Science.gov

Sample records for allstars star lick

  1. NASA Exhibit at the NBA All-Star Jam Session

    NASA Image and Video Library

    2006-02-18

    JSC2006-E-04816 (18 Feb. 2006) --- Astronauts Joan Higginbotham and Robert L. Satcher Jr. autograph portraits for an attendee at the NBA All-Star Jam Session in Houston's central business district. The autograph table was part of NASA's exhibit at the event.

  2. After-School All-Stars: Providing Structured Health and Physical Activity Programs in Urban Environments

    ERIC Educational Resources Information Center

    Thompson, Walter R.

    2009-01-01

    Physical education time has been reduced or even eliminated in middle and high schools in favor of more time for standardized test preparation, especially in urban schools and inner cities. One way to replace the time lost is by providing it after school as part of a comprehensive program. After-School All-Stars (ASAS) is such a program, networked…

  3. Measurements of the Lick Observatory Sodium Laser Guide Star

    SciTech Connect

    Gavel, D. T., LLNL

    1998-03-01

    The Lick Observatory guide star laser has provided a beacon sufficient to close the adaptive optics loop and produce corrected images during runs in 1996 and 1997. This report summarizes measurements of the wavefront quality of the outgoing beam, photoreturn signal from the sodium beacon, and radiance distribution of the guide star on the sky, and follows with an analysis of the impact of the laser on adaptive optics system performance.

  4. Planets around Giant Stars: Results from the Lick Survey

    NASA Astrophysics Data System (ADS)

    Quirrenbach, Andreas; Reffert, Sabine; Trifonov, Trifon; Bergmann, Christoph; Schwab, Christian

    2015-12-01

    We present results from a radial-velocity survey of 373 giant stars at Lick Observatory, which started in 1999. We have detected planets around 15 of these stars; an additional 20 stars host planet candidates. Companions with up to 25 Jupiter masses are rather commonly found around stars with about 2 Solar masses. The frequency of detected planetary companions appears to increase with metallicity. No planets or planet candidates are found around stars with more than 2.7 Solar masses, although our sample contains 113 such stars. We conclude that the occurrence rate of giant planets as a function of Stellar mass peaks around 2 Solar masses. This has important consequences for our understanding of giant planet formation.The stars 91 Aqr and tau Gem have companions with orbits that are among those with the lowest eccentricities of all known exoplanets, perhaps due to tidal circularization during the RGB phase. If confirmed, this would be the first evidence of planetary orbits modified through stellar evolution.We have discovered several multiple systems in our sample. An extensive dynamical analysis of the eta Cet system indicates that it contains two massive planets in a 2:1 orbital resonance. The star nu Oph is orbited by two brown dwarf companions in a 6:1 resonance. It is likely that they arrived in this resonance through migration in a circumstellar disk, arguing strongly that objects with more than 20 Jupiter masses can be formed in disks around Herbig Ae stars.

  5. Adaptive optics and laser guide stars at Lick observatory

    SciTech Connect

    Brase, J.M.

    1994-11-15

    For the past several years LLNL has been developing adaptive optics systems for correction of both atmospheric turbulence effects and thermal distortions in optics for high-power lasers. Our early work focused on adaptive optics for beam control in laser isotope separation and ground-based free electron lasers. We are currently developing innovative adaptive optics and laser systems for sodium laser guide star applications at the University of California`s Lick and Keck Observeratories. This talk will describe our adaptive optics technology and some of its applications in high-resolution imaging and beam control.

  6. Science with laser guide stars at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Gavel, Donald T.; Max, Claire E.; Olivier, Scot S.; Bauman, Brian J.; Pennington, Deanna M.; Macintosh, Bruce A.; Patience, Jennifer; Brown, Curtis G.; Danforth, Pamela M.; Hurd, Randall L.; Gates, Elinor L.; Severson, Scott A.; Lloyd, James P.

    2002-02-01

    The Lick Observatory laser guide star adaptive optics system has been significantly upgraded over the past two years in order to establish it as a facility science instrument on the Shane 3 meter telescope. Natural Guide Star (NGS) mode has been in use in regular science observing programs for over a year. The Laser Guide Star (LGS) mode has been tested in engineering runs and is now starting to do science observing. In good seeing conditions, the system produces K-band Strehl ratios >0.7 (NGS) and >0.6 (LGS). In LGS mode tip/tilt guiding is achieved with a V~16 natural star anywhere inside a 1 arcminute radius field, which provides about 50% sky coverage. This enables diffraction-limited imaging of regions where few bright guidestars suitable for NGS mode are available. NGS mode requires at least a V~13 guidestar and has a sky coverage of <1%. LGS science programs will include high resolution studies of galaxies, active galactic nuclei, QSO host galaxies and dim pre-main sequence stars.

  7. Performance of laser guide star adaptive optics at Lick Observatory

    SciTech Connect

    Olivier, S.S.; An, J.; Avicola, K.

    1995-07-19

    A sodium-layer laser guide star adaptive optics system has been developed at Lawrence Livermore National Laboratory (LLNL) for use on the 3-meter Shane telescope at Lick Observatory. The system is based on a 127-actuator continuous-surface deformable mirror, a Hartmann wavefront sensor equipped with a fast-framing low-noise CCD camera, and a pulsed solid-state-pumped dye laser tuned to the atomic sodium resonance line at 589 nm. The adaptive optics system has been tested on the Shane telescope using natural reference stars yielding up to a factor of 12 increase in image peak intensity and a factor of 6.5 reduction in image full width at half maximum (FWHM). The results are consistent with theoretical expectations. The laser guide star system has been installed and operated on the Shane telescope yielding a beam with 22 W average power at 589 nm. Based on experimental data, this laser should generate an 8th magnitude guide star at this site, and the integrated laser guide star adaptive optics system should produce images with Strehl ratios of 0.4 at 2.2 {mu}m in median seeing and 0.7 at 2.2 {mu}m in good seeing.

  8. Documentation for the machine-readable version of the Lick Jupiter-Voyager Reference Star Catalogue

    NASA Technical Reports Server (NTRS)

    Warren, W. H., Jr.

    1982-01-01

    A machine-readable version is described of the Lick Jupiter-Voyager Reference Star Catalogue (Klemola, Morabito Taraji 1978) prepared for purposes of determining up-to-date, reasonably accurate, equatorial coordinates for reference stars in a band of sky against which cameras of the Voyager spacecraft were aligned for observations of Jovian satellites during the flyby.

  9. The Orion Radio All-Stars: extreme YSO radio and X-ray variability

    NASA Astrophysics Data System (ADS)

    Forbrich, Jan

    2017-05-01

    The sensitivity upgrades of both the NRAO Very Large Array (VLA) and the NRAO Very Long Baseline Array (VLBA) have begun to provide us with a much improved perspective on stellar centimeter radio emission, particularly concerning young stellar objects (YSOs) and ultracool dwarfs. I will mainly present a deep VLA and VLBA radio survey of the Orion Nebula Cluster (ONC), where we have found 556 compact radio sources, a sevenfold increase over previous studies, and intricate detail on the radio emission of proplyds. We can now better disentangle thermal and nonthermal radio emission by assessing spectral indices, polarization, variability, and brightness temperatures (VLBA). With simultaneous radio-X-ray time domain information (Chandra), this project is providing unprecedented constraints on the magnetospheric activity of YSOs across a wide mass range, including the massive Trapezium stars and their impact on the interstellar medium. A particular focus of this talk will be the occurrence of radio flares in Orion and their correlation with X-ray flares. Starting with our ongoing Orion observations, I will additionally discuss the use of the VLBA for precision stellar astrometry in the Gaia era, highlighting how VLBI astrometry is allowing us to extend the Gaia sample of YSOs and ultracool dwarfs by including embedded objects, distant obscured sources in the Galactic plane, and faint ultracool dwarfs, while providing important opportunities for astrometric cross-calibration.

  10. Laser Guide Star Based Astrophysics at Lick Observatory

    SciTech Connect

    Max, C; Gavel, D.; Friedman, H.; Olivier, S.; Macintosh, B.; Brase, J.; Avicola, K.; Gibbard, S.; An, J.

    2000-03-10

    The resolution of ground-based telescopes is typically limited to {approx}1 second of arc because of the blurring effects of atmospheric turbulence. Adaptive optics (AO) technology senses and corrects for the optical distortions due to turbulence hundreds of times per second using high-speed sensors, computers, deformable mirror, and laser technology. The goal of this project is to make AO systems widely useful astronomical tools providing resolutions up to an order of magnitude better than current, ground-based telescopes. Astronomers at the University of California Lick Observatory at Mt. Hamilton now routinely use the LLNL developed AO system for high resolution imaging of astrophysical objects. We report here on the instrument development progress and on the science observations made with this system during this 3-year ERI project.

  11. Improved performance of the laser guide star adaptive optics system at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Olivier, Scot S.; Gavel, Donald T.; Friedman, Herbert W.; Max, Claire E.; An, Jong R.; Avicola, Kenneth; Bauman, Brian J.; Brase, James M.; Campbell, Eugene W.; Carrano, Carmen J.; Cooke, Jeffrey B.; Freeze, Gary J.; Gates, Elinor L.; Kanz, Vernon K.; Kuklo, Thomas C.; Macintosh, Bruce A.; Newman, Michael J.; Pierce, Edward L.; Waltjen, Kenneth E.; Watson, James A.

    1999-09-01

    Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2 micrometers were corrected to over 40 percent of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to approximately 10 percent of the theoretical peak intensity limit. After a campaign to improve the beam quality of the laser system, and to improve calibration accuracy and stability of the adaptive optics system using new techniques for phase retrieval and phase-shifting diffraction interferometry, the system performance has been substantially increased. The next step will be to use the Lick system for astronomical science observations, and to demonstrate this level of performance with the new system being installed on the 10-meter Keck II telescope.

  12. Improved performance of the laser guide star adaptive optics system at Lick Observatory

    SciTech Connect

    An, J R; Avicola, K; Bauman, B J; Brase, J M; Campbell, E W; Carrano, C; Cooke, J B; Freeze, G J; Friedman, H W; Max, C E; Gates, E L; Gavel, D T; Kanz, V K; Kuklo, T C; Macintosh, B A; Newman, M J; Olivier, S S; Pierce, E L; Waltjen, K E; Watson, A

    1999-07-20

    Results of experiments with the laser guide star adaptive optics system on the 3-meter Shane telescope at Lick Observatory have demonstrated a factor of 4 performance improvement over previous results. Stellar images recorded at a wavelength of 2 {micro}m were corrected to over 40% of the theoretical diffraction-limited peak intensity. For the previous two years, this sodium-layer laser guide star system has corrected stellar images at this wavelength to {approx}10% of the theoretical peak intensity limit. After a campaign to improve the beam quality of the laser system, and to improve calibration accuracy and stability of the adaptive optics system using new techniques for phase retrieval and phase-shifting diffraction interferometry, the system performance has been substantially increased. The next step will be to use the Lick system for astronomical science observations, and to demonstrate this level of performance with the new system being installed on the 10-meter Keck II telescope.

  13. NASA ALLSTAR Project

    NASA Technical Reports Server (NTRS)

    Levy, Cesar; Ebadian, M. A.

    1998-01-01

    We finished the material development of Level 1, Level 2 and most of Level 3. We created three new galleries, one of streaming videos enabling the user to select his/her appropriate speed of Internet connectivity for better performance. The second gallery on NASA's X-series aircraft and the third is on F-series aircraft, We also completed the placement and activation of all thirteen kiosks. We added one more kiosk over the number suggested in the proposal at Baker Aviation High School - a Dade County Public School for special aviation programs. We felt that the goals of this school matched ALLSTAR's goals and that the placement of the kiosk would better help the local students become interested in the Aviation and Aeronautics field. We continue to work on the development of our "Teacher Resource Guide to ALLSTAR material" in which we tied our material into the national and Florida State standards. We finished the Florida Sunshine State standards, getting positive feedback from local and other educators who use the material on a regular basis. We had another successful workshop on October 29th, 1997. We introduced the ALLSTAR website and kiosk to about twenty science and history teachers from Dade County Public Schools (DCPS). Most teachers were from middle schools, although we had some from elementary schools also. We provided several demonstrations of the ALLSTAR material to local schools in the Dade County Public Schools (DCPS) system. We used the ALLSTAR material with FIU's summer immersion program for FLAME students. This program includes a high number of minority students interested in science and engineering. We also presented the material at National Science Teachers Association (NSTA) and National Congress on Aviation and Space Education (NCASE) conferences and will be presenting the material at the Southeast Florida Aviation Consortium (SEFAC). We provided two on-site workshops in the NSTA conference with total attended of about 70 teachers. The BBS was

  14. NASA ALLSTAR Project

    NASA Technical Reports Server (NTRS)

    Levy, Cesar; Ebadian, M. A.

    1998-01-01

    We finished the material development of Level 1, Level 2 and most of Level 3. We created three new galleries, one of streaming videos enabling the user to select his/her appropriate speed of Internet connectivity for better performance. The second gallery on NASA's X-series aircraft and the third is on F-series aircraft, We also completed the placement and activation of all thirteen kiosks. We added one more kiosk over the number suggested in the proposal at Baker Aviation High School - a Dade County Public School for special aviation programs. We felt that the goals of this school matched ALLSTAR's goals and that the placement of the kiosk would better help the local students become interested in the Aviation and Aeronautics field. We continue to work on the development of our "Teacher Resource Guide to ALLSTAR material" in which we tied our material into the national and Florida State standards. We finished the Florida Sunshine State standards, getting positive feedback from local and other educators who use the material on a regular basis. We had another successful workshop on October 29th, 1997. We introduced the ALLSTAR website and kiosk to about twenty science and history teachers from Dade County Public Schools (DCPS). Most teachers were from middle schools, although we had some from elementary schools also. We provided several demonstrations of the ALLSTAR material to local schools in the Dade County Public Schools (DCPS) system. We used the ALLSTAR material with FIU's summer immersion program for FLAME students. This program includes a high number of minority students interested in science and engineering. We also presented the material at National Science Teachers Association (NSTA) and National Congress on Aviation and Space Education (NCASE) conferences and will be presenting the material at the Southeast Florida Aviation Consortium (SEFAC). We provided two on-site workshops in the NSTA conference with total attended of about 70 teachers. The BBS was

  15. Initial results from the Lick Observatory Laser Guide Star Adaptive Optics System

    SciTech Connect

    Olivier, S.S.; An, J.; Avicola, K.

    1995-11-08

    A prototype adaptive optics system has been installed and tested on the 3 m Shane telescope at Lick Observatory. The adaptive optics system performance, using bright natural guide stars, is consistent with expectations based on theory. A sodium-layer laser guide star system has also been installed and tested on the Shane telescope. Operating at 15 W, the laser system produces a 9th magnitude guide star with seeing-limited size at 589 nm. Using the laser guide star, the adaptive optics system has reduced the wavefront phase variance on scales above 50 cm by a factor of 4. These results represent the first continuous wavefront phase correction using a sodium-layer laser guide star. Assuming tip-tilt is removed using a natural guide star, the measured control loop performance should produce images with a Strehl ratio of 0.4 at 2.2 {mu}m in 1 arc second seeing. Additional calibration procedures must be implemented in order to achieve these results with the prototype Lick adaptive optics system.

  16. Cartoon All-Stars to the Rescue. Joint Hearing before the Senate Committee on the Judiciary and the House Committee on the Judiciary on An Entertaining Way of Enlightening Children about the Dangers of Substance Abuse. One Hundred First Congress, Second Session.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on the Judiciary.

    This document presents witness testimony and supplemental materials from a Congressional hearing called to examine Cartoon All-Stars to the Rescue, a cartoon designed to teach children about the danger of substance abuse. Opening statements are included by Senator Joseph Biden, Jr., chairman of the Senate Judiciary Committee, and by Senators Strom…

  17. Lick slit spectra of thirty-eight objective prism quasar candidates and low metallicity halo stars

    NASA Technical Reports Server (NTRS)

    Tytler, David; Fan, Xiao-Ming; Junkkarinen, Vesa T.; Cohen, Ross D.

    1993-01-01

    Lick Observatory slit spectra of 38 objects which were claimed to have pronounced UV excess and emission lines are presented. Eleven QSOs, four galaxies at z of about 0.1, 22 stars, and one unidentified object with a low S/N spectrum were found. Of 11 objects which Zhan and Chen (1987, 1989) suggested were QSO with z(prism) not greater than 2.8; eight are QSOs. Six of the QSOs show absorption systems, including Q0000+027A with a relatively strong associated C IV absorption system, and Q0008+008 with a damped Ly-alpha system with an H I column density of 10 exp 21/sq cm. The equivalent widths of the Ca II K line, the G band, and the Balmer lines in 10 stars with the best spectra are measured, and metallicities are derived. Seven of them are in the range -2.5 to -1.7, while the others are less metal-poor.

  18. The FEROS-Lick/SDSS observational data base of spectral indices of FGK stars for stellar population studies

    NASA Astrophysics Data System (ADS)

    Franchini, M.; Morossi, C.; di Marcantonio, P.; Malagnini, M. L.; Chavez, M.

    2014-07-01

    We present FEROS-Lick/SDSS, an empirical data base of Lick/SDSS spectral indices of FGK stars to be used in population synthesis projects for discriminating different stellar populations within the integrated light of galaxies and globular clusters. From about 2500 FEROS stellar spectra obtained from the European Southern Observatory Science Archive Facility, we computed line-strength indices for 1085 non-supergiant stars with atmospheric parameter estimates from the AMBRE project. Two samples of 312 dwarfs and of 83 subgiants with solar chemical composition and no significant α-element abundance enhancement are used to compare their observational indices with the predictions of the Lick/SDSS library of synthetic indices. In general, the synthetic library reproduces very well the behaviour of observational indices as a function of temperature, but in the case of low-temperature (Teff ≲ 5000 K) dwarfs; low-temperature subgiants are not numerous enough to derive any conclusion. Several possible causes of the disagreement are discussed and promising theoretical improvements are presented.

  19. First significant image improvement from a sodium-layer laser guide star adaptive optics system at Lick Observatory

    SciTech Connect

    Olivier, S.S.; Max, C.E.; Friedman, H.W.; An, J.; Avicola, K.; Beeman, B.V.; Bissinger, H.D.; Brase, J.M.; Erbert, G.V.; Gavel, D.T.; Kanz, K.; Macintosh, B.; Neeb, K.P.; Waltjen, K.E.

    1997-07-14

    Atmospheric turbulence severely limits the resolution of ground-based telescopes. Adaptive optics can correct for the aberrations caused by the atmosphere, but requires a bright wavefront reference source in close angular proximity to the object being imaged. Since natural reference stars of the necessary brightness are relatively rare, methods of generating artificial reference beacons have been under active investigation for more than a decade. In this paper, we report the first significant image improvement achieved using a sodium-layer laser guide star as a wavefront reference for a high- order adaptive optics system. An artificial beacon was created by resonant scattering from atomic sodium in the mesosphere, at an altitude of 95 km. Using this laser guide star, an adaptive optics system on the 3 m Shane Telescope at Lick Observatory produced a factor of 2.4 increase in peak intensity and a factor of 2 decrease in full width at half maximum of a stellar image, compared with image motion compensation alone. The Strehl ratio when using the laser guide star as the reference was 65% of that obtained with a natural guide star, and the image full widths at half maximum were identical, 0.3 arc sec, using either the laser or the natural guide star. This sodium-layer laser guide star technique holds great promise for the world`s largest telescopes. 24 refs., 4 figs., 1 tab.

  20. VizieR Online Data Catalog: Lick indices for FGK stars (Franchini+, 2014)

    NASA Astrophysics Data System (ADS)

    Franchini, M.; Morossi, C.; Marcantonio, P. D.; Malagnini, M. L.; Chavez, M.

    2015-02-01

    The stars observed by FEROS and studied by the AMBRE project (Worley et al., 2012A&A...542A..48W) constitute an ideal working data set for our purposes since they include a large number of non-supergiant FGK stars with individual estimates of Teff, log g, [M/H], and α-to-iron ratio ([alpha/Fe]). We searched the European Southern Observatory (ESO) Science Archive Facility and retrieved, through the FEROS/HARPS pipeline processed data Query Form, all the public available spectra of FGK stars with AMBRE atmospheric parameter values in the following ranges: 38003.5, and global metallicity [M/H]>-3.0. A list of 1085 stars, corresponding to 2511 available spectra, was obtained. Since AMBRE provides individual estimates of stellar parameters derived from each spectrum, we computed for 202 stars with more than one observed spectrum average atmospheric parameter values. In any case, the dispersion of values for the same object resulted to be less than the external errors associated with AMBRE results. (1 data file).

  1. Documentation for the machine-readable version of the lick Saturn-Voyager Reference Star Catalogue

    NASA Technical Reports Server (NTRS)

    Warren, W. H., Jr.

    1982-01-01

    The machine-readable version of the catalog is described. The catalog was prepared in order to determine accurate equatorial coordinates for reference stars in a band of sky against which cameras of the Voyager spacecraft were aligned for observations in the region of Saturn during the flyby. Tape contents and characteristics are described and a sample listing presented.

  2. VizieR Online Data Catalog: Lick indices for 51 stars (Sansom+, 2013)

    NASA Astrophysics Data System (ADS)

    Sansom, A. E.; de Castro Milone, A.; Vazdekis, A.; Sanchez-Blazquez, P.

    2014-09-01

    A method that is widely used to analyse stellar populations in galaxies is to apply the theoretically derived responses of stellar spectra and line indices to element abundance variations, which are hereafter referred to as response functions. These are applied in a differential way, to base models, in order to generate spectra or indices with different abundance patterns. In this paper, sets of such response functions for three different stellar evolutionary stages are tested with new empirical [Mg/Fe] abundance data for the medium-resolution Isaac Newton Telescope library of empirical spectra (MILES). Recent theoretical models and observations are used to investigate the effects of [Fe/H], [Mg/H] and overall [Z/H] on spectra, via ratios of spectra for similar stars. The global effects of changes in abundance patterns are investigated empirically through direct comparisons of similar stars from MILES, highlighting the impact of abundance effects in the blue part of the spectrum, particularly for lower temperature stars. It is found that the relative behaviour of iron-sensitive line indices are generally well predicted by response functions, whereas Balmer line indices are not. Other indices tend to show large scatter about the predicted mean relations. Implications for element abundance and age studies in stellar populations are discussed and ways forward are suggested to improve the match with the behaviour of spectra and line-strength indices observed in real stars. (1 data file).

