to the eclipse, especially solar UV and x-rays, provides an impulse function to the upper atmosphere that modifies the neutral dynamics, plasma concentrations, and related properties. Despite more than 60 years of research, questions remain regarding eclipse-induced ionospheric impacts. Ham radio operators' advanced technical skills and inherent interest in ionospheric science make the amateur radio community ideal for contributing to and and participating in large-scale ionospheric sounding experiments. We present initial results from three amateur radio experiments designed to study the 2017 total solar eclipse: the Solar Eclipse QSO Party (SEQP), the HF Wideband Recording Experiment, and the Eclipse Frequency Measurement Test (FMT). These experiments are coordinated by HamSCI, the Ham Radio Science Citizen Investigation, a citizen science organization that connects the amateur radio community to the professional space science research community for mutual benefit.

The (Almost) Unseen Total Eclipse of 1831

NASA Astrophysics Data System (ADS)

Bartky, Ian R.

2008-03-01

The total eclipse of August 1831 began at sunrise in Australia, swept across the western South Pacific Ocean, and ended at sunset in the central South Pacific. As a result of the eclipse's path over mostly uninhabited ocean, the region's sparse European (British) population, and near-useless local predictions of the event at Hobart and Sydney in almanacs sold to the general public, almost no one witnessed its passage. In an attempt to document the eclipse, journals of naive observers - those having no access to a prediction - were examined. Thus far, the sole record is in the Pitcairn Island Register Book. Considering the Pitcairners' extreme isolation and the rather modest partial eclipse that occurred there, the entry is a surprising one; however, it can be explained in terms of events associated with their initial removal to Tahiti in March 1831 followed by their return home in June. Further, an authoritative means to identify any issues associated with eclipse predictions compiled for private-sector almanacs came in 1833 when sweeping changes in the British Nautical Almanac's section on eclipses were instituted.

SU-E-T-436: Feasibility of Using the 'Irregular Surface Compensator' Planning Feature of the Eclipse TPS for Total Body Irradiation (TBI) Treatment Planning.

PubMed

Ayan, A; Lu, L; Rong, Y; Cunningham, M; Weldon, M; Welliver, M; Woollard, J; Gupta, N

2012-06-01

To investigate the feasibility of using the Irregular Surface Compensator (ISC) planning feature of the Eclipse treatment planning system (TPS) for Total Body Irradiation (TBI). TBI treatments require that the whole body receives within +-10% of the prescribed dose. Different body parts with different thicknesses compared to the umbilicus separation may receive higher or lower doses compared to the prescribed dose. Another challenge is to keep the lung dose below 10Gy to avoid complications. To mitigate this problem, physical compensators and blocks are used during the treatment for different body parts and lungs. This method presents a challenge during the treatment delivery and prolongs the treatment time due to patient setup, in-vivo on-line dosimetric monitoring and the adjustment of the compensators frequently during the treatment. We investigated the use of ISC planning feature of Eclipse TPS which is an electronic compensation method that calculates a fluence map based on the body contour from the CT image. The fluence map is delivered with dynamic MLCs . This TBI treatment technique was tested using a Rando phantom in Head First Supine position with lateral beams at SSD=250cm.The calculated fluence were edited so that the lung received <∼10Gy for 12Gy prescription. A single fraction of 2Gy was delivered and the in-vivo measurements were performed in the neck, lung and the umbilicus by using OSLDs. OSLD measurements and the Eclipse TPS predictionswere 200.4/195.0, 162.2/168.9, and 196.1/208.9 cGy for the neck, lung and the umbilicus respectively. The feasibility of using the 'Irregular Surface Compensator' feature of Eclipse TPS for TBI treatment planning was demonstrated. Good agreement (<6%) between the predicted and measured doses was obtained. The proposed planning and delivery simplifies the compensation and blocking to achieve uniform dose distributions and reduces the treatment time. © 2012 American Association of Physicists in Medicine.

Io Eclipse Montage

NASA Technical Reports Server (NTRS)

2007-01-01

New Horizons took this montage of images of Jupiter's volcanic moon Io, glowing in the dark of Jupiter's shadow, as the Pluto-bound spacecraft sped through the Jupiter system on Feb. 27, 2007.

(A): In this picture from the Long-Range Reconnaissance Imager (LORRI), dark blotches and straight lines are artifacts. The brightest spots (including the volcanoes Pele [P] and East Girru [EG]) are incandescent lava from active volcanoes. The more diffuse glows, and the many faint spots, are from gas in the plumes and atmosphere, glowing due to bombardment by plasma in Jupiter's magnetosphere, in a display similar to the Earth's aurorae. (B): The same image with a latitude/longitude grid, showing that the cluster of faint spots is centered near longitude 0 degrees, the point on Io that faces Jupiter. The image also shows the locations of the plumes seen in sunlit images (indicated by red diamonds), which glow with auroral emission in eclipse. (C): Simulated sunlit view of Io with the same geometry, based on sunlit LORRI images. (D): A combination of the sunlit image (in cyan) and the eclipse image (in red), showing that all point-like glows in the eclipse image arise from dark volcanoes in the eclipse image. (E): This infrared image, at a wavelength of 2.3 microns, obtained by New Horizons Linear Etalon Spectral Imaging Array (LEISA) an hour after the LORRI image, showing thermal emission from active volcanoes. Elongation of the hot spots is an artifact. (F): Combined visible albedo (cyan) and LEISA thermal emission (red) image, showing the sources of the volcanic emission. That most of the faint point-like glows near longitude zero, seen in visible light in images A, B, and D, do not appear in the infrared view of volcanic heat radiation, is one reason scientists believe that these glows are due to auroral emission, not heat radiation.

This image appears in the Oct. 12, 2007, issue of Science magazine, in a paper by John Spencer, et al.

Eclipse - tow flight closeup and release

NASA Technical Reports Server (NTRS)

1998-01-01

This clip, running 15 seconds in length, shows the QF-106 'Delta Dart' gear down, with the tow rope secured to the attachment point above the aircraft nose. First there is a view looking back from the C-141A, then looking forward from the nose of the QF-106, and finally a shot of the aircraft being released from the tow rope. NASA Dryden Flight Research Center, Edwards, California, supported a Kelly Space and Technology, Inc. (KST)/U.S. Air Force project known as Eclipse, which demonstrated a reusable tow launch vehicle concept. The purpose of the project was to demonstrate a reusable tow launch vehicle concept that had been conceived and patented by KST. Kelly Space obtained a contract with the USAF Research Laboratory for the tow launch demonstration project under the Small Business Innovation Research (SBIR) program. The USAF SBIR contract included the modifications to turn the QF-106 into the Experimental Demonstrator #1 (EXD-01), and the C141A aircraft to incorporate the tow provisions to link the two aircraft, as well as conducting flight tests. The demonstration consisted of ground and flight tests. These tests included a Combined Systems Test of both airplanes joined by a tow rope, a towed taxi test, and six towed flights. The primary goal of the project was demonstrating the tow phase of the Eclipse concept using a scaled-down tow aircraft (C-141A) and a representative aerodynamically-shaped aircraft (QF-106A) as a launch vehicle. This was successfully accomplished. On December 20, 1997, NASA research pilot Mark Stucky flew a QF-106 on the first towed flight behind an Air Force C-141 in the joint Eclipse project with KST to demonstrate a reusable tow launch vehicle concept developed by KST. Kelly Space and Technology hoped to use the data from the tow tests to validate a tow-to-launch procedure for reusable space launch vehicles. Stucky flew six successful tow tests between December 1997 and February 6, 1998. On February 6, 1998, the sixth and final towed flight brought the project to a successful completion. Preliminary flight results determined that the handling qualities of the QF-106 on tow were very stable; actual flight-measured values of tow rope tension were well within predictions made by the simulation, aerodynamic characteristics and elastic properties of the tow rope were a significant component of the towing system; and the Dryden high-fidelity simulation provided a representative model of the performance of the QF-106 and C-141A airplanes in tow configuration. Total time on tow for the entire project was 5 hours, 34 minutes, and 29 seconds. All six flights were highly productive, and all project objectives were achieved. All three of the project objectives were successfully accomplished. The objectives were: demonstration of towed takeoff, climb-out, and separation of the EXD-01 from the towing aircraft; validation of simulation models of the towed aircraft systems; and development of ground and flight procedures for towing and launching a delta-winged airplane configuration safely behind a transport-type aircraft. NASA Dryden served as the responsible test organization and had flight safety responsibility for the Eclipse project. Dryden also supplied engineering, simulation, instrumentation, range support, research pilots, and chase aircraft for the test series. Dryden personnel also performed the modifications to convert the QF-106 into the piloted EXD-01 aircraft. During the early flight phase of the project, Tracor, Inc. provided maintenance and ground support for the two QF-106 airplanes.The Air Force Flight Test Center (AFFTC), Edwards, California, provided the C-141A transport aircraft for the project, its flight and engineering support, and the aircrew. Kelly Space and Technology provided the modification design and fabrication of the hardware that was installed on the EXD-01 aircraft. Kelly Space and Technology hopes to use the data gleaned from the tow tests to develop a series of low-cost reusable launch vehicles, in particular to gain experience towing delta-wing aircraft having high wing loading, and in general to demonstrate various operational procedures such as ground processing and abort scenarios. The first successful towed flight occurred on Dec. 20, 1997. Prior to this first tow test flight, the C-141A and EXD-01 were used to conduct a series of tethered taxi tests to validate the tow procedures. Before these tethered taxi tests, a successful joint flight test was conducted in late October 1996, by Dryden, AFFTC, and KST, in which one of the Dryden F-18 chase aircraft flew at various ranges and locations behind the C-141A to define the wake turbulence and wingtip vortex environment. This flight test was replicated in July 1997, with an unmodified QF-106 flight proficiency aircraft.

Envelopes in eclipsing binary stars

NASA Technical Reports Server (NTRS)

Huang, S.

1972-01-01

Theoretical research on eclipsing binaries is presented. The specific areas of investigation are the following: (1) the relevance of envelopes to the study of the light curves of eclipsing binaries, (2) the disk envelope, and (3) the spherical envelope.

2017 Total Solar Eclipse Across America Promo

NASA Image and Video Library

2017-08-10

On Monday, August 21, 2017, all of North America will be treated to an eclipse of the sun. Anyone within the path of totality can see one of nature’s most awe inspiring sights - a total solar eclipse.

A1540-53, an eclipsing X-ray binary pulsator

NASA Technical Reports Server (NTRS)

Becker, R. H.; Swank, J. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Saba, J. R.; Serlemitsos, P. J.

1977-01-01

An eclipsing X-ray binary pulsator consistent with the location of A1540-53 was observed. The source pulse period was 528.93 plus or minus 0.10 seconds. The binary nature is confirmed by a Doppler curve for the pulsation period. The eclipse angle of 30.5 deg plus or minus 3 deg and the 4 h transition to and from eclipse suggest an early type, giant or supergiant, primary star.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen passing in front of the Sun at the point of the maximum of the partial solar eclipse near Banner, Wyoming on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Joel Kowsky)

A Photometric Study of the Eclipsing Binary Star PY Boötis

NASA Astrophysics Data System (ADS)

Michaels, E. J.

2016-12-01

Presented here are the first precision multi-band CCD photometry of the eclipsing binary star PY Boötis. Best-fit stellar models were determined by analyzing the light curves with the Wilson-Devinney program. Asymmetries in the light curves were interpreted as resulting from magnetic activity which required spots to be included in the model. The resulting model is consistent with a W-type contact eclipsing binary having total eclipses.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen as it starts passing in front of the Sun during a solar eclipse from Ross Lake, Northern Cascades National Park, Washington on Monday, Aug. 21, 2017. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Bill Ingalls)

Eclipse cooling of selected lunar features

NASA Technical Reports Server (NTRS)

Shorthill, R. W.; Saari, J. M.; Baird, F. E.; Lecompte, J. R.

1970-01-01

Thermal measurements were made in the 10 to 12 micron band of the lunar surface during the total eclipse of December19, 1964. A normalized differential thermal contour map is included, showing the location of the thermal anomalies or hot spots on the disk and the eclipse cooling curves of 400 sites, of which more than 300 were hot spots. The eclipse cooling data is compared to a particulate thermophysical model of the soil.

VizieR Online Data Catalog: Kepler Mission. VII. Eclipsing binaries in DR3 (Kirk+, 2016)

NASA Astrophysics Data System (ADS)

Kirk, B.; Conroy, K.; Prsa, A.; Abdul-Masih, M.; Kochoska, A.; Matijevic, G.; Hambleton, K.; Barclay, T.; Bloemen, S.; Boyajian, T.; Doyle, L. R.; Fulton, B. J.; Hoekstra, A. J.; Jek, K.; Kane, S. R.; Kostov, V.; Latham, D.; Mazeh, T.; Orosz, J. A.; Pepper, J.; Quarles, B.; Ragozzine, D.; Shporer, A.; Southworth, J.; Stassun, K.; Thompson, S. E.; Welsh, W. F.; Agol, E.; Derekas, A.; Devor, J.; Fischer, D.; Green, G.; Gropp, J.; Jacobs, T.; Johnston, C.; Lacourse, D. M.; Saetre, K.; Schwengeler, H.; Toczyski, J.; Werner, G.; Garrett, M.; Gore, J.; Martinez, A. O.; Spitzer, I.; Stevick, J.; Thomadis, P. C.; Vrijmoet, E. H.; Yenawine, M.; Batalha, N.; Borucki, W.

2016-07-01

The Kepler Eclipsing Binary Catalog lists the stellar parameters from the Kepler Input Catalog (KIC) augmented by: primary and secondary eclipse depth, eclipse width, separation of eclipse, ephemeris, morphological classification parameter, and principal parameters determined by geometric analysis of the phased light curve. The previous release of the Catalog (Paper II; Slawson et al. 2011, cat. J/AJ/142/160) contained 2165 objects, through the second Kepler data release (Q0-Q2). In this release, 2878 objects are identified and analyzed from the entire data set of the primary Kepler mission (Q0-Q17). The online version of the Catalog is currently maintained at http://keplerEBs.villanova.edu/. A static version of the online Catalog associated with this paper is maintained at MAST https://archive.stsci.edu/kepler/eclipsing_binaries.html. (10 data files).

Monitoring a photovoltaic system during the partial solar eclipse of August 2017

NASA Astrophysics Data System (ADS)

Kurinec, Santosh K.; Kucer, Michal; Schlein, Bill

2018-05-01

The power output of a 4.85 kW residential photovoltaic (PV) system located in Rochester, NY is monitored during the partial solar eclipse of August 21, 2017. The data is compared with the data on a day before and on the same day, a year ago. The area of exposed solar disk is measured using astrophotography every 16 s of the eclipse. Global solar irradiance is estimated using the eclipse shading, time of the day, location coordinates, atmospheric conditions and panel orientation. A sharp decline, as expected in the energy produced is observed at the time of the peak of the eclipse. The observed data of the PV energy produced is related with the model calculations taking into account solar eclipse coverage and cloudiness conditions. The paper provides a cohesive approach of irradiance calculations and obtaining anticipated PV performance.

Fall 2011 Eclipse Season Begins

NASA Image and Video Library

2011-09-13

The Fall 2011 eclipse season started on September 11, 2011. Here is an AIA 304 image from 0658 UT. SDO has eclipse seasons twice a year near each equinox. For three weeks near midnight Las Cruces time (about 0700 UT) our orbit has the Earth pass between SDO and the Sun. These eclipses can last up to 72 minutes in the middle of an eclipse season. The current eclipse season started on September 11 and lasts until October 4. To read more about SDO go to: sdo.gsfc.nasa.gov/ Credit: NASA/GSFC/SDO NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

SPECIAL SEMINAR - The NOTTE experiment, or how to become a Total Solar Eclipse chaser

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2011-02-08

The NOTTE experiment (Neutrino Oscillations with Telescope during Total Eclipse) aims at searching for visible photons emitted through a possible radiative decay of solar neutrinos. The experiment and the expeditions organized by a group of physicists and astrophysicists from INFN and INAF Bologna hunting for Total Solar Eclipses from 1998 to 2006 wil be described. The results of observations performed during total solar eclipse expeditions in 2001 (Zambia) and 2006 (Sahara desert, Libya) are presented and a beautiful photo gallery will be shown. Other peculiar observations that can be made during a solar eclipse are also illustrated. The seminar willmore » be followed by a brief presentation of future camps for solar eclipse chasers and scientists organized in 2008 in Russia, Kazakhstan, China and Mongolia, in 2009 in Shanghai and on the Easter Island in 2010.« less

Clear-Sky Probability for the August 21, 2017, Total Solar Eclipse Using the NREL National Solar Radiation Database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habte, Aron M; Roberts, Billy J; Kutchenreiter, Mark C

The National Renewable Energy Laboratory (NREL) and collaborators have created a clear-sky probability analysis to help guide viewers of the August 21, 2017, total solar eclipse, the first continent-spanning eclipse in nearly 100 years in the United States. Using cloud and solar data from NREL's National Solar Radiation Database (NSRDB), the analysis provides cloudless sky probabilities specific to the date and time of the eclipse. Although this paper is not intended to be an eclipse weather forecast, the detailed maps can help guide eclipse enthusiasts to likely optimal viewing locations. Additionally, high-resolution data are presented for the centerline of themore » path of totality, representing the likelihood for cloudless skies and atmospheric clarity. The NSRDB provides industry, academia, and other stakeholders with high-resolution solar irradiance data to support feasibility analyses for photovoltaic and concentrating solar power generation projects.« less

Effects of the 2017 Solar Eclipse on HF Radio Propagation and the D-Region Ionosphere: Citizen Science Investigation

NASA Technical Reports Server (NTRS)

Fry, C. D.; Rawlins, L.; Krause, L. H.; Suggs, R. M.; McTernan, J. K.; Adams, M. L.; Gallagher, D. L.; Anderson, Scott; Allsbrooks, Robert IV

2017-01-01

August 21, 2017 provided a unique opportunity to investigate the effects of the total solar eclipse on high frequency (HF) radio propagation and ionospheric variability. In Marshall Space Flight Center's partnership with the US Space and Rocket Center (USSRC) and Austin Peay State University (APSU), we engaged students and citizen scientists in an investigation of the eclipse effects on the mid-latitude ionosphere. Activities included implementing and configuring software, monitoring the HF Amateur Radio frequency bands and collecting radio transmission data on days before, the day of, and days after the eclipse to build a continuous record of changing propagation conditions as the moon's shadow marched across the United States. Post-eclipse radio propagation analysis provided insights into ionospheric variability due to the eclipse. We report on results, interpretation, and conclusions of these investigations.