  3. Lick sodium laser guide star: performance during the 1998 LGS observing campaign

    SciTech Connect

    Bauman, B; Friedman, H; Gavel, D T

    1999-07-19

    The performance of a sodium laser guide star adaptive optics system depends crucially on the characteristics of the laser guide star in the sodium layer. System performance is quite sensitive to sodium layer spot radiance, that is, return per unit sterradian on the sky, hence we have been working to improve projected beam quality via improvements to the laser and changes to the launched beam format. The laser amplifier was reconfigured to a ''bounce-beam'' geometry, which considerably improves wavefront quality and allows a larger round instead of square launch beam aperture. The smaller beacon makes it easier to block the unwanted Rayleigh light and improves the accuracy of Hartmann sensor wavefront measurements in the A0 system. We present measurements of the beam quality and of the resulting sodium beacon and compare to similar measurements from last year.

  4. THE LICK-CARNEGIE SURVEY: A NEW TWO-PLANET SYSTEM AROUND THE STAR HD 207832

    SciTech Connect

    Haghighipour, Nader; Butler, R. Paul; Rivera, Eugenio J.; Vogt, Steven S.

    2012-09-01

    Keck/HIRES precision radial velocities of HD 207832 indicate the presence of two Jovian-type planetary companions in Keplerian orbits around this G star. The planets have minimum masses of Msin i = 0.56 M{sub Jup} and 0.73 M{sub Jup}, with orbital periods of {approx}162 and {approx}1156 days, and eccentricities of 0.13 and 0.27, respectively. Stroemgren b and y photometry reveals a clear stellar rotation signature of the host star with a period of 17.8 days, well separated from the period of the radial velocity variations, reinforcing their Keplerian origin. The values of the semimajor axes of the planets suggest that these objects have migrated from the region of giant planet formation to closer orbits. In order to examine the possibility of the existence of additional (small) planets in the system, we studied the orbital stability of hypothetical terrestrial-sized objects in the region between the two planets and interior to the orbit of the inner body. Results indicated that stable orbits exist only in a small region interior to planet b. However, the current observational data offer no evidence for the existence of additional objects in this system.

  5. All-STAR Act of 2010

    THOMAS, 111th Congress

    Sen. Durbin, Richard [D-IL

    2010-05-27

    05/27/2010 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (text of measure as introduced: CR S4541-4544) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  6. All-STAR Act of 2011

    THOMAS, 112th Congress

    Sen. Durbin, Richard [D-IL

    2011-04-13

    04/13/2011 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (text of measure as introduced: CR S2450-2453) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  7. All-STAR Act of 2011

    THOMAS, 112th Congress

    Rep. Polis, Jared [D-CO-2

    2011-04-13

    05/20/2011 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  8. All-STAR Act of 2013

    THOMAS, 113th Congress

    Rep. Polis, Jared [D-CO-2

    2013-06-04

    07/08/2013 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  9. All-STAR Act of 2013

    THOMAS, 113th Congress

    Sen. Durbin, Richard [D-IL

    2013-05-23

    05/23/2013 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (text of measure as introduced: CR S3859-3863) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  10. All-STAR Act of 2010

    THOMAS, 111th Congress

    Sen. Durbin, Richard J. [D-IL

    2010-05-27

    Senate - 05/27/2010 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  11. All-STAR Act of 2011

    THOMAS, 112th Congress

    Rep. Polis, Jared [D-CO-2

    2011-04-13

    House - 05/20/2011 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  12. All-STAR Act of 2011

    THOMAS, 112th Congress

    Sen. Durbin, Richard J. [D-IL

    2011-04-13

    Senate - 04/13/2011 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  13. All-STAR Act of 2013

    THOMAS, 113th Congress

    Sen. Durbin, Richard J. [D-IL

    2013-05-23

    Senate - 05/23/2013 Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  14. All-STAR Act of 2013

    THOMAS, 113th Congress

    Rep. Polis, Jared [D-CO-2

    2013-06-04

    House - 07/08/2013 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  15. All-STAR Act of 2011

    THOMAS, 112th Congress

    Rep. Polis, Jared [D-CO-2

    2011-04-13

    05/20/2011 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  16. All-STAR Act of 2013

    THOMAS, 113th Congress

    Rep. Polis, Jared [D-CO-2

    2013-06-04

    07/08/2013 Referred to the Subcommittee on Early Childhood, Elementary, and Secondary Education. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  17. THE LICK/SDSS LIBRARY. II. [Ca/Fe] AND [Mg/Fe] IN F, G, AND K STARS FROM SDSS-DR7

    SciTech Connect

    Franchini, M.; Morossi, C.; Di Marcantonio, P.; Malagnini, M. L.; Chavez, M. E-mail: morossi@oats.inaf.it E-mail: malagnini@oats.inaf.it

    2011-04-01

    We analyzed the spectra of 17,600 F, G, and K stars extracted from the seventh Sloan Digital Sky Survey Data Release (SDSS-DR7) database in order to derive ([{alpha}/Fe]), [Ca/Fe], and [Mg/Fe] ratios. Particular attention has been devoted to estimating homogeneous and self-consistent atmospheric parameter values, T{sub eff}, log g, and [Fe/H], by comparing synthetic and observational Lick/SDSS indices. We present results for the sub-sample of more than 4000 spectra whose overall quality allowed us to derive fairly accurate stellar atmospheric parameter values and, therefore, reliable abundance ratios. A Monte Carlo approach was adopted to evaluate both the errors in the observational Lick/SDSS indices and in the derived parameter estimates. The analysis of the trends of [Ca/Fe] and [Mg/Fe] versus [Fe/H] pointed out that (1) the [Ca/Fe] and [Mg/Fe] ratios increase with decreasing [Fe/H] with different slopes reaching maximum average levels of +0.25 and +0.40 dex at [Fe/H] {approx_equal} -1.75, respectively; (2) our sample contains, at a given [Fe/H], stars characterized by significantly different amounts of {alpha}-enhancement, thus belonging to different Galactic populations; and (3) the analyzed sample shows a predominance of thick disk stars for [Fe/H] > - 0.5 and the presence of stars belonging to the 'high-{alpha}' halo population for -2.0 < [Fe/H] <-0.5.

  18. NASA Allstar Project Aeronautics Learning Laboratory for Science,Technology, and Research (Allstar)

    NASA Technical Reports Server (NTRS)

    Levy, Cesar; Ebadian M. A.

    1998-01-01

    We finished the material development of Level 1, Level 2 and most of Level 3. We created three new galleries, one of streaming videos enabling the user to select his/her appropriate speed of Internet connectivity for better performance. The second gallery on NASA's X-series aircraft and the third is on F-series aircraft. We also completed the placement and activation of all thirteen kiosks. We added one more kiosk over the number suggested in the proposal at Baker Aviation High School - a Dade County Public School for special aviation programs. We felt that the goals of this school matched ALLSTAR's goals and that the placement of the kiosk would better help the local students become interested in the Aviation and Aeronautics field. We continue to work on the development of our "Teacher Resource Guide to ALLSTAR material" in which we tied our material into the national and Florida State standards. We finished the Florida Sunshine State standards, getting positive feedback from local and other educators who use the material on a regular basis. We had another successful workshop on October 29', 1997. We introduced the ALLSTAR website and kiosk to about twenty science and history teachers from Dade County Public Schools (DCPS). Most teachers were from middle schools, although we had some from elementary schools also. We provided several demonstrations of the ALLSTAR material to local schools in the Dade County Public Schools (DCPS) system. We used the ALLSTAR material with FIU's summer immersion program for FLAME students. This program includes a high number of minority students interested in science and engineering. We also presented the material at National Science Teachers Association (NSTA) and National Congress on Aviation and Space Education (NCASE) conferences and will be presenting the material at the Southeast Florida Aviation Consortium (SEFAC). We provided two on-site workshops in the NSTA conference with total attended of about 70 teachers. The BBS was

  19. NASA Allstar Project Aeronautics Learning Laboratory for Science,Technology, and Research (Allstar)

    NASA Technical Reports Server (NTRS)

    Levy, Cesar; Ebadian M. A.

    1998-01-01

    We finished the material development of Level 1, Level 2 and most of Level 3. We created three new galleries, one of streaming videos enabling the user to select his/her appropriate speed of Internet connectivity for better performance. The second gallery on NASA's X-series aircraft and the third is on F-series aircraft. We also completed the placement and activation of all thirteen kiosks. We added one more kiosk over the number suggested in the proposal at Baker Aviation High School - a Dade County Public School for special aviation programs. We felt that the goals of this school matched ALLSTAR's goals and that the placement of the kiosk would better help the local students become interested in the Aviation and Aeronautics field. We continue to work on the development of our "Teacher Resource Guide to ALLSTAR material" in which we tied our material into the national and Florida State standards. We finished the Florida Sunshine State standards, getting positive feedback from local and other educators who use the material on a regular basis. We had another successful workshop on October 29', 1997. We introduced the ALLSTAR website and kiosk to about twenty science and history teachers from Dade County Public Schools (DCPS). Most teachers were from middle schools, although we had some from elementary schools also. We provided several demonstrations of the ALLSTAR material to local schools in the Dade County Public Schools (DCPS) system. We used the ALLSTAR material with FIU's summer immersion program for FLAME students. This program includes a high number of minority students interested in science and engineering. We also presented the material at National Science Teachers Association (NSTA) and National Congress on Aviation and Space Education (NCASE) conferences and will be presenting the material at the Southeast Florida Aviation Consortium (SEFAC). We provided two on-site workshops in the NSTA conference with total attended of about 70 teachers. The BBS was

  20. Lick Jupiter-Voyager reference star catalogue (Klemola, Morabito, and Taraji 1978): Documentation for the machine-readable version

    NASA Technical Reports Server (NTRS)

    Warren, Wayne H., Jr.

    1990-01-01

    The machine-readable version of the catalog, as it is currently being distributed from the Astronomical Data Center, is described. The catalog contains accurate equatorial coordinates for 4983 stars in a band of sky against which cameras of the Voyager spacecraft were pointed for observations in the region of Jupiter during the flyby. All of the reference stars are in the range 6 hr 00 min to 8 hr 04 min in right ascension (1950), declination zones +16 to +23 degrees, and 8 hr to 31 min to 8 hr 57 min, zones +08 to +14 degrees. Mean errors of the positions are about 0.4 sec.

  1. Lick Saturn-Voyager reference star catalogue (Klemola, Taraji, and Ocampo 1979): Documentation for the machine-readable version

    NASA Technical Reports Server (NTRS)

    Warren, Wayne H., Jr.

    1990-01-01

    The machine readable version of the catalog, as it is currently being distributed from the Astronomical Data Center, is described. The catalog contains accurate equatorial coordinates for 4551 stars in a band of sky against which cameras of the Voyager spacecraft were pointed for observations in the region of Saturn during the flyby. All of the reference stars are in the range 12(exp h) 40(exp m) to 14(exp h) 12(exp m) in right ascension (1950) and +02 to -09 degs in declination. Mean errors of the positions are about 0.25 sec.

  2. The Lick-Carnegie Exoplanet Survey: HD 32963—A New Jupiter Analog Orbiting a Sun-like Star

    NASA Astrophysics Data System (ADS)

    Rowan, Dominick; Meschiari, Stefano; Laughlin, Gregory; Vogt, Steven S.; Butler, R. Paul; Burt, Jennifer; Wang, Songhu; Holden, Brad; Hanson, Russell; Arriagada, Pamela; Keiser, Sandy; Teske, Johanna; Diaz, Matias

    2016-02-01

    We present a set of 109 new, high-precision Keck/HIRES radial velocity (RV) observations for the solar-type star HD 32963. Our data set reveals a candidate planetary signal with a period of 6.49 ± 0.07 years and a corresponding minimum mass of 0.7 ± 0.03 Jupiter masses. Given Jupiter's crucial role in shaping the evolution of the early Solar System, we emphasize the importance of long-term RV surveys. Finally, using our complete set of Keck radial velocities and correcting for the relative detectability of synthetic planetary candidates orbiting each of the 1122 stars in our sample, we estimate the frequency of Jupiter analogs across our survey at approximately 3%.

  3. Aeronautics Learning Laboratory for Science, Technology, and Research (ALLSTAR)

    NASA Technical Reports Server (NTRS)

    Levy, Cesar; Ebadian, M. A.

    1998-01-01

    We finished the material development of Level 1, Level 2 and most of Level 3. We created three new galleries, one of streaming videos enabling the user to select his/her appropriate speed of Internet connectivity for better performance. The second gallery on NASA's X-series aircraft and the third is on F-series aircraft. We also completed the placement and activation of all thirteen kiosks. We added one more kiosk over the number suggested in the proposal at Baker Aviation High School - a Dade County Public School for special aviation programs. We felt that the goals of this school matched ALLSTAR's goals and that the placement of the kiosk would better help the local students become interested in the Aviation and Aeronautics field. We continue to work on the development of our "Teacher Resource Guide to ALLSTAR material" in which we tied our material into the national and Florida State standards. We finished the Florida Sunshine State standards, getting positive feedback from local and other educators who use the material on a regular basis. We had another successful workshop on October 29 th, 1997. We introduced the ALLSTAR website and kiosk to about twenty science and history teachers from Dade County Public Schools (DCPS). Most teachers were from middle schools, although we had some from elementary schools also. We provided several demonstrations of the ALLSTAR material to local schools in the Dade County Public Schools (DCPS) system. We used the ALLSTAR material with FIU's summer immersion program for FLAME students. This program includes a high number of minority students interested in science and engineering. We also presented the material at National Science Teachers Association (NSTA) and National Congress on Aviation and Space Education (NCASE) conferences and will be presenting the material at the Southeast Florida Aviation Consortium (SEFAC). We provided two on-site workshops in the NSTA conference with total attended of about 70 teachers. The BBS was

  4. Performance of adaptive optics at Lick Observatory

    SciTech Connect

    Olivier, S.S.; An, J.; Avicola, K.

    1994-03-01

    A prototype adaptive optics system has been developed at Lawrence Livermore National Laboratory (LLNL) for use at Lick Observatory. This system is based on an ITEX 69-actuator continuous-surface deformable mirror, a Kodak fast-framing intensified CCD camera, and a Mercury VME board containing four Intel i860 processors. The system has been tested using natural reference stars on the 40-inch Nickel telescope at Lick Observatory yielding up to a factor of 10 increase in image peak intensity and a factor of 6 reduction in image full width at half maximum (FWHM). These results are consistent with theoretical expectations. In order to improve performance, the intensified CCD camera will be replaced by a high-quantum-efficiency low-noise fast CCD camera built for LLNL by Adaptive Optics Associates using a chip developed by Lincoln Laboratory, and the 69-actuator deformable mirror will be replaced by a 127-actuator deformable mirror developed at LLNL. With these upgrades, the system should perform well in median seeing conditions on the 120-inch Shane telescope for observing wavelengths longer than {approximately}1 {mu}m and using natural reference stars brighter than m{sub R} {approximately} 10 or using the laser currently being developed at LLNL for use at Lick Observatory to generate a sodium-layer reference star.

  5. Campus Technology Innovators Awards 2011: Technology All-Stars

    ERIC Educational Resources Information Center

    Lloyd, Meg; Raths, David

    2011-01-01

    Out of a total of 393 entries for the 2011 Campus Technology Innovators award, 10 winners rose to the top in six categories: (1) Leadership, Governance, and Policy; (2) Teaching and Learning; (3) Student Systems and Services; (4) Administrative Systems; (5) IT Infrastructure and Systems; and (6) Education Futurists. These innovative IT leaders…

  6. Campus Technology Innovators Awards 2011: Technology All-Stars

    ERIC Educational Resources Information Center

    Lloyd, Meg; Raths, David

    2011-01-01

    Out of a total of 393 entries for the 2011 Campus Technology Innovators award, 10 winners rose to the top in six categories: (1) Leadership, Governance, and Policy; (2) Teaching and Learning; (3) Student Systems and Services; (4) Administrative Systems; (5) IT Infrastructure and Systems; and (6) Education Futurists. These innovative IT leaders…

  7. Beware of dogs licking ears.

    PubMed

    Godey, B; Morandi, X; Bourdinière, J; Heurtin, C

    1999-10-09

    A patient with right-sided chronic purulent otorrhoea developed meningitis due to Pasteurella multocida transmitted by a dog that frequently licked his ear. We suggest that patients with a perforated tympanic membrane should avoid being licked on their ears by animals.

  8. Progress with the lick adaptive optics system

    SciTech Connect

    Gavel, D T; Olivier, S S; Bauman, B; Max, C E; Macintosh, B

    2000-03-01

    Progress and results of observations with the Lick Observatory Laser Guide Star Adaptive Optics System are presented. This system is optimized for diffraction-limited imaging in the near infrared, 1-2 micron wavelength bands. We describe our development efforts in a number of component areas including, a redesign of the optical bench layout, the commissioning of a new infrared science camera, and improvements to the software and user interface. There is also an ongoing effort to characterize the system performance with both natural and laser guide stars and to fold this data into a refined system model. Such a model can be used to help plan future observations, for example, predicting the point-spread function as a function of seeing and guide star magnitude.

  9. Progress with the Lick adaptive optics system

    NASA Astrophysics Data System (ADS)

    Gavel, Donald T.; Olivier, Scot S.; Bauman, Brian J.; Max, Claire E.; Macintosh, Bruce A.

    2000-07-01

    Progress and results of observations with the Lick Observatory Laser Guide Star Adaptive Optics System are presented. This system is optimized for diffraction-limited imaging in the near infrared, 1 - 2 micron wavelength bands. We describe our development efforts in a number of component areas including, a redesign of the optical bench layout, the commissioning of a new infrared science camera, and improvements to the software and user interface. There is also an ongoing effort to characterize the system performance with both natural and laser guide stars and to fold this data into a refined system model. Such a model can be used to help plan future observations, for example, predicting the point-spread function as a function of seeing and guide star magnitude.

  10. THE LICK-CARNEGIE EXOPLANET SURVEY: A SATURN-MASS PLANET IN THE HABITABLE ZONE OF THE NEARBY M4V STAR HIP 57050

    SciTech Connect

    Haghighipour, Nader; Vogt, Steven S.; Rivera, Eugenio J.; Laughlin, Greg; Meschiari, Stefano; Henry, Gregory W.

    2010-05-20

    Precision radial velocities (RV) from Keck/HIRES reveal a Saturn-mass planet orbiting the nearby M4V star HIP 57050. The planet has a minimum mass of Msin i {approx} 0.3 M{sub J}, an orbital period of 41.4 days, and an orbital eccentricity of 0.31. V-band photometry reveals a clear stellar rotation signature of the host star with a period of 98 days, well separated from the period of the RV variations and reinforcing a Keplerian origin for the observed velocity variations. The orbital period of this planet corresponds to an orbit in the habitable zone of HIP 57050, with an expected planetary temperature of {approx}230 K. The star has a metallicity of [Fe/H] = 0.32 {+-} 0.06 dex, of order twice solar and among the highest metallicity stars in the immediate solar neighborhood. This newly discovered planet provides further support that the well-known planet-metallicity correlation for F, G, and K stars also extends down into the M-dwarf regime. The a priori geometric probability for transits of this planet is only about 1%. However, the expected eclipse depth is {approx}7%, considerably larger than that yet observed for any transiting planet. Though long on the odds, such a transit is worth pursuing as it would allow for high quality studies of the atmosphere via transmission spectroscopy with Hubble Space Telescope. At the expected planetary effective temperature, the atmosphere may contain water clouds.

  11. THE LICK-CARNEGIE EXOPLANET SURVEY: A 3.1 M{sub +} PLANET IN THE HABITABLE ZONE OF THE NEARBY M3V STAR GLIESE 581

    SciTech Connect

    Vogt, Steven S.; Rivera, E. J.; Haghighipour, N.; Henry, Gregory W.; Williamson, Michael H.

    2010-11-01

    We present 11 years of HIRES precision radial velocities (RVs) of the nearby M3V star Gliese 581, combining our data set of 122 precision RVs with an existing published 4.3-year set of 119 HARPS precision RVs. The velocity set now indicates six companions in Keplerian motion around this star. Differential photometry indicates a likely stellar rotation period of {approx}94 days and reveals no significant periodic variability at any of the Keplerian periods, supporting planetary orbital motion as the cause of all the RV variations. The combined data set strongly confirms the 5.37-day, 12.9-day, 3.15-day, and 67-day planets previously announced by Bonfils et al., Udry et al., and Mayor et al.. The observations also indicate a fifth planet in the system, GJ 581f, a minimum-mass 7.0 M{sub +} planet orbiting in a 0.758 AU orbit of period 433 days, and a sixth planet, GJ 581g, a minimum-mass 3.1 M{sub +} planet orbiting at 0.146 AU with a period of 36.6 days. The estimated equilibrium temperature of GJ 581g is 228 K, placing it squarely in the middle of the habitable zone of the star and offering a very compelling case for a potentially habitable planet around a very nearby star. That a system harboring a potentially habitable planet has been found this nearby, and this soon in the relatively early history of precision RV surveys, indicates that {eta}{sub +}, the fraction of stars with potentially habitable planets, is likely to be substantial. This detection, coupled with statistics of the incompleteness of present-day precision RV surveys for volume-limited samples of stars in the immediate solar neighborhood, suggests that {eta}{sub +} could well be on the order of a few tens of percent. If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets.

  12. The Lick-Carnegie Exoplanet Survey: A 3.1 M ⊕ Planet in the Habitable Zone of the Nearby M3V Star Gliese 581

    NASA Astrophysics Data System (ADS)

    Vogt, Steven S.; Butler, R. Paul; Rivera, E. J.; Haghighipour, N.; Henry, Gregory W.; Williamson, Michael H.

    2010-11-01

    We present 11 years of HIRES precision radial velocities (RVs) of the nearby M3V star Gliese 581, combining our data set of 122 precision RVs with an existing published 4.3-year set of 119 HARPS precision RVs. The velocity set now indicates six companions in Keplerian motion around this star. Differential photometry indicates a likely stellar rotation period of ~94 days and reveals no significant periodic variability at any of the Keplerian periods, supporting planetary orbital motion as the cause of all the RV variations. The combined data set strongly confirms the 5.37-day, 12.9-day, 3.15-day, and 67-day planets previously announced by Bonfils et al., Udry et al., and Mayor et al.. The observations also indicate a fifth planet in the system, GJ 581f, a minimum-mass 7.0 M ⊕ planet orbiting in a 0.758 AU orbit of period 433 days, and a sixth planet, GJ 581g, a minimum-mass 3.1 M ⊕ planet orbiting at 0.146 AU with a period of 36.6 days. The estimated equilibrium temperature of GJ 581g is 228 K, placing it squarely in the middle of the habitable zone of the star and offering a very compelling case for a potentially habitable planet around a very nearby star. That a system harboring a potentially habitable planet has been found this nearby, and this soon in the relatively early history of precision RV surveys, indicates that η⊕, the fraction of stars with potentially habitable planets, is likely to be substantial. This detection, coupled with statistics of the incompleteness of present-day precision RV surveys for volume-limited samples of stars in the immediate solar neighborhood, suggests that η⊕ could well be on the order of a few tens of percent. If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets.

  13. Recent science and engineering results with the laser guidestar adaptive optic system at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Gavel, Donald T.; Gates, Elinor L.; Max, Claire E.; Olivier, Scot S.; Bauman, Brian J.; Pennington, Deanna M.; Macintosh, Bruce A.; Patience, Jennifer; Brown, Curtis G.; Danforth, Pamela M.; Hurd, Randall L.; Severson, Scott A.; Lloyd, James P.

    2003-02-01

    The Lick Observatory laser guide star adaptive optics system has undergone continual improvement and testing as it is being integrated as a facility science instrument on the Shane 3 meter telescope. Both Natural Guide Star (NGS) and Laser Guide Star (LGS) modes are now used in science observing programs. We report on system performance results as derived from data taken on both science and engineering nights and also describe the newly developed on-line techniques for seeing and system performance characterization. We also describe the future enhancements to the Lick system that will enable additional science goals such as long-exposure spectroscopy.

  14. Recent Science and Engineering Results with the Laser Guidestar Adaptive Optics System at Lick Observatory

    SciTech Connect

    Gavel, D T; Gates, E; Max, C; Olivier, S; Bauman, B; Pennington, D; Macintosh, B; Patience, J; Brown, C; Danforth, P; Hurd, R; Severson, S; Lloyd, J

    2002-10-17

    The Lick Observatory laser guide star adaptive optics system has undergone continual improvement and testing as it is being integrated as a facility science instrument on the Shane 3 meter telescope. Both Natural Guide Star (NGS) and Laser Guide Star (LGS) modes are now used in science observing programs. We report on system performance results as derived from data taken on both science and engineering nights and also describe the newly developed on-line techniques for seeing and system performance characterization. We also describe the future enhancements to the Lick system that will enable additional science goals such as long-exposure spectroscopy.

  15. Graduate Astronomy Education in the Early Days of Lick Observatory.

    ERIC Educational Resources Information Center

    Osterbrock, Donald E.

    1980-01-01

    Discusses Lick Observatory's (University of California) early graduate students and graduate program in astronomy. The history of the Lick Observatory and famous astronomy professors and astronomers associated with the Lick Observatory are also discussed. (DS)

  16. Graduate Astronomy Education in the Early Days of Lick Observatory.

    ERIC Educational Resources Information Center

    Osterbrock, Donald E.

    1980-01-01

    Discusses Lick Observatory's (University of California) early graduate students and graduate program in astronomy. The history of the Lick Observatory and famous astronomy professors and astronomers associated with the Lick Observatory are also discussed. (DS)

  17. THE LICK/SDSS LIBRARY. I. SYNTHETIC INDEX DEFINITION AND CALIBRATION

    SciTech Connect

    Franchini, M.; Morossi, C.; Di Marcantonio, P.; Malagnini, M. L.; Chavez, M. E-mail: morossi@oats.inaf.i E-mail: malagnini@oats.inaf.i

    2010-08-10

    A new synthetic library of spectral feature indices, Lick/Sloan Digital Sky Survey (SDSS), for stellar population studies is presented. Lick/SDSS is computed from synthetic spectra with resolving power R = 1800 to fully exploit the content of the spectroscopic SDSS-DR7 stellar database. The Lick/SDSS system is based on the Lick/IDS one complemented with a UV index in the wavelength region of Ca II H and K lines. The system is well suited to study {alpha}-element abundances in F, G, and K stars. The reliability of synthetic indices in reproducing the behaviors of observational ones with effective temperature, surface gravity, overall metallicity, and {alpha}-element abundances is tested by using empirical stellar libraries (ELODIE, INDO-U.S., and MILES) and the SDSS-DR7 spectroscopic database. The importance of using the same temperature scale in comparing theoretical and observational indices is discussed. The full consistency between Lick/SDSS and observational indices derived from the above mentioned stellar libraries is assessed. The comparison with indices computed from SDSS-DR7 spectra evidences good consistency for 'dwarf' stars and significant disagreement for 'giant' stars due to systematic overestimation of the stellar T {sub eff} by the SEGUE Stellar Parameter Pipeline.

  18. The automated planet finder at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Radovan, Matt V.; Lanclos, Kyle; Holden, Bradford P.; Kibrick, Robert I.; Allen, S. L.; Deich, William T. S.; Rivera, Eugenio; Burt, Jennifer; Fulton, Benjamin; Butler, Paul; Vogt, Steven S.

    2014-07-01

    By July 2014, the Automated Planet Finder (APF) at Lick Observatory on Mount Hamilton will have completed its first year of operation. This facility combines a modern 2.4m computer-controlled telescope with a flexible development environment that enables efficient use of the Levy Spectrometer for high cadence observations. The Levy provides both sub-meter per second radial velocity precision and high efficiency, with a peak total system throughput of 24%. The modern telescope combined with efficient spectrometer routinely yields over 100 observations of 40 stars in a single night, each of which has velocity errors of 0.7 to 1.4 meters per second, all with typical seeing of < 1 arc second full-width-half-maximum (FWHM). The whole observing process is automated using a common application programming interface (API) for inter-process communication which allows scripting to be done in a variety of languages (Python, Tcl, bash, csh, etc.) The flexibility and ease-of-use of the common API allowed the science teams to be directly involved in the automation of the observing process, ensuring that the facility met their requirements. Since November 2013, the APF has been routinely conducting autonomous observations without human intervention.

  19. Social Licking in Pregnant Dairy Heifers

    PubMed Central

    Tresoldi, Grazyne; Weary, Daniel M.; Pinheiro Machado Filho, Luiz Carlos; von Keyserlingk, Marina A. G.

    2015-01-01

    Simple Summary Social licking is often associated with good animal welfare, but little is known about this behavior in cattle. Licking behavior was compared in heifers housed indoors versus on pasture. Licking frequency was four-fold higher when heifers were indoors. However, when considering all social interactions recorded (licking and aggressions) licking events represented about 10% of all interactions regardless of housing. This behavior happened more frequently between heifers that were observed more repeatedly in close vicinity of each other. Provision of smaller indoor floor spaces likely brought animals into closer proximity thus facilitating social interactions. Abstract Housing affects social behaviors, such as competition, but little work has addressed affiliative behaviors. This study compared social licking (SL) in pregnant heifers housed indoors (in a free-stall barn) versus outdoors (on pasture), and relationships with competition, feeding and physical proximity to others. Six heifer groups were observed during two six-hour-periods in both treatments. The total number of social events (SL and agonistic interactions) was four times higher when heifers were housed indoors compared to pasture (546 ± 43 vs. 128 ± 7 events/group; P < 0.05). SL as a ratio of the total number of social events was similar in the two treatments (12% vs. 8% of interactions, free-stall and pasture, respectively; P > 0.05). Housing did not affect how the SL bout was initiated and terminated, the duration, the body part licked and behavior preceding licking (P > 0.05). Animals in close proximity showed higher rates of SL (P < 0.0001) but not agonistic interactions (P > 0.05). A previous agonistic event did not predict occurrence or the role of heifers in the following licking event. The higher stocking density indoors likely resulted in increased social interactions. PMID:26610578

  20. Making star teams out of star players.

    PubMed

    Mankins, Michael; Bird, Alan; Root, James

    2013-01-01

    Top talent is an invaluable asset: In highly specialized or creative work, for instance, "A" players are likely to be six times as productive as "B" players. So when your company has a crucial strategic project, why not multiply all that firepower and have a team of your best performers tackle it? Yet many companies hesitate to do this, believing that all-star teams don't work: Big egos will get in the way. The stars won't be able to work with one another. They'll drive the team Leader crazy. Mankins, Bird, and Root of Bain & Company believe it's time to set aside that thinking. They have seen all-star teams do extraordinary work. But there is a right way and a wrong way to organize them. Before you can even begin to assemble such a team, you need to have the right talent management practices, so you hire and develop the best people and know what they're capable of. You have to give the team appropriate incentives and leaders and support staffers who are stars in their own right. And projects that are ill-defined or small scale are not for all-star teams. Use them only for critical missions, and make sure their objectives are clear. Even with the right setup, things can still go wrong. The wise executive will take steps to manage egos, prune non-team-players, and prevent average coworkers from feeling completely undervalued. She will also invest a lot of time in choosing the right team Leader and will ask members for lots of feedback to monitor how that leader is doing.

  1. Organic diseases mimicking acral lick dermatitis in six dogs.

    PubMed

    Denerolle, Philippe; White, Stephen D; Taylor, Tara S; Vandenabeele, Sophie I J

    2007-01-01

    Acral lick dermatitis ("lick granuloma") in dogs is often thought to have a behavioral etiology. However, other diseases may cause lesions on the distal legs, mimicking acral lick dermatitis. In this report, six dogs were presented with acral lick dermatitis-like lesions from different underlying causes-namely lymphoma, an orthopedic pin, deep pyoderma, mast cell tumor, leishmaniasis, and (presumptive) sporotrichosis.

  2. [Is being licked by dogs not dirty?].

    PubMed

    Overgaauw, Paul; van Knapen, Frans

    2012-09-01

    Being licked by pet dogs is frequently a common advice in articles for the uninitiated. An overview is given about the special antibacterial and wound healing properties of human and canine saliva. New developments in the human area are presumably assigned to dog saliva. Because of the presence of a quite different mouth flora including various potential zoonotic pathogens, it is strictly not advised to let dogs lick the wounds or face of the human.

  3. Lick Observatory Optical SETI: targeted search and new directions.

    PubMed

    Stone, R P S; Wright, S A; Drake, F; Muñoz, M; Treffers, R; Werthimer, D

    2005-10-01

    Lick Observatory's Optical SETI (search for extraterrestrial intelligence) program has been in regular operation for 4.5 years. We have observed 4,605 stars of spectral types F-M within 200 light-years of Earth. Occasionally, we have appended objects of special interest, such as stars with known planetary systems. We have observed 14 candidate signals ("triple coincidences"), all but one of which are explained by transient local difficulties. Additional observations of the remaining candidate have failed to confirm arriving pulse events. We now plan to proceed in a more economical manner by operating in an unattended drift scan mode. Between operational and equipment modifications, efficiency will more than double.

  4. Adaptive Optics Performance at Lick and Keck Observatory

    NASA Astrophysics Data System (ADS)

    Max, C. E.; Olivier, S. S.; Avicola, K.; Bissinger, H. D.; Brase, J. M.; Friedman, H. W.; Gavel, D. T.; Salmon, J. T.; Waltjen, K. E.

    1993-12-01

    The performance of an adaptive optics system developed for the 40 inch Nickel and 120 inch Shane telescopes at Lick Observatory is discussed. The system is based on a 69 actuator continuous-surface deformable mirror and a Hartmann wavefront sensor equipped with a commercial intensified CCD fast-framing camera. Results from tests of this adaptive optics system using natural reference stars on the 40 inch Nickel telescope are presented. These results are compared to the performance predicted by simulations and analyses. Predictions for the system performance on the 120 inch Shane telescope and on the 10 meter Keck telescope using both natural and laser reference stars are also presented. Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

  5. Differential Suppression by Punishment of Nonconsummatory Licking and Lever Pressing

    ERIC Educational Resources Information Center

    Walters, Gary C.; Herring, Barbara

    1978-01-01

    Five experiments investigated the differential effects of shock punishment on nonconsummatory licking (dry licking) and lever pressing. Results support a motivationally based theory of punishment involving the role of incentive stimuli associated with the particular responses studied. (Editor/RK)

  6. The Lick Planet Search: Detectability and Mass Thresholds

    NASA Astrophysics Data System (ADS)

    Cumming, Andrew; Marcy, Geoffrey W.; Butler, R. Paul

    1999-12-01

    We present an analysis of 11 yr of precision radial velocity measurements of 76 nearby solar-type stars from the Lick radial velocity survey. For each star, we report on variability, periodicity, and long-term velocity trends. Our sample of stars contains eight known companions with mass (Mpsini) less than 8 Jupiter masses (MJ), six of which were discovered at Lick. For the remaining stars, we place upper limits on the companion mass as a function of orbital period. For most stars, we can exclude companions with velocity amplitude K>~20 m s-1 at the 99% level, or Mpsini>~0.7MJ(a/AU)1/2 for orbital radii a<~5 AU. We examine the implications of our results for the observed distribution of mass and orbital radius of companions. We show that the combination of intrinsic stellar variability and measurement errors most likely explains why all confirmed companions so far have K>~40 m s-1. The finite duration of the observations limits detection of Jupiter-mass companions to a<~3 AU. Thus it remains possible that the majority of solar-type stars harbor Jupiter-mass companions much like our own, and if so these companions should be detectable in a few years. It is striking that more massive companions with Mpsini>3MJ are rare at orbital radii 4-6 AU; we could have detected such objects in ~90% of stars, yet found none. The observed companions show a ``piling-up'' toward small orbital radii, and there is a paucity of confirmed and candidate companions with orbital radii between ~0.2 and ~1 AU. The small number of confirmed companions means that we are not able to rule out selection effects as the cause of these features. We show that the traditional method for detecting periodicities, the Lomb-Scargle periodogram, fails to account for statistical fluctuations in the mean of a sampled sinusoid, making it nonrobust when the number of observations is small, the sampling is uneven, or for periods comparable to or greater than the duration of the observations. We adopt a

  7. Drinking spout orifice size affects licking behavior in inbred mice.

    PubMed

    Dotson, Cedrick D; Spector, Alan C

    2005-08-07

    Using a lickometer, we assessed the effect of drinking spout orifice size on the licking behavior of inbred mice [C57BL/6J, SWR/J, 129P3/J and DBA/2J]. Animals licked from drinking spout sipper tubes that had what were defined as either a large (2.7 mm) or a small (1.5 mm) orifice. Mice took approximately twice as many licks from a stationary single small orifice drinking spout than when licking from a spout with a large orifice during separate 30-min sessions. However, their total intake volume was approximately the same. We calculated that mice received a mean of 0.55 muL per lick from the drinking tubes with a small orifice and a mean of 1.15 muL per lick from the drinking tubes with a large orifice. Thus, the animals appear to have regulated their fluid intake by proportionally adjusting their licking as a function of the lick volume. On average, this regulation occurred through modulation of the size of licking bursts and not their frequency. However, strain differences in compensation strategy were observed. When licking was restricted to a series of 5-s trials in a 30-min brief access test session, the smaller orifice size increased the range of responsiveness that was expressed. Mice increased their average licks per trial by 20% and took 60% more trials when licking from a spout with a small orifice. Interestingly, when the orifice size was quasi-randomly varied within a brief access session, licking was greater from large orifice drinking spouts, suggesting that water delivered from the two orifice sizes differs in its reinforcement efficacy. These findings demonstrate that drinking spout orifice size can significantly influence experimental outcomes in licking tests involving mice and care should be taken in controlling this variable in testing the effects of taste or other factors on ingestive behavior.

  8. Conceptual design for a user-friendly adaptive optics system at Lick Observatory

    SciTech Connect

    Bissinger, H.D.; Olivier, S.; Max, C.

    1996-03-08

    In this paper, we present a conceptual design for a general-purpose adaptive optics system, usable with all Cassegrain facility instruments on the 3 meter Shane telescope at the University of California`s Lick Observatory located on Mt. Hamilton near San Jose, California. The overall design goal for this system is to take the sodium-layer laser guide star adaptive optics technology out of the demonstration stage and to build a user-friendly astronomical tool. The emphasis will be on ease of calibration, improved stability and operational simplicity in order to allow the system to be run routinely by observatory staff. A prototype adaptive optics system and a 20 watt sodium-layer laser guide star system have already been built at Lawrence Livermore National Laboratory for use at Lick Observatory. The design presented in this paper is for a next- generation adaptive optics system that extends the capabilities of the prototype system into the visible with more degrees of freedom. When coupled with a laser guide star system that is upgraded to a power matching the new adaptive optics system, the combined system will produce diffraction-limited images for near-IR cameras. Atmospheric correction at wavelengths of 0.6-1 mm will significantly increase the throughput of the most heavily used facility instrument at Lick, the Kast Spectrograph, and will allow it to operate with smaller slit widths and deeper limiting magnitudes. 8 refs., 2 figs.

  9. Licking Microstructure Reveals Rapid Attenuation of Neophobia

    PubMed Central

    Monk, Kevin J.; Rubin, Benjamin D.

    2014-01-01

    Many animals hesitate when initially consuming a novel food and increase their consumption of that food between the first and second sessions of access—a process termed attenuation of neophobia (AN). AN has received attention as a model of learning and memory; it has been suggested that plasticity resulting from an association of the novel tastant with “safe outcome” results in a change in the neural response to the tastant during the second session, such that consumption increases. Most studies have reported that AN emerges only an hour or more after the end of the first exposure to the tastant, consistent with what is known of learning-related plasticity. But these studies have typically measured consumption, rather than real-time behavior, and thus the possibility exists that a more rapidly developing AN remains to be discovered. Here, we tested this possibility, examining both consumption and individual lick times in a novel variant of a brief-access task (BAT). When quantified in terms of consumption, data from the BAT accorded well with the results of a classic one-bottle task—both revealed neophobia/AN specific to higher concentrations (for instance, 28mM) of saccharin. An analysis of licking microstructure, however, additionally revealed a real-time correlate of neophobia—an explicit tendency, similarly specific for 28-mM saccharin, to cut short the initial bout of licks in a single trial (compared with water). This relative hesitancy (i.e., the shortness of the first lick bout to 28-mM saccharin compared with water) that constitutes neophobia not only disappeared between sessions but also gradually declined in magnitude across session 1. These data demonstrate that the BAT accurately measures AN, and that aspects of AN—and the processes underlying familiarization—begin within minutes of the very first taste. PMID:24363269

  10. Mineralogical characterization of asteroid (1951) Lick

    NASA Astrophysics Data System (ADS)

    de Leon, J.; Duffard, R.; Licandro, J.; Lazzaro, D.

    A-type asteroids are usually found in the main asteroid belt and their spectra are very similar to spectra of the silicate mineral olivine (Cruikshank and Hartmann 1984). The existence of olivine-rich asteroids is a result of differentiation, those being the pieces of the mantle of a larger parent body. Extraterrestrial sources of such material must exist because we have meteorites that are nearly pure olivine (dunites). There is a limited number of observed asteroids classified as A-type, all of them belonging to the Main Belt and the study of such objects is crucial to better understand their origin and formation and their relation with dunites. We have obtained visible and near infrared reflectance spectra of asteroid (1951) Lick using the telescopes located at Observatorio del Roque de los Muchachos (Canary Islands, Spain). According to its spectral characteristics in the visible region, this object has been classified as an A-type asteroid by Bus and Binzel (2002). Although considered an Amor object by several authors, according to its orbital parameters (a = 1.390 AU, e = 0.061, i = 39.093 deg, q = 1.304) this object is just in the limit that separates Amors from Mars Crossers (q = 1.3). Whether it is classified as an Amor or a Mars Crosser, (1951) Lick is the first object with such orbital characteristics classified as an A-type asteroid. Here we present a mineralogical analysis of the reflectance spectra obtained for (1951) Lick. We calculate several parameters that are extracted from the spectrum of the asteroid and that give relevant information about its mineralogical composition, using the method defined by Gaffey et al. (1993). We also present results obtained by a preliminary fit to the absorption band associated to the presence of the olivine mineral using the Modified Gaussian Model method (MGM) developed by Sunshine et al.(1990). References Bus, J. S. and Binzel, R. P. 2002. Icarus, 158, 146 Cuikshank, D. P. and Hartmann, W. K. 1984. Science, 223

  11. Adaptive Optics System Design and Operation at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Olivier, S. S.; Max, C. E.; Avicola, K.; Bissinger, H. D.; Brase, J. M.; Friedman, H. W.; Gavel, D. T.; Salmon, J. T.; Waltjen, K. E.

    1993-12-01

    An adaptive optics system developed for the 40 inch Nickel and 120 inch Shane telescopes at Lick Observatory is described. The adaptive optics system design is based on a 69 actuator continuous-surface deformable mirror and a Hartmann wavefront sensor equipped with a commercial intensified CCD fast-framing camera. The system has been tested at the Cassegrain focus of the 40 inch Nickel telescope where the subaperture diameter is 12 cm. The subaperture slope and mirror control calculations are performed on a four processor single board computer controlled by a Unix workstation. This configuration is capable of up to 1 KHz frame rates. The optical configuration of the system and its interface to the telescope is described. Details of the control system design, operation, and user interface are given. Initial test results emphasizing control system operations of this adaptive optics system using natural reference stars on the 40 inch Nickel telescope are presented. The initial test results are compared to predictions from analyses and simulations. Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

  12. Update on Optical Design of Adaptive Optics System at Lick Observatory

    SciTech Connect

    Bauman, B J; Gavel, D T; Waltjen, K E; Freeze, G J; Hurd, R L; Gates, E I; Max, C E; Olivier, S S; Pennington, D M

    2001-07-31

    In 1999, we presented our plan to upgrade the adaptive optics (AO) system on the Lick Observatory Shane telescope (3m) from a prototype instrument pressed into field service to a facility instrument. This paper updates the progress of that plan and details several important improvements in the alignment and calibration of the AO bench. The paper also includes a discussion of the problems seen in the original design of the tip/tilt (t/t) sensor used in laser guide star mode, and how these problems were corrected with excellent results.

  13. Update on optical design of adaptive optics system at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Bauman, Brian J.; Gavel, Donald T.; Waltjen, Kenneth E.; Freeze, Gary J.; Hurd, Randall L.; Gates, Elinor L.; Max, Claire E.; Olivier, Scot S.; Pennington, Deanna M.