Orbital variability in the eclipsing pulsar binary PSR B1957+20

NASA Technical Reports Server (NTRS)

Arzoumanian, Z.; Fruchter, A. S.; Taylor, J. H.

1994-01-01

We have conducted timing observations of the eclipsing millisecond binary pulsar PSR B1957+20, extending the span of data on this pulsar to more than five years. During this time the orbital period of the system has varied by roughly Delta P(sub b)/P(sub b) = 1.6 x 10(exp -7), changing quardratically with time and displaying with time and displaying an orbital period second derivative of P(sub b) = (1.43 +/- 0.08) x 10(exp -18)/sec. The previous measurement of a large negative orbital period derivative reflected only the short-term behavior of the system during the early observations; the orbital period derivative is now positive. If, as we suspect, the PSR B1957+20 system is undergoing quasi-cyclic orbital period variations similar to those found in other close binaries such as Algol and RS CVn, then the 0.025 solar mass companion to PSR B1957+20 is most likely non-degenerate, convective, and magnetically active.

The Orbit and Position of the X-ray Pulsar XTE J1855-026: An Eclipsing Supergiant System

NASA Technical Reports Server (NTRS)

Corbet, Robin H. D.; Mukai, Koji; White, Nicholas E. (Technical Monitor)

2002-01-01

A pulse timing orbit has been obtained for the X-ray binary XTEJ1855-026 using observations made with the Proportional Counter Array on board the Rossi X-ray Timing Explorer. The mass function obtained of approximately 16 solar mass together with the detection of an extended near-total eclipse confirm that the primary star is supergiant as predicted. The orbital eccentricity is found to be very low with a best fit value of 0.04 +/- 0.02. The orbital period is also refined to be 6.0724 +/- 0.0009 days using an improved and extended light curve obtained with RXTE's All Sky Monitor. Observations with the ASCA satellite provide an improved source location of R.A.= 18 hr 55 min 31.3 sec, decl.= -02 deg 36 min 24.0 sec (2000) with an estimated systematic uncertainty of less than 12 min. A serendipitous new source, AX J1855.4-0232, was also discovered during the ASCA observations.

Simultaneous determination of andrographolide, dehydroandrographolide and neoandrographolide in dog plasma by LC-MS/MS and its application to a dog pharmacokinetic study of Andrographis paniculata tablet.

PubMed

Xu, Fang-fang; Fu, Shu-jun; Gu, Sheng-pan; Wang, Zhi-min; Wang, Zhen-zhong; He, Xin; Xiao, Wei

2015-05-15

In this study, a sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determinate andrographolide (AP), dehydroandrographolide (DP), and neoandrographolide (NP) in plasma of beagle dogs after oral administration of Andrographis paniculata tablet (A. paniculata). The analytes and bilobalide (internal standard) were separated on an Agilent ZORBAX XDB-C18 column (50mm×2.1mm, 3.5μm) by using gradient elution consisting of methanol and water at a flow rate of 0.50mL/min in 7min. Multiple reaction monitoring (MRM) mode was performed to quantify data under monitoring precursor-product ion transitions of m/z 348.8→286.9, 330.9→107.9, 479.1→160.8 and 325.0→163.0 for AP, DP, NP and internal standard (IS) at negative ion mode, respectively. This method was developed at linearity ranging from 0.50 to 250ng/mL for AP, 1.00 to 500ng/mL for DP and 0.20 to 100ng/mL for NP. The accuracy of each analyte ranged between 94.8% and 107.1% and the precision was within 14.6%. No significant matrix effect was observed. AP, DP and NP were stable during sample storage, preparation and analytic procedures. Furthermore, this method was successfully applied in the investigation of the pharmacokinetic profile of AP, DP and NP in beagle dogs after oral administration of A. paniculata tablet (49.5mg for AP, 7.0mg for DP, 22.0mg for NP). Biological half-life (t1/2) was 2.08±0.99, 3.13±1.19 and 1.07±0.38h for AP, DP and NP, respectively. The areas under curves (AUC0-t) of AP, DP and NP was 494.50±150.64, 26.01±8.72 and 78.78±18.29ngh/mL, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Constraints on the atmospheric circulation and variability of the eccentric hot Jupiter XO-3b

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Ian; Knutson, Heather A.; Cowan, Nicolas B.

We report secondary eclipse photometry of the hot Jupiter XO-3b in the 4.5 μm band taken with the Infrared Array Camera on the Spitzer Space Telescope. We measure individual eclipse depths and center of eclipse times for a total of 12 secondary eclipses. We fit these data simultaneously with two transits observed in the same band in order to obtain a global best-fit secondary eclipse depth of 0.1580% ± 0.0036% and a center of eclipse phase of 0.67004 ± 0.00013. We assess the relative magnitude of variations in the dayside brightness of the planet by measuring the size of themore » residuals during ingress and egress from fitting the combined eclipse light curve with a uniform disk model and place an upper limit of 0.05%. The new secondary eclipse observations extend the total baseline from one and a half years to nearly three years, allowing us to place an upper limit on the periastron precession rate of 2.9 × 10{sup –3} deg day{sup –1}— the tightest constraint to date on the periastron precession rate of a hot Jupiter. We use the new transit observations to calculate improved estimates for the system properties, including an updated orbital ephemeris. We also use the large number of secondary eclipses to obtain the most stringent limits to date on the orbit-to-orbit variability of an eccentric hot Jupiter and demonstrate the consistency of multiple-epoch Spitzer observations.« less

Repeatability and Accuracy of Exoplanet Eclipse Depths Measured with Post-cryogenic Spitzer

NASA Astrophysics Data System (ADS)

Ingalls, James G.; Krick, J. E.; Carey, S. J.; Stauffer, John R.; Lowrance, Patrick J.; Grillmair, Carl J.; Buzasi, Derek; Deming, Drake; Diamond-Lowe, Hannah; Evans, Thomas M.; Morello, G.; Stevenson, Kevin B.; Wong, Ian; Capak, Peter; Glaccum, William; Laine, Seppo; Surace, Jason; Storrie-Lombardi, Lisa

2016-08-01

We examine the repeatability, reliability, and accuracy of differential exoplanet eclipse depth measurements made using the InfraRed Array Camera (IRAC) on the Spitzer Space Telescope during the post-cryogenic mission. We have re-analyzed an existing 4.5 μm data set, consisting of 10 observations of the XO-3b system during secondary eclipse, using seven different techniques for removing correlated noise. We find that, on average, for a given technique, the eclipse depth estimate is repeatable from epoch to epoch to within 156 parts per million (ppm). Most techniques derive eclipse depths that do not vary by more than a factor 3 of the photon noise limit. All methods but one accurately assess their own errors: for these methods, the individual measurement uncertainties are comparable to the scatter in eclipse depths over the 10 epoch sample. To assess the accuracy of the techniques as well as to clarify the difference between instrumental and other sources of measurement error, we have also analyzed a simulated data set of 10 visits to XO-3b, for which the eclipse depth is known. We find that three of the methods (BLISS mapping, Pixel Level Decorrelation, and Independent Component Analysis) obtain results that are within three times the photon limit of the true eclipse depth. When averaged over the 10 epoch ensemble, 5 out of 7 techniques come within 60 ppm of the true value. Spitzer exoplanet data, if obtained following current best practices and reduced using methods such as those described here, can measure repeatable and accurate single eclipse depths, with close to photon-limited results.

Comparisons of Measurements and Modeling of Solar Eclipse Effects on VLF Transmissions

NASA Astrophysics Data System (ADS)

Eccles, J. V.; Rice, D. D.; Sojka, J. J.; Marshall, R. A.; Drob, D. P.; Decena, J. C.

2017-12-01

The solar eclipse of 2017 August 21 provides an excellent opportunity to examine Very Low Frequency (VLF) radio signal propagation through the path of the solar eclipse between Navy VLF transmitters and several VLF receivers. The VLF transmitters available for this study radio signal propagation study are NLK in Jim Creek, Washington (24.8 kHz, 192 kW, 48.20N, 121.90W), NML in LaMour, North Dakota (25.2 kHz, 500 kW 46.37N, 93.34W), and NAA in Cutler, Maine (24.0 kHz, 1000 kW, 44.65N, 67.29W). These VLF transmitters provide propagation paths to three VLF receivers at Utah State University (41.75N, 111.76W), Bear Lake Observatory (41.95N, 111.39W), Salt Lake City (40.76N, 111.89W) and one receiver in Boulder, Colorado (40.02N, 105.27W). The solar eclipse shadow will cross all propagations paths during the day and will modify the D region electron density within the solar shadow. The week prior to the solar eclipse will be used to generate a diurnal baseline of VLF single strength for each transmitter-receiver pair. These will be compared to the day of the solar eclipse to identify VLF propagation differences through the solar eclipse shawdow. Additionally, the electron density effects of the week prior and of the solar eclipse day will be modeled using the Data-Driven D Region (DDDR) model [Eccles et al., 2005] with a detailed eclipse solar flux mask. The Long-Wave Propagation Code and the HASEL RF ray-tracing code will be used to generate VLF signal strength for each measured propagation path through the days prior and the solar eclipse day. Model-measurement comparisons will be presented and the D region electron density effects of the solar eclipse will be examined. The DDDR is a time-dependent D region model, which makes it very suitable for the solar eclipse effects on the electron density for the altitude range of 36 to 130 km. Eccles J. V., R. D. Hunsucker, D. Rice, J. J. Sojka (2005), Space weather effects on midlatitude HF propagation paths: Observations and a data-driven D region model, Space Weather, 3, S01002, doi:10.1029/2004SW000094.

Analysis of partial-reflection data from the solar eclipse of 10 Jul. 1972. [ground-based experiment using vertical incident radio waves partially reflected from D region

NASA Technical Reports Server (NTRS)

Bean, T. A.; Bowhill, S. A.

1973-01-01

Partial-reflection data collected for the eclipse of July 10, 1972 as well as for July 9 and 11, 1972, are analyzed to determine eclipse effects on D-region electron densities. The partial-reflection experiment was set up to collect data using an on-line PDP-15 computer and DECtape storage. The electron-density profiles show good agreement with results from other eclipses. The partial-reflection programs were changed after the eclipse data collection to improve the operation of the partial-reflection system. These changes were mainly due to expanded computer hardware and have simplified the operations of the system considerably.

Impact Results From the Astronomers Without Borders Building on the Eclipse Education Program

NASA Astrophysics Data System (ADS)

Bartolone, L. M.; Simmons, M.; Nelson, A.; Kruse, B.

2017-12-01

Astronomers Without Borders "Building on the Eclipse Education Program" was its first to move beyond outreach, exploring how to impact science identity, attitudes towards STEM and inspire audiences to explore careers in STEM. Inspired by the eclipse, educators and scientists were brought together in an online community to support one another in learning about the Sun and light after audiences were inspired by the Total Solar Eclipse. The program also collected and analyzed data on participating groups in an attempt to have more information about audiences for the next total solar eclipse to cross the United States in 2024. Although we anticipate the program will be ongoing, preliminary results will be presented.

Experimental Observation of the Ground-State Geometric Phase of Three-Spin XY Model

NASA Astrophysics Data System (ADS)

Hui, Zhou; Zhao-Kai, Li; Heng-Yan, Wang; Hong-Wei, Chen; Xin-Hua, Peng; Jiang-Feng, Du

2016-06-01

Not Available Supported by the National Key Basic Research Program under Grant Nos 2013CB921800 and 2014CB848700, the National Science Fund for Distinguished Young Scholars under Grant No 11425523, the National Natural Science Foundation of China under Grant Nos 11375167, 11227901, 91021005 and 11575173, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences under Grant No XDB01030400, the Research Fund for the Doctoral Program of Higher Education of China under Grant No 20113402110044, the China Postdoctoral Science Foundation, and the Fundamental Research Funds for the Central Universities.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The Moon is seen passing in front of the Sun during a total solar eclipse on Monday, August 21, 2017 from onboard a NASA Gulfstream III aircraft flying 25,000 feet above the Oregon coast. A total solar eclipse swept across a narrow portion of the contiguous United States from Lincoln Beach, Oregon to Charleston, South Carolina. A partial solar eclipse was visible across the entire North American continent along with parts of South America, Africa, and Europe. Photo Credit: (NASA/Carla Thomas)

Total Eclipse From Onboard NASA's G-III Research Aircraft

NASA Image and Video Library

2017-09-13

As the 2017 solar eclipse approaches and enters totality, NASA Armstrong staff and NASA senior management share their excitement and first-hand experience from aboard NASA’s Armstrong Flight Research Center Gulfstream III aircraft. The G-III aircraft flew at 35,000 feet above the coast of Oregon during the 2017 total solar eclipse, capturing some of the very first views of the 2017 total solar eclipse as it made its way across the United States.

Effects Total Solar Eclipse to Nasty Behaviour of the Several Legume Plants as a Result Student Research

NASA Astrophysics Data System (ADS)

Anggraeni, S.; Diana, S.; Supriatno, B.

2017-09-01

Some group students of plant Physiology course have given task to do free inquiry. They investigated of the nasty behaviour of several legume plants in response to changes in light during the partial solar eclipse that occurred at March 9, 2016. The investigation carried out in UPI Bandung, West Java, Indonesia, which is in the penumbra region of a total solar eclipse with the location coordinates of latitude: -6.86105, longitude: 07.59071, S 6057’ 37.53553 “and E 107035’ 24.29141”. They were measuring the movement of opening leaves every ten minutes at the beginning of the start until the end of the eclipse compared with the behaviour without eclipsing. Influence is expressed by comparing the leaf opening movement (measured in the form of leaf angular) at the time of the eclipse with a normal day. Each group was observed for one plant of the legume, there are: Mimosa pudica, Bauhinia purpurea, Caesalpinia pulcherrima, and Arachis pintoi. The results showed that the changes in leaf angular in plants Mimosa pudica, Caesalpinia pulcherrima, and Arachis pintoi differently significant, except for Bauhinia purpurea. In conclusion, the total solar eclipse in the penumbra area affects the movement of some nasty legume plants. It is recommended to conduct a study of the nasty behaviour of legume plants in the area umbra in the path of a total solar eclipse.

Educational, scientific, tourist and outreach potential of the September 1, 2016 Annular Solar Eclipse in Tanzania

NASA Astrophysics Data System (ADS)

Tayabali Jiwaji, Noorali

2015-08-01

Tanzania will witness a major astronomical spectacle of an annular eclipse on September 1, 2016. The central part of the eclipse will pass through southern Tanzania, crossing national parks and game reserves such as Katavi and the world famous Selous. For the rest of Tanzania and neighbouring countries it will be a memorable event with large of the proportion of the Sun being covered up. The climate in Tanzania during September is cool and dry which will provide ideal viewing conditions. Solar eclipse events attract "eclipse chasers" from around the globe.Scientific interest in measuring the properties of the Sun and the effects of the eclipse on the atmosphere will allow local scientists to partner with leading scientists to gain valuable experience and knowledge.Local population's wonder and interest in eclipses can be exploited through public-private partnerships by encouraging students and local people to travel to the central path or to observe from their backyards. Large number of eclipse glasses can be manufactured cheaply using safe solar filters for supplying to students and general population in Tanzania and neigbouring countries. This will raise science awareness about the wonders of our Universe.When combined with the attraction of Tanzania's treasures in the north and the 16 tonne Mbozi meteorite in southern Tanzania, the touristic potential of this event can be exploited through tour packages and worldwide advertisements during the coming year.

Eclipsing binary stars with a δ Scuti component

NASA Astrophysics Data System (ADS)

Kahraman Aliçavuş, F.; Soydugan, E.; Smalley, B.; Kubát, J.