    2002-02-01

    In 1999, we presented our plan to upgrade the adaptive optics (AO) system on the Lick Observatory Shane telescope (3m) from a prototype instrument pressed into field service to a facility instrument. This paper updates the progress of that plan and details several important improvements in the alignment and calibration of the AO bench. The paper also includes a discussion of the problems seen in the original design of the tip/tilt (t/t) sensor used in laser guide star mode, and how these problems were corrected with excellent results.

  14. Naltrexone for treatment of acral lick dermatitis in dogs.

    PubMed

    White, S D

    1990-04-01

    Acral lick dermatitis (lick granuloma) was diagnosed in 11 dogs on the basis of history, physical examination, and histopathologic findings. A predilection for the left forelimb was noticed. All 11 dogs were given the narcotic antagonist naltrexone. Successful treatment (cessation of licking, reepithelialization of lesions) was seen in 7 dogs. All 7 dogs' lesions recurred when naltrexone was stopped, but reepithelialized in 5 dogs when the drug was readministered. Adverse effects (drowsiness, withdrawal from owner) were seen in 1 dog, but resolved within 48 hours of stopping the drug.

  15. Geochemistry of mineral licks at Loskop Dam Nature Reserve, Mpumalanga, South Africa.

    PubMed

    Stephenson, J D; Mills, A; Eksteen, J J; Milewski, A V; Myburgh, J G

    2011-02-01

    Although numerous hypotheses have been proposed to explain geophagy, the primary driver of this behaviour remains elusive. Supplementation of scarce nutrients is one commonly cited explanation. We examined the element concentration of three licks relative to adjacent topsoils to infer the possible reasons for geophagy at Loskop Dam Nature Reserve. Lick samples had greater concentrations of B, Co, Zn, Se, Mo and Mn (Loskop Main Lick); Cu (Klopperskloof Lick); and Na (Klopperskloof Lick and Rhenosterhoek Lick) than those of adjacent topsoil. We suggest that supplementation with all or some of these nutrients is a likely driver of geophagy in this fenced reserve, with different licks providing herbivores with different suites of nutrients.

  16. On the filamentary structures in the Lick galaxy catalogue

    NASA Astrophysics Data System (ADS)

    Dobrzycki, Adam

    1989-01-01

    The positions of the filaments observed by Moody et al. (1983) are discussed with respect to the arrangement of the plates in the Lick galaxy survey. An apparent difficiency of filaments near the plate centers is noted. Although the most prominent filaments appear to pass through the areas in the sky where the Lick survey plates overlap, on the whole there is no statistical tendency for the filaments to lie only on the overlapping areas.

  17. Flood-inundation map library for the Licking River and South Fork Licking River near Falmouth, Kentucky

    USGS Publications Warehouse

    Lant, Jeremiah G.

    2016-09-19

    Digital flood inundation maps for a 17-mile reach of Licking River and 4-mile reach of South Fork Licking River near Falmouth, Kentucky, were created by the U.S. Geological Survey (USGS) in cooperation with Pendleton County and the U.S. Army Corps of Engineers–Louisville District. The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://wim.usgs.gov/FIMI/FloodInundationMapper.html, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the Licking River at Catawba, Ky., (station 03253500) and the USGS streamgage on the South Fork Licking River at Hayes, Ky., (station 03253000). Current conditions (2015) for the USGS streamgages may be obtained online at the USGS National Water Information System site (http://waterdata.usgs.gov/nwis). In addition, the streamgage information has been provided to the National Weather Service (NWS) for incorporation into their Advanced Hydrologic Prediction Service (AHPS) flood warning system (http:/water.weather.gov/ahps/). The flood hydrograph forecasts provided by the NWS are usually collocated with USGS streamgages. The forecasted peak-stage information, also available on the NWS Web site, may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation.In this study, flood profiles were computed for the Licking River reach and South Fork Licking River reach by using a one-dimensional step-backwater model. The hydraulic model was calibrated by using the most current (2015) stage-discharge relations for the Licking River at Catawba, Ky., and the South Fork Licking River at Hayes, Ky., USGS streamgages. The calibrated model was then used to calculate 60 water-surface profiles for a sequence of flood stages, at 2-foot intervals, referenced to the streamgage datum and ranging from an elevation near bankfull to the elevation associated with a major flood that

  18. Proposed multiconjugate adaptive optics experiment at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Bauman, Brian J.; Gavel, Donald T.; Flath, Laurence M.; Hurd, Randall L.; Max, Claire E.; Olivier, Scot S.

    2002-02-01

    While the theory behind design of multiconjugate adaptive optics (MCAO) systems is growing, there is still a paucity of experience building and testing such instruments. We propose using the Lick adaptive optics (AO) system as a basis for demonstrating the feasibility/workability of MCAO systems, testing underlying assumptions, and experimenting with different approaches to solving MCAO system issues.

  19. Proposed Multiconjugate Adaptive Optics Experiment at Lick Observatory

    SciTech Connect

    Bauman, B J; Gavel, D T; Flath, L M; Hurd, R L; Max, C E; Olivier, S S

    2001-08-15

    While the theory behind design of multiconjugate adaptive optics (MCAO) systems is growing, there is still a paucity of experience building and testing such instruments. We propose using the Lick adaptive optics (AO) system as a basis for demonstrating the feasibility/workability of MCAO systems, testing underlying assumptions, and experimenting with different approaches to solving MCAO system issues.

  20. An analysis of licking microstructure in three strains of mice.

    PubMed

    Johnson, A W; Sherwood, A; Smith, D R; Wosiski-Kuhn, M; Gallagher, M; Holland, P C

    2010-04-01

    Mouse models of feeding provide a useful tool for elucidating the molecular pathways of energy regulation. The majority of studies in mice have been limited to intake analyses conducted over extended periods of time, which fail to distinguish between a variety of factors that influence nutrient intake. Using licking microstructure analyses we examined both the size and number of licking bursts for water, polycose, sucrose and lecithin in three strains of mice (C57BL/6J, 129Sv/ImJ and C57129F1 hybrids), using pause criteria (250-500, >500 and >1000 ms) that have previously been described in the rat. Burst size and number varied both as a function of tastant concentration and mouse strain; however, these differences were most evident with the >1000 ms pause criterion. Consistent with previous reports, during water consumption C57 mice showed longer mean interlick intervals, a larger number of bursts but reduced burst size relative to the two other strains. F1 mice showed larger burst sizes for polycose, while C57 mice displayed a greater number of bursts for both polycose and sucrose. Both 129 and F1 mice were insensitive to sucrose concentration, whereas C57 mice showed attenuated lecithin intake influenced by a reduction in the size of bursts for this tastant. These results suggest that these strains of mice display differences in the pattern of licking that are most evident with the use of larger pause criteria. These differences in licking behavior might reflect influences of genetic background on pre- and post-ingestive factors controlling intake, the reinforcing properties of each tastant, or native differences in licking style. Copyright 2009 Elsevier Ltd. All rights reserved.

  1. COCOA: Simulating Observations of Star Cluster Simulations

    NASA Astrophysics Data System (ADS)

    Askar, Abbas; Giersz, Mirek; Pych, Wojciech; Dalessandro, Emanuele

    2017-03-01

    COCOA (Cluster simulatiOn Comparison with ObservAtions) creates idealized mock photometric observations using results from numerical simulations of star cluster evolution. COCOA is able to present the output of realistic numerical simulations of star clusters carried out using Monte Carlo or N-body codes in a way that is useful for direct comparison with photometric observations. The code can simulate optical observations from simulation snapshots in which positions and magnitudes of objects are known. The parameters for simulating the observations can be adjusted to mimic telescopes of various sizes. COCOA also has a photometry pipeline that can use standalone versions of DAOPHOT (ascl:1104.011) and ALLSTAR to produce photometric catalogs for all observed stars.

  2. Treatment of canine acral lick dermatitis by behavior modification using electronic stimulation.

    PubMed

    Eckstein, R A; Hart, B L

    1996-01-01

    Canine acral lick dermatitis is characterized by excessive licking on areas of one or more limbs, usually near the carpus or tarsus. In this prospective study, five dogs with acral lick dermatitis were treated with remote punishment utilizing precisely controlled, momentary shock from an electronic training collar. The problem resolved in four dogs. Resolution was defined as one month in which no shocks (i.e., no electronic shock collar worn) or Elizabethan collars were utilized and no licking had occurred sufficiently to recreate a gross skin lesion. Relapse during the follow-up period of six-to-12 months occurred in two dogs, but licking stopped after brief retraining periods.

  3. VizieR Online Data Catalog: The LickX Spectra library (Worthey+, 2014)

    NASA Astrophysics Data System (ADS)

    Worthey, G.; Bianca Danilet, A.; Faber, S. M.

    2013-11-01

    Table2 lists spectral index measurements from the stellar spectral library that forms the basis of the Lick index system. Each star was cross-correlated with a template spectrum to improve the wavelength scale, removing most of the wavelength jitter from the original library, and some mistakes in names of objects were corrected. This collection of FITS files is a reworked version of the stellar spectral library that forms the basis of the Lick index system. Each star was cross-correlated with a template spectrum to improve the wavelength scale, removing most of the wavelength jitter from the original library, and some mistakes in names of objects were corrected. New FITS header Keywords give updated wavelength scale: WCRVAL is the wavelength of the first pixel in angstroms WCDELT is the dispersion in angstroms per pixel Occasionally wavelength limit information is include with keywords WLIMIT1 the wavelength in angstroms of the first reliable blue-end pixel WLIMIT2 the wavelength in angstroms of the first reliable red-end pixel Note that the old, unimproved wavelength scale is still present, using the standard keywords CRVAL and CDELT, and users are cautioned that those keywords are included only for historical reference and should not be used as the wavelength scale for scientific applications. The binary data parts of the files are 2048 pixels x 1 pixel in size. The file names are in time order and are of the form sdrXXNNMM, where XX = the number of the observing run NN = the "tape number" MM = the "scan number" Some observing runs have no data and are missing. The tape and scan numbers refer to the original PDP-11 data storage system and are no longer relevant except that the final series of integers remains in time-sequence order when alphabetized. There are 1043 FITS files, each containing one spectrum. (3 data files).

  4. The Visual Double Star Catalogs

    NASA Astrophysics Data System (ADS)

    Mason, Brian D.

    2015-08-01

    In visual double star work, production of the first comprehensive attempt to list all discovered pairs in his accessible sky was prepared by S.W. Burnham in 1906. A double star catalog for the southern hemisphere was prepared by R.T.A. Innes et al. in 1927 and the northern hemisphere catalog was updated by R.G. Aitken and E. Doolittle in 1932. Eventually, this led to Lick Observatory maintaining what became known as the Index Catalogue, an all-sky visual double star database.In 1964, under the aegis of Commission 26, the Lick double star database was transferred to the U.S. Naval Observatory where it was redesignated the Washington Double Star Catalog where it and it's ancillary catalogs, have been maintained for over half a century. The current statistics of the catalog and it's supplements are presented as are the enhancements currently under consideration.

  5. FIVE PLANETS AND AN INDEPENDENT CONFIRMATION OF HD 196885Ab FROM LICK OBSERVATORY

    SciTech Connect

    Fischer, Debra; Isaacson, Howard; Giguere, Matt; McCarthy, Chris; Driscoll, Peter; Marcy, Geoffrey W.; Howard, Andrew; Peek, Katherine; Valenti, Jeff; Wright, Jason T.; Henry, Gregory W.; Johnson, John Asher

    2009-10-01

    We present time series Doppler data from Lick Observatory that reveal the presence of long-period planetary companions orbiting nearby stars. The typical eccentricity of these massive planets are greater than the mean eccentricity of known exoplanets. HD 30562b has Msin i = 1.29 M {sub Jup}, with semimajor axis of 2.3 AU and eccentricity 0.76. The host star has a spectral type F8V and is metal rich. HD 86264b has Msin i = 7.0 M {sub Jup}, a {sub rel} = 2.86 AU, an eccentricity e = 0.7 and orbits a metal-rich, F7V star. HD 87883b has Msin i = 1.78 M {sub Jup}, a {sub rel} = 3.6 AU, e = 0.53 and orbits a metal-rich K0V star. HD 89307b has Msin i = 1.78 M {sub Jup}, a {sub rel} = 3.3 AU, e = 0.24 and orbits a G0V star with slightly subsolar metallicity. HD 148427b has Msin i = 0.96 M {sub Jup}, a {sub rel} = 0.93 AU, eccentricity of 0.16 and orbits a metal rich K0 subgiant. We also present velocities for a planet orbiting the F8V metal-rich binary star, HD 196885A. The planet has Msin i = 2.58 M {sub Jup}, a {sub rel} = 2.37 AU, and orbital eccentricity of 0.48, in agreement with the independent discovery by Correia et al.

  6. An open source device for operant licking in rats

    PubMed Central

    Longley, Matthew; Willis, Ethan L.; Tay, Cindy X.

    2017-01-01

    We created an easy-to-use device for operant licking experiments and another device that records environmental variables. Both devices use the Raspberry Pi computer to obtain data from multiple input devices (e.g., radio frequency identification tag readers, touch and motion sensors, environmental sensors) and activate output devices (e.g., LED lights, syringe pumps) as needed. Data gathered from these devices are stored locally on the computer but can be automatically transferred to a remote server via a wireless network. We tested the operant device by training rats to obtain either sucrose or water under the control of a fixed ratio, a variable ratio, or a progressive ratio reinforcement schedule. The lick data demonstrated that the device has sufficient precision and time resolution to record the fast licking behavior of rats. Data from the environment monitoring device also showed reliable measurements. By providing the source code and 3D design under an open source license, we believe these examples will stimulate innovation in behavioral studies. The source code can be found at http://github.com/chen42/openbehavior. PMID:28229020

  7. Remote observing with the Nickel Telescope at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Grigsby, Bryant; Chloros, Konstantinos; Gates, John; Deich, William T. S.; Gates, Elinor; Kibrick, Robert

    2008-07-01

    We describe a project to enable remote observing on the Nickel 1-meter Telescope at Lick Observatory. The purpose was to increase the subscription rate and create more economical means for graduate- and undergraduate students to observe with this telescope. The Nickel Telescope resides in a 125 year old dome on Mount Hamilton. Remote observers may work from any of the University of California (UC) remote observing facilities that have been created to support remote work at both Keck Observatory and Lick Observatory. The project included hardware and software upgrades to enable computer control of all equipment that must be operated by the astronomer; a remote observing architecture that is closely modeled on UCO/Lick's work to implement remote observing between UC campuses and Keck Observatory; new policies to ensure safety of Observatory staff and equipment, while ensuring that the telescope subsystems would be suitably configured for remote use; and new software to enforce the safety-related policies. The results increased the subscription rate from a few nights per month to nearly full subscription, and has spurred the installation of remote observing sites at more UC campuses. Thanks to the increased automation and computer control, local observing has also benefitted and is more efficient. Remote observing is now being implemented for the Shane 3- meter telescope.

  8. An open source device for operant licking in rats.

    PubMed

    Longley, Matthew; Willis, Ethan L; Tay, Cindy X; Chen, Hao

    2017-01-01

    We created an easy-to-use device for operant licking experiments and another device that records environmental variables. Both devices use the Raspberry Pi computer to obtain data from multiple input devices (e.g., radio frequency identification tag readers, touch and motion sensors, environmental sensors) and activate output devices (e.g., LED lights, syringe pumps) as needed. Data gathered from these devices are stored locally on the computer but can be automatically transferred to a remote server via a wireless network. We tested the operant device by training rats to obtain either sucrose or water under the control of a fixed ratio, a variable ratio, or a progressive ratio reinforcement schedule. The lick data demonstrated that the device has sufficient precision and time resolution to record the fast licking behavior of rats. Data from the environment monitoring device also showed reliable measurements. By providing the source code and 3D design under an open source license, we believe these examples will stimulate innovation in behavioral studies. The source code can be found at http://github.com/chen42/openbehavior.

  9. World coordinate system keywords for FITS files from Lick Observatory

    NASA Astrophysics Data System (ADS)

    Allen, Steven L.; Gates, John; Kibrick, Robert I.

    2010-07-01

    Every bit of metadata added at the time of acquisition increases the value of image data, facilitates automated processing of those data, and decreases the effort required during subsequent data curation activities. In 2002 the FITS community completed a standard for World Coordinate System (WCS) information which describes the celestial coordinates of pixels in astronomical image data. Most of the instruments in use at Lick Observatory and Keck Observatory predate this standard. None of them was designed to produce FITS files with celestial WCS information. We report on the status of WCS keywords in the FITS files of various astronomical detectors at Lick and Keck. These keywords combine the information from sources which include the telescope pointing system, the optics of the telescope and instrument, a description of the pixel layout of the detector focal plane, and the hardware and software mappings between the silicon pixels of the detector and the pixels in the data array of the FITS file. The existing WCS keywords include coordinates which refer to the detector structure itself (for locating defects and artifacts), but not celestial coordinates. We also present proof-of-concept from the first data acquisition system at Lick Observatory which inserts the WCS keywords for a celestial coordinate system.

  10. Drug treatment of canine acral lick. An animal model of obsessive-compulsive disorder.

    PubMed

    Rapoport, J L; Ryland, D H; Kriete, M

    1992-07-01

    Canine acral lick dermatitis is a naturally occurring disorder in which excessive licking of paws or flank can produce ulcers and infection that require medical treatment. Forty-two dogs with severe chronic canine acral lick dermatitis were treated in three double-blind crossover comparisons of clomipramine hydrochloride/desipramine hydrochloride, fluoxetine hydrochloride/fenfluramine hydrochloride, and sertraline hydrochloride/placebo. The serotonin uptake blocking drugs were clinically effective, while the other drugs were not. Based on phenomenology and pharmacological response, we propose canine acral lick dermatitis as an animal model of obsessive-compulsive disorder.

  11. Lick Observatory charge-coupled-device data acquisition system

    NASA Technical Reports Server (NTRS)

    Robinson, L. B.; Stover, R. J.; Osborne, J.; Miller, J. S.; Vogt, S. S.

    1987-01-01

    The Lick Observatory CCD data acquisition system is described, with some observational results to illustrate the system capability. The electronics for the CCD are subdivided into those attached to the dewar, a 'smart' controller near the dewar, and a computer connected by serial link to the smart controller. Software for the controller is in assembler code, while the software for data acquisition and on-line analysis is written in C and uses the UNIX operating system. The computers and controllers are programmed to recognize and operate several different types of CCD. Three separate instruments that use the CCDs are described briefly, together with examples of the data they produce.

  12. Within-session decrement of the emission of licking bursts following reward devaluation in rats licking for sucrose

    PubMed Central

    Galistu, Adriana

    2017-01-01

    We previously observed that dopamine D2-like receptor blockade in rats licking for sucrose produced a within-session decrement of the emission of licking bursts similar to the effect of either reward devaluation, or neuroleptics, on operant responding for different rewards, which, accordingly, we interpreted as an extinction-like effect. This implies that exposing animals to reward devaluation would result in a drop of burst number taking place only after the contact with the devalued reward. To test this prediction, we compared the difference in the within-session time course of burst number in response to high (10%) versus low (2%) concentration sucrose solutions, either in a condition of reward devaluation (exposure to 2% after daily 10%), or in a condition which does not involve changes in the reward value (two groups of subjects each repeatedly exposed to only one of the two concentrations). Reward devaluation resulted in a within-session decrement of the burst number, with the response rate dropping only after the contact with the devalued reward, as predicted. This response pattern was reliably observed only in subjects at their first devaluation experience. In contrast, exposure of separate groups of animals to the two different concentrations yielded lower levels of burst number in the low concentration group apparent since the beginning of the session, as previously observed with dopamine D1-like receptor blockade. These results show that the analysis of burst number, but not of burst size, reveals a specific activation pattern in response to reward devaluation, which differs from the pattern observed comparing the response to two different sucrose concentrations in separate groups of subjects, i.e. in a condition not involving reward devaluation. Finally, the characterisation of the experimental measures of the analysis of licking microstructure in behaviourally (and psychologically) meaningful functional terms, might be relevant for the investigation of

  13. Within-session decrement of the emission of licking bursts following reward devaluation in rats licking for sucrose.

    PubMed

    D'Aquila, Paolo S; Galistu, Adriana

    2017-01-01

    We previously observed that dopamine D2-like receptor blockade in rats licking for sucrose produced a within-session decrement of the emission of licking bursts similar to the effect of either reward devaluation, or neuroleptics, on operant responding for different rewards, which, accordingly, we interpreted as an extinction-like effect. This implies that exposing animals to reward devaluation would result in a drop of burst number taking place only after the contact with the devalued reward. To test this prediction, we compared the difference in the within-session time course of burst number in response to high (10%) versus low (2%) concentration sucrose solutions, either in a condition of reward devaluation (exposure to 2% after daily 10%), or in a condition which does not involve changes in the reward value (two groups of subjects each repeatedly exposed to only one of the two concentrations). Reward devaluation resulted in a within-session decrement of the burst number, with the response rate dropping only after the contact with the devalued reward, as predicted. This response pattern was reliably observed only in subjects at their first devaluation experience. In contrast, exposure of separate groups of animals to the two different concentrations yielded lower levels of burst number in the low concentration group apparent since the beginning of the session, as previously observed with dopamine D1-like receptor blockade. These results show that the analysis of burst number, but not of burst size, reveals a specific activation pattern in response to reward devaluation, which differs from the pattern observed comparing the response to two different sucrose concentrations in separate groups of subjects, i.e. in a condition not involving reward devaluation. Finally, the characterisation of the experimental measures of the analysis of licking microstructure in behaviourally (and psychologically) meaningful functional terms, might be relevant for the investigation of

  14. Operant licking for intragastric sugar infusions: Differential reinforcing actions of glucose, sucrose and fructose in mice.

    PubMed

    Sclafani, Anthony; Ackroff, Karen

    2016-01-01

    Intragastric (IG) flavor conditioning studies in rodents indicate that isocaloric sugar infusions differ in their reinforcing actions, with glucose and sucrose more potent than fructose. Here we determined if the sugars also differ in their ability to maintain operant self-administration by licking an empty spout for IG infusions. Food-restricted C57BL/6J mice were trained 1 h/day to lick a food-baited spout, which triggered IG infusions of 16% sucrose. In testing, the mice licked an empty spout, which triggered IG infusions of different sugars. Mice shifted from sucrose to 16% glucose increased dry licking, whereas mice shifted to 16% fructose rapidly reduced licking to low levels. Other mice shifted from sucrose to IG water reduced licking more slowly but reached the same low levels. Thus IG fructose, like water, is not reinforcing to hungry mice. The more rapid decline in licking induced by fructose may be due to the sugar's satiating effects. Further tests revealed that the Glucose mice increased their dry licking when shifted from 16% to 8% glucose, and reduced their dry licking when shifted to 32% glucose. This may reflect caloric regulation and/or differences in satiation. The Glucose mice did not maintain caloric intake when tested with different sugars. They self-infused less sugar when shifted from 16% glucose to 16% sucrose, and even more so when shifted to 16% fructose. Reduced sucrose self-administration may occur because the fructose component of the disaccharide reduces its reinforcing potency. FVB mice also reduced operant licking when tested with 16% fructose, yet learned to prefer a flavor paired with IG fructose. These data indicate that sugars differ substantially in their ability to support IG self-administration and flavor preference learning. The same post-oral reinforcement process appears to mediate operant licking and flavor learning, although flavor learning provides a more sensitive measure of sugar reinforcement. Copyright © 2015

  15. Operant licking for intragastric sugar infusions: differential reinforcing actions of glucose, sucrose and fructose in mice

    PubMed Central

    Sclafani, Anthony; Ackroff, Karen

    2015-01-01

    Intragastric (IG) flavor conditioning studies in rodents indicate that isocaloric sugar infusions differ in their reinforcing actions, with glucose and sucrose more potent than fructose. Here we determined if the sugars also differ in their ability to maintain operant self-administration by licking an empty spout for IG infusions. Food-restricted C57BL/6J mice were trained 1 h/day to lick a food-baited spout, which triggered IG infusions of 16% sucrose. In testing, the mice licked an empty spout, which triggered IG infusions of different sugars. Mice shifted from sucrose to 16% glucose increased dry licking, whereas mice shifted to 16% fructose rapidly reduced licking to low levels. Other mice shifted from sucrose to IG water reduced licking more slowly but reached the same low levels. Thus IG fructose, like water, is not reinforcing to hungry mice. The more rapid decline in licking induced by fructose may be due to the sugar's satiating effects. Further tests revealed that the Glucose mice increased their dry licking when shifted from 16% to 8% glucose, and reduced their dry licking when shifted to 32% glucose. This may reflect caloric regulation and/or differences in satiation. The Glucose mice did not maintain caloric intake when tested with different sugars. They self-infused less sugar when shifted from 16% glucose to 16% sucrose, and even more so when shifted to 16% fructose. Reduced sucrose self-administration may occur because the fructose component of the disaccharide reduces its reinforcing potency. FVB mice also reduced operant licking when tested with 16% fructose, yet learned to prefer a flavor paired with IG fructose. These data indicate that sugars differ substantially in their ability to support IG self-administration and flavor preference learning. The same post-oral reinforcement process appears to mediate operant licking and flavor learning, although flavor learning provides a more sensitive measure of sugar reinforcement. PMID:26485294

  16. 75 FR 9530 - FM TABLE OF ALLOTMENTS, French Lick, Indiana, and Irvington, Kentucky.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-03

    ... COMMISSION 47 CFR Part 73 FM TABLE OF ALLOTMENTS, French Lick, Indiana, and Irvington, Kentucky. AGENCY... filed by L. Dean Spencer to allot FM Channel 261A at Irvington, Kentucky, as a first local service. To accommodate this new allotment, the staff modifies the license of Station WFLQ(FM), French Lick, Indiana,...

  17. Parsing the hedonic and motivational influences of nociceptin on feeding using licking microstructure analysis in mice

    PubMed Central

    Mendez, Ian A.; Maidment, Nigel T.; Murphy, Niall P.

    2016-01-01

    Opioid peptides are implicated in processes related to reward and aversion; however, how specific opioid peptides are involved remains unclear. We investigated the role of nociceptin (NOC) in voluntary licking for palatable and aversive tastants by studying the effect of intracerebroventricularly (i.c.v.) administered NOC on licking microstructure in wild-type and NOC receptor knockout (NOP KO) mice. Compared to wildtypes, NOP KO mice emitted fewer bouts of licking when training to lick for a 20% sucrose solution. Correspondingly, i.c.v. administration of NOC increased the number of licking bouts for sucrose and sucralose in wildtype, but not NOP KO mice. The ability of NOC to initiate new bouts of licking for sweet solutions suggests that NOC may drive motivational aspects of feeding behavior. Conversely, adulterating a sucrose solution with the aversive tastant quinine reduced licking bout lengths in wildtype and NOP KOs, suggesting that NOC signaling is not involved in driving voluntary consumption of semi-aversive tastants. Interestingly, when consuming sucrose following 20 hours of food deprivation, NOP KO mice emitted longer bouts of licking than wildtypes, suggesting that under hungry conditions NOC may also contribute to hedonic aspects of feeding. Together, these results suggest differential roles for NOC in the motivational and hedonic aspects of feeding. PMID:27100061

  18. Archaeological Reconnaissance Survey and Salvage Excavation in the Salt Lick Recreation Area.

    DTIC Science & Technology

    1979-04-01

    REPORT & PERIOD COVERED Archaeological Reconnaissancei Survey and Salvage Survey Excavations in-the Salt Lick Recreation Area, Jackson County...reverse side if necessary end Identify by block number) Jackson County, Tennessee Salt Lick Recreation Area Archaeological excavations Paleo-Indian period...the Cordell llull Reservoir/Cumberland River in Jackson County, (north central) Tennessee, has documented nine prehistoric sites manifesting

  19. Parsing the hedonic and motivational influences of nociceptin on feeding using licking microstructure analysis in mice.

    PubMed

    Mendez, Ian A; Maidment, Nigel T; Murphy, Niall P

    2016-09-01

    Opioid peptides are implicated in processes related to reward and aversion; however, how specific opioid peptides are involved remains unclear. We investigated the role of nociceptin (NOC) in voluntary licking for palatable and aversive tastants by studying the effect of intracerebroventricularly administered NOC on licking microstructure in wild-type and NOC receptor knockout (NOP KO) mice. Compared with the wild-type mice, NOP KO mice emitted fewer bouts of licking when training to lick for a 20% sucrose solution. Correspondingly, intracerebroventricular administration of NOC increased the number of licking bouts for sucrose and sucralose in wild-type, but not in NOP KO mice. The ability of NOC to initiate new bouts of licking for sweet solutions suggests that NOC may drive motivational aspects of feeding behavior. Conversely, adulterating a sucrose solution with the aversive tastant quinine reduced licking bout lengths in wild-type and NOP KOs, suggesting that NOC signaling is not involved in driving voluntary consumption of semiaversive tastants. Interestingly, when consuming sucrose following 20 h of food deprivation, NOP KO mice emitted longer bouts of licking than wild types, suggesting that under hungry conditions, NOC may also contribute toward hedonic aspects of feeding. Together, these results suggest differential roles for NOC in the motivational and hedonic aspects of feeding.

  20. Suppression of operant behavior and schedule-induced licking in rats1

    PubMed Central

    Bond, N. W.; Blackman, D. E.; Scruton, Pamela

    1973-01-01

    The first experiment studied the effects of punishment on rats' lever pressing maintained by a fixed-interval schedule of food reinforcement and on the associated schedule-induced licking. When licking was followed by shock, licking was suppressed but lever pressing was largely unaffected. When lever pressing was followed by shock, lever pressing was suppressed but licking was unaffected. In both cases, the punished behavior recovered its previous unpunished level when the shocks were discontinued. In a second experiment, the rats' lever pressing was maintained by a variable-interval schedule of food reinforcement under which polydipsic licking also developed. Both lever pressing and licking were partially suppressed during a stimulus correlated with occasional unavoidable electric shocks. With a higher shock intensity, both behaviors were suppressed further. Both lever pressing and licking recovered their previous levels when shocks were discontinued. These results show that schedule-induced licking, which has been described as adjunctive behavior, can be suppressed by procedures that suppress reinforced lever pressing, an operant behavior. PMID:4759059

  1. Alopecia in four kittens caused by abnormal maternal licking behaviour.

    PubMed

    Fanton, N; Michelazzi, M; Cornegliani, L

    2015-11-01

    Abnormal maternal behaviour has been reported in cats, but is generally not included among the causes of alopecia in kittens. A litter of four kittens, 2 months old, was referred for evaluation of facial alopecia of differing severity. The 2-year-old queen was unaffected. Dermatological examination of the kittens did not find any infectious cause. Trichograms showed broken hair shafts with longitudinal splitting. Congenital alopecia was unlikely based on the clinical presentation. A behavioural consultation revealed abnormal grooming behaviour by the mother, who chewed and removed the hair from the kittens. The kittens were separated from the queen and alopecia resolved within a few weeks. To the authors' knowledge, this is the first report of alopecia caused by abnormal maternal licking behaviour. Abnormal maternal behaviour should be considered in cases of alopecia affecting a litter of kittens, when infectious and congenital causes have been ruled out. © 2015 Australian Veterinary Association.

  2. Adaptive optics at Lick Observatory: system architecture and operations

    NASA Astrophysics Data System (ADS)

    Brase, James M.; An, Jong; Avicola, Kenneth; Bissinger, Horst D.; Friedman, Herbert W.; Gavel, Donald T.; Johnston, Brooks; Max, Claire E.; Olivier, Scot S.; Presta, Robert W.; Rapp, David A.; Salmon, J. Thaddeus; Waltjen, Kenneth E.; Fisher, William A.

    1994-05-01

    We will describe an adaptive optics system developed for the 1 meter Nickel and 3 meter Shane telescopes at Lick Observatory. Observing wavelengths will be in the visible for the 1 meter telescope and in the near IR on the 3 meter. The adaptive optics system design is based on a 69 actuator continuous surface deformable mirror and a Hartmann wavefront sensor equipped with an intensified CCD framing camera. The system has been tested at the Cassegrain focus of the 1 meter telescope where the subaperture size is 12.5 cm. The wavefront control calculations are performed on a four processor single board computer controlled by a Unix-based system. We will describe the optical system and give details of the wavefront control system design. We will present predictions of the system performance and initial test results.

  3. Adaptive optics at Lick Observatory: System architecture and operations

    SciTech Connect

    Brase, J.M.; An, J.; Avicola, K.

    1994-03-01

    We will describe an adaptive optics system developed for the 1 meter Nickel and 3 meter Shane telescopes at Lick Observatory. Observing wavelengths will be in the visible for the 1 meter telescope and in the near IR on the 3 meter. The adaptive optics system design is based on a 69 actuator continuous surface deformable mirror and a Hartmann wavefront sensor equipped with an intensified CCD framing camera. The system has been tested at the Cassegrain focus of the 1 meter telescope where the subaperture size is 12.5 cm. The wavefront control calculations are performed on a four processor single board computer controlled by a Unix-based system. We will describe the optical system and give details of the wavefront control system design. We will present predictions of the system performance and initial test results.

  4. Analysis of on-sky sodium profile data from Lick Observatory.

    PubMed

    Thomas, Sandrine J; Gavel, Donald; Kibrick, Robert

    2010-01-20

    The next generation of adaptive optics will depend on laser guide stars to increase sky coverage. However, there are a few limitations. The thickness of the sodium layer in the mesosphere at 90 km causes spot elongation, which is more severe for large telescopes. Moreover, the outer-edge subaperture of such large telescopes will resolve variations of sodium atom density seen over the thick layer. We quantify these density fluctuations using real data taken at Lick Observatory. We used the 1 m Nickel telescope to image the return flux due to laser-induced fluorescence from a dye laser launched from the nearby 3 m Shane telescope. This view was from the side allowing the resolution of the sodium return as a function of height. We used drift scanning of the 1 m telescope to provide resolution in time. We show qualitative images of the sodium distribution for different nights and quantitatively study the temporal power spectra of those fluctuations. We conclude that the sodium profiles have an average full width half-maximum of 10 km. However, the extent beyond the nominal 10 km thickness is important for accurate wavefront sensing. The variations in the height of the sodium layer occur on short enough time scales that AO systems for 30 m class telescopes will likely need focus updates on time scales shorter than 100 ms.

  5. Photometric light curves for ten rapidly rotating stars in Alpha Persei, the Pleiades, and the field

    NASA Technical Reports Server (NTRS)

    Prosser, Charles F.; Schild, Rudolph E.; Stauffer, John R.; Jones, Burton F.

    1993-01-01

    We present the results from a photometric monitoring program of ten rapidly rotating stars observed during 1991 using the FLWO 48-in. telescope. Brightness variations for an additional six cluster stars observed with the Lick 40-in. telescope are also given. The periods and light curves for seven Alpha Persei members, two Pleiades members, and one naked T Tauri field star are reported.

  6. New tools for the tracing of ancient starbursts: Analysing globular cluster systems using Lick indices

    NASA Astrophysics Data System (ADS)

    Lilly, T.; Fritze-v. Alvensleben, U.; de Grijs, R.

    2005-05-01

    We present mathematically advanced tools for the determination of age, metallicity, and mass of old Globular Clusters (CGs) using both broad-band colors and spectral indices, and we present their application to the Globular Cluster Systems (GCSs) of elliptical galaxies. Since one of the most intriguing questions of today's astronomy aims at the evolutionary connection between (young) violently interacting galaxies at high-redshift and the (old) elliptical galaxies we observe nearby, it is necessary to reveal the possibly violent star-formation history of these old galaxies. By means of evolutionary synthesis models, we can show that, using the integrated light of a galaxy's (composite) stellar content alone, it is impossible to date (and, actually, to identify) even very strong starbursts if these events took place more than two or three Gyr ago. However, since large and violent starbursts are associated with the formation of GCs, GCSs are very good tracers of the most violent starburst events in the history of their host galaxies. Using our well-established Göttingen SED (Spectral Energy Distribution) analysis tool, we can reveal the age, metallicity, mass (and possibly extinction) of GCs by comparing the observations with an extensive grid of SSP model colors. This is done in a statistically advanced and reasonable way, including their 1 σ uncertainties. However, since for all colors the evolution slows down considerably at ages older than about 8 Gyr, even with several passbands and a long wavelength base line, the results are severely uncertain for old clusters. Therefore, we incorporated empirical calibrations for Lick indices in our models and developed a Lick indices analysis tool that works in the same way as the SED analysis tool described above. We compare the theoretical possibilities and limitations of both methods as well as their results for the example of the cD galaxy NGC 1399, for which both multi-color observations and, for a subsample of

  7. Lick-trading by rats: on the substitutability of dry, water, and saccharin tubes.

    PubMed Central

    Allison, J; Moore, K E

    1985-01-01

    Thirsty rats licked two metal tubes: a water tube paired with another water tube, with saccharin, or with a dry tube. For each pair, a multipoint baseline function was measured by offering free access to one tube throughout each session, and free or restricted access to the other. The three resulting baseline functions showed the members of each pair to be mutual substitutes: When access to either tube was restricted, the rats made more licks at the other. A linear function identified the two water tubes as perfect substitutes. Convex functions identified the members of the saccharin-water and the dry-water pair as imperfect substitutes. Each pair was also tested under several reciprocal fixed-ratio schedules that required instrumental licking of either tube for contingent access to the other. The resulting schedule functions showed the members of each pair to be perfect substitutes: Water licks decreased linearly as licks at the other water tube, the saccharin, or the dry tube increased, in agreement with a conservation model of instrumental performance. Baseline and schedule functions, indistinguishable in the water-water pair, indicated a schedule facilitation of dry-tube licking in the dry-water pair and of water-tube licking in the saccharin-water pair. PMID:3998658

  8. Lick-trading by rats: on the substitutability of dry, water, and saccharin tubes.

    PubMed

    Allison, J; Moore, K E

    1985-03-01

    Thirsty rats licked two metal tubes: a water tube paired with another water tube, with saccharin, or with a dry tube. For each pair, a multipoint baseline function was measured by offering free access to one tube throughout each session, and free or restricted access to the other. The three resulting baseline functions showed the members of each pair to be mutual substitutes: When access to either tube was restricted, the rats made more licks at the other. A linear function identified the two water tubes as perfect substitutes. Convex functions identified the members of the saccharin-water and the dry-water pair as imperfect substitutes. Each pair was also tested under several reciprocal fixed-ratio schedules that required instrumental licking of either tube for contingent access to the other. The resulting schedule functions showed the members of each pair to be perfect substitutes: Water licks decreased linearly as licks at the other water tube, the saccharin, or the dry tube increased, in agreement with a conservation model of instrumental performance. Baseline and schedule functions, indistinguishable in the water-water pair, indicated a schedule facilitation of dry-tube licking in the dry-water pair and of water-tube licking in the saccharin-water pair.

  9. Snapshot Metallicity Estimate of Resolved Stellar Systems Through Lick Fe5270 Diagnostic

    NASA Astrophysics Data System (ADS)

    Buzzoni, A.; Bertone, E.; Chavez, M.

    2009-10-01

    We outline a new method to derive a "snapshot" metallicity estimate of stellar systems (providing one resolves at least the brightest part of the color-magnitude diagram) on the basis of low-resolution (i.e., 6-8 Å FWHM) spectroscopy of a small stellar sample. Our method relies on the Fe5270 Lick index measurements and takes advantage of the special behavior of this spectral feature that reaches its maximum strength among the ubiquitous component of K-type giants. This makes the Fe5270max estimate a robust and model-independent tracer of cluster [Fe/H], being particularly insensitive to the age of the stellar population. A comparison of the Fe5270max distribution derived from globular and open clusters, as well as from the field giant population in the Galaxy disk, confirms a tight correlation of the index maximum versus cluster [Fe/H] over the entire metallicity range for a stellar population with [Fe/H] gsim-2.0. Relying on a theoretical calibration of the feature, we trust to infer effectively cluster metallicity within a typical uncertainty of 0.1-0.2 dex, depending on red giant branch (RGB) luminosity sampling of the observations. A handful of stars (5-10 objects) is required for the method to be applied, with low-metallicity stellar populations more easily managed, being Fe5270max located within the few brightest RGB stars of the system. In any case, we show that even the observation of a coarse stellar set would allow us to place a confident lower limit on cluster metallicity.

  10. SNAPSHOT METALLICITY ESTIMATE OF RESOLVED STELLAR SYSTEMS THROUGH LICK Fe5270 DIAGNOSTIC

    SciTech Connect

    Buzzoni, A.; Bertone, E.; Chavez, M.

    2009-10-01

    We outline a new method to derive a 'snapshot' metallicity estimate of stellar systems (providing one resolves at least the brightest part of the color-magnitude diagram) on the basis of low-resolution (i.e., 6-8 A FWHM) spectroscopy of a small stellar sample. Our method relies on the Fe5270 Lick index measurements and takes advantage of the special behavior of this spectral feature that reaches its maximum strength among the ubiquitous component of K-type giants. This makes the Fe5270{sub max} estimate a robust and model-independent tracer of cluster [Fe/H], being particularly insensitive to the age of the stellar population. A comparison of the Fe5270{sub max} distribution derived from globular and open clusters, as well as from the field giant population in the Galaxy disk, confirms a tight correlation of the index maximum versus cluster [Fe/H] over the entire metallicity range for a stellar population with [Fe/H] approx>-2.0. Relying on a theoretical calibration of the feature, we trust to infer effectively cluster metallicity within a typical uncertainty of 0.1-0.2 dex, depending on red giant branch (RGB) luminosity sampling of the observations. A handful of stars (5-10 objects) is required for the method to be applied, with low-metallicity stellar populations more easily managed, being Fe5270{sub max} located within the few brightest RGB stars of the system. In any case, we show that even the observation of a coarse stellar set would allow us to place a confident lower limit on cluster metallicity.

  11. Keepers of the double stars

    NASA Astrophysics Data System (ADS)

    Tenn, Joseph S.

    2013-03-01

    Astronomers have long tracked double stars in efforts to find those that are gravitationally-bound binaries and then to determine their orbits. Early catalogues by the Herschels, Struves, and others began with their own discoveries. In 1906 court reporter and amateur astronomer Sherburne Wesley Burnham published a massive double star catalogue containing data from many observers on more than 13,000 systems. Lick Observatory astronomer Robert Grant Aitken produced a much larger catalogue in 1932 and coordinated with Robert Innes of Johannesburg, who catalogued the southern systems. Aitken maintained and expanded Burnham's records of observations on handwritten file cards, and eventually turned them over to the Lick Observatory, where astrometrist Hamilton Jeffers further expanded the collection and put all the observations on punched cards. With the aid of Frances M. "Rete" Greeby he made two catalogues: an Index Catalogue with basic data about each star, and a complete catalogue of observations, with one observation per punched card. He enlisted Willem van den Bos of Johannesburg to add southern stars, and together they published the Index Catalogue of Visual Double Stars, 1961.0. As Jeffers approached retirement he became greatly concerned about the disposition of the catalogues. He wanted to be replaced by another "double star man," but Lick Director Albert E. Whitford had the new 120-inch reflector, the world's second largest telescope, and he wanted to pursue modern astrophysics instead. Jeffers was vociferously opposed to turning over the card files to another institution, and especially against their coming under the control of Kaj Strand of the United States Naval Observatory. In the end the USNO got the files and has maintained the records ever since, first under Charles Worley, and, since 1997, under Brian Mason. Now called the Washington Double Star Catalog (WDS), it is completely online and currently contains more than 1,200,000 measures of more than 125

  12. Influence of different histamine receptor agonists and antagonists on apomorphine-induced licking behavior in rat.

    PubMed

    Farzin, D; Attarzadeh, M

    2000-09-15

    The effects of different histamine receptor agonists and antagonists on apomorphine-induced licking behavior in rats were investigated. Subcutaneous (s.c.) injection of various doses of apomorphine (0. 125-1.25 mg/kg) induced licking. The licking response was counted by direct observation and recorded for a 75-min period. Intracerebroventricular (i.c.v.) or intraperitoneal (i.p.) injection of the histamine H(1) or H(2) receptor agonist, HTMT (6-[2-(4-imidazolyl)ethylamino]-N-(4-trifluoromethylphenyl) heptanecarboxamide) (50 and 100 microg per rat), or dimaprit (10 and 15 mg/kg, i.p.), respectively, potentiated apomorphine-induced licking, while the histamine H(3) receptor agonist, imetit (5 and 10 mg/kg, i.p.), reduced the licking response induced by apomorphine. Pretreatment with various histamine receptor antagonists, dexchlorpheniramine (30 and 40 mg/kg, i.p.), diphenhydramine (20, 30 and 40 mg/kg, i.p.), famotidine (30 and 40 mg/kg, s.c.) and ranitidine (20, 30 and 40 mg/kg), reduced apomorphine-induced licking, while thioperamide (5 and 10 mg/kg, i.p.) potentiated the apomorphine effect. The effects of HTMT and dimaprit were blocked by dexchlorpheniramine (20 mg/kg, i.p.) and famotidine (20 mg/kg, s.c.), respectively. The inhibitory effect elicited by imetit on apomorphine-induced licking behavior was also abolished in animals treated with thioperamide (2.5 mg/kg, i.p.). The results suggest that histaminergic mechanisms may be involved in the modulation of apomorphine-induced licking behavior.