2017-09-01

Eclipsing binaries with a δ Sct component are powerful tools to derive the fundamental parameters and probe the internal structure of stars. In this study, spectral analysis of six primary δ Sct components in eclipsing binaries has been performed. Values of Teff, v sin I, and metallicity for the stars have been derived from medium-resolution spectroscopy. Additionally, a revised list of δ Sct stars in eclipsing binaries is presented. In this list, we have only given the δ Sct stars in eclipsing binaries to show the effects of the secondary components and tidal-locking on the pulsations of primary δ Sct components. The stellar pulsation, atmospheric and fundamental parameters (e.g. mass, radius) of 92 δ Sct stars in eclipsing binaries have been gathered. Comparison of the properties of single and eclipsing binary member δ Sct stars has been made. We find that single δ Sct stars pulsate in longer periods and with higher amplitudes than the primary δ Sct components in eclipsing binaries. The v sin I of δ Sct components is found to be significantly lower than that of single δ Sct stars. Relationships between the pulsation periods, amplitudes and stellar parameters in our list have been examined. Significant correlations between the pulsation periods and the orbital periods, Teff, log g, radius, mass ratio, v sin I and the filling factor have been found.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piro, Anthony L., E-mail: piro@caltech.edu

The recently discovered system J0651 is the tightest known detached white dwarf (WD) binary. Since it has not yet initiated Roche-lobe overflow, it provides a relatively clean environment for testing our understanding of tidal interactions. I investigate the tidal heating of each WD, parameterized in terms of its tidal Q parameter. Assuming that the heating can be radiated efficiently, the current luminosities are consistent with Q {sub 1} {approx} 7 x 10{sup 10} and Q {sub 2} {approx} 2 x 10{sup 7}, for the He and C/O WDs, respectively. Conversely, if the observed luminosities are merely from the cooling ofmore » the WDs, these estimated values of Q represent the upper limits. A large Q {sub 1} for the He WD means its spin velocity will be slower than that expected if it was tidally locked, which, since the binary is eclipsing, may be measurable via the Rossiter-McLaughlin effect. After one year, gravitational wave emission shifts the time of eclipses by 5.5 s, but tidal interactions cause the orbit to shrink more rapidly, changing the time by up to an additional 0.3 s after a year. Future eclipse timing measurements may therefore infer the degree of tidal locking.« less

Soft-short management and remediation in 10-year-old NiCds in Geo orbit

NASA Technical Reports Server (NTRS)

Flordeliza, Nicanor A.; Bounds, Ronald W.

1996-01-01

After 10 years in Geo orbit, during the spring 1993 eclipse season, soft shorts occurred in cells of two of the three batteries on the F2R spacecraft On battery #1, the cell soft short turned suddenly into a hard short; the resulting sudden 1.2V fall in battery voltage and rise in temperature was observed via telemetry. On battery #3, the deleterious impact of its soft short increased day by day, manifesting itself as a drop in battery voltage part-way through each eclipse, causing high loading on the remaining good battery. This paper reports how by planned charge management, including applying (against-the-book) overcharge ratios (C/D) exceeding 1.75, the battery #3 cell soft short was 'built down' until the cell voltage fade ceased. The problem with the battery #3 soft-shorted cell was fought with partial success throughout the latter half of the fall 93 season, and the lessons learned were applied to alleviate the problem during the spring 94 and fall 94 eclipse seasons. The life of the spacecraft was successfully prolonged until it was retired in March 1995.

Discovery of deep eclipses in the cataclysmic variable IPHAS J051814.33+294113.0

NASA Astrophysics Data System (ADS)

Kozhevnikov, V. P.

2018-06-01

Performing the photometric observations of the cataclysmic variable IPHAS J051814.33+294113.0, we discovered very deep eclipses. The observations were obtained over 14 nights, had a total duration of 56 hours and covered one year. The large time span, during which we observed the eclipses, allowed us to measure the orbital period in IPHAS J051814.33+294113.0 with high precision, P_{orb}=0.20603098± 0.00000025 d. The prominent parts of the eclipses lasted 0.1± 0.01 phases or 30± 3 min. The depth of the eclipses was variable in the range 1.8-2.9 mag. The average eclipse depth was equal to 2.42± 0.06 mag. The prominent parts of the eclipses revealed a smooth and symmetric shape. We derived the eclipse ephemeris, which, according to the precision of the orbital period, has a formal validity time of 500 years. This ephemeris can be useful for future investigations of the long-term period changes. During the latter four observational nights in 2017 January, we observed the sharp brightness decrease of IPHAS J051814.33+294113.0 by 2.3 mag. This brightness decrease imitated the end of the dwarf nova outburst. However, the long-term light curve of IPHAS J051814.33+294113.0 obtained in the course of the Catalina Sky Survey during 8 years showed no dwarf nova outbursts. From this we conclude that IPHAS J051814.33+294113.0 is a novalike variable. Moreover, the sharp brightness decrease, which we observed in IPHAS J051814.33+294113.0, suggests that this novalike variable belongs to the VY Scl-subtype. Due to very deep eclipses, IPHAS J051814.33+294113.0 is suitable to study the accretion disc structure using eclipse mapping techniques. Because this novalike variable has the long orbital period, it is of interest to determine the masses of the stellar components from radial velocity measurements. Then, our precise eclipse ephemeris can be useful to the phasing of spectroscopic data.

Solar Activity and Motions in the Solar Chromosphere and Corona at the 2012 and 2013 Total and Annular Eclipses in the U.S., Australia, and Africa

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.; Babcock, B. A.; Davis, A. B.; Demianski, M.; Lucas, R.; Lu, M.; Dantowitz, R.; Rusin, V.; Saniga, M.; Seaton, D. B.; Gaintatzis, P.; Voulgaris, A.; Seiradakis, J. H.; Gary, D. E.; Shaik, S. B.

2014-01-01

Our studies of the solar chromosphere and corona at the 2012 and 2013 eclipses shortly after cycle maximum 24 (2011/2012) of solar activity (see: http://www.swpc.noaa.gov/SolarCycle/) involved radio observations of the 2012 annular eclipse with the Jansky Very Large Array, optical observations of the 2012 total eclipse from Australia, optical observations of the 2013 annular eclipse from Tennant Creek, Australia, and the 3 November 2013 total solar eclipse from Gabon. Our observations are coordinated with those from solar spacecraft: Solar Dynamics Observatory AIA and HMI, Hinode XRT and SOT, SOHO LASCO and EIT, PROBA2 SWAP, and STEREO SECCHI. Our 2012 totality observations include a CME whose motion was observed with a 37-minute interval. We include first results from the expedition to Gabon for the 3 November 2013 eclipse, a summary of eclipse results from along the path of totality across Africa, and a summary of the concomitant spacecraft observations. The Williams College 2012 expeditions were supported in part by NSF grant AGS-1047726 from Solar Terrestrial Research/NSF AGS, and by the Rob Spring Fund and Science Center funds at Williams. The JVLA is supported by the NSF. The Williams College 2013 total-eclipse expedition was supported in part by grant 9327-13 from the Committee for Research and Exploration of the National Geographic Society. ML was also supported in part by a Grant-In-Aid of Research from the National Academy of Sciences, administered by Sigma Xi, The Scientific Research Society (Grant ID: G20120315159311). VR and MS acknowledge support for 2012 from projects VEGA 2/0003/13 and NGS-3139-12 of the National Geographic Society. We are grateful to K. Shiota (Japan) for kindly providing us with some of his 2012 eclipse coronal images. We thank Alec Engell (Montana State U) for assistance on site, and Terry Cuttle (Queensland Amateur Astronomers) for help with site arrangements. We thank Aram Friedman (Ansible Technologies), Michael Kentrianakis, and Nicholas Weber (Dexter Southfield School) for collaboration on imaging at the Australian total eclipse.

KIC 7177553: A QUADRUPLE SYSTEM OF TWO CLOSE BINARIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehmann, H.; Borkovits, T.; Rappaport, S. A.

2016-03-01

KIC 7177553 was observed by the Kepler satellite to be an eclipsing eccentric binary star system with an 18-day orbital period. Recently, an eclipse timing study of the Kepler binaries has revealed eclipse timing variations (ETVs) in this object with an amplitude of ∼100 s and an outer period of 529 days. The implied mass of the third body is that of a super-Jupiter, but below the mass of a brown dwarf. We therefore embarked on a radial velocity (RV) study of this binary to determine its system configuration and to check the hypothesis that it hosts a giant planet. Frommore » the RV measurements, it became immediately obvious that the same Kepler target contains another eccentric binary, this one with a 16.5-day orbital period. Direct imaging using adaptive optics reveals that the two binaries are separated by 0.″4 (∼167 AU) and have nearly the same magnitude (to within 2%). The close angular proximity of the two binaries and very similar γ velocities strongly suggest that KIC 7177553 is one of the rare SB4 systems consisting of two eccentric binaries where at least one system is eclipsing. Both systems consist of slowly rotating, nonevolved, solar-like stars of comparable masses. From the orbital separation and the small difference in γ velocity, we infer that the period of the outer orbit most likely lies in the range of 1000–3000 yr. New images taken over the next few years, as well as the high-precision astrometry of the Gaia satellite mission, will allow us to set much narrower constraints on the system geometry. Finally, we note that the observed ETVs in the Kepler data cannot be produced by the second binary. Further spectroscopic observations on a longer timescale will be required to prove the existence of the massive planet.« less

Pre-Venus-Transit Dark Lunar Eclipse Reveals a Very Large Volcanic Eruption in 1761

NASA Astrophysics Data System (ADS)

Pang, Kevin

2009-01-01

Kepler's third law states Sun-planet distances in AU. International observations of the solar parallax during the 1761/1769 Venus transits gave us the first AU in miles. Benjamin Franklin promoted American participation in the project. While serving as Ambassador to France he observed that a "dry fog” from the 1783 Laki eruption in Iceland had obscured the Sun, and led to a cold summer and winter. Using Benjamin Franklin's method I analyzed photometric observations of the dark lunar eclipse made just before the 1761 Venus transit, ice core, tree ring, and Chinese weather data, and conclude that a very large previously unknown volcanic eruption in early 1761 had cooled the world climate. Observers worldwide found the 18 May 1761 totally eclipsed Moon very dark or invisible, e.g., Wargentin could not see the Moon for 38 minutes even with a 2-ft telescope (Phil. Trans. 52, 208, 1761-1762). Since the totally eclipsed Moon is illuminated only by sunlight refracted by the Earth's atmosphere, the obscuration must have been very severe. Ice cores from Greenland and Antarctica have large sulfuric acid contents in 1761-1762, precipitated from the global volcanic acid cloud (Zeilinski, J. Geophys. Res. 102, 26625, 1997). Frost-damaged rings in American bristlecone pines confirm that 1761 was very cold (LaMarche, Nature 307, 121, 1984). Contemporary Chinese chronicles report that heavy sustained snow fell from the Tropic of Cancer to the Yellow River. Wells and rivers froze, e.g., Taihu "Great Lake” and nearby Yangtze tributaries were not navigable. Innumerable trees, birds and livestock perished, etc. All observations are consistent with the above conclusion. Finally Benjamin Franklin's criteria for a climate-altering volcanic eruption are still universally used. Moreover his legacy continues to inspire climate researchers. See Pang, Eos 74, no. 43, 106, 1993; and as cited in "Earth in Balance,” Al Gore, p. 379, 1993.

Detection of the Secondary Eclipse of Exoplanet HAT P-11b

NASA Technical Reports Server (NTRS)

Barry, R. K.; Deming, L. D.; Bakos, G.; Harrington, J.; Madhusudhan, N.; Noyes, R.; Seager, S.

2010-01-01

We have successfully conducted secondary eclipse observations of exoplanet HAT-P-11b using the Spitzer Space Telescope. HAT-P-11b was, until very recently, the smallest transiting extrasolar planet yet found and one of only two known exo-Neptunes. We observed the system at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Having detected the secondary eclipse, we are at present making a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will serve to clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. A precise determination of the orbit phase for the secondary eclipse will also be of great utility for Kepler observations of this system at visible wavelengths.

Boise State's Idaho Eclipse Outreach Program

NASA Astrophysics Data System (ADS)

Davis, Karan; Jackson, Brian

2017-10-01

The 2017 total solar eclipse is an unprecedented opportunity for astronomical education throughout the continental United States. With the path of totality passing through 14 states, from Oregon to South Carolina, the United States is expecting visitors from all around the world. Due to the likelihood of clear skies, Idaho was a popular destination for eclipse-chasers. In spite of considerable enthusiasm and interest by the general population, the resources for STEM outreach in the rural Pacific Northwest are very limited. In order to help prepare Idaho for the eclipse, we put together a crowdfunding campaign through the university and raised over $10,000. Donors received eclipse shades as well as information about the eclipse specific to Idaho. Idaho expects 500,000 visitors, which could present a problem for the many small, rural towns scattered across the path of totality. In order to help prepare and equip the public for the solar eclipse, we conducted a series of site visits to towns in and near the path of totality throughout Idaho. To maximize the impact of this effort, the program included several partnerships with local educational and community organizations and a focus on the sizable refugee and low-income populations in Idaho, with considerable attendance at most events.

EC 10246-2707: an eclipsing subdwarf B + M dwarf binary

NASA Astrophysics Data System (ADS)

Barlow, B. N.; Kilkenny, D.; Drechsel, H.; Dunlap, B. H.; O'Donoghue, D.; Geier, S.; O'Steen, R. G.; Clemens, J. C.; LaCluyze, A. P.; Reichart, D. E.; Haislip, J. B.; Nysewander, M. C.; Ivarsen, K. M.

2013-03-01

We announce the discovery of a new eclipsing hot subdwarf B + M dwarf binary, EC 10246-2707, and present multicolour photometric and spectroscopic observations of this system. Similar to other HW Vir-type binaries, the light curve shows both primary and secondary eclipses, along with a strong reflection effect from the M dwarf; no intrinsic light contribution is detected from the cool companion. The orbital period is 0.118 507 9936 ± 0.000 000 0009 d, or about 3 h. Analysis of our time series spectroscopy reveals a velocity semi-amplitude of K1 = 71.6 ± 1.7 km s-1 for the sdB and best-fitting atmospheric parameters of Teff = 28 900 ± 500 K, log g = 5.64 ± 0.06 and log N(He)/N(H) = -2.5 ± 0.2. Although we cannot claim a unique solution from modelling the light curve, the best-fitting model has an sdB mass of 0.45 M⊙ and a cool companion mass of 0.12 M⊙. These results are roughly consistent with a canonical-mass sdB and M dwarf separated by a ˜ 0.84 R⊙. We find no evidence of pulsations in the light curve and limit the amplitude of rapid photometric oscillations to <0.08 per cent. Using 15 yr of eclipse timings, we construct an observed minus calculated (O - C) diagram but find no statistically significant period changes; we rule out |dot{P}| > 7.2 × 10^{-12}. If EC 10246-2707 evolves into a cataclysmic variable, its period should fall below the famous cataclysmic variable period gap.