  13. Benzodiazepine effects on licking responses for sodium chloride solutions in water-deprived male rats.

    PubMed

    Cooper, Steven J; Higgs, Suzanne

    2005-06-30

    The aim of this study was to investigate, for the first time, the effects of a centrally active benzodiazepine receptor agonist, midazolam maleate, on the microstructure of licking responses for a range of sodium chloride (NaCl) solutions in mildly water-deprived male rats. Doses of midazolam were chosen (0.3-3.0 mg/kg. i.p.) which have been characterised in studies of licking responses for several different kinds of nutrients. NaCl concentrations (0.075 M-0.45 M) were chosen to cover a range of taste preferences and acceptability. A brief-contact testing session was employed to focus on the initial determinants of licking responses (i.e. taste palatability), and to minimise any contribution of post-ingestional effects. The results indicate the midazolam significantly increased the total number of licks recorded across all salt concentrations, but that it had no effect on the number of bouts of licking. Instead, midazolam specifically enhanced the mean duration of licking bouts, an effect that was most evident at the weaker but more acceptable NaCl concentrations (0.075 M and 0.15 M). In addition, midazolam diminished the intrabout rate of licking across all salt concentrations. These results confirm that benzodiazepines can exert a specific pattern of effects on the microstructure of licking for salt solutions. They are discussed in terms of the oropharyngeal stimulation controlling intake and the palatability or "liking" hypothesis for the effects of benzodiazepines on taste stimuli, and indicate that the hypothesis is applicable to salt solution ingestive behaviour.

  14. Head rubbing and licking reinforce social bonds in a group of captive African lions, Panthera leo.

    PubMed

    Matoba, Tomoyuki; Kutsukake, Nobuyuki; Hasegawa, Toshikazu

    2013-01-01

    Many social animals have a species-specific repertoire of affiliative behaviours that characterise individualised relationships within a group. To date, however, quantitative studies on intragroup affiliative behaviours in social carnivores have been limited. Here, we investigated the social functions of the two most commonly observed affiliative behaviours in captive African lions (Panthera leo): head rubbing and licking. We conducted behavioural observations on a captive group of lions composed of 7 males and 14 females, and tested hypotheses regarding three social functions: tension reduction, social bonding, and social status expression. Disproportionately frequent male-male and female-to-male head rubbing was observed, while more than 95% of all licking interactions occurred in female-female dyads. In accordance with the social bond hypothesis, and in disagreement with the social status expression hypothesis, both head rubbing and licking interactions were reciprocal. After controlling for spatial association, the dyadic frequency of head rubbing was negatively correlated with age difference while licking was positively correlated with relatedness. Group reunion after daily separation did not affect the frequencies of the affiliative behaviours, which was in disagreement with the predictions from the tension reduction hypothesis. These results support the social bond hypothesis for the functions of head rubbing and licking. Different patterns of affiliative behaviour between the sexes may reflect differences in the relationship quality in each sex or the differential predisposition to licking due to its original function in offspring care.

  15. Dose- and Rate-Dependent Effects of Cocaine on Striatal Firing Related to Licking

    PubMed Central

    Tang, Chengke; Mittler, Taliah; Duke, Dawn C.; Zhu, Yun; Pawlak, Anthony P.; West, Mark O.

    2011-01-01

    To examine the role of striatal mechanisms in cocaine-induced stereotyped licking, we investigated the acute effects of cocaine on striatal neurons in awake, freely moving rats before and after cocaine administration (0, 5, 10, or 20 mg/kg). Stereotyped licking was induced only by the high dose. Relative to control (saline), cocaine reduced lick duration and concurrently increased interlick interval, particularly at the high dose, but it did not affect licking rhythm. Firing rates of striatal neurons phasically related to licking movements were compared between matched licks before and after injection, minimizing any influence of sensorimotor variables on changes in firing. Both increases and decreases in average firing rate of striatal neurons were observed after cocaine injection, and these changes exhibited a dose-dependent pattern that strongly depended on predrug firing rate. At the middle and high doses relative to the saline group, the average firing rates of slow firing neurons were increased by cocaine, resulting from a general elevation of movement-related firing rates. In contrast, fast firing neurons showed decreased average firing rates only in the high-dose group, with reduced firing rates across the entire range for these neurons. Our findings suggest that at the high dose, increased phasic activity of slow firing striatal neurons and simultaneously reduced phasic activity of fast firing striatal neurons may contribute, respectively, to the continual initiation of stereotypic movements and the absence of longer movements. PMID:17991811

  16. Head Rubbing and Licking Reinforce Social Bonds in a Group of Captive African Lions, Panthera leo

    PubMed Central

    Matoba, Tomoyuki; Kutsukake, Nobuyuki; Hasegawa, Toshikazu

    2013-01-01

    Many social animals have a species-specific repertoire of affiliative behaviours that characterise individualised relationships within a group. To date, however, quantitative studies on intragroup affiliative behaviours in social carnivores have been limited. Here, we investigated the social functions of the two most commonly observed affiliative behaviours in captive African lions (Panthera leo): head rubbing and licking. We conducted behavioural observations on a captive group of lions composed of 7 males and 14 females, and tested hypotheses regarding three social functions: tension reduction, social bonding, and social status expression. Disproportionately frequent male–male and female-to-male head rubbing was observed, while more than 95% of all licking interactions occurred in female–female dyads. In accordance with the social bond hypothesis, and in disagreement with the social status expression hypothesis, both head rubbing and licking interactions were reciprocal. After controlling for spatial association, the dyadic frequency of head rubbing was negatively correlated with age difference while licking was positively correlated with relatedness. Group reunion after daily separation did not affect the frequencies of the affiliative behaviours, which was in disagreement with the predictions from the tension reduction hypothesis. These results support the social bond hypothesis for the functions of head rubbing and licking. Different patterns of affiliative behaviour between the sexes may reflect differences in the relationship quality in each sex or the differential predisposition to licking due to its original function in offspring care. PMID:24023806

  17. The Fine Temporal Structure of the Rat Licking Pattern: What Causes the Variabiliy in the Interlick Intervals and How is it Affected by the Drinking Solution?

    PubMed Central

    2013-01-01

    Licking is a repetitive behavior controlled by a central pattern generator. Even though interlick intervals (ILIs) within bursts of licks are considered fairly regular, the conditions that affect their variability are unknown. We analyzed the licking pattern in rats that licked water, 10% sucrose solution, or 10% ethanol solution, in 90-min recording sessions after 4h of water deprivation. The histograms of ILIs indicate that licking typically occurred at a preferred ILI of about 130−140ms with evidence of bimodal or multimodal distributions due to occasional licking failures. We found that the longer the pause between bursts of licks, the shorter was the first ILI of the burst. When bursts of licks were preceded by a pause >4 s, the ILI was the shortest (~110ms) at the beginning of the burst, and then it increased rapidly in the first few licks and slowly in subsequent licks. Interestingly, the first ILI of a burst of licks was not significantly different when licking any of the 3 solutions, but subsequent licks exhibited a temporal pattern characteristic of each solution. The rapid deceleration in intraburst licking rate was due to an increase from ~27ms to ~56ms in the tongue-spout contact duration while the intercontact interval was only slightly changed (80−90ms). Therefore, the contact duration seems to be the major factor that increases the variability in the ILIs and could be another means for the rat to adjust the amount of fluid ingested in each individual lick. PMID:23902635

  18. Constraints on Type IIn supernova progenitor outbursts from the Lick Observatory Supernova Search

    NASA Astrophysics Data System (ADS)

    Bilinski, Christopher; Smith, Nathan; Li, Weidong; Williams, G. Grant; Zheng, WeiKang; Filippenko, Alexei V.

    2015-06-01

    We searched through roughly 12 years of archival survey data acquired by the Katzman Automatic Imaging Telescope (KAIT) as part of the Lick Observatory Supernova Search in order to detect or place limits on possible progenitor outbursts of Type IIn supernovae (SNe IIn). The KAIT data base contains multiple pre-SN images for five SNe IIn (plus one ambiguous case of an SN IIn/imposter) within 50 Mpc. No progenitor outbursts are found using the false discovery rate statistical method in any of our targets. Instead, we derive limiting magnitudes (LMs) at the locations of the SNe. These LMs (typically reaching mR ≈ 19.5 mag) are compared to outbursts of SN 2009ip and η Car, plus additional simulated outbursts. We find that the data for SN 1999el and SN 2003dv are of sufficient quality to rule out events ˜40 d before the main peak caused by initially faint SNe from blue supergiant precursor stars, as in the cases of SN 2009ip and SN 2010mc. These SNe IIn may thus have arisen from red supergiant progenitors, or they may have had a more rapid onset of circumstellar matter interaction. We also estimate the probability of detecting at least one outburst in our data set to be ≳60% for each type of the example outbursts, so the lack of any detections suggests that such outbursts are either typically less luminous (intrinsically or owing to dust) than ˜-13 mag, or not very common among SNe IIn within a few years prior to explosion.

  19. Microbiological and histopathological features of canine acral lick dermatitis.

    PubMed

    Shumaker, A K; Angus, J C; Coyner, K S; Loeffler, D G; Rankin, S C; Lewis, T P

    2008-10-01

    The purpose of this study was to investigate microbiological and histopathological features of canine acral lick dermatitis (ALD). Microbial characteristics of ALD are poorly described in current literature. If infection is recognized, antimicrobial selection is usually empirical, based on appearance, cytology or surface culture, rather than deep tissue culture. It was hypothesized that cultures obtained from deep tissue would yield different results than predicted by surface culture and cytology, and that isolates from ALD have unpredictable susceptibility patterns showing resistance to antibiotics routinely administered for canine pyoderma. Biopsies were obtained from 31 lesions and submitted for aerobic, anaerobic and fungal culture, and histopathological evaluation. Surface aerobic culture and susceptibility and cytology were obtained for comparison in 22 dogs. Skin scrapings and dermatophyte culture were performed. Bacteria were isolated in 30 of 31 cases. Staphylococcus intermedius was isolated in 58% of deep cultures. Twenty per cent of deep isolates were methicillin-resistant Staphylococcus species. Forty-eight per cent of cases yielded organisms defined as multidrug resistant on deep culture. Only 57% and 55% of bacteria isolated from tissue culture were sensitive to amoxicillin-clavulanic acid and cefazolin, respectively. Cytology and superficial cultures did not correlate well with deep cultures. Surface culture predicted deep tissue isolates in eight of 22 cases. Microsporum gypseum was isolated from one dog. Histopathological features included acanthosis, follicular elongation, lymphoplasmacytic dermal inflammation, folliculitis, furunculosis, perihidradenitis, hidradenitis and vertical streaking fibrosis. Lesions associated with ALD warrant tissue bacterial cultures as the majority of cases yielded positive growth of bacteria differing from superficial culture and often resistant to empirical drugs.

  20. Localization of the central rhythm generator involved in spontaneous consummatory licking in rats: functional ablation and electrical brain stimulation studies.

    PubMed Central

    Brozek, G; Zhuravin, I A; Megirian, D; Bures, J

    1996-01-01

    Localization of the central rhythm generator (CRG) of spontaneous consummatory licking was studied in freely moving rats by microinjection of tetrodotoxin (TTX) into the pontine reticular formation. Maximum suppression of spontaneous water consumption was elicited by TTX (1 ng) blockade of the oral part of the nucleus reticularis gigantocellularis (NRG), whereas TTX injections into more caudal or rostral locations caused significantly weaker disruption of drinking. To verify the assumption that TTX blocked the proper CRG of licking rather than some relay in its output, spontaneously drinking thirsty rats were intracranially stimulated via electrodes chronically implanted into the oral part of the NRG. Lick-synchronized stimulation (a 100-ms train of 0.1-ms-wide rectangular pulses at 100 Hz and 25-150 microA) applied during continuous licking (after eight regular consecutive licks) caused a phase shift of licks emitted after stimulus delivery. The results suggest that the stimulation has reset the CRG of licking without changing its frequency. The reset-inducing threshold current was lowest during the tongue retraction and highest during the tongue protrusion period of the lick cycle. It is concluded that the CRG of licking is located in the oral part of NRG. PMID:8622936

  1. The Michigan Binary Star Program

    NASA Astrophysics Data System (ADS)

    Lindner, Rudi P.

    2007-07-01

    At the end of the nineteenth century, William J. Hussey and Robert G. Aitken, both at Lick Observatory, began a systematic search for unrecorded binary stars with the aid of the 12" and 36" refracting telescopes at Lick Observatory. Aitken's work (and book on binary stars) are well known, Hussey's contributions less so. In 1905 Hussey, a Michigan engineering graduate, returned to direct the Ann Arbor astronomy program, and immediately he began to design new instrumentation for the study of binary stars and to train potential observers. For a time, he spent six months a year at the La Plata Observatory, where he discovered a number of new pairs and decided upon a major southern hemisphere campaign. He spent a decade obtaining the lenses for a large refractor, through the vicissitudes of war and depression. Finally, he obtained a site in South Africa, a 26" refractor, and a small corps of observers, but he died in London en route to fulfill his dream. His right hand man, Richard Rossiter, established the observatory and spent the next thirty years discovering and measuring binary stars: his personal total is a record for the field. This talk is an account of the methods, results, and utility of the extraordinary binary star factory in the veldt.

  2. Development of a flood-warning system and flood-inundation mapping in Licking County, Ohio

    USGS Publications Warehouse

    Ostheimer, Chad J.

    2012-01-01

    Digital flood-inundation maps for selected reaches of South Fork Licking River, Raccoon Creek, North Fork Licking River, and the Licking River in Licking County, Ohio, were created by the U.S. Geological Survey (USGS), in cooperation with the Ohio Department of Transportation; U.S. Department of Transportation, Federal Highway Administration; Muskingum Watershed Conservancy District; U.S. Department of Agriculture, Natural Resources Conservation Service; and the City of Newark and Village of Granville, Ohio. The inundation maps depict estimates of the areal extent of flooding corresponding to water levels (stages) at the following USGS streamgages: South Fork Licking River at Heath, Ohio (03145173); Raccoon Creek below Wilson Street at Newark, Ohio (03145534); North Fork Licking River at East Main Street at Newark, Ohio (03146402); and Licking River near Newark, Ohio (03146500). The maps were provided to the National Weather Service (NWS) for incorporation into a Web-based flood-warning system that can be used in conjunction with NWS flood-forecast data to show areas of predicted flood inundation associated with forecasted flood-peak stages. As part of the flood-warning streamflow network, the USGS re-installed one streamgage on North Fork Licking River, and added three new streamgages, one each on North Fork Licking River, South Fork Licking River, and Raccoon Creek. Additionally, the USGS upgraded a lake-level gage on Buckeye Lake. Data from the streamgages and lake-level gage can be used by emergency-management personnel, in conjunction with the flood-inundation maps, to help determine a course of action when flooding is imminent. Flood profiles for selected reaches were prepared by calibrating steady-state step-backwater models to selected, established streamgage rating curves. The step-backwater models then were used to determine water-surface-elevation profiles for up to 10 flood stages at a streamgage with corresponding streamflows ranging from approximately

  3. A resolution congratulating the Park View All-Star Little League team for winning the 2009 Little League World Series championship.

    THOMAS, 111th Congress

    Sen. Boxer, Barbara [D-CA

    2009-09-29

    09/29/2009 Referred to the Committee on the Judiciary. (text of measure as introduced: CR S9937) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  4. Division G Commission 42: Close Binary Stars

    NASA Astrophysics Data System (ADS)

    Richards, Mercedes T.; Pribulla, Theodor; Ribas, Ignasi; Bradstreet, David H.; Dreschsel, Horst; Maceroni, Carla; Mikolajewska, Joanna; Munari, Ulisse; Prsa, Andrej; Scharfe, Colin; Southworth, John; Trimble, Virginia

    2016-04-01

    Commission 42 began life as Photometric Double Stars in 1948 at the 7th General Assembly in Zurich, under the presidency of Zdenek Kopal. As early as 1961, then General Secretary Lukas Plaut recommended a merger between C42 and C26, Double Stars, one of the original 32 commissions going back to 1919-22 (first president Aitken, assistant director at Lick). C42 became Close Binary Stars in 1970, at the 14th GA in Brighton (the first one I attended). Table 1 shows the presidents of C42, and vice presidents, from when the office started, through the history of the Commission.

  5. THE LICK-CARNEGIE SURVEY: FOUR NEW EXOPLANET CANDIDATES

    SciTech Connect

    Meschiari, Stefano; Laughlin, Gregory; Vogt, Steven S.; Rivera, Eugenio J.; Haghighipour, Nader; Jalowiczor, Peter

    2011-02-01

    We present new precise HIRES radial velocity (RV) data sets of five nearby stars obtained at Keck Observatory. HD 31253, HD 218566, HD 177830, HD 99492, and HD 74156 are host stars of spectral classes F through K and show RV variations consistent with new or additional planetary companions in Keplerian motion. The orbital parameters of the candidate planets in the five planetary systems span minimum masses of M sin i = 27.43 M{sub +} to 8.28 M{sub J}, periods of 17.05-4696.95 days and eccentricities ranging from circular to extremely eccentric (e {approx} 0.63). The fifth star, HD 74156, was known to have both a 52 day and a 2500 day planet, and was claimed to also harbor a third planet at 336 days, in apparent support of the 'Packed Planetary System' hypothesis. Our greatly expanded data set for HD 74156 provides strong confirmation of both the 52 day and 2500 day planets, but strongly contradicts the existence of a 336 day planet, and offers no significant evidence for any other planets in the system.

  6. Hamilton Jeffers and the Double Star Catalogues

    NASA Astrophysics Data System (ADS)

    Tenn, Joseph S.

    2013-01-01

    Astronomers have long tracked double stars in efforts to find those that are gravitationally-bound binaries and then to determine their orbits. Court reporter and amateur astronomer Shelburne Wesley Burnham (1838-1921) published a massive double star catalogue containing more than 13,000 systems in 1906. The next keeper of the double stars was Lick Observatory astronomer Robert Grant Aitken (1864-1951), who produced a much larger catalogue in 1932. Aitken maintained and expanded Burnham’s records of observations on handwritten file cards, eventually turning them over to Lick Observatory astrometrist Hamilton Moore Jeffers (1893-1976). Jeffers further expanded the collection and put all the observations on punched cards. With the aid of Frances M. "Rete" Greeby (1921-2002), he made two catalogues: an Index Catalogue with basic data about each star, and a complete catalogue of observations, with one observation per punched card. He enlisted Willem van den Bos of Johannesburg to add southern stars, and they published the Index Catalogue of Visual Double Stars, 1961.0. As Jeffers approached retirement he became greatly concerned about the disposition of the catalogues. He wanted to be replaced by another "double star man," but Lick Director Albert E. Whitford (1905-2002) had the new 120-inch reflector, the world’s second largest telescope, and he wanted to pursue modern astrophysics instead. Jeffers was vociferously opposed to turning over the card files to another institution, and especially against their coming under the control of Kaj Strand of the U.S. Naval Observatory. In the end the USNO got the files and has maintained the records ever since, first under Charles Worley (1935-1997), and, since 1997, under Brian Mason. Now called the Washington Double Star Catalog (WDS), it is completely online and currently contains more than 1,000,000 measures of more than 100,000 pairs.

  7. The medial prefrontal cortex is crucial for the maintenance of persistent licking and the expression of incentive contrast

    PubMed Central

    Parent, Marc A.; Amarante, Linda M.; Liu, Benjamine; Weikum, Damian; Laubach, Mark

    2015-01-01

    We examined the role of the medial prefrontal cortex (mPFC) in reward processing and the control of consummatory behavior. Rats were trained in an operant licking procedure in which they received alternating access to solutions with relatively high and low levels of sucrose (20 and 4%, w/v). Each level of sucrose was available for fixed intervals of 30 s over 30 min test sessions. Over several days of training, rats came to lick persistently when the high level of sucrose was available and suppressed licking when the low level of sucrose was available. Pharmacological inactivations of the mPFC, specifically the rostral part of the prelimbic area, greatly reduced intake of the higher value fluid and only slightly increased intake of the lower value fluid. In addition, the inactivations altered within-session patterns and microstructural measures of licking. Rats licked equally for the high and low levels of sucrose at the beginning of the test sessions and “relearned” to reduce intake of the low value fluid over the test sessions. Durations of licking bouts (clusters of licks with inter-lick intervals <0.5 s) were reduced for the high value fluid and there were many more brief licking bouts (<1 s) when the low value fluid was available. These effects were verified using an alternative approach (optogenetic silencing using archaerhodopsin) and were distinct from inactivation of the ventral striatum, which simply increased overall intake. Our findings suggest that the mPFC is crucial for the maintenance of persistent licking and the expression of learned feeding strategies. PMID:25870544

  8. Paleontologic investigations at Big Bone Lick State Park, Kentucky: A preliminary report

    USGS Publications Warehouse

    Schultz, C.B.; Tanner, L.G.; Whitmore, F.C.; Ray, L.L.; Crawford, E.C.

    1963-01-01

    The Big Bone Lick area in Kentucky, the first widely known collecting locality for vertebrate fossils in North America, is being investigated for further faunal and geologic evidence. Mammal bones, ranging in age from Wisconsin (Tazewell?) to Recent, were recovered in 1962 from four different faunal zones in two terrace fills.

  9. Dilute bird nectars: viscosity constrains food intake by licking in a sunbird.

    PubMed

    Köhler, Angela; Leseigneur, Carolina D C; Verburgt, Luke; Nicolson, Susan W

    2010-10-01

    Floral nectars of bird-pollinated plants are relatively dilute. One hypothesis proposed to explain this concerns the difficulty for birds of drinking nectar of high viscosity. We examined the effects of viscosity, separately from those of sugar concentration, on feeding by captive whitebellied sunbirds (Cinnyris talatala). Viscosities of artificial nectar (sucrose solutions ranging in concentration from 0.25 to 1.5 mol/l) were altered with Tylose, an inert polysaccharide. Food consumption was measured over 3 h, and lick frequency and duration were recorded using photodetection devices on feeding apertures too small for the bill but large enough for the extended tongue. Volumetric intake rates (ml/s) were inversely proportional to nectar viscosity, and were similar over the range of sucrose concentrations when viscosity was held constant. Sucrose intake rates (mg/s) remained the same on pure sucrose solutions, but they decreased with increasing viscosity at a constant sucrose concentration. Lick frequencies and tongue loads were reduced at high viscosities, and lick duration increased, which confirms that sunbirds take longer to ingest viscous solutions. Licking behavior was remarkably similar in birds feeding on different sucrose concentrations if viscosity was held constant. Nectar ingestion rate is determined by viscosity; however, total food intake is mainly modulated by sugar concentration. Similar effects of food viscosity have been observed in insects that suck nectar.

  10. Fatal Pasteurella multocida septicemia and necrotizing fasciitis related with wound licked by a domestic dog.

    PubMed

    Chang, Ko; Siu, L K; Chen, Yen-Hsu; Lu, Po-Liang; Chen, Tun-Chieh; Hsieh, Hsiao-Chen; Lin, Chun-Lu

    2007-01-01

    A 68-y-old male had necrotizing fasciitis and bacteremia due to Pasteurella multocida. Saliva culture from his dog grew P. multocida and Pseudomonas aeruginosa. The human and dog P. multocida strains were of the same antibiogram but not identical tested with ribotyping. The wound licked by his dog was the only risk factor.

  11. Relevance of Lick Creek ecosystem-based management treatments to National Forest management

    Treesearch

    Cathy Stewart

    1999-01-01

    Treatments applied at Lick Creek were the first landscape-scale applications of ecosystem management on the Bitterroot National Forest. The coordinated effort between educators, researchers, resource managers, and the public helped gain acceptance and understanding of new approaches to management, both internally and externally. The longer skidding distances, high...

  12. The Lick Creek Demonstration - Forest Renewal Through Partial Harvest and Fire

    Treesearch

    Benjamin Zamora; Melinda Martin

    2006-01-01

    The Lick Creek Demonstration Site on the Pomeroy Ranger District, Umatilla National Forest, is a Joint Fire Science Program sponsored project to create a demonstration of the effects of fuels management on forest health. The project was initiated in 2001 and involved the integration of two levels of partial harvest with prescribed fire, a burn only treatment and an...

  13. Reconstruction of a nonhealing lick granuloma in a dog using a phalangeal fillet technique.

    PubMed

    Demetriou, Jackie L; Shales, Christopher J; Hamilton, Michael H; Sissener, Thomas R

    2007-01-01

    A 6.5-year-old, castrated male Dalmatian was presented with a 3-month history of a chronic, nonhealing wound related to a previously excised lick granuloma. Reconstruction of the wound on the lateral metatarsal region was achieved using a phalangeal fillet technique, without digital pad transposition. The skin flap healed successfully with very good cosmetic and functional results.

  14. 77 FR 55796 - Sand Lick Fork Watershed Restoration Project; Daniel Boone National Forest, KY

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... area. The project is located on National Forest System Lands in Powell County, Kentucky bounded on the east by Natural Bridge State Resort Park. Includes lands in Sand Lick Fork, Barker Branch, Pot Hollow... they are allowed to stay open, the greater the pollution they will cause. Homes are located less than...

  15. Bone mineral response to ammonium sulphate offered as a lick supplement in beef calves.

    PubMed

    Motsei, L E; Beighle, D E

    2006-03-01

    Sixteen Bonsmara calves (4 males, 12 females) between 10 and 18 months of age were blocked according to age and sex and randomly assigned to 2 groups. They were offered licks containing bone meal and salt (50:50 ratio) (control) and bone meal and ammonium sulphate (NH4SO4) at 1.25, 2.5, 5, 10, 15, and 18% (treatment) to evaluate the effects of dietary anions on bone phosphate (P) concentration. Bone P concentration was significantly (P < 0.05) higher in the NH4SO4 group compared with the control group, indicating that NH4SO4 was able to increase the P content of bone at each of the 6 concentrations used in the lick relative to the control animals, thereby improving the P status of the animals. Ammonium sulphate at 15% and 18 % in the lick also significantly (P < 0.05) increased bone P compared with the lower concentrations of NH4SO4. Bone calcium (Ca) fluctuated as a result of the acidogenic lick. There was absorption of Ca when P was being resorbed and resorption of Ca when P was being absorbed into and out of bone. Bone Ca:P ratio ranged from 3.2 to 6.4 among the control group and 1.6 to 4.3 among the treatment group. Animals receiving the acidogenic lick had a higher percentage ash compared to the control group for most of the experimental period. Bone magnesium (Mg) fluctuated in response to the acidogenic lick, and it was difficult to show a relationship between bone Mg and Ca or P. The overall mean cortical bone thickness was significantly (P < 0.05) greater in treatment (1.60 mm) compared with control (1.43 mm) calves and this was also true at sampling periods 2, 4, 5 and 6. Bone thickness followed bone P and not bone Ca. Results from this research indicate that the addition of ammonium sulphate to a lick had a beneficial effect in improving the P status by increasing bone P and improving the mineral status of bone by increasing the thickness of cortical bone and percentage ash.

  16. An Infrared Method for Discovering AGN: Lick Spectroscopy of New Seyfert I’s in the Kepler Fields

    NASA Astrophysics Data System (ADS)

    Tsan, Tran; Edelson, Rick; Smith, Krista Lynne; Malkan, Matthew Arnold

    2016-06-01

    Spectra of Active Galactic Nuclei (AGN) candidates in the Kepler fields were observed at Lick Observatory. We used the Shane 3.0-meter telescope with the Kast double spectrograph, covering from 0.35-0.8 μm. Using IRAF, we extracted 1D spectra from the original 2D long-slit images of the candidates. Our main goals are to determine the redshift of the candidates and identify any new AGN. The wavelength and flux calibration are fairly accurate, and most spectra have a good signal-to-noise ratio. Twenty- seven nights of data (consisting of 106 candidates) have been analyzed. For 89% of them, we have determined the redshifts to a precision of δz = 0.0005 in most cases. The rest give inconclusive results. 19 of the candidates turn out to be galactic stars. The most commonly identified emission lines are Hα+[NII], the [OIII] doublet, and Hβ. 44 of the candidates show a Broad Line Region, meaning that their wide permitted lines classify them as either Seyfert I’s or quasars. 6 of these have redshifts above 0.5, indicating that they are highly luminous quasars. One candidate appears to be a bl-lac object. We are now analyzing the Kepler light curves of these Seyfert galaxies.

  17. Search for binary asteroids using Lick, Keck and VLT Adaptive Optics systems: new candidates, orbits and dynamical models

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Berthier, J.; Descamps, P.; Hestroffer, D.; de Pater, I.; Vachier, F.; Conrad, A.; Le Mignant, D.; Chaffee, F.; Roos-Serote, M.

    2003-04-01

    Our group started a search program for binary asteroids in 2000, using Adaptive Optics systems on the Lick-3m, Keck-10m, and VLT-8m telescopes. Several techniques such as appulse observations (see http://astron.berkeley.edu/˜fmarchis/Science/TNOs_Appulse/), Laser Guide Star observations and direct imaging were used to observe more than 80 main-belt asteroids, 14 Trojans and 4 trans-neptunian objects. Among them we have identified as binary objects, four main-belt asteroids (22,87,90,121), one TNO (1996 TC36). A search amongst Trojan asteroids did not result in any candidates. Additional main-belts candidates may be confirmed in the following weeks. We will derive limits on the fraction of binary systems from our data. For some binary asteroids, such as 22 Kalliope, our observations span enough time to permit the determination of accurate orbital elements. We will present a dynamical model for the companion orbit of 22 Kalliope, which gives direct information on the internal structure of Kalliope itself.

  18. APF—The Lick Observatory Automated Planet Finder

    NASA Astrophysics Data System (ADS)

    Vogt, Steven S.; Radovan, Matthew; Kibrick, Robert; Butler, R. Paul; Alcott, Barry; Allen, Steve; Arriagada, Pamela; Bolte, Mike; Burt, Jennifer; Cabak, Jerry; Chloros, Kostas; Cowley, David; Deich, William; Dupraw, Brian; Earthman, Wayne; Epps, Harland; Faber, Sandra; Fischer, Debra; Gates, Elinor; Hilyard, David; Holden, Brad; Johnston, Ken; Keiser, Sandy; Kanto, Dick; Katsuki, Myra; Laiterman, Lee; Lanclos, Kyle; Laughlin, Greg; Lewis, Jeff; Lockwood, Chris; Lynam, Paul; Marcy, Geoffrey; McLean, Maureen; Miller, Joe; Misch, Tony; Peck, Michael; Pfister, Terry; Phillips, Andrew; Rivera, Eugenio; Sandford, Dale; Saylor, Mike; Stover, Richard; Thompson, Matthew; Walp, Bernie; Ward, James; Wareham, John; Wei, Mingzhi; Wright, Chris

    2014-04-01

    The Automated Planet Finder (APF) is a facility purpose-built for the discovery and characterization of extrasolar planets through high-cadence Doppler velocimetry of the reflex barycentric accelerations of their host stars. Located atop Mt. Hamilton, the APF facility consists of a 2.4-m telescope and its Levy spectrometer, an optical echelle spectrometer optimized for precision Doppler velocimetry. APF features a fixed format spectral range from 374 nm - 970 nm, and delivers a "Throughput" (resolution * slit width product) of 114,000 arc-seconds, with spectral resolutions up to 150,000. Overall system efficiency (fraction of photons incident on the primary mirror that are detected by the science CCD) on blaze at 560 nm in planet-hunting mode is 15%. First-light tests on the RV standard stars HD 185144 and HD 9407 demonstrate sub-meter per second precision (RMS per observation) held over a 3-month period. This paper reviews the basic features of the telescope, dome, and spectrometer, and gives a brief summary of first-light performance.

  19. The Eclipse Expeditions of the Lick Observatory and the Beginnings of Astrophysics in the United States

    NASA Astrophysics Data System (ADS)

    Malville, J. McKim; Pearson, John

    2012-09-01

    During the years 1898 to 1932, Lick Observatory organized a remarkable series of 17 solar eclipse expeditions, all the more remarkable because Lick astronomers evidenced no enduring interest in solar physics. The science of these expeditions involved three issues of major significance during the development of astrophysics during the first three decades of the twentieth century: (1) testing of General Relativity; (2) non-LTE in extended atmospheres and gaseous nebulae; (3) role of magnetic fields in the sun. The expeditions made major contributions to the first two topics. Even though W.W. Campbell, the director of Lick, had extensive contact with George Ellery Hale, who had measured the magnetic fields of sunspots at Mt. Wilson, Lick astronomers missed the clues concerning the importance of magnetic fields in the corona. Campbell's measurement of the deflection of starlight at the eclipse of 1922 was his major achievement of the many eclipse expeditions. He had approached that test of General Relativity with considerable distrust of Einstein's theory and considered Eddington's 1919 results to be suspect. It is to Campbell's great credit that the results published jointly with Trumpler confirmed the predictions of Einstein with higher precision than Eddington had achieved. Donald Menzel joined the staff of Lick Observatory in 1926 as their first astrophysicist. Osterbrock describes him as a ``stranger in a strange land.'' He was given the analysis of the eclipse flash spectra. This work, published in 1931, represents the beginning of the astrophysical study of chromospheres and laid the foundation for the quantitative analysis of extended atmospheres and gaseous nebula.

  20. Licking for taste solutions by potassium-deprived rats: specificity and mechanisms.

    PubMed

    Guenthner, C J; McCaughey, S A; Tordoff, M G; Baird, J P

    2008-03-18

    There has been little work on the specificity and mechanisms underlying the appetite of potassium (K(+)) deprived rats, and there are conflicting results. To investigate the contribution of oral factors to changes in intake induced by K(+) deficiency, we conducted two experiments using 20-s "brief access" tests. In Experiment 1, K(+)-deprived rats licked less for water than did replete rats. After adjusting for this difference, K(+)-deprived rats exhibited increased licking for 100 mM CaCl(2), 100 mM MgCl(2), and 100 mM FeCl(2) compared with K(+)-replete rats. In Experiment 2, which used larger rats, the K(+)-deprived and replete groups licked equally for water, 500 mM Na.Gluconate, 350 mM KCl, 500 mM KHCO(3), and 1 mM quinine.HCl, but the K(+)-deprived rats licked more for 500 mM KCl, 500 mM CsCl, and 500 mM NaCl than did the replete rats. Licking was unaffected by addition to NaCl of 200 muM amiloride, an epithelial Na(+) channel (ENaC) blocker, or 100 muM ruthenium red, a vanilloid receptor 1 (VR-1) antagonist, or by addition to KCl of 50 muM 4-aminopyridine, a K(+) channel blocker. These findings suggest that K(+)-deprivation produces a non-specific appetite that is guided by oral factors. We found no evidence that this response was mediated by ENaC, VR-1, or K(+) channels in taste receptor cells.

  1. Licking for taste solutions by potassium-deprived rats: Specificity and mechanisms

    PubMed Central

    Guenthner, C.J.; McCaughey, S.A.; Tordoff, M.G.; Baird, J.P.

    2008-01-01

    There has been little work on the specificity and mechanisms underlying the appetite of potassium (K+) deprived rats, and there are conflicting results. To investigate the contribution of oral factors to changes in intake induced by K+ deficiency, we conducted two experiments using 20-s “brief access” tests. In Experiment 1, K+-deprived rats licked less for water than did replete rats. After adjusting for this difference, K+-deprived rats exhibited increased licking for 100 mM CaCl2, 100 mM MgCl2, and 100 mM FeCl2 compared with K+-replete rats. In Experiment 2, which used larger rats, the K+-deprived and replete groups licked equally for water, 500 mM Na·Gluconate, 350 mM KCl, 500 mM KHCO3, and 1 mM quinine·HCl, but the K+-deprived rats licked more for 500 mM KCl, 500 mM CsCl, and 500 mM NaCl than did the replete rats. Licking was unaffected by addition to NaCl of 200 μM amiloride, an epithelial Na+ channel (ENaC) blocker, or 100 μM ruthenium red, a vanilloid receptor 1 (VR-1) antagonist, or by addition to KCl of 50 μM 4-aminopyridine, a K+ channel blocker. These findings suggest that K+-deprivation produces a non-specific appetite that is guided by oral factors. We found no evidence that this response was mediated by ENaC, VR-1, or K+ channels in taste receptor cells. PMID:18255104

  2. Salt licks do not increase local densities of the deer ked, Lipoptena cervi, an abundant ectoparasite of cervids.

    PubMed

    Paakkonen, T; Nieminen, P; Roininen, H; Mustonen, A-M

    2014-09-01

    The deer ked, Lipoptena cervi (Diptera: Hippoboscidae), is a common ectoparasite of the moose, Alces alces (Artiodactyla: Cervidae). Salt licks are widely used to manipulate moose movements to prevent damage to saplings and traffic accidents. They may cause moose to gather in small areas, which could create aggregates of deer ked pupae as the parasite is a short-distance flyer and its dispersion depends on its hosts. We investigated whether the population density of flying deer keds could be influenced by manipulating salt licks and how environmental variables affect parasite density. Densities were estimated in 40 experimental sites with four treatments (no salt licks, introduced salt licks, removed salt licks, permanent salt licks) in September during 2007-2010. Forest edges, mixed forests on mineral soil and coniferous forests on peat soil were the habitats with high numbers of parasites. The manipulation of salt licks seemed to be ineffective in reducing the density of deer keds as the only factor to show statistical significance with parasite numbers in the mixed-model analysis was year of determination. Annual deer ked densities correlated with the abundance of moose in the region. Moreover, high spring and summer temperatures seemed to increase the numbers of flying imagos. © 2013 The Royal Entomological Society.

  3. Ground-based detectability of terrestrial and Jovian extrasolar planets: observations of CM Draconis at Lick Observatory.

    PubMed

    Doyle, L R; Dunham, E T; Deeg, H J; Blue, J E; Jenkins, J M

    1996-06-25

    The detection of terrestrial-sized extrasolar planets from the ground has been thought to be virtually impossible due to atmospheric scintillation limits. However, we show that this is not the case especially selected (but nevertheless main sequence) stars, namely small eclipsing binaries. For the smallest of these systems, CM Draconis, several months to a few years of photometric observations with 1-m-class telescopes will be sufficient to detect the transits of any short-period planets of sizes > or = 1.5 Earth radii (RE), using cross-correlation analysis with moderately good photometry. Somewhat larger telescopes will be needed to extend this detectability to terrestrial planets in larger eclipsing binary systems. (We arbitrarily define "terrestrial planets" herein as those whose disc areas are closer to that of Earth's than Neptune's i.e., less than about 2.78 RE.) As a "spin-off" of such observations, we will also be able to detect the presence of Jovian-mass planets without transits using the timing of the eclipse minima. Eclipse minima will drift in time as the binary system is offset by a sufficiently massive planet (i.e., one Jupiter mass) about the binary/giant-planet barycenter, causing a periodic variation in the light travel time to the observer. We present here an outline of present observations taking place at the University of California Lick Observatory using the Crossley 0.9-m telescope in collaboration with other observatories (in South Korea, Crete, France, Canary Islands, and New York) to detect or constrain the existence of terrestrial planets around main sequence eclipsing binary star systems, starting with CM Draconis. We demonstrate the applicability of photometric data to the general detection of gas giant planets via eclipse minima timings in many other small-mass eclipsing binary systems as well.

  4. Ground-based detectability of terrestrial and Jovian extrasolar planets: Observations of CM Draconis at Lick Observatory

    NASA Astrophysics Data System (ADS)

    Doyle, Laurance R.; Dunham, Edward T.; Deeg, Hans-Jörg; Blue, J. Ellen; Jenkins, Jon M.

    The detection of terrestrial-sized extrasolar planets from the ground has been thought to be virtually impossible due to atmospheric scintillation limits. However, we show that this is not the case for specially selected (but nevertheless main sequence) stars, namely small eclipsing binaries. For the smallest of these systems, CM Draconis, several months to a few years of photometric observations with 1-m-class telescopes will be sufficient to detect the transits of any short-period planets of sizes >=1.5 Earth radii (RE), using cross-correlation analysis with moderately good photometry. Somewhat larger telescopes will be needed to extend this detectability to terrestrial planets in larger eclipsing binary systems. (We arbitrarily define ``terrestrial planets'' herein as those whose disc areas are closer to that of Earth's than Neptune's i.e., less than about 2.78 RE.) As a ``spin-off'' of such observations, we will also be able to detect the presence of Jovian-mass planets without transits using the timing of the eclipse minima. Eclipse minima will drift in time as the binary system is offset by a sufficiently massive planet (i.e., one Jupiter mass) about the binary/giant-planet barycenter, causing a periodic variation in the light travel time to the observer. We present here an outline of present observations taking place at the University of California Lick Observatory using the Crossley 0.9-m telescope in collaboration with other observatories (in South Korea, Crete, France, Canary Islands, and New York) to detect or constrain the existence of terrestrial planets around main sequence eclipsing binary star systems, starting with CM Draconis. We demonstrate the applicability of photometric data to the general detection of gas giant planets via eclipse minima timings in many other small-mass eclipsing binary systems as well.

  5. Laser guide star measurements at Lawrence Livermore National Laboratory

    SciTech Connect

    Friedman, H.; Avicola, K.; Bissinger, H.; Brase, J.; Duff, J.; Gavel, D.; Horton, J.; Max, C.; Olivier, S.; Rapp, D.; Salmon, T.; Smauley, D.; Waltjen, K.

    1993-02-01

    Recent studies from the Laser Guide Star Project at Lawrence Livermore National Laboratory are presented. Photometry of the return signal has shown that the photon return is approximately 10 photons/cm{sup 2}ms at the pupil of the receiving telescope in agreement with a detailed model of the sodium interaction. Wavefronts of the laser guide star have also been measured with a Shack-Hartmann technique and power spectra have been shown to agree with those of nearby natural stars. Plans for closed loop demonstrations using the laser guide star at LLNL and nearby Lick Observatory are discussed.

  6. A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Little Lick and Big Lick Creeks, Blackford and Delaware counties, Indiana

    USGS Publications Warehouse

    Peters, James G.; Crawford, Charles G.; Wilber, William G.

    1980-01-01

    A digital computer model was used to predict alternatives for future waste loadings on Little Lick and Big Lick Creeks, Blackford and Delaware Counties, IN, that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model parameters included atmospheric reaeration, carbonaceous and nitrogenous biochemical-oxygen demand, and benthic-oxygen demand. The model was calibrated with data collected during three water-quality surveys at low flow. During these surveys, in-stream dissolved-oxygen concentrations averaged less than 3 mg/L, well below the State minimum requirement of 5.0 mg/L. The model indicated that these low concentrations were caused by high waste loadings, lack of dilution, low reaeration, and benthic-oxygen demand. The summer waste-assimilation study assumed that future reductions in discharge loadings would decrease carbonaceous and benthic decay and increase nitrogenous decay. This study indicated that projected effluent waste loads that would provide acceptable in-stream dissolved-oxygen concentrations are highly dependent on rates of nitrification. Ammonia toxicity became the limiting water-quality criterion at low nitrification rates. The winter waste-assimilation study indicated that projected dissolved-oxygen concentrations in Little Lick and Big Lick Creeks did not fall below the State standard. Owing to a lack of dilution, however, ammonia-nitrogen concentrations would violate in-stream toxicity standards in both Little Lick and Big Lick Creeks.

  7. Use of narcotic antagonists to modify stereotypic self-licking, self-chewing, and scratching behavior in dogs.

    PubMed

    Dodman, N H; Shuster, L; White, S D; Court, M H; Parker, D; Dixon, R

    1988-10-01

    We evaluated 2 narcotic antagonists, naltrexone and nalmefene, for treatment of refractory self-licking, self-chewing, and scratching behavior in dogs. Eleven dogs with various irritative or pruritic disorders were medicated with naltrexone (1 mg/kg of body weight, sc) or nalmefene (1 to 4 mg/kg, sc), after a period of control observation during which the dogs had not been medicated. The time for which the dogs were involved in self-licking, self-chewing, or scratching was determined retrospectively by analysis of videotapes. The rates of involvement in either activity before and after treatment were calculated and compared statistically. Treatment with a narcotic antagonist significantly reduced the time spent self-licking, self-chewing, or scratching in 7 of 11 dogs, was partially effective in 3 dogs, and was ineffective in one dog. Dogs with acral lick dermatitis responded most to treatment.