Ep7_Total Eclipse over America

NASA Image and Video Library

2017-08-18

>> Houston, we have a podcast. Welcome to the official podcast of the nasa johnson space center, episode 7: total eclipse over america. I m gary jordan and i ll be your host today. So this is the podcast where we bring in the experts-- nasa scientists, engineers, astronauts-- all to tell you the coolest stuff about nasa. So today we re talking about eclipses with mark matney. He s a space debris scientist here at the nasa johnson space center in houston texas, and he also has degrees in astronomy and space physics, and is an avid eclipse aficionado. We had a great discussion about what an eclipse is, some of the history of eclipses, and some of the science that we ve learned and continue to learn from them. This is an exciting conversation, especially because on august 21, 2017, a total solar eclipse will sweep across america. Mark and i talked about where the eclipse will pass through and how you ll be able to see it. They don t happen very often-- the last time a total solar eclipse happened over the states was back in 1991, and we won t see another until 2024. Anyway, we ll get into all that good stuff during this episode. So with no further delay, let s go light speed and jump right ahead to our talk with dr. Mark matney. Enjoy. [ Music ] >> t minus five seconds and counting. Mark. [ Indistinct radio chatter ] >> houston, we have a podcast. [ Music ] >> all right, well, mark, thank you for coming on the podcast today. Perfect timing, because very soon we re going to have a total solar eclipse that s going to pass over the united states. And so i think this is a good chance for us to sit down and talk about eclipses. And you went above and beyond for this one, mark, because you have a lot of different things. I mean, we re talking a lot of science, we re talking a long and detailed history of eclipses. You know, this is not just a, ooh, look at that. Pretty eclipse. No, nasa s going all out for this-- is that fair to say? >> Well, i think this is-- i mean, eclipses have been part of human history as far back as we can record. People have been fascinated, scared, terrified by eclipses. >> Oh, sure. >> And a lot of important scientific discoveries have been driven by eclipses. I think today-- we re doing some science today, but much of the important science was done in the past. But this kind of links us in some sort of way to those early scientists who were trying to puzzle out the mysteries of the universe by using this amazing sight in the sky. So we have some science that s going on, we have some citizen science that s going on, and there s going to be a whole lot of people traveling to see this eclipse. In fact, i was reading that this eclipse is the first cross continent eclipse across the united states since the interstate system was built. >> Oh, wow. >> And so we might see one of the largest migrations of americans in a short period of time that we ve ever seen. [ Laughter ] because there s going to be a lot of people, perhaps tens of millions of people, traveling to see this eclipse. >> That s very true, and they re all going to be, i mean, closer to that nice, thin line-- we re talking about that path of totality, and we ll get into that really shortly, but you know, let s go and start at the very beginning, right? So we re talking about a total solar eclipse-- this is great-- passing over the united states. But what is that? What is a total solar eclipse? >> So a total eclipse is when the disk of the sun is completely covered by the moon. So the moon s size is maybe slightly larger than the sun, so we can get complete coverage. This particular eclipse is going to be about two and a half minutes of totality. Some eclipses are as high as seven minutes. Some of them are just a few seconds. >> And it s just the way things are aligning? >> Well, it turns out that the moon is actually not on a perfectly circular orbit. It s in a slightly elliptical orbit. So sometimes it s a little closer, and sometimes it s a little farther. >> Oh, i see. >> And so [ indistinct ] a little farther, it doesn t quite cover the surface of the sun. And what you end up with is a narrow ring all around. That s called an annular eclipse. And if the moon s a little larger-- in other words, a little closer, it appears a little larger in the sky, you get a total eclipse. And sometimes we actually have what s called a hybrid eclipse where you get an annular eclipse, but the mountains on the moon make it so it s actually a broken ring in the sky. It s so close, because actually, the mountains peeking up cover part of that sun ring. >> So can you see some of the sun peeking through those alleys, i guess? >> That s right, yes. >> Oh, interesting. >> And then that one, turns out if you could get higher in the altitude, in a balloon or plane, you might see a total eclipse in those kinds. But that s a special kind of eclipse that s actually quite rare. >> Wow. >> And then we also have a partial eclipse, and that s what-- it turns out this eclipse is interesting-- as far as i can tell, anyone in any of the 50 united states-- weather permitting-- should be able to see a partial eclipse, including alaska and hawaii. The partial eclipse is where the disk of the moon covers part of the sun but doesn t actually get to-- it s off to one side. >> Okay. >> And so you-- we re going to get a pretty good partial eclipse here from houston, but i think everybody, like i said, somewhere in the united states, one of the 50 states, should be able to see a partial eclipse. >> That ll be cool. >> So by the way, it s august 21st-- we didn t say the date. >> Yeah, so august 21st. And this will come out august 18th, so this ll be like-- >> oh, okay-- perfect. >> This ll be right next to it, yeah, absolutely. So a partial eclipse-- is there-- how-- is there a way that is very apparent to observe that? Like, will the sky get a little bit darker, or-- >> it depends on the percentage. When it s like about 50%, it s hard to notice. But once you get on to 60, 70, 80, 90%, the sky takes on an unusual color. And in fact, that s one of the things i m going to recommend eclipse observers-- just kind of note how the sky changes color, because it s a very interesting phenomenon. >> Yeah. >> But unless it s really-- in ancient times, people did not even notice a partial eclipse unless it was like 80, 90% because they started to see the sun dim, and they would look up at the sun and see there was no longer a disk in the sky. >> Wow. Okay, so from here in houston, what are we expecting percentage-wise? >> Well, i tried-- it s about somewhere around 70%. I don t know the exact area, but there s several tables. Also, that s another thing, is where you are, where the maximum eclipse changes on the clock. So there are computer resources where you can look and put in your location or your city and find out when the maximum eclipse is and how much. >> Oh, okay. Very cool. That s a lot of good stuff. All right, so that s 70%. We ll be able to see-- >> something like 70, yeah. >> A somewhat noticeable change in the sky, then, at least here from houston. That s really cool. So yeah, you said total versus partial. This is the solar eclipse, though, right? >> Right. >> This is when the moon is going in between the earth and the sun. >> Right. >> Like you said, they re relatively the same size in the sky, just based on distance and size, and so it only blocks off this tiny little strip of shadow that s going to go across the united states. And it goes-- you said it happens quite often, but just i guess at different parts of the world. >> Correct. >> It just so happens that it s going to line up this time going from coast to coast. >> And sometimes it s an annular, and sometimes-- but it turns out we get from three to five eclipses, solar eclipses, every year. >> Oh, okay. >> Which is actually kind of surprising. >> We meaning the earth. >> Someone on the earth, in other words, can see an eclipse. We actually have fewer-- there s another kind of eclipse called a lunar eclipse, and the lunar eclipse is when the earth gets between the moon and the sun. >> Right. >> And so as the moon moves into the shadow, it starts to turn dark, and sometimes has an interesting red color. >> Yeah. >> It turns out there are actually fewer of those than solar eclipses. >> Really? >> But because a whole hemisphere can see it, they re much-- you can see them much more often than solar eclipses. >> Oh, that-- okay. >> Because you re looking up in the sky and seeing the moon eclipse, so anybody on that side of the earth can see it-- weather permitting, of course. >> Wow. Why is it that color, though? >> Well, that s an interesting phenomenon. As you know, the sky is blue from the scattering of particles in the atmosphere-- it scatters the blue light. But the red is transmitted just like we see in a red sunset. Well, the earth s atmosphere actually refracts the red light, and so if you were standing on the moon during a lunar eclipse, the earth, of course, would block the sun, but you would see this red ring around the earth, which is the atmosphere refracting the light of the sun. >> So that s the red ring of the earth refracting off the surface of the moon? >> No, no, it s-- the light is coming through the atmosphere and refracting slightly to your position on the moon. >> Oh. >> So you would see this narrow, narrow red glowing ring around the earth. >> Oh, wow. >> So it s-- but of course, no one s ever seen that. >> Yeah. >> Maybe someday when we have a base on the moon. >> Oh, and so wait-- okay, so this is assuming that-- yeah, you re assuming that you are an observer on the moon. >> You re an astronaut standing on the moon, right. >> I see, and there s a red ring. So what about the lunar eclipse-- the perception from the earth? Doesn t a lunar eclipse-- the moon looks a little orange? >> Yeah, it s orange-ish, sometimes. It actually depends on-- it depends on what s happening in the atmosphere. >> Oh, okay. >> For instance, i saw an eclipse in 1982. We were expecting the red moon, but in fact, the moon looked charcoal gray. And that was right after the el chichon volcano in mexico erupted. And so the dust from the volcano had changed the dust in the atmosphere, so we didn t get much red. >> Oh. >> So it actually-- you never know what you re going to see when you see a lunar eclipse, but they re often red. And again, that s the red light that is bent by the earth s atmosphere and shines on the moon. >> Yeah, and it s reflecting-- interesting. So it s all entirely about perception, then, it s about the-- so you re a person on the earth, and this is what you perceive from the perspective of earth. If you were outside floating millions of miles away just observing it from afar, it would just look like the earth and the moon-- the moon wouldn t look a certain color. >> Well, you could see the color, because it s lit up with that color. Let me-- let s change it around. Let s say you were on the moon looking at the earth during a solar eclipse. And we have some photographs from the iss of previous eclipses, and you actually see a-- you can actually see the dark shadow. You can t see the sharp edge of the shadow, but you see this fuzzy black thing on the surface of the earth. And so you would see-- but instead of being the whole earth swallowed up, you just see this black fuzzy spot moving across the earth from space. >> Interesting. >> So hopefully-- it depends on where the iss will be at the time of the eclipse, but hopefully they ll be able to photograph it from-- they probably will not be in the eclipse path, but they could look down on the earth and see the shadow, hopefully, of the eclipse. >> Yeah, i think-- i think they are predicting that the iss is going to be somewhere over canada but will have a nice view of the states whenever it s actually the solar eclipse. >> It would be very, very coincidental if we happened to fly through the shadow, because the shadow is very narrow. It could happen, but i mean-- >> the odds are against us. >> The odds are against us. So a lunar eclipse happens at the full moon. >> Okay. >> When, of course, the sun is on the other side of the earth and the moon is-- if you re standing on the earth, the sun is behind you, because it s nighttime, and you see the-- and a solar eclipse happens at a new moon, when the moon is-- you can t really see it in the sky, because you re seeing the dark side of the moon. >> So you ll never see a crescent moon in a lunar eclipse? >> No, no, it s definitely a full moon, so as full as it gets. Another thing is lunar and solar eclipses are often paired, because that tilt of the moon s orbit, the point when it crosses the earth-sun orbit plane, is on both sides. And so usually we get an accompanying lunar eclipse with a solar eclipse. And in fact, the accompanying lunar eclipse for this eclipse is on august 7th, and will be visible from europe, africa, asia, and australia. >> Oh, okay. Well, there you go. >> Or was visible, i guess. >> August 7th, yeah. I guess-- aw. >> You want me to say that again? [ Laughter ] >> if we could go back in time okay, so i mean, that s kind of from the perspective of earth, right? We ve got solar eclipses, and when the moon is in between us here on earth and the sun, and then the opposite for the lunar eclipse. In general, if you had to give like a general overview, where else in the universe do eclipses happen? >> Everywhere. >> How about that. >> Anywhere where you have bodies moving around, one will often eclipse the view of another. But usually, what you-- you won t get to see the amazing sight on earth, because it s very rare that the object eclipsing looks in the sky the same size as the sun. >> Oh. >> So we know, for instance, there are eclipses caused by jupiter s moons as it orbits jupiter, and you can see the shadow on the surface of jupiter-- or the clouds, actually, of jupiter. >> Right. >> And in fact, there was a fellow named ole r mer-- if i m pronouncing correctly-- back in the 1600s that first detected the finite speed of light by looking at the timing of those eclipses on jupiter. So that s one of those science things that eclipses have allowed us to do. >> That s amazing-- just by looking at shadows across the universe, you can get all this crazy science. >> And sometimes-- i know we ve done occultations of stars, where a planet moves between us and the starlight of a star, and by measuring that star, we ve seen, like-- we ve found the rings of uranus, as the star would twinkle or would blink out just before uranus crossed the star. >> Oh. >> So you can actually do things like look for difficult to see rings, or also, as the light comes through the atmosphere, sometimes you can see the absorption of different chemicals in the atmosphere of the planet. >> And then understand the composition of the planet itself. >> Exactly. >> That s amazing. >> Let me add one thing we hadn t talked about. >> Yeah, sure. >> I found an interesting statistic, and it said that if you picked a random spot on the earth and you just stayed right there, you would see a solar eclipse about once every 375 years, on average. >> Okay, so you should move a little bit. >> Yeah, well-- you re not following. [ Laughter ] so during a normal person s long lifetime-- say, 70 years-- we re looking at a 20-25% chance that you would sometime in your lifetime see an eclipse, a total eclipse of the sun. So yes, it s rare, but not totally unknown. >> Yeah. >> So i just know that one never comes by my house, so i have to go chase it down. [ Laughter ] >> well, that s the great thing, is we have nasa-- we folks at nasa are actually looking at this stuff and making predictions. We know exactly where it s going to be on august 21st. >> That s correct, that s right. >> Yeah, so that kind of will help you see it a little bit, too. [ Laughter ] i think one of my favorites, though, when it comes to eclipses across the universe, is kepler, right? So if you think about-- you said occultations as one of them. That s when something passes in front of a star and changes the light that we re receiving. >> Right. >> That s how we are detecting planets outside of our solar system, correct? >> That s correct, yeah. The kepler mission is looking at a large group of stars and monitoring them constantly. And it has very, very sensitive instruments, so they can look at very small dips in the light as a planet-- a previously unknown planet-- transits the face of that star. And we ve been able-- and when they see them repeating, they can work out the relative sizes of the planets and their period, and work out where they are in orbit around that star. And we ve seen-- i don t know what the count is-- a thousand? >> Yeah, yeah. We keep finding more and more. >> There s a bunch of them. So this is actually one of the most interesting discoveries, i think, astronomers have made in the last several years, is that our galaxy is full of stars with planets. And it s pretty exciting-- it s kind of star trek stuff. >> It is! Especially just recently, the discovery of the trappist-1 system. >> Yes, indeed. >> And those-- we re talking about earth-like planets, and some of which are in what we like to call the goldilocks zone, right? >> That s right. >> And that s-- you know, water doesn t freeze, it doesn t-- >> that s right, it s not too hot, not too cold. >> Not too cold, right, and liquid water can exist. And that s conditions for life, and it s very exciting. >> It is. >> That s what we re looking for, right-- life outside of the universe. >> And i ll also mention we also have transits here, just like what we see with kepler, of the planets mercury and venus, which are inside the orbit of earth. And we recently had a venus transit visible from the us. >> Yeah, 2012, right?? >> That s right, i think it was 2012. And i ve also seen mercury transits as well. Those have an interesting history, because scientists in the 18th century were trying-- they d figured out the relative distance to the different planets, but they didn t know an absolute distance. And they were actually going to use different observers on the earth to measure the transit of venus to try and get an absolute scale. And so that was the cutting edge science in the 18th century. >> Wow. [ Laughter ] >> but so that s another point where transits and eclipses have been an important part of the history of science. >> Amazing. I mean, that s kind of a big theme here, right, especially for eclipses, is the science that we can get from observing these phenomena. >> That s right. >> So i mean, from here on the ground, what are some of the things that we can learn-- and i guess in the instance of a solar eclipse, but you know, eclipses in general-- what are some of the things that we can learn from studying these? >> Well, let s kind of go through some of the discoveries that were made with eclipses. >> Sure. >> So from ecl-- we all look up at the sun and see a bright disk. That s called the photosphere. It s very, very bright, and we ll talk about that a little bit. That s the part we re familiar with. It s about 10,000 degrees fahrenheit-- it s nice and hot. But during eclipses, astronomers notice some red layer-- a thin red layer around the sun. And that s known as the chromosphere. And that was discovered by eclipses, and it turns out chromosphere is due to emissions from atomic hydrogen in the sun s atmosphere. >> Okay. >> And so if you-- the soho spacecraft sometimes show-- i mean-- the soho spacecraft show-- is constantly monitoring the sun. And one of its instruments is a hydrogen alpha filter, and you can see what that chromosphere looks like. It s a very thin layer of the sun, again, that we discovered by looking at eclipses. The next section-- oh, by the way, some scientists-- in 1868, there was a new instrument that was developed called the spectroscope. And the spectroscope splits light into its component colors. And they had discovered that there were specific lines, almost like a fingerprint, that defined-- that were unique to each chemical, to each chemical element. >> Okay. >> And so there were-- some scientists were very excited to use the spectroscope to look at the eclipse. And in the chromosphere, they saw some lines from an element that they had never seen before. And they couldn t figure out what it was. So one of the scientists named it after the greek word for the sun-- helios. They named it helium. >> Oh! [ Laughter ] >> and it was several decades before helium was finally isolated and studied on the earth, but it was first discovered in the sun s atmosphere. >> How about that. That s-- is it called spectroscopy? >> Spectroscopy, yeah. They use a spectroscope for spectroscopy. >> Yeah, yeah, and studying the-- i guess there s little gaps in the light, and they look like gaps in the-- >> sometimes there s bright lines, sometimes there s dark lines. >> Okay. >> It depends on the situation. But the point is these lines are like a fingerprint. And that s how we understand the components of stars millions of lightyears away. We can-- >> so you said photosphere, and then you discovered the chromosphere, right? >> Chromosphere. >> So what s the difference between those? >> Well, the chromosphere is actually a very thin layer-- it s actually-- starts as cooler than the photosphere, and then it heats up again. >> Ooh. >> Solar astronomers are always trying to figure out the exact details, but what gets interesting is when you look up at the eclipse when it s total eclipse, there s what looks like a halo, or a garland, or a crown around it, and that s called the corona. So the chromosphere s a transition between the hot photosphere and the much hotter corona. And the corona is up to-- it s more than 100 times hotter than the photosphere. It s very, very hot. >> Wow. >> And that s, like i said, this halo that you see around the sun. That is actually very important-- to monitor that part of the sun-- in predicting solar storms. >> Oh. >> And solar storms affect things like satellites and our communication and our power systems. And so there are solar astronomers who are constantly monitoring the sun looking for these types of solar storms. But the corona was discovered by looking at eclipses. >> Wow. >> And in fact, it s so important that we ve launched satellites that create artificial eclipses. They put a little obstacle in the way so that we can monitor the chromosphere-- i m sorry, the corona-- at all times. >> So i guess, are they hard to predict, solar storms? >> They re getting better at it. The big thing is they need to be able to see on the far side of the sun. So we ve actually launched a couple of spacecraft called stereo, and they re now on the far side of the sun-- not totally-- they re part way around the earth s orbit, but they can see the other parts of the sun, and we can see storms developing as the sun rotates around. The sun actually rotates, also. >> Wow. So what happens if-- say there s an instance, if there s a solar storm, and it does disrupt satellite communications coverage, whatever it is. What can we expect if that were to happen? Are you talking about cell phones? Are you talking about-- what would happen here on earth? >> Well, one of the worst things we re worried about is a really, really big solar storm which could knock out power grids in certain areas. >> Wow. >> And so you could actually have power outages. >> That s heavy. >> But usually satellites, they put them in safe mode. But it can damage satellites. And as you know, telecommunications is a multi-million dollar business. >> Right. >> So there s a lot of interest in solar storms. >> But they have a safe mode to-- >> yep, that s right. >> That s amazing, okay. So they just put it in there if they see something bad coming. >> It s still dangerous, but they can put it in a safer mode. [ Laughter ] one other thing that was observed during eclipses is there s sometimes these little arcs-- they re not little-- they re bigger than the earth, but these little arcs of plasma jutting off the sun. And you ve probably seen pictures of them. They look like arches or flames coming off the sun. >> Yeah. >> They re called prominences, and they re plasma in the strong magnetic field of the sun moving through the atmosphere. And they re really quite spectacular. >> Yeah, i ve seen some images and videos of them-- they really are. It s amazing. >> Again, those were discovered by eclipses. And i ll tell you another set of experiments. It turned out that by the mid 1800s, scientists had started working out the mathematics of planets, and had noticed when a planet gets perturbed and sort of gets nudged a little bit, they said, well, that must mean another planet that s tugging on it with its gravity. And that s how neptune was discovered. They saw the perturbation in the motion of uranus. And they noticed that there was a slight perturbation in the orbit of mercury. So scientists began speculating that that was due to another planet even closer in to the sun, which they nicknamed vulcan. So what happened was they then sent-- in the 1860s and 1870s, scientists deployed around the world for some eclipses to try and look for vulcan. And they didn t find anything, which puzzled them. They looked at multiple eclipses, multiple times-- no vulcan. But in 1915, albert einstein began publishing-- began communicating his work on the general theory of relativity. And einstein had postulated that gravity is caused by the bending of spacetime. And one of his-- one of his-- one of the predictions of his theory was that you would see this perturbation of the orbit of mercury. So he explained that with his general theory of relativity. But another prediction was that this bending of spacetime would actually bend light. So he showed why there wasn t a vulcan, but then he said, if you look at an eclipse of the sun, and look at the light of stars very, very close to the disk of the sun, you should be able to see the light bent in a way that it displaces the apparent position of the star. In 1919, arthur eddington, the british astronomer, deployed for an eclipse out on an island in the atlantic ocean. And they actually measured this slight change in the apparent position of the stars. And it was a huge event, because when einstein postulated his theory of general relativity, it was crazy. It was overturning newton. And here they actually-- his prediction turned true, and that s sort of what propelled einstein into his fame, was that discovery. So that was perhaps the most important scientific discovery ever during an eclipse, was showing how the light of stars is bent by the presence of the mass of the sun. >> And that-- so it was just the mass of the sun. >> That's right. >> And there was no vulcan. >> No vulcan. [ Laughter ] although, there are two eclipse stories related, sort of quasi-related to the same thing there. >> But everything comes together, right? That s why we re-- like, going back to the general theme here, a lot of science to learn from eclipses. >> A lot of science. Let me talk about a couple things that are going on with the science this time around. >> Okay. >> We have one group that s going to have a series of telescopic cameras set up along the eclipse path. And they re going to try and take video of the inner corona, which is very difficult to see except during the eclipse. And the idea is one camera will record a little segment of the inner corona, and the next camera will record the next segment, and they can stitch them together and have a rather extended video of the corona. >> Oh. >> So for scientists who study the interaction of the corona. Another one is some other scientists are going to be studying the polarization. Some light is polarized in different directions that tells us information about the magnetic fields and other things. But they re going to be looking at the spectrum and the polarization of the-- again, the inner corona, which is difficult to measure in other ways, because it s difficult to get so close-- to measure such dim phenomena so close to the disk of the sun. >> And this is-- going back, i m sorry-- you might ve already addressed this, but these are nasa telescopes, or these are others? >> It s a variety of-- nasa s cooperating on some of these, and some of them are universities, and some of them are amateur. So it s actually a whole team of different kinds of people. >> Wow, okay. >> Nasa s helping to coordinate some of these. >> Yeah, all working together, okay. Cool. >> We ve got another group that are actually going to repeat the general theory of relativity experiment with some more modern digital equipment with more sensitive cameras to look for some very dim stars, again, to try and fine tune those measurements to see how close einstein got to the prediction. >> Wow. >> And then, we also have some radio enthusiasts who are-- during the daylight, the sun ionizes gas in the upper atmosphere and we have an ionosphere. And it, both enhances and sometimes interferes with radio communications. So these scientists are going to look at how the ionosphere changes as the sun gets eclipsed, and the sunlight starts to drop off, and then go back up again. So, they re going to observe how the ionosphere changes. >> Interesting. >> So lots of interesting experiments. And of course-- and many of these are by these amatuer citizen scientists, which is kind of a fun thing, too. >> Yeah, absolutely. So, we re measuring the earth s atmosphere, we re measuring a lot of about the sun. >> Mm-hmm. >> I know out of here, the wb-57, those high altitude planes, they re going to be flying above most of the atmosphere, about 90% of it, and they re going to take a look at the sun and study the sun s corona. >> Yeah, a bit. >> And measure how energy goes through the sun s atmosphere, but then also take a look at mercury. >> Oh, that s right. >> Yeah. >> I wanted to tell you, when you see the eclipse you will see a number of planets visible in the sky. >> Oh. >> So, if you get a chance, you ll see stars. Venus is off to the west, mars is even closer. It s-- venus is about 35 degrees to the west, mars is about 10 degrees to the west, mercury s about 10 degrees to the east, and jupiter s way over on the other side of the sky at 60 degrees to the east. And the star, regulus, which is a bright star, will be about 5 degrees to the east of the sun, so you can see if you can see that. >> And this will happen during totality, right? >> During totality, because the stars will come out. >> Wow, amazing. So you ll be able to see all of these, and you re talking about from the perspective if you re looking up and-- the sun-- >> right. >> Once it goes to totality-- and we can get to safety in a minute, but i do know, once it gets to totality you can take off your glasses for about that two minutes, right? >> That s right. Yeah. >> And then, that s when you ll be able to see all those different parts. >> Yes. >> That s really cool. >> Yeah, that s it. Let s talk a little about the history, because there s some interesting history, of course. >> Sure, yeah. >> The most famous story, which is probably legendary, but the story about a chinese astronomer, or possibly two chinese astronomers, named xi he, who was hired by the king. He was the high astronomer, the head astronomer. >> Mm-hmm. >> To make predictions about primarily with astrology to make sure that nothing bad was going to happen to the king. Well, apparently there was a solar eclipse he did not predict. >> Oh. >> And apparently, he had had a little too much to drink and he wasn t on the job when the time came. >> Oh. >> And the chinese actually thought, and a lot of ancient cultures thought, that something bad was happening. The chinese thought a dragon was swallowing the sun, and they would bang on pots and pans to scare the dragon away. And that s actually still practiced in many parts of the world, the bang on pots and pans. >> Yeah, they don t know the-- like, the science behind this total solar eclipse, so they re-- >> that s right. >> Yeah, right, go ahead. >> I think part of this tradition is passed on. >> Yeah, tradition, yeah. >> Well, unfortunately, this poor chinese astronomer that didn t do his job, he got executed. >> Oh. >> So, fortunately, we don t hold our scientists to this same level there. >> I m very thankful of that. >> Yes. >> I m sure we are. Yeah. >> But, lots of ancient people were scared of eclipses because they thought they-- i mean, it s a very amazing thing to happen in the sky and they were worried about it. It s warning of some tragedy. >> Mm-hmm. >> So early scientists in multiple cultures-- the mayans, the babylonians, the chinese-- studied eclipses and tried to understand and predict when they would occur. It turned out there was a greek by the name of thales who predicted an eclipse in 585 b.c. And this was recorded and the greek historian, herodotus, there was a big battle going on between two countries. There were the medes and the lydians, in what s now turkey. >> Hmm. >> And there was a war going on and they had lined up for battle. And they were about to do battle and suddenly there was a solar eclipse. >> Oh. >> Os, needless to say, the two generals met in the middle of the field and said, maybe we ought not to fight today. And so they drew up a peace treaty and those two countries never fought again. So just a-- >> all right. So an example of solar eclipse saving lives. >> That s right. Indeed, indeed. And so, but what happened was, a lot of these-- as people began to learn to write things down-- the babylonians on clay tablets, and the chinese court records, and the greek historians-- people began to pull together this information to understand how to predict eclipses and understand how the cycles occur. And that helped the-- that sort of spawned the whole science of astronomy. How do you-- how d the mathematics occur on these objects. >> Hmm. >> And one of the things they discovered was called the saros cycle, and this actually-- edmond halley named it the saros cycle. They didn t-- they had different names in ancient times. But what they discovered was that an eclipse will recur approximately every 6,585.3 days, which is 18 years, 11 days, and 8 hours. So it turns out that the eclipse we re about to have is part of a saros cycle that occurred-- the last one was in europe in august 11, 1999, and the next one will be in asia and the pacific one september 2nd, 2035. And it looks almost exactly the same except shifted by 8 hours around the other, 123 degrees in longitude. >> Oh. >> So these repeating cycles were how the ancients were able to predict eclipses. >> How about that. Wow. >> And it s just all the different cycles of the sun and the moon add up to this repeating cycle of eclipses. >> Interesting. >> Another thing that science that was done in ancient times was the greeks looked up at a lunar eclipse-- when we re talking about how the moon moves into the shadow of the earth. And what they discovered is when the moon is near the horizon and eclipsed the shadow of the earth is not a line, if the earth were flat. It s still round. So the greeks realized that the earth must be a sphere based on-- based on the shadow of the earth on the moon under an eclipse. >> Oh, wow. >> So that was the first scientific discovery that the earth was indeed a sphere. >> Back in the mayan-- wow, okay. >> Back in the greek times, that was. >> Oh, that was greek times. >> Yeah, it was. >> Okay, okay. Interesting. Wow! >> There s a lot of interesting history associated with eclipses. >> Absolutely. >> That-- so we ve learned a lot through history. I mean, we re talking about, yeah, the shape of the earth. We re talking about-- it stopped a battle. >> Nature of the sun, yeah. >> The nature of the sun. >> Yup. The earliest eclipse that was-- that, as far as we know, was recorded, that chinese eclipse was probably about 2000 b.c. And there was maybe the one in 2137 b.c. But, the one we re sure about was there was an eclipse recorded in the town of ugerit, or ugarit, on-- in what is now, i believe, syria. >> Hmm. >> It was may 3rd, 1375 b.c. It was recorded that the sun grew dark. >> Oh. >> So there s a number of those recorded in ancient texts and tablets. >> Okay. So, wait, so the chinese one was not recorded? It was just-- >> well, just know it s actually probably semi legendary. We re not sure. >> Got it, okay. >> But this is the one we know for sure we can date the eclipse. >> Yeah. >> And actually-- oh, that was what i was going to tell you, is we have a number of these dated eclipses-- eclipse of thales, we talked about. >> Mm-hmm. >> Eclipse in ugarit. And what happens if you just run-- if you just take your computer models and putting gravity and everything and just run the sun and moon backwards in time, it turns out the eclipse is in the wrong place. So, from that, what we ve learned is that the earth rotation very, very gradually starting to slow down. >> Hmm. >> Starting to, it s been a long time. It s mainly due to the tidal effects of the moon. It s actually dragging the earth slightly down. So it s actually in those several thousand years the earth has slowed down a little bit, a fraction of an-- a fraction of a rotation. >> Oh. >> But, keep in mind, we re talking about-- we re talking about 800,000 rotations or something like that since those times. And so, we ve-- the earth s rotation has changed just a little bit in those times. But, that s another discovery we ve made that you need that long time scale to see this very gradual slowing down of the earth s rotation. >> So, over that long period of time, you said a fraction of a day, is it like an hour? Couple of hours? >> A couple of hours i think, yeah. >> Wow. >> But, and recently, some scientists have gone back and looked at chinese records, and again, been able to fine tune that. So that s a-- that s using ancient records to fine tune some modern science, so. >> All right. Cool. Okay, so let s go to this eclipse coming up on the 21st. >> All right, do you want to talk about safety or what to expect? >> All of it. Let s do it. >> All right. All right, let s talk about-- >> however you want to start. >> Let s talk about safety a little bit. >> Okay, safety. >> Okay, everybody has heard, don t look at an eclipse, you ll go blind, right? We ve all heard that. >> Yeah. >> And i remember as a boy, puzzling and puzzling over that. What is it about an eclipse that makes it so dangerous? >> Mm-hmm. >> Well, it turns out, you don t want to stare at the sun ever. It s bad for your eyes. Your eyes are not designed to be-- handle direct sunlight for any length of time. >> I feel like it s a good general rule. >> It s a good general rule. And when our kids go outside, we say, now, kids, don t look at the sun, you ll go blind. It s true, you don t want them looking at the sun. >> Yeah, yeah. >> The reason why-- the eclipse is not any different. It s just you're more likely to stare at the sun during an eclipse because you want to see what s happening. >> Oh. >> So, this really-- there s people that think there is some sort of mysterious rays coming off the sun. The only thing is just the sun like we're normally familiar with, you just don t want to stare at it. Okay. >> Okay. >> All right, so that s the first thing. So any time the bright disk, that photosphere of the sun, any time the bright disk is visible, even just a little sliver, you really don t want to look at the sun with your unaided eye. It s dangerous. You want to keep your eye for a long -- your eyes for a long time, right? >> Yeah, i would hope so. >> But we have special-- nowadays, we have special eclipse glasses that you can get in museums and different places. >> Yeah. >> That are-- it s perfectly safe to put those on and look. By the way, don t do what i did. I was checking my eclipse glasses the other day. I looked up at the sun, i said, yeah. And i pulled the eclipse glasses off before i stopped looking at the sun, so then i had a bright blob. Just for a second, i had a bright blob in my eyes for a little while. So be careful with them. They re often made of aluminized mylar and they look-- they re kind of silvery. >> Okay. >> And also, don t put any pinholes or anything in them. That-- you want to-- you want to keep them like they are. >> Keep them-- so what are the special eclipse glasses? They have-- they re just like really intense sunglasses? Is that kind of what i think? >> Yeah, it s kind of super sunglasses. >> Okay. >> Which here s the thing, you want to avoid any homemade glasses. >> Oh. >> Don t put on multiple sunglasses or something. Don t use smoked glass, or photographic film, or neutral density filters, or anything like that. You re not sure there s enough there to block the light to make it safe. >> Okay. >> So stick with the-- with the-- with the kind that you can get. They re not very expensive and you can-- you can get them online and other places. >> Okay. >> One exception is number 14 welder s glass is safe, because that s designed also for very bright. Like the welders use. >> Oh, okay. >> All right, so that s okay. And the-- and even more important part is don t look at the sun-- don t look at the bright disk of the sun with any instruments, with telescopes or binoculars without proper filters on them, because those things actually magnify the strength of the sun. >> Ooh. They ll your-- >> and just like when i was a boy, i used to use the magnifying glass on the ants, you know? That could do that to your eye, so you need to be very, very careful. >> Yeah. >> So i would avoid-- i would avoid those, unless you have properly designed equipment. Now, don t like take your binoculars and put your sunglasses at the eyepiece, because it s so intense it could burn right through your special glasses. So there s-- be very, very careful unless you know what you re doing with binoculars and telescopes. Don t even use those. >> Right, and that s, again, that s only a two minute eclipse. >> It s only a two and a half minute at the most. >> Yeah. >> So, that s-- that little window of time during totality, after the moon has completely covered the disk of the sun-- >> mm-hmm. >> --That is the only time you can look safely without glasses. >> Okay. >> And it-- and the brightness of the-- of the eclipsed sun and the corona-- it s like the brightness of a full moon, so there s no dangerous rays. You just don t want to be staring at the sun when the sun re-emerges. So, okay. So, just good rules of thumb. >> So, when you re looking at it-- say you have the glasses on. >> Mm-hmm. >> Is there a specific amount of time that we can say is safe to have the glasses on and be looking at the moon about to cover the sun? >> Well, what s going to happen-- >> you don t want to stare at it for hours. >> No, no. Well, what you re probably looking for is as the sun-- as the very last piece of the sun starts to disappear, you ll see actually little dots that form, and those are called baily s beads. >> Hmm. >> And it s an interesting phenomena of what-- it has to do with the different brightnesses on the edge of the sun, and also the mountains on the moon. >> Mm-hmm. >> When those disappear, that s the time you can take your glasses off and-- so you don t want to be-- because that s actually tiny little pieces of the photosphere of the sun. >> Right. >> Oh, there s the other way-- if you don t have the glasses, there s some other ways you can look at-- and it s-- by the way, if you re seeing a partial eclipse, you just want to use the glasses. You don t want to look at the sun directly. >> Will you be able to see the moon partially covering the sun with the glasses? >> Yes, it ll look like a cookie with a bite taken out of it. >> How about that. That s cool. >> That s pretty cool. One method you probably heard of is a pinhole projector, and it s very easy to make. You need some opaque material, like cardboard, and you make a pinhole, and then you project onto like a white sheet of paper an image of the sun. A pinhole acts like a lens. And i think it s important, don t actually look through the pinhole with your eye. It s not intended to look inside. It s a projector. It s a little projector. >> You look at the paper. >> You look at the paper and you ll see a little image of the sun with that. And you can see the progress of the eclipse. Another method i used to do when i was in high school, is if you take a very small mirror or a large mirror with a piece of paper with a circular hole cut out, and you can reflect the image on the sun-- of the sun onto a shaded wall, and you can watch the eclipse that way. >> Oh. >> And i tell the story, i was in-- i was in history class when there was an eclipse of the sun when i was in high school, and i asked the teacher, i said, is it okay if i put this in the window and we can watch the eclipse during class time? The teacher said, okay. So we put it in the window and it put an image of the sun during the eclipse up on the ceiling. We just went along with class and you could watch the progress of the eclipse. >> All right. >> So those are-- so the mirror, there s the projector, or your glasses are the three ways to watch the eclipse. And then, the only time, again, to watch the sun-- watch the eclipse unaided is during totality, that little short period of time. >> Okay, and totality is by far the most narrow section of the u.s. >> That s right. >> So you really have to be in that spot and we-- you can go to the website eclipse2017.nasa.gov and find out exactly where that s going to be passing through. >> That s right. And it starts-- i think i started this, but it comes on the west coast. >> Oh, right. >> It arrives in oregon, it goes across oregon, idaho, wyoming, nebraska, missouri, kentucky, tennessee, south carolina. It s a nice path that goes right through the middle of the united states. >> All right. >> And it s a relatively narrow-- relatively narrow path and, of course, it s actually moving. It s a round shadow that s moving across the surface of the earth. >> Mm-hmm. >> And if you re actually anywhere in that band you will see a total eclipse. The closer you are to the center, the longer it will last. Up to a max of two and a half minutes. >> All right. >> The other thing though is the weather. >> Oh, yeah. >> Yeah. So, it turns out that what eclipse aficionados like to do is they ll look at the historical weather at that point in the u.s. At that time of year and it turns out some of the areas are more likely to have-- to have clouds than others. So it turns out, eastern oregon is a really good place. They tend to have nice clear weather at that time of year. >> Okay. >> Wyoming, nebraska, missouri, all the way to tennessee, tend to be pretty cloud free at that time of year. And then, there s another-- as it goes over the appalachians, they tend to be cloudier. And then the little section of south carolina will also have, hopefully, less clouds than other places. But again, you never know. It;s the weather. >> Yeah. Oh, yeah. >> All you can do is roll the dice and figure-- and hope that you re lucky, because if-- there have been many eclipses that people have gone-- scientists have gone specific trips to see and it s been interfered-- the weather interferes. >> Yeah, that s just-- yeah, poor luck. But that s based on data of this day over time at this place. >> That s right. How often has it been cloudy on this day at this place. >> Yeah, and so you re really rolling the dice, but playing the odds. But those based on statistical data are better off than others. >> Right. >> Very cool. Is there any particular spot during the path of totality that may be would be better? Like, for example, is it better to go to like a state park and be away from city lights or anything? Or is being in the city just as fine? >> It s just as fine. >> Okay. >> It doesn t get totality dark during an eclipse. >> Okay. >> It gets dark, but i don t think that s-- i don t think that part of it is particularly important. >> Okay. >> The main thing, it s actually much more practical, you want to be somewhere where you re close to restrooms. >> Okay. >> The eclipse itself lasts three hours and there may be a lot of traffic, so the ability to get around maybe limited. >> Ooh, yeah. >> So, just very practical things-- are you close to food> are you close to supplies? Things like that. >> Mm-hmm. >> So let s talk a little bit about what to expect. >> Yeah. >> As i said, there may be a lot of heavy traffic so you want to get to where you want to go early. >> Okay. >> And bring things that you re going to need-- your glasses-- your eclipse glasses, a camera if you re going to bring a camera, chairs, sunscreen, water, food, toilet paper, anything that you think you might need while you re on the road. >> Wow, yeah. >> I once had to evacuate here in houston during hurricane rita, and it s maybe a little bit like that and may be stuck on the road with heavy traffic if you re not careful. >> Wow! Are you talking about people stopping on the highway just to-- >> no, just talking about large numbers of people moving to see the eclipse. >> To see-- to be in the path of totality. >> If you re traveling-- for instance, i m going to be in the carolinas. >> Mm-hmm. >> And every eclipse watched on the atlantic coast is going to be headed for south carolina. >> Yeah. >> So the interstates are going to be pretty full. >> Wow. >> So just allow plenty of time. The total eclipse-- i mean, the entire eclipse lasts about three hours, so it s about an hour and a half leading up to totality and an hour and a half until the moon completely uncovers the sun. >> Okay, okay. >> But again, i-- and one of the things i thought was interesting was the eclipse veterans gave some very sage advice. They said, if this is your first eclipse, don t try to photograph it. Don t try to take telephotos of it. You ll be so worried about your camera, you ll miss the spectacular nature of the eclipse. So i think that s good advice. And so, if you re a veteran eclipse guy and you want to-- and you want to make photographs of things, that s fine. >> Yeah. >> Let the professionals do it. Just enjoy the experience. >> Yeah. >> I think that s a good idea. >> I m sure there s going to be plenty of imagery coming out from all over the u.s. >> Oh, there will. I bet there s going to be lots of selfies with people with the moon and the eclipsed sun behind them. But that s fine. >> Do you think selfies will come out, at least during totality? Maybe when it s dark enough it ll be okay. >> You may need a flash on yourself. >> Oh, okay. A flash on yourself, okay. >> A couple of suggestions to do, so a little citizen science you can do. >> Okay. >> One of them is, notice how the sky colors change. >> Hmm. >> They re very unusual colors that you don t normally see, so that s an interesting thing. Also, when there s a tree casting shadows, there are lots of little tiny holes between the leaves that act like pinhole cameras. So sometimes you can see little crescent suns during the partial eclipse on the ground. So you can look for that. It s kind of fun to take pictures of that. >> Oh, that s really cool. >> Does the temperature change? Does it feel cooler during the eclipse? Does the wind pick up or calm down during the eclipse? Just some kind of scientific things you can observe. >> Just is there-- are there things that we know of that-- what atmospheric changes in the earth? Like-- >> it will-- it does change the heating of the earth from the sun. >> Oh, it does? >> Yeah, and you will feel colder. And people actually have noticed it feels considerably cooler, which will be pleasant probably on august 21st, especially in south carolina. So just things to notice. Again, the other thing is as totality approaches observers have sometimes noticed what s called shadow bands, and these are alternating light and dark bands that quickly move across the ground, especially where you have light colored surfaces. >> Hmm. >> They occur just before totality and after totality. They re-- actually, we don t fully understand how they work. They probably have something to do with the atmosphere, the same reason the stars twinkle. But if you can see them-- sometimes they re seen, and sometimes they re not. Something to look for. >> Hmm. >> Another thing to observe is right a s the totality is beginning, there s just a tiny little sliver of the sun, and it looks very much like a diamond ring in the sky, and it s called the diamond ring effect. And that s definitely when the diamond ring occurs at the end of the eclipse. So the baily s beads-- that s the time to put your sunglasses-- your special eclipse glasses back on. >> Oh, okay. >> But, as the eclipse is about to happen you ll see the diamond ring effect, and then the diamond will go away, the baily s beads will go away, and then you ll see the full totality. And again, you can take your eclipse glasses off during totality, but be ready to put them back on. >> Yeah. >> And another thing you can look around is take a moment-- while you re enjoying the eclipse, take a moment to observe people around you. See how people react to it. >> Yeah. >> The expressions on their face. Another thing, is sometimes animals behave strangely during eclipses. >> Chicken shave been known to roost, birds behave differently. Even wasps and bees sometimes behave strangely. >> Wow. >> Cows, insect-- dogs, insects, anything you can think of that s close by, just for fun, observe and see if you notice anything. >> It is a strange and rare phenomenon to them. >> It is strange and they re confused by it. >> Yeah, yeah. >> And by the way, after totality, the whole sequence will reverse it. So you have all those sequence of things, the partial eclipse, the diamond ring, the baily s beads. >> Mm-hmm. >> And that will reverse as the moon uncovers the sun. >> Wow. Amazing. >> So if you miss this eclipse, or the weather doesn t cooperate, we have another chance in 7 years from now. >> All right. >> In 2024, there will be an eclipse that will move through texas and up through new england, and it will be another total eclipse of the sun. So we have two in a very short period of time, but it s been a long time since we ve had an eclipse. >> All right, yeah. >> So, we re due. We re due. We get two-- so, two chances, and my wife said, well, why don t we just go to the one in 7 years? And i said, well, we don t know what our lives are going to be like in 7 years. >> Yeah. >> So i said, carpe eclipsum. Seize the eclipse. So this is your chance. >> Fantastic. Yeah, no, i mean, i m-- if anything, why not both, right? >> Well, why not? We can try both. I may become an eclipse junkie, i guess. >> Yeah, yeah. No, i mean, it s so cool. And the fact that we re able to predict them, and we can go and-- we have a bunch of best practices on how you can observe the eclipse, the best that you can possibly do it. >> Yeah. >> I know, going back, just one quick thing. Well, you said early. Arrive to your destination early. >> Yeah, if you can, yes. >> How early are you-- are you talking about like days, or day, or hours? >> Well, it s difficult to arrive days early now, because virtually every hotel is booked along the eclipse path. >> Oh. >> We re going to be some distance away from the eclipse, so we re going to have to start early. The eclipse is maximum in south carolina about 2:30, so i figure if we get off at 8:00 in the morning that gives us about 6 hours to get there. And that may or may not be enough time. We ll just have to do the best we can. That was just where we-- i m staying with relatives, so that s-- >> okay. >> But, a lot of people i know have their hotel rooms booked in the-- at-- underneath the eclipse, so they can just step outside and watch it. >> Yeah, that s the-- oh, i wish i planned ahead there. That would ve been nice just get a nice, like, resort or something and just lay by the pool, watch the eclipse go by. That d be pretty cool. >> Actually, what i had originally planned-- i ve been planning for this eclipse since i was in graduate school many, many years ago. >> Wow. >> And i noticed that it would actually go through grand teton national park. And i thought, that s what i ll do. I ll go to the grand tetons and see the eclipse. But it turns out, the weather s not so-- it s a higher probability of clouds there, so i backed away from that. >> Wow. >> Good luck to those of you that-- the tetons. But that would be a beautiful photograph, actually, to see the eclipse over the grand tetons. >> Oh, absolutely. Let s keep our fingers crossed for that good weather all across the board. >> Hopefully it ll be clear all across the united states. >> Yeah. >> And everybody will be able to enjoy the eclipse. >> That would be fantastic. Well, i think that s all the time we have, unless you have one more story. But-- anything? >> I have other stories, but-- there are lots of good stories. >> Well, hey, yeah. Actually, we have a website and if you stay tuned until after the music here, we ll tell you where you can go and check out some more info on the eclipse and learn a little bit more about the history, the science, and all kinds of cool stuff, including the citizen science that mark was talking about here and how you can-- what you can do to observe some phenomena about this eclipse. So stay tuned for after the music there. Mark, thank you so much for coming on the podcast today. >> You re welcome. >> I feel like that was-- i m not going to say everything about the eclipse, because like you said, there s definitely more. But that s the-- i feel like i have a good understanding about eclipses and the science that goes behind it. So there s a lot about eclipses and a lot that we can learn just from shadows, and it s just amazing that there s so much behind it. So thanks for coming on the podcast and talking all about it. And everyone, i hope you enjoy the eclipse on the august 21st. So thanks again, mark. >> Thank you. [ Music ] >> houston, go ahead. >> I m on the space shuttle. >> Roger, zero-g and i feel fine. >> Shuttle has cleared the tower. >> We came in peace for all mankind. >> It s actually a huge honor to break the record like this. >> Not because they are easy, but because they are hard. >> Houston, welcome to space. >> Hey, thanks for sticking around. So, once again, this monday, august 21st, a total solar eclipse will sweep across america. If you want to know all the information that we have, if this podcast was not enough for you, go to eclipse2017.nasa.gov. You can find out all the science of eclipses, even more than we talked about with mark matney today, where it will be, and then how to safely view it from the ground. Just be sure to make sure that you check the glasses and make sure that they are nasa certified. After talking with mark matney after the show, we found out that the shadow itself is going to be 68 miles wide, and then that shadow travels faster than 1,000 miles per hour. So, he went back and he was trying to find the width of the shadow. It s actually a little bit smaller than you would imagine, but how fast it travels-- i mean, we re talking about some of those planes that are going to be following the shadow and studying it, they re only going to get only a few extra minutes out of it because the shadow s traveling so fast. But, if you think about it, it s the moon going around the earth, so it s probably going to be a little bit faster than you would think. Anyway, you can find out more about the eclipse by following us on social media. Obviously, our nasa accounts will be talking about this, but also here at the nasa johnson space center you can follow our accounts there. We ll be talking about it. If you follow international space station you can see some of the imagery. You ll get from there 250 miles above the earth. And then also, aries astral materials research, you ll find them on multiple accounts and you can talk-- they will be talking mostly about the science of eclipses, and they are also based here in the johnson space center. All of these are on either facebook, twitter, and instagram. If you want to join the conversation for-- and maybe submit some pictures that you are taking from wherever you re going to be observing the eclipse, and then also sort of see what everyone else is doing, the official hashtag for this event is #eclipse2017. Just use that on your favorite platform and share your experience and maybe ask a couple questions in case all of the information we told you today and anything you can t find on the website we can still answer even more questions that you have. So this podcast was recorded on july 19th, 2017. Thanks to alex perryman, john stoll, and tracy calhoun. And thanks again to dr. Mark matney for coming on the show. We ll be back next week.

Accuracy of lunar eclipse observations made by Jesuit astronomers in China.

NASA Astrophysics Data System (ADS)

Fatoohi, L. J.; Stephenson, F. R.

1996-02-01

The Jesuit astronomers observed numerous lunar eclipses at Beijing and summaries of their observations - made between 1644 and 1785 - are preserved. The various lunar eclipse measurements that the Jesuits made are compared with the results of present-day computation.

2017 Solar Eclipse Event

NASA Image and Video Library

2017-06-11

Former Spacelab 1 Mission scientist Rick Chappell views the August 21, 2017 solar eclipse with his wife. Chappell, a former associate director for science at Marshall and now a physics professor at Vanderbilt University in Nashville, joined a throng of Marshall personnel to marvel at the eclipse.

GK Dra: a delta Scuti Star in a New Eclipsing System Discovered by Hipparcos

NASA Astrophysics Data System (ADS)

Dallaporta, Sergio; Tomov, Toma; Zwitter, Tomaz; Munari, Ulisse

2002-09-01

GK Dra has been discovered by the Hipparcos mission as a 17 days eclipsing binary. We present here the first ground-based study of this star, based on extensive BV photoelectric photometry. We found a period of 9.974 days, equal depth primary and secondary eclipse (m=0.35 mag), no color variation in eclipse, and one of the components being a Sct star with an amplitude of 0.04 mag and a period of about 2.7 hours.

Determination of the Io heat flow. 1: Eclipse observations

NASA Technical Reports Server (NTRS)

Sinton, W. M.; Kaminski, C.

1983-01-01

The thermal emission from Io during eclipse by Jupiter yields data from which the total thermal flux from the volcanoes on the satellite surface can be estimated. Thermal infrared observations in spectral bands between 3.5 and 30 microns of five Io eclipse reappearances and one eclipse disappearance are reported and discussed. The thermal emission of the volcanoes which occurs almost all of the time was determined from the Io heat flux data. The thermal observations of Io are discussed with respect to previous thermophysical theories.

Properties OF M31. V. 298 eclipsing binaries from PAndromeda

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, C.-H.; Koppenhoefer, J.; Seitz, S.

2014-12-10

The goal of this work is to conduct a photometric study of eclipsing binaries in M31. We apply a modified box-fitting algorithm to search for eclipsing binary candidates and determine their period. We classify these candidates into detached, semi-detached, and contact systems using the Fourier decomposition method. We cross-match the position of our detached candidates with the photometry from Local Group Survey and select 13 candidates brighter than 20.5 mag in V. The relative physical parameters of these detached candidates are further characterized with the Detached Eclipsing Binary Light curve fitter (DEBiL) by Devor. We will follow up the detachedmore » eclipsing binaries spectroscopically and determine the distance to M31.« less

An ultraviolet investigation of the unusual eclipsing binary system FF AQR

NASA Technical Reports Server (NTRS)

Dorren, J. D.; Guinan, E. F.; Sion, E. M.

1982-01-01

A series of seven low dispersion IUE exposures in ultraviolet and wavelength regions obtained on December 6, 1981 during the eclipse of the subdwarf, during egress, and out of eclipse is analyzed. These observations and the binary phase at which they were made are shown on a schematic representation of the V-band light curve obtained in 1975. The depth in V is 0.15 mag. The circles are IUE V magnitudes from FES measures obtained during the observing run. They indicate an eclipse depth some 0.05 mag lower than expected, possibly due to difficulties with the color term in the FES calibration. The eclipse depths of Dworetsky in U, B and V were assumed in the calculations.

Interacting Winds in Eclipsing Symbiotic Systems - The Case Study of EG Andromedae

NASA Astrophysics Data System (ADS)

Calabrò, Emanuele

2014-03-01

We report the mathematical representation of the so called eccentric eclipse model, whose numerical solutions can be used to obtain the physical parameters of a quiescent eclipsing symbiotic system. Indeed the nebular region produced by the collision of the stellar winds should be shifted to the orbital axis because of the orbital motion of the system. This mechanism is not negligible, and it led us to modify the classical concept of an eclipse. The orbital elements obtained from spectroscopy and photometry of the symbiotic EG Andromedae were used to test the eccentric eclipse model. Consistent values for the unknown orbital elements of this symbiotic were obtained. The physical parameters are in agreement with those obtained by means of other simulations for this system.

Response of Cassava canopy to mid-day pseudo sunrise induced by solar eclipse.

PubMed

Latha, R; Murthy, B S

2013-07-01

Variations in CO(2) concentration over a cassava canopy were measured during a solar eclipse at Thiruvananthapuram, India. The analysis presented attempts to differentiate between the eclipse effect and the possible effect of thick clouds, taking CO(2) as a proxy for photosynthesis. CO(2) and water vapor were measured at a rate of 10 Hz, and radiation at 1 Hz, together with other meteorological parameters. A rapid reduction in CO(2) observed post-peak eclipse, due apparently to intense photosynthesis, appears similar to what happens at daybreak/post-sunrise. The increase in CO(2) (4 ppm) during peak eclipse, with radiation levels falling below the photosynthesis cut-off for cassava, indicates domination of respiration due to the light-limiting conditions.

Data Collection During the Great American Eclipse

NASA Astrophysics Data System (ADS)

Vernier, Dave

2017-12-01

I am lucky enough (and old enough) to have seen three total eclipses. About a year ago, I became aware of the total eclipse that was coming to the United States on August 21, 2017. Because I knew how exciting a total eclipse can be, I spent a lot of time encouraging people to travel to the zone of totality if they possibly could. I also encouraged teachers to turn this event into a STEM lesson by taking data. We asked teachers to join us in collecting data during the eclipse and to share it. The people collecting these data were either teachers or former teachers (like me). Many times, the sensors were mounted with duct tape and rubber bands, but we got some great data!

Response of Cassava canopy to mid-day pseudo sunrise induced by solar eclipse

NASA Astrophysics Data System (ADS)

Latha, R.; Murthy, B. S.

2013-07-01

Variations in CO2 concentration over a cassava canopy were measured during a solar eclipse at Thiruvananthapuram, India. The analysis presented attempts to differentiate between the eclipse effect and the possible effect of thick clouds, taking CO2 as a proxy for photosynthesis. CO2 and water vapor were measured at a rate of 10 Hz, and radiation at 1 Hz, together with other meteorological parameters. A rapid reduction in CO2 observed post-peak eclipse, due apparently to intense photosynthesis, appears similar to what happens at daybreak/post-sunrise. The increase in CO2 (4 ppm) during peak eclipse, with radiation levels falling below the photosynthesis cut-off for cassava, indicates domination of respiration due to the light-limiting conditions.

Reliability of the totality of the eclipse in AD 628 in Nihongi

NASA Astrophysics Data System (ADS)

Tanikawa, Kiyotaka; Soma, Mitsuru

It is generally accepted that the solar eclipse on April 10, 628 (the second day, the third month, the thirty-sixth year of Empress Suiko) recorded in Nihongi is not total but partial though it is written as a total eclipse. We argue for the record appealing to the contemporary total or near total eclipses in Chinese history books and Japanese occultation observation. If the value of the tidal term in the lunar longitude (the coefficient of T2 term) is different from the present value by about -2"/cy-2, then there disappears an apparent contradiction of ΔT around AD 600 derived from lunar and solar eclipses. Grazing occultation data are found to be useful.

ISAAC Photometric Comparison of ECLIPSE Jitter and the ORAC-DR Equivalent Recipe for ISAAC

NASA Astrophysics Data System (ADS)

Currie, M. J.

2005-12-01

Motivated by a request from astronomers demanding accurate and consistent infrared photometry, I compare the photometry and quality of mosaics generated by the ECLIPSE jitter task and the ORAC-DR JITTER_SELF_FLAT recipe in two fields. The current (v4.9.0) ECLIPSE produces photometry a few percent fainter than ORAC-DR; the systematic trend with magnitude seen in v4.4.1 is now removed. Random errors arising from poor flat-fielding are not resolved. ECLIPSE generates noisier mosaics; ORAC-DR has poorer bias removal in crowded fields and defaults to larger mosaics. ORAC-DR runs a few times slower than ECLIPSE, but its recipe development is measured in weeks, not years.

Crowd-Sourced Radio Science at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Fry, C. D.; McTernan, J. K.; Suggs, R. M.; Rawlins, L.; Krause, L. H.; Gallagher, D. L.; Adams, M. L.

2018-01-01

August 21, 2017 provided a unique opportunity to investigate the effects of the total solar eclipse on high frequency (HF) radio propagation and ionospheric variability. In Marshall Space Flight Center's partnership with the US Space and Rocket Center (USSRC) and Austin Peay State University (APSU), we engaged citizen scientists and students in an investigation of the effects of an eclipse on the mid-latitude ionosphere. Activities included fieldwork and station-based data collection of HF Amateur Radio frequency bands and VLF radio waves before, during, and after the eclipse to build a continuous record of changing propagation conditions as the moon's shadow marched across the United States. Post-eclipse radio propagation analysis provided insights into ionospheric variability due to the eclipse.

RW Per - Nodal motion changes its amplitude by 1.4 mag

NASA Technical Reports Server (NTRS)

Schaefer, Bradley E.; Fried, Robert E.

1991-01-01

RW Per was found to have large secular changes in its eclipse amplitude. In blue light, for example, the amplitude was 3.2 mag in the early 1900s, 2.2 mag in the late 1960s, and 1.75 mag in 1990. Throughout this time, the brightness at maximum was constant in all colors. It is shown that the only possible explanation is nodal motion, where the inclination varies with a period of roughly 100,000 yr. The nodal motion is caused by a third star, for which the light curve, the colors, and the O - C curve already provide evidence. Thus, RW Per is only the fourth known star with large changes of eclipse amplitude and is only the second example of nodal motion.

The PHESAT95 catalogue of observations of the mutual events of the Saturnian satellites

NASA Astrophysics Data System (ADS)

Thuillot, W.; Arlot, J.-E.; Ruatti, C.; Berthier, J.; Blanco, C.; Colas, F.; Czech, W.; Damani, M.; D'Ambrosio, V.; Descamps, P.; Dourneau, G.; Emelianov, N.; Foglia, S.; Helmer, G.; Irsmambetova, T. R.; James, N.; Laques, P.; Lecacheux, J.; Le Campion, J.-F.; Ledoux, C.; Le Floch, J.-C.; Oprescu, G.; Rapaport, M.; Riccioli, R.; Starosta, B.; Tejfel, V. G.; Trunkovsky, E. M.; Viateau, B.; Veiga, C. H.; Vu, D. T.

2001-05-01

In 1994-1996 the Sun and the Earth passed through the equatorial plane of Saturn and therefore through the orbital planes of its main satellites. During this period, phenomena involving seven of these satellites were observed. Light curves of eclipses by Saturn and of mutual eclipses and occultations were recorded by the observers of the international campaign PHESAT95 organized by the Institut de mécanique céleste, Paris, France. Herein, we report 66 observations of 43 mutual events from 16 sites. For each observation, information is given about the telescope, the receptor, the site and the observational conditions. This paper gathers together all these data and gives a first estimate of the precision providing accurate astrometric data useful for the development of dynamical models.

Methods to Secure Databases Against Vulnerabilities

DTIC Science & Technology

2015-12-01

for several languages such as C, C++, PHP, Java and Python [16]. MySQL will work well with very large databases. The documentation references...using Eclipse and connected to each database management system using Python and Java drivers provided by MySQL , MongoDB, and Datastax (for Cassandra...tiers in Python and Java . Problem MySQL MongoDB Cassandra 1. Injection a. Tautologies Vulnerable Vulnerable Not Vulnerable b. Illegal query

NASA in Silicon Valley Uses Eclipses to Study Our Galaxy

NASA Image and Video Library

2017-08-11

The August 2017 total solar eclipse seen across the United States was an epic event. However, scientists and researchers at NASA's Ames Research Center use different types of eclipses every day to learn about the mysteries of our sun and our galaxy!

Simulation of the 21 August 2017 Solar Eclipse Using the Whole Atmosphere Community Climate Model-eXtended

NASA Astrophysics Data System (ADS)

McInerney, Joseph M.; Marsh, Daniel R.; Liu, Han-Li; Solomon, Stanley C.; Conley, Andrew J.; Drob, Douglas P.

2018-05-01

We performed simulations of the atmosphere-ionosphere response to the solar eclipse of 21 August 2017 using the Whole Atmosphere Community Climate Model-eXtended (WACCM-X v. 2.0) with a fully interactive ionosphere and thermosphere. Eclipse simulations show temperature changes in the path of totality up to -3 K near the surface, -1 K at the stratopause, ±4 K in the mesosphere, and -40 K in the thermosphere. In the F region ionosphere, electron density is depleted by about 55%. Both the temperature and electron density exhibit global effects in the hours following the eclipse. There are also significant effects on stratosphere-mesosphere chemistry, including an increase in ozone by nearly a factor of 2 at 65 km. Dynamical impacts of the eclipse in the lower atmosphere appear to propagate to the upper atmosphere. This study provides insight into coupled eclipse effects through the entire atmosphere from the surface through the ionosphere.

Implications of the Secondary Eclipse of Exoplanet HAT-P-11b

NASA Technical Reports Server (NTRS)

Barry, Richard K.; Deming, L. D.; Bakos, G.; Harrington, J.; Madhusudhan, N.; Noyes, R.; Seager, S.

2010-01-01

We observed exoplanet HAT-P-11b and have successfully detected its secondary eclipse. We conducted observations using the Spitzer Space Telescope in the post-cryo mission at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Having detected the secondary eclipse, we are at present making a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b is one of only two known exo-Neptunes and has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will serve to clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. We discuss implications of these observations.

Eclipse SteerTech liquid lenslet beam steering technology

NASA Astrophysics Data System (ADS)

Westfall, Raymond T.; Rogers, Stanley; Shannon, Kenneth C., III

2007-09-01

Eclipse SteerTech TM transmissive fluid state electrowetting technology has successfully demonstrated the ability to control the shape and position of a fluid lenslet. In its final form, the technology will incorporate a dual fluid lenslet approach capable of operating in extremely high acceleration environments. The beam steering system works on the principle of electro-wetting. A substrate is covered with a closely spaced array of, independently addressable, transparent, electrically conductive pixels utilizing Eclipse's proprietary EclipseTEC TM technology. By activating and deactivating selected EclipseTEC TM pixels in the proper sequence, the shape and position of fluid lenslets or arrays of lenslets can be dynamically changed at will. The position and shape of individual fluid lenslets may be accurately controlled on any flat, simply curved, or complex curved, transparent or reflective surface. The smaller the pixels the better control of the position and shape of the fluid lenslets. Information on the successful testing of the Eclipse SteerTech TM lenslet and discussion of its use in a de-centered lenslet array will be presented.

Solar Coronal Jets Extending to High Altitudes Observed during the 2017 August 21 Total Eclipse

NASA Astrophysics Data System (ADS)

Hanaoka, Yoichiro; Hasuo, Ryuichi; Hirose, Tsukasa; Ikeda, Akiko C.; Ishibashi, Tsutomu; Manago, Norihiro; Masuda, Yukio; Morita, Sakuhiro; Nakazawa, Jun; Ohgoe, Osamu; Sakai, Yoshiaki; Sasaki, Kazuhiro; Takahashi, Koichi; Toi, Toshiyuki

2018-06-01

Coronal jets, which extend from the solar surface to beyond 2 R ⊙, were observed in the polar coronal hole regions during the total solar eclipse on 2017 August 21. In a time-series of white-light images of the corona spanning 70 minutes taken with our multi-site observations of this eclipse, six jets were found as narrow structures upwardly ejected with an apparent speed of about 450 km s‑1 in polar plumes. On the other hand, extreme-ultraviolet (EUV) images taken with the Atmospheric Image Assembly of the Solar Dynamics Observatory show that all of the eclipse jets were preceded by EUV jets. Conversely, all the EUV jets whose brightnesses are comparable to ordinary soft X-ray jets and that occurred in the polar regions near the eclipse period, were observed as eclipse jets. These results suggest that ordinary polar jets generally reach high altitudes and escape from the Sun as part of the solar wind.

Time Series Observations of the 2015 Eclipse of b Persei (not beta Persei) (Abstract)

NASA Astrophysics Data System (ADS)

Collins, D. F.

2016-06-01

(Abstract only) The bright (V = 4.6) ellipsoidal variable b Persei consists of a close non-eclipsing binary pair that shows a nearly sinusoidal light curve with a ~1.5 day period. This system also contains a third star that orbits the binary pair every 702 days. AAVSO observers recently detected the first ever optical eclipse of A-B binary pair by the third star as a series of snapshots (D. Collins, R. Zavala, J. Sanborn - AAVSO Spring Meeting, 2013); abstract published in Collins, JAAVSO, 41, 2, 391 (2013); b Per mis-printed as b Per therein. A follow-up eclipse campaign in mid-January 2015 recorded time-series observations. These new time-series observations clearly show multiple ingress and egress of each component of the binary system by the third star over the eclipse duration of 2 to 3 days. A simulation of the eclipse was created. Orbital and some astrophysical parameters were adjusted within constraints to give a reasonable fit to the observed light curve.

An Atlas of Far-ultraviolet Spectra of the Zeta Aurigae Binary 31 Cygni with Line Identifications

NASA Astrophysics Data System (ADS)

Hagen Bauer, Wendy; Bennett, Philip D.

2014-04-01

The ζ Aurigae system 31 Cygni (K4 Ib + B4 V) was observed by the FUSE satellite during total eclipse and at three phases during chromospheric eclipse. We present the coadded, calibrated spectra and atlases with line identifications. During total eclipse, emission from high ionization states (e.g., Fe III and Cr III) shows asymmetric profiles redshifted from the systemic velocity, while emission from lower ionization states (e.g., Fe II and O I) appears more symmetric and is centered closer to the systemic velocity. Absorption from neutral and singly ionized elements is detected during chromospheric eclipse. Late in chromospheric eclipse, absorption from the K star wind is detected at a terminal velocity of ~80 km s-1. These atlases will be useful for interpreting the far-UV spectra of other ζ Aur systems, as the observed FUSE spectra of 32 Cyg, KQ Pup, and VV Cep during chromospheric eclipse resemble that of 31 Cyg.

1-D DSMC simulation of Io's atmospheric collapse and reformation during and after eclipse

NASA Astrophysics Data System (ADS)

Moore, C. H.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.; Stewart, B.

2009-06-01

A one-dimensional Direct Simulation Monte Carlo (DSMC) model is used to examine the effects of a non-condensable species on Io's sulfur dioxide sublimation atmosphere during eclipse and just after egress. Since the vapor pressure of SO 2 is extremely sensitive to temperature, the frost-supported dayside sublimation atmosphere had generally been expected to collapse during eclipse as the surface temperature dropped. For a pure SO 2 atmosphere, however, it was found that during the first 10 min of eclipse, essentially no change in the atmospheric properties occurs at altitudes above ˜100 km due to the finite ballistic/acoustic time. Hence immediately after ingress the auroral emission morphology above 100 km should resemble that of the immediate pre-eclipse state. Furthermore, the collapse dynamics are found to be greatly altered by the presence of even a small amount of a non-condensable species which forms a diffusion layer near the surface that prevents rapid collapse. It is found that after 10 min essentially no collapse has occurred at altitudes above ˜20 km when a nominal mole fraction of non-condensable gas is present. Collapse near the surface occurs relatively quickly until a static diffusion layer many mean free paths thick of the non-condensable gas builds up which then retards further collapse of the SO 2 atmosphere. For example, for an initial surface temperature of 110 K and 35% non-condensable mole-fraction, the ratio of the SO 2 column density to the initial column density was found to be 0.73 after 10 min, 0.50 after 30 min, and 0.18 at the end of eclipse. However, real gas species (SO, O 2) may not be perfectly non-condensable at Io's surface temperatures. If the gas species was even weakly condensable (non-zero sticking/reaction coefficient) then the effect of the diffusion layer on the dynamics was dramatically reduced. In fact, if the sticking coefficient of the non-condensable exceeds ˜0.25, the collapse dynamics are effectively the same as if there were no non-condensable present. This sensitivity results because the loss of non-condensable to the surface reduces the effective diffusion layer size, and the formation of an effective diffusion layer requires that the layer be stationary; this does not occur if the surface is a sink. Upon egress, vertical stratification of the condensable and non-condensable species occurs, with the non-condensable species being lifted (or pushed) to higher altitudes by the sublimating SO 2 after the sublimating atmosphere becomes collisional. Stratification should affect the morphology and intensity of auroral glows shortly after egress.

Lysinibacillus louembei sp. nov., a spore-forming bacterium isolated from Ntoba Mbodi, alkaline fermented leaves of cassava from the Republic of the Congo.

PubMed

Ouoba, Labia Irène I; Vouidibio Mbozo, Alain B; Thorsen, Line; Anyogu, Amarachukwu; Nielsen, Dennis S; Kobawila, Simon C; Sutherland, Jane P

2015-11-01

Investigation of the microbial diversity of Ntoba Mbodi, an African food made from the alkaline fermentation of cassava leaves, revealed the presence of a Gram-positive, catalase-positive, aerobic, motile and rod-shaped endospore-forming bacterium (NM73) with unusual phenotypic and genotypic characteristics. The analysis of the 16S rRNA gene sequence revealed that the isolate was most closely related to Lysinibacillus meyeri WS 4626T (98.93%), Lysinibacillus xylanilyticus XDB9T (96.95%) and Lysinibacillus odysseyi 34hs-1T (96.94%). The DNA-DNA relatedness of the isolate with L. meyeri LMG 26643T, L. xylanilyticus DSM 23493T and L. odysseyi DSM 18869T was 41%, 16% and 15%, respectively. The internal transcribed spacer-PCR profile of the isolate was different from those of closely related bacteria. The cell-wall peptidoglycan type was A4α, L-Lys-D-Asp and the major fatty acids were iso-C15:0, anteiso-C15:0, anteiso-C17:0 and iso-C17:0 and iso-C17:1ω10c. The polar lipids included phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphoaminolipid, aminolipid, two phospholipids and two unknown lipids. The predominant menaquinones were MK-7 and MK-6. Ribose was the only whole-cell sugar detected. The DNA G+C content was 38 mol%. Based on the results of the phenotypic and genotypic characterization, it was concluded that the isolate represents a novel species of the genus Lysinibacillus, for which the name of Lysinibacillus louembei sp. nov. is proposed. NM73T ( = DSM 25583T = LMG 26837T) represents the type strain.

Nationwide Eclipse Ballooning Project

NASA Astrophysics Data System (ADS)

Colman Des Jardins, Angela; Berk Knighton, W.; Larimer, Randal; Mayer-Gawlik, Shane; Fowler, Jennifer; Harmon, Christina; Koehler, Christopher; Guzik, Gregory; Flaten, James; Nolby, Caitlin; Granger, Douglas; Stewart, Michael

2016-05-01

The purpose of the Nationwide Eclipse Ballooning Project is to make the most of the 2017 rare eclipse event in four main areas: public engagement, workforce development, partnership development, and science. The Project is focused on two efforts, both student-led: online live video of the eclipse from the edge of space and the study of the atmospheric response to the eclipse. These efforts, however, involving more than 60 teams across the US, are challenging in many ways. Therefore, the Project is leveraging the NASA Space Grant and NOAA atmospheric science communities to make it a success. The first and primary topic of this poster is the NASA Space Grant supported online live video effort. College and high school students on 48 teams from 31 states will conduct high altitude balloon flights from 15-20 locations across the 8/21/2017 total eclipse path, sending live video and images from near space to a national website. Video and images of a total solar eclipse from near space are fascinating and rare. It’s never been done live and certainly not in a network of coverage across a continent. In addition to the live video to the web, these teams are engaged in several other science experiments as secondary payloads. We also briefly highlight the eclipse atmospheric science effort, where about a dozen teams will launch over one hundred radiosondes from across the 2017 path, recording an unprecedented atmospheric data sample. Collected data will include temperature, density, wind, humidity, and ozone measurements.

Preparing for the Eclipse

ERIC Educational Resources Information Center

Hurst, Anna; Plummer, Julia; Gurton, Suzanne; Schatz, Dennis

2017-01-01

On August 21, 2017, sky gazers all across North America will experience a total solar eclipse, arguably the most breathtaking of all astronomical phenomena. The August eclipse is an ideal astronomical event to observe with young children because it allows them to observe a powerful and easily accessible astronomical phenomenon. Observing…

VizieR Online Data Catalog: Parameters of 529 Kepler eclipsing binaries (Kjurkchieva+, 2017)

NASA Astrophysics Data System (ADS)

Kjurkchieva, D.; Vasileva, D.; Atanasova, T.

2017-11-01

We reviewed the Kepler eclipsing binary catalog (Prsa et al. 2011, Cat. J/AJ/141/83; Slawson et al. 2011, Cat. J/AJ/142/160; Matijevic et al. 2012) to search for detached eclipsing binaries with eccentric orbits. (5 data files).

A possible additional body in eclipsing binary system HS 2231+2441

NASA Astrophysics Data System (ADS)

Vidmachenko, A. P.; Shliakhetska, Ya. O.; Romanyuk, Ya. O.

2016-12-01

Analysis of the light curves of eclipsing binary systems HS 2231+2441, obtained with the 36-cm telescope, is made. In processing the photometric data on eclipses by method of timing, obtained evidence for the existence of a third body in the system.

Monitoring HD 148703 during upcoming eclipses

NASA Astrophysics Data System (ADS)

Waagen, Elizabeth O.

2017-06-01

Dr. Milena Ratajczak (University of Wrocław) has requested AAVSO observers' assistance in monitoring the very bright (V = 4.23) and very unusual eclipsing binary HD 148703 (HR 6143, N Sco) during its infrequent primary and secondary eclipses scheduled for 2017 June 11 and June 14, respectively. Dr. Ratajczak writes: "[HD 148703] N Sco is a B-type detached eclipsing binary, which turned out to be an exceptionally interesting object to study when we realised its orbital period is 223 days and time between eclipses is only 3.5 days. Such configuration makes it an extremely eccentric system, probably the most eccentric from any objects of that class ever studied...Since the object is very bright, it's difficult to use professional photometric telescopes due to saturation issues. That is why we kindly invite amateur astronomers to join the campaign. Data taken during times of eclipses (photometry) and time between eclipses (radial velocities from spectroscopy) which occur next week are crucial to cover in order to determine orbital and stellar parameters of system's components. Data taken over that time will be of very high value for us." The next primary eclipse time of minimum is on 2017 June 11 (UT 00:41:45), and the secondary on June 14 (UT 09:17:34). Each eclipse lasts about 20 hours. The amplitude of the primary eclipse is 0.15 magnitude, and the secondary 0.35 mag. PEP V and DSLR V photometry is requested. (CCD V is welcome if saturation can be avoided.) Beginning immediately, one to a few snapshots each night are requested to establish an out-of-eclipse baseline for each observer; they should continue for a few nights after the secondary eclipse has occurred.Time series photometry is requested beginning 12 hours before each time of minimum and continuing until 12 hours after. Precision to 0.01 mag or better per single observation is needed. Exposures should be as long as possible without saturating; don't make very short exposures simply for the purpose of gathering more data points. B or Ic data would also be useful; B is preferred to Ic. If imaging in more than one filter, please make five V observations for each B or Ic.Visual observations are also welcome. For spectroscopy now through June 20, resolution of at least a few thousands is needed. Coordinates: RA = 16 31 22.93 Dec = -34 42 15.7 (2000.0). Finder charts may be created and data from the AAVSO International Database may be viewed, plotted, or downloaded (www.aavso.org).

Communicating Solar System as experienced on March 29 TSE

NASA Astrophysics Data System (ADS)

Stavinschi, M.

The Earth becomes increasingly known as we explore the Solar System. The more answers we find on exoplanets, for instance, the better we know our planet. We discover many enigmas in the outer space and, surprisingly, solving them may lead to a higher perception of the land we are pacing. We must be aware of science news that means communicating valuable information to the public. As a consequence, a higher level of collaboration between scientists and science journalists is necessary. An informed and clever audience depends on their results. Our comment is focused on outreach of the last Total Solar Eclipse, from March 29 2006, an astronomical event that gathered around the same idea professional astronomers, and science journalists. Furthermore, even a cake shop has been involved and made for commercialization mini-eclipses cakes. If we cannot deliver the taste of the pastry, the free download soundtrack `Nobody Steals the Sun' may give the general public a sense of what is happening before, during, and after a solar eclipse. The Romanians witnessed different spectacular astronomical events such as the 1999 total solar eclipse and Venus transit. However, the latest TSE gives us a greater opportunity to find new ways of communicating the beauty of science to the public and to inform people about the Solar System. Even the eclipse doesn't happened on the Romanian territory, we managed to form mixed groups of professional and amateur astronomers, ordinary people and journalists, which traveled to Turkey for watching the eclipse. Most of them traveled by coach and had the opportunity to meet beautiful landscapes and know their history, and last but not in the least, to make friends. There were discussions from the scientific point of view that mixed with the curiosity of the participants. Moreover, sessions of popularizing the Sun and phenomenon among locals in different towns were such successful that the Turkish media - newspaper and TV - mentioned it. Scientists lectured at the national conference of Turkish physics teachers. Among the interviews, newspaper articles and radio programs given by professional astronomers there was an interesting musical experiment. It brought together a scientist, a composer and a science journalist. A young and talented composer wrote `Nobody Steals the Sun' soundtrack on the supervision of a professional astronomer. Based on an idea of a science journalist, C? t? lin Mosoia, and supervised by a professional astronomer, PhD Magda Stavinschi, the work of the Romanian composer Cristian Matei was produced taking into account the most important moments of a total eclipse of the Sun and its duration. Composed for non-commercial purposes only, it may be downloaded from the Astronomical Institute of the Romanian Academy website www.astro.ro. 2

What does C II lambda 2325 A emission tell us about chromospheres of red supergiants? - A critical test using Zeta Aurigae-type K supergiants

NASA Technical Reports Server (NTRS)

Schroeder, K.-P.; Reimers, D.; Carpenter, K. G.; Brown, A.

1988-01-01

The limitations of the Carpenter et al. (1985) C II intercombination multiplet method of determining the density and geometric extent of red giant chromospheres are presently tested through observation of the C II 2325 A emission of two K-type supergiants whose empirical model chromospheres have been derived by high-resolution IUE observations at eclipse phases. While the observed C II emission fluxes are well reproduced, much of this emission originates in the high-density lower chromosphere.

The Optical Gravitational Lensing Experiment. Catalog of RR Lyr Stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Soszynski, I.; Udalski, A.; Szymanski, M.; Kubiak, M.; Pietrzynski, G.; Wozniak, P.; Zebrun, K.; Szewczyk, O.; Wyrzykowski, L.

2003-06-01

We present the catalog of RR Lyr stars discovered in a 4.5 square degrees area in the central parts of the Large Magellanic Cloud (LMC). Presented sample contains 7612 objects, including 5455 fundamental mode pulsators (RRab), 1655 first-overtone (RRc), 272 second-overtone (RRe) and 230 double-mode RR Lyr stars (RRd). Additionally we attach alist of several dozen other short-period pulsating variables. The catalog data include astrometry, periods, BVI photometry, amplitudes, and parameters of the Fourier decomposition of the I-band light curve of each object. We present density map of RR Lyr stars in the observed fields which shows that the variables are strongly concentrated toward the LMC center. The modal values of the period distribution for RRab, RRc and RRe stars are 0.573, 0.339 and 0.276 days, respectively. The period-luminosity diagrams for BVI magnitudes and for extinction insensitive index W_I are constructed. We provide the log P-I, log P-V and log P-W_I relations for RRab, RRc and RRe stars. The mean observed V-band magnitudes of RR Lyr stars in the LMC are 19.36 mag and 19.31 mag for ab and c types, respectively, while the extinction free values are 18.91 mag and 18.89 mag. We found a large number of RR Lyr stars pulsating in two modes closely spaced in the power spectrum. These stars are believed to exhibit non-radial pulsating modes. We discovered three stars which simultaneously reveal RR Lyr-type and eclipsing-type variability. If any of these objects were an eclipsing binary system containing RR Lyr star, then for the first time the direct determination of the mass of RR Lyr variable would be possible. We provide a list of six LMC star clusters which contain RR Lyr stars. The richest cluster, NGC 1835, hosts 84 RR Lyr variables. The period distribution of these stars suggests that NGC1835 shares features of Oosterhoff type I and type II groups. All presented data, including individual BVI observations and finding charts are available from the OGLE Internet archive.

Practical comparison of 2.7 microm fused-core silica particles and porous sub-2 microm particles for fast separations in pharmaceutical process development.

PubMed

Abrahim, Ahmed; Al-Sayah, Mohammad; Skrdla, Peter; Bereznitski, Yuri; Chen, Yadan; Wu, Naijun

2010-01-05

Fused-core silica stationary phases represent a key technological advancement in the arena of fast HPLC separations. These phases are made by fusing a 0.5 microm porous silica layer onto 1.7 microm nonporous silica cores. The reduced intra-particle flow path of the fused particles provides superior mass transfer kinetics and better performance at high mobile phase velocities, while the fused-core particles provide lower pressure than sub-2 microm particles. In this work, chromatographic performance of the fused-core particles (Ascentis Express) was investigated and compared to that of sub-2 microm porous particles (1.8 microm Zorbax Eclipse Plus C18 and 1.7 microm Acquity BEH C18). Specifically, retention, selectivity, and loading capacity were systematically compared for these two types of columns. Other chromatographic parameters such as efficiency and pressure drop were also studied. Although the fused-core column was found to provide better analyte shape selectivity, both columns had similar hydrophobic, hydrogen bonding, total ion-exchange, and acidic ion-exchange selectivities. As expected, the retention factors and sample loading capacity on the fused-core particle column were slightly lower than those for the sub-2 microm particle column. However, the most dramatic observation was that similar efficiency separations to the sub-2 microm particles could be achieved using the fused-core particles, without the expense of high column back pressure. The low pressure of the fused-core column allows fast separations to be performed routinely on a conventional LC system without significant loss in efficiency or resolution. Applications to the HPLC impurity profiling of drug substance candidates were performed using both types of columns to validate this last point.

H‑ Opacity and Water Dissociation in the Dayside Atmosphere of the Very Hot Gas Giant WASP-18b

NASA Astrophysics Data System (ADS)

Arcangeli, Jacob; Désert, Jean-Michel; Line, Michael R.; Bean, Jacob L.; Parmentier, Vivien; Stevenson, Kevin B.; Kreidberg, Laura; Fortney, Jonathan J.; Mansfield, Megan; Showman, Adam P.

2018-03-01

We present one of the most precise emission spectra of an exoplanet observed so far. We combine five secondary eclipses of the hot Jupiter WASP-18b (T day ∼ 2900 K) that we secured between 1.1 and 1.7 μm with the Wide Field Camera 3 instrument on board the Hubble Space Telescope. Our extracted spectrum (S/N = 50, R ∼ 40) does not exhibit clearly identifiable molecular features but is poorly matched by a blackbody spectrum. We complement this data with previously published Spitzer/Infrared Array Camera observations of this target and interpret the combined spectrum by computing a grid of self-consistent, 1D forward models, varying the composition and energy budget. At these high temperatures, we find there are important contributions to the overall opacity from H‑ ions, as well as the removal of major molecules by thermal dissociation (including water), and thermal ionization of metals. These effects were omitted in previous spectral retrievals for very hot gas giants, and we argue that they must be included to properly interpret the spectra of these objects. We infer a new metallicity and C/O ratio for WASP-18b, and find them well constrained to be solar ([M/H] = ‑0.01 ± 0.35, C/O < 0.85 at 3σ confidence level), unlike previous work but in line with expectations for giant planets. The best-fitting self-consistent temperature–pressure profiles are inverted, resulting in an emission feature at 4.5 μm seen in the Spitzer photometry. These results further strengthen the evidence that the family of very hot gas giant exoplanets commonly exhibit thermal inversions.

Thermal vacuum real-life test of an Marconi Space and Defence Systems (MSDS) solar-array drive mechanism (MSDS 002). First four years of operation

NASA Astrophysics Data System (ADS)

Parker, K.; Douglas, A.; Burke, W. R.

1981-01-01

The first part of a 7 yr life test on a mechanism which turns a satellite solar array at 1rev/day is reported. A thermal transfer shroud, surrounding the mechanism in a vacuum chamber, is held at a constant temperature of 22.5 C while the shaft temperature, measured near the top of the shaft at the large bearing, is changed at 6-monthly intervals so that it operates alternately at 60 and 10 C. At the beginning of each 6-monthly cycle, 30 eclipse simulations are performed, i.e., the shaft temperature is reduced from 60 C to 0 C in 72 min and is returned to 60 C in as short a time as possible. Apart from a very small increase in motor power during eclipse simulation, no changes in the mechanism parameters occur with temperature. The mechanism operates within motor power and angular rotation accuracy specifications. The electrical noise on all slip rings increased during the first two years, but then slowly decreased. Certain slip ring pairs show a noise level in excess of the arbitrary limits set at the start of the test, and two slip ring pairs give large periodic noise transients which may be due to mechanical damage to the slip rings or brushes.

Paper Moon: Simulating a Total Solar Eclipse

ERIC Educational Resources Information Center

Madden, Sean P.; Downing, James P.; Comstock, Jocelyne M.

2006-01-01

This article describes a classroom activity in which a solar eclipse is simulated and a mathematical model is developed to explain the data. Students use manipulative devices and graphing calculators to carry out the experiment and then compare their results to those collected in Koolymilka, Australia, during the 2002 eclipse.

2017 Solar Eclipse, Ames Research Center

NASA Image and Video Library

2017-08-21

Taking a break from his duties at the Ames Vertical Gun Range to look up at the eclipse over Ames Research Center in Mountain View Adam Parrish not only views but wears, on his forehead, the image of the 2017 Solar eclipse at 09:20:56 on August 21, 2017.

2017 Solar Eclipse Event

NASA Image and Video Library

2017-06-11

Former Spacelab 1 mission scientist Rick Chappell addresses Marshall team members during the Aug. 21 eclipse-watching event in Activities Building 4316. Chappell, a former associate director for science at Marshall and now a physics professor at Vanderbilt University in Nashville, joined a throng of Marshall personnel to marvel at the eclipse.

Observing the 2017 Total Solar Eclipse from the Pisgah Astronomical Research Institute

NASA Astrophysics Data System (ADS)

Kirwan, Sean Matthew; Cline, J. Donald; Krochmal, Mark; Donald Cline, Mark Krochmal

2017-01-01

The Pisgah Astronomical Research Institute (PARI) is located directly under the path of totality of next year’s solar eclipse and possesses two 26m radio telescopes capable of interferometry at simultaneously at 2.3 GHz and 8.4 GHZ. PARI is preparing these radio telescopes for use by the astronomical community to observe solar eclipse. We will present the status of PARI’s radio telescopes and information on access for the eclipse. We will also present the status and availability of several optical telescopes.

Total Solar Eclipse: “Through The Eyes of NASA,” Part 4

NASA Image and Video Library

2017-08-21

During the eclipse, 14 states across the U.S. were in the path of totality and experienced more than two minutes of darkness in the middle of the day – with a partial eclipse viewable all across North America. The broadcast – Eclipse Across America: Through the Eyes of NASA – covered locations along the path of totality, from Oregon to South Carolina including public reactions from all ages. The eclipse’s long path over land provided a unique opportunity to study the Sun, Earth, Moon and their interaction.

Total Solar Eclipse: “Through The Eyes of NASA,” Part 3

NASA Image and Video Library

2017-08-21

During the eclipse, 14 states across the U.S. were in the path of totality and experienced more than two minutes of darkness in the middle of the day – with a partial eclipse viewable all across North America. The broadcast – Eclipse Across America: Through the Eyes of NASA – covered locations along the path of totality, from Oregon to South Carolina including public reactions from all ages. The eclipse’s long path over land provided a unique opportunity to study the Sun, Earth, Moon and their interaction.

A Smoothed Eclipse Model for Solar Electric Propulsion Trajectory Optimization

NASA Technical Reports Server (NTRS)

Aziz, Jonathan D.; Scheeres, Daniel J.; Parker, Jeffrey S.; Englander, Jacob A.

2017-01-01

Solar electric propulsion (SEP) is the dominant design option for employing low-thrust propulsion on a space mission. Spacecraft solar arrays power the SEP system but are subject to blackout periods during solar eclipse conditions. Discontinuity in power available to the spacecraft must be accounted for in trajectory optimization, but gradient-based methods require a differentiable power model. This work presents a power model that smooths the eclipse transition from total eclipse to total sunlight with a logistic function. Example trajectories are computed with differential dynamic programming, a second-order gradient-based method.