  8. Fluoxetine treatment of acral lick dermatitis in dogs: a placebo-controlled randomized double blind trial.

    PubMed

    Wynchank, D; Berk, M

    1998-01-01

    The aim of the study was to assess the efficacy and tolerability of fluoxetine treatment of acral lick dermatitis (ALD) in dogs and to investigate ALD as an animal model of obsessive-compulsive disorder (OCD). Sixty-three dogs with ALD were treated with fluoxetine 20 mg daily, or placebo, for 6 weeks. In the fluoxetine group, owners rated both appearance of the lesion (t = 10.2, df = 29, P < 0.0001) and licking behavior (t = 10.2, df = 29, P < 0.0001) as significantly improved by the end of the trial. Veterinarian-rated pre- and post-treatment photographs showed statistically significant improvement in the fluoxetine group (mean = 2.55). There were no significant changes in the placebo group as rated by owners and veterinarians. These results demonstrate the efficacy of fluoxetine in the treatment of ALD and lend further support to ALD as an animal model of OCD.

  9. Detection of large-scale alignment of Lick counts around Abell clusters

    NASA Technical Reports Server (NTRS)

    Argyres, P. C.; Groth, E. J.; Peebles, P. J. E.; Struble, M. F.

    1986-01-01

    The possible tendency of galaxies to be distributed in an aligned fashion, on sheets or filaments, on scales greater than the Abell radius, has been tested by a variety of statistics. The subject remains controversial because the statistical tests have either not been sensitive to the alignment or capable of unambiguously signalling alignment in a general, clumpy distribution of galaxies. The present approach combines ideas of Bingelli (1982) and Fry and Peebles (1980) in an examination of the cross correlation of Lick counts relative to the preferred direction defined by the cluster. This can substantially reduce the noise, and it is suggested on this basis that alignment has been found on large scales for Lick galaxy counts and Abell cluster positions and their angles.

  10. VizieR Online Data Catalog: Lick indices of EDCSN galaxies (Sanchez-Blazquez+, 2009)

    NASA Astrophysics Data System (ADS)

    Sanchez-Blazquez, P.; Jablonka, P.; Noll, S.; Poggianti, B. M.; Moustakas, J.; Milvang-Jensen, B.; Halliday, C.; Aragon-Salamanca, A.; Saglia, R. P.; Desai, V.; de, G. Lucia; Clowe, D. I.; Pello, R.; Rudnick, G.; Simard, L.; White, S. D. M.; Zaritsky, D.

    2009-05-01

    We present a table with the 11 Lick/IDS spectroscopic indices and the velocity dispersions for a sample of galaxies in the RED-sequence of 24 clusters extracted from EDisCS. The table include only galaxies with no-or-weak (EW[OII]3727<7{AA}) emission lines, with a minimum signal-to-noise per Angstroem of 10 and with velocity dispersions larger than 100km/s. (1 data file).

  11. Reinforcement of schedule-induced drinking in rats by lick-contingent shortening of food delivery.

    PubMed

    Álvarez, Beatriz; Íbias, Javier; Pellón, Ricardo

    2016-12-01

    Schedule-induced drinking has been a theoretical question of concern ever since it was first described more than 50 years ago. It has been classified as adjunctive behavior; that is, behavior that is induced by an incentive but not reinforced by it. Nevertheless, some authors have argued against this view, claiming that adjunctive drinking is actually a type of operant behavior. If this were true, schedule-induced drinking should be controlled by its consequences, which is the major definition of an operant. The present study tested this hypothesis. In a first experimental phase, a single pellet of food was delivered at regular 90-s intervals, but the interfood interval could be shortened depending on the rat's licking. The degree of contingency between licking the bottle spout and hastening the delivery of the food pellet was 100 %, 50 %, and 0 % for 3 separate groups of animals. Rats that could shorten the interval (100 % and 50 % contingency) drank at a higher rate than those that could not (0 %), and the level of acquisition was positively related to the degree of contingency. In a second phase of the experiment, all groups were exposed to a 100 % contingency, which resulted in all rats developing high levels of schedule-induced drinking. Licking is enhanced if it hastens reinforcement, and can do so at delay characteristics of those present in studies of schedule-induced drinking, thus supporting the view that adjunctive behavior is an operant.

  12. Antibacterial properties of saliva: role in maternal periparturient grooming and in licking wounds.

    PubMed

    Hart, B L; Powell, K L

    1990-09-01

    Canine saliva was tested for its bactericidal effects against pathogens relevant to the presumed hygienic functions of maternal grooming of the mammary and anogenital areas and licking of wounds. Both female and male saliva were bactericidal against Escherichia coli and Streptococcus canis but only slightly, and nonsignificantly, bactericidal against coagulase positive staphylococcus and Pseudomonas aeruginosa. E. coli is the cause of highly fatal coliform enteritis of neonatal mammals and E. coli and S. canis are the main pathogens implicated in neonatal septicemia of dogs. The bactericidal effects of saliva would facilitate the hygienic function of maternal licking of the mammary and anogenital areas in protecting newborns from these diseases. E. coli and S. canis along with coagulase positive staphylococcus and P. aeruginosa are among the common wound contaminants of dogs. Wound licking, and the application of saliva, would thus reduce wound contamination by E. coli and S. canis. The resistance of staphylococcus to bactericidal effects of saliva may be a factor in the high frequency (46 percent) with which coagulase positive staphylococcus was isolated from wounds compared with much lower frequency (9-17 percent) with which E. coli and S. canis were isolated.

  13. Control of the temporal locations of polydipsic licking in the rat.

    PubMed

    Alferink, L A; Bartness, T J; Harder, S R

    1980-01-01

    We studied the variables controlling the temporal location of polydipsic licking. Four rats were trained on a mixed fixed-ratio 10 (no tone) chained fixed-ratio 10 (no tone) fixed-ratio 90 (tone) schedule and on a multiple fixed-ratio 10 (tone) fixed ratio 100 (no tone) schedule. On the multiple schedule, drinking followed pellets if a fixed ratio 100 was upcoming for all four subjects and for two of the subjects if a fixed ratio 10 was upcoming. On the mixed schedule, drinking preceded the fixed-ratio 90 component of the chain. Two subjects also drank after pellet delivery on the mixed schedule before both the fixed ration 10 and the chain components. The number of licks was greater following a pellet than following a response. In a second phase with two of these subjects, the total response requirement of the chain was held constant at 100, while the size of the two ratios that constituted the chain was varied inversely. The tone signaled onset of the second link. Drinking followed the tone when it signaled fixed-ratio 90, 95, or 100 but not when it signaled fixed ratio 75, 80, or 85. These results show, on the one hand, that polydipsic licking is controlled by discriminative properties of the pellet rather than by its eliciting or "thirst-producing" characteristics. On the other hand, the fact that drinks were longer following a pellet than following a response suggests a contribution of thirst to polydipsia.

  14. Response-food delay gradients for lever pressing and schedule-induced licking in rats.

    PubMed

    Pellón, Ricardo; Pérez-Padilla, Angeles

    2013-06-01

    Eight food-deprived Wistar rats developed stable patterns of lever pressing and licking when exposed to a fixed-time 30-s schedule of food pellet presentation. The rats were trained to lever press by presenting the lever 10 s before the programmed food delivery, with the food pellet being delivered immediately upon a lever press. The operant contingency was then removed and the lever was inserted through the entire interfood interval, being withdrawn with food delivery and reinserted 2 s later. On successive phases of the study, a protective contingency postponed food delivery if responses (lever presses or licks) occurred within the last 1, 2, 5, 10, 20, or 25 s of the interfood interval. Lever pressing was reduced at much shorter response-food delays than those that reduced licking. These results demonstrate that reinforcement contributes to the maintenance of different response patterns on periodic schedules, and that different responses are differentially sensitive to delays.

  15. The effect of self-licking behavior on pharmacokinetics of eprinomectin and clinical efficacy against Psoroptes cuniculi in topically administered rabbits.

    PubMed

    Wen, Huiqiang; Pan, Baoliang; Wang, Fangfei; Yang, Zhenzhong; Wang, Zhujun; Liu, Shuai; Wang, Ming

    2010-02-01

    Ear mange mite Psoroptes cuniculi, one of the predominant parasites in rabbits, can cause considerable weight loss, low favorable fee conversion rates, and meningitis. The present experiment was to investigate the difference of plasma disposition and the variation of clinical efficacy under the effect of animal self-licking behavior in topically administered rabbits. Ten rabbits for pharmacokinetic study in two groups (the self-licking and the nonlicking)were topically administered with 1 mg kg(-1) of eprinomectin. In the self-licking group, rabbits were allowed to self-lick freely, while, to prevent self-licking, each animal in the non-licking group was fitted with a pet collar. Compared to the non-licking group, self-licking behavior contributed to an extremely significant shorter half-life of absorption (14.85+/-2.79 h in licking group vs.29.44+/-7.81 h in non-licking group, p<0.01) and an extremely significant higher C(max) value for eprinomectin (21.95+/-5.36 h in licking group vs. 6.98+/-0.72 ng ml(-1) in non-licking group, p<0.01) in plasma disposition. An extremely significantly shorter mean residence time (50.72+/-3.45 h) in self-licking group was also determined compared with the value obtained in non-licking group (106.66+/-7.39 h; p<0.01). Clinical efficacy study of eprinomectin was examined in rabbits naturally infested with P. cuniculi which were randomly allocated in three groups: the self-licking, the non-licking, and control groups. All rabbits in the self-licking and the non-licking groups were treated with topical eprinomectin at a single dose of 2 mg kg(-1) (day 0). Topical eprinomection led to a complete parasitological recovery in both treated groups on day 14 and remained free of live mites and clinical lesions from day 21 to the end of the study period (day 35).

  16. Online correction of licking-induced brain motion during two-photon imaging with a tunable lens

    PubMed Central

    Chen, Jerry L; Pfäffli, Oliver A; Voigt, Fabian F; Margolis, David J; Helmchen, Fritjof

    2013-01-01

    Two-photon calcium imaging in awake, head-fixed animals enables the measurement of neuronal activity during behaviour. Often, licking for the retrieval of water reward is used as a measurable report of the animal's decision during reward-driven behaviour. However, licking behaviour can induce severe motion artifacts that interfere with two-photon imaging of cellular activity. Here, we describe a simple method for the online correction of licking-induced focus shifts for two-photon calcium imaging of neocortical neurons in the head-fixed mouse. We found that licking causes a stereotyped drop of neocortical tissue, shifting neurons up to 20 μm out of focus. Based on the measurement of licking with a piezo film sensor, we developed a feedback model, which provides a corrective signal for fast optical focus adjustments with an electrically tunable lens. Using online correction with this feedback model, we demonstrate a reduction of licking-related focus changes below 3 μm, minimizing motion artifact contamination of cellular calcium signals. Focus correction with a tunable lens is a simple and effective method to improve the ability to monitor neuronal activity during reward-based behaviour. PMID:23940380

  17. A resolution recognizing Major League Baseball as an important part of the cultural history of American society, celebrating the 2012 Major League Baseball All-Star Game, and honoring Kansas City, Missouri, as the host city of the 83rd All-Star Game.

    THOMAS, 112th Congress

    Sen. Blunt, Roy [R-MO

    2012-06-26

    Senate - 06/26/2012 Submitted in the Senate, considered, and agreed to without amendment and with a preamble by Unanimous Consent. (All Actions) Tracker: This bill has the status Agreed to in SenateHere are the steps for Status of Legislation:

  18. A resolution recognizing Major League Baseball as an important part of the cultural history of American society, celebrating the 2012 Major League Baseball All-Star Game, and honoring Kansas City, Missouri, as the host city of the 83rd All-Star Game.

    THOMAS, 112th Congress

    Sen. Blunt, Roy [R-MO

    2012-06-26

    06/26/2012 Submitted in the Senate, considered, and agreed to without amendment and with a preamble by Unanimous Consent. (All Actions) Tracker: This bill has the status Agreed to in SenateHere are the steps for Status of Legislation:

  19. Searching for Planets Around other Stars

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this colloquim presentation, Professor of Astronomy, Geoffrey Marcy discusses the discovery of planets orbiting other stars. Using the Doppler shift caused by stellar wobble that is caused by nearby planetary mass, astronomers have been able to infer the existence of Jupiter-sized planets around other stars. Using a special spectrometer at Lick Observatory, the wobble of several stars have been traced over the years required to generate an accurate pattern required to infer the stellar wobble. Professor Marcy, discusses the findings of planets around 47 Ursae Majoris, 16 Cygni B, 51 Pegasus, and 56 Rho 1 Cne. In the case of 56 Rho 1 Cne the planet appears to be close to the star, within 1.5 astronomical units. The observations from the smaller Lick Observatory will be augmented by new observations from the larger telescope at the Kek observatory. This move will allow observations of smaller planets, as opposed to the massive planets thus far discovered. The astronomers also hope to observe smaller stars with the Kek data. Future spaceborne observations will allow the discovery of even smaller planets. A spaceborne interferometer is in the planning stages, and an even larger observatory, called the Terrestrial Planet Finder, is hoped for. Professor Marcy shows artists' renderings of two of the planets thus far discovered. He also briefly discusses planetary formation and shows slides of both observations from the Orion Nebula and models of stellar system formation.

  20. Design of a fieldable laser system for a sodium guide star

    SciTech Connect

    Friedman, H.; Erbert, G.; Kuklo, T.; Salmon, T.; Smauley, D.; Thompson, G.; Wong, Nan

    1994-03-17

    The design and background data for a sodium layer laser guide star system to be installed on the 3 meter telescope at Lick Observatory is presented. A 30 W dye laser at 589 nm and 10 kHz will be mounted on the telescope and will be pumped by fiber coupled frequency doubled YAG laser located in a separate room.

  1. Modelling the star formation histories of nearby elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Bird, Katy

    Since Lick indices were introduced in 1994, they have been used as a source of observational data against which computer models of galaxy evolution have been compared. However, as this thesis demonstrates, observed Lick indices lead to mathematical ill-conditioning: small variations in observations can lead to very large differences in population synthesis models attempting to recreate the observed values. As such, limited reliance should be placed on any results currently or historically in the literature purporting to give the star formation history of a galaxy, or group of galaxies, where this is deduced from Lick observations taken from a single instrument, without separate verification from at least one other source. Within these limitations, this thesis also constrains the star formation histories of 21 nearby elliptical galaxies, finding that they formed 13.26 +0.09 -0.06 Gyrs ago, that all mergers are dry, and that galactic winds are formed from AGN activity (rather than being supernovae-driven). This thesis also finds evidence to support the established galaxy-formation theory of "downsizing". An existing galactic model from the literature is examined and evaluated, and the reasons for it being unable to establish star formation histories of individual galaxies are ascertained. A brand-new model is designed, developed, tested and used with two separate data sets, corroborated for 10 galaxies by data from a third source, and compared to results from a Single Stellar Population model from the literature, to model the star formation histories of nearby elliptical galaxies.

  2. Mineral licks: motivational factors for visitation and accompanying disease risk at communal use sites of elk and deer.

    PubMed

    Lavelle, Michael J; Phillips, Gregory E; Fischer, Justin W; Burke, Patrick W; Seward, Nathan W; Stahl, Randal S; Nichols, Tracy A; Wunder, Bruce A; VerCauteren, Kurt C

    2014-12-01

    Free-ranging cervids acquire most of their essential minerals through forage consumption, though occasionally seek other sources to account for seasonal mineral deficiencies. Mineral sources occur as natural geological deposits (i.e., licks) or as anthropogenic mineral supplements. In both scenarios, these sources commonly serve as focal sites for visitation. We monitored 11 licks in Rocky Mountain National Park, north-central Colorado, using trail cameras to quantify daily visitation indices (DVI) and soil consumption indices (SCI) for Rocky Mountain elk (Cervus elaphus) and mule deer (Odocoileus hemionus) during summer 2006 and documented elk, mule deer, and moose (Alces alces) visiting licks. Additionally, soil samples were collected, and mineral concentrations were compared to discern levels that explain rates of visitation. Relationships between response variables; DVI and SCI, and explanatory variables; elevation class, moisture class, period of study, and concentrations of minerals were examined. We found that DVI and SCI were greatest at two wet, low-elevation licks exhibiting relatively high concentrations of manganese and sodium. Because cervids are known to seek Na from soils, we suggest our observed association of Mn with DVI and SCI was a likely consequence of deer and elk seeking supplemental dietary Na. Additionally, highly utilized licks such as these provide an area of concentrated cervid occupation and interaction, thus increasing risk for environmental transmission of infectious pathogens such as chronic wasting disease, which has been shown to be shed in the saliva, urine, and feces of infected cervids.

  3. BINARIES AMONG DEBRIS DISK STARS

    SciTech Connect

    Rodriguez, David R.; Zuckerman, B.

    2012-02-01

    We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics observations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of 628 AU. We found that 25% {+-} 4% of our debris disk systems are binary or triple star systems, substantially less than the expected {approx}50%. The period distribution for these suggests a relative lack of systems with 1-100 AU separations. Only a few systems have blackbody disk radii comparable to the binary/triple separation. Together, these two characteristics suggest that binaries with intermediate separations of 1-100 AU readily clear out their disks. We find that the fractional disk luminosity, as a proxy for disk mass, is generally lower for multiple systems than for single stars at any given age. Hence, for a binary to possess a disk (or form planets) it must either be a very widely separated binary with disk particles orbiting a single star or it must be a small separation binary with a circumbinary disk.

  4. VizieR Online Data Catalog: Lick AGN monitoring 2011: light curves (Barth+, 2015)

    NASA Astrophysics Data System (ADS)

    Barth, A. J.; Bennert, V. N.; Canalizo, G.; Filippenko, A. V.; Gates, E. L.; Greene, J. E.; Li, W.; Malkan, M. A.; Pancoast, A.; Sand, D. J.; Stern, D.; Treu, T.; Woo, J.-H.; Assef, R. J.; Bae, H.-J.; Brewer, B. J.; Cenko, S. B.; Clubb, K. I.; Cooper, M. C.; Diamond-Stanic, A. M.; Hiner, K. D.; Honig, S. F.; Hsiao, E.; Kandrashoff, M. T.; Lazarova, M. S.; Nierenberg, A. M.; Rex, J.; Silverman, J. M.; Tollerud, E. J.; Walsh, J. L.

    2015-05-01

    This project was allocated 69 nights at the Lick 3m Shane telescope, distributed between 2011 March 27 and June 13. Observations were conducted using the Kast double spectrograph (3440-5515Å on the blue side and 5410-8200Å on the red side). In order to extend our light curves for two AGNs, we also requested additional observations from other observers using the Kast spectrograph: Mrk 50 from 2011 January through March, and Zw 229-015 in June and July. For Zw 229-015, three additional observations were taken 20-23 days after the end of our main campaign. See section 3. (2 data files).

  5. A library of Lick Observatory Image Dissector Scanner indices for binary stellar populations

    NASA Astrophysics Data System (ADS)

    Zhang, Fenghui; Li, Lifang

    2006-08-01

    Using evolutionary population synthesis, we present 13 refined absorption-line indices defined by the Lick Observatory Image Dissector Scanner (Lick/IDS) system for an extensive set of instantaneous-burst binary stellar populations (BSPs) at high resolution (~0.3 Å), and 38 indices at intermediate resolution (3 Å). The ages of the populations are at an interval of 1Gyr in the range 1-15Gyr, and the metallicities are in the range 0.004-0.03. These indices are obtained by two methods: (i) using the empirical fitting functions (FFs method); (ii) measured directly from the synthetic spectra (DC method). Together with our previous paper, a data base of Lick/IDS spectral absorption-line indices for BSPs at high and intermediate resolutions is provided. This set of indices includes 21 indices of Worthey et al., four Balmer indices defined by Worthey & Ottaviani, and 13 indices with the new passband definitions of Trager et al. The full set of synthetic indices and the integrated pseudo-continuum are listed in the Appendices, which are only available online at http://www.blackwell-synergy.com/ or from our website (http://www.ast9.com/), or on request from the first author. Moreover, the full set of the integrated spectral energy distributions can be obtained from our website. We compare the synthetic Lick/IDS indices obtained by the FFs method and those by the DC method for BSPs with various metallicities, and find that the discrepancies are significant: Ca4455 (index 6), Fe4668 (8), Mgb (13), Fe5709 (17), NaD (19), TiO1 (20) and TiO2 (21, except for Z = 0.02) in the W94 system, Ca4455T (6T), C24668T (8T), NaDT (19T), TiOT1 (20T) and TiOT2 (21T, except for Z = 0.02) in the T98 system obtained by the DC method are less (bluer) than the corresponding ones obtained by the FFs method for all metallicities. Ca4227 (index 3), Fe5782 (18), Ca4227T (3T) and Fe5782T (18T) are greater at Z = 0.03 and become bluer at Z = 0.004; the Fe5709T (17T) index is less at Z = 0.03 and

  6. Lick of death: Capnocytophaga canimorsus is an important cause of sepsis in the elderly.

    PubMed

    Wilson, James P; Kafetz, Kalman; Fink, Douglas

    2016-06-30

    A 70-year-old Caucasian woman was treated for Capnocytophaga canimorsus septicaemia. The source of bacteraemia was very likely to be her household pet, an Italian greyhound. The patient presented with a presumed complex partial seizure but deteriorated rapidly with sepsis and multiorgan dysfunction. Neither scratch nor bite was established, although close petting including licks was reported. Blood cultures grew Gram-negative rods, identified by molecular techniques as C. canimorsus-a bacterium frequently isolated in the oral cavities of dogs and cats. A full recovery was made following 2 weeks of intensive care support and broad-spectrum antibiotics. No underlying immune dysfunction was found.

  7. Geochemical study of acid mine drainage of the Big Lick Tunnel area, Williamstown, PA

    SciTech Connect

    Tollin, S. . Dept. of Geosciences)

    1993-03-01

    Acid mine drainage in the anthracite region of Pennsylvania continues to be a significant environmental problem. This study examines the acid mine outflow from the Big Lick Tunnel, north of Williamstown, Dauphin County, Pennsylvania. The tunnel drains abandoned mines on the north side of the Big Lick Mountain. Mining ceased in the area circa 1940, and the tunnel has been in operation since that time. The water, soil and stream bed sediment geochemistry has been studied to determine their changes in chemistry over distance. The pH, TDS and metal concentrations were the primary focus. Metal concentrations were determined using an ICP unit. Data indicates the pH of the outflow to range between 6.7 and 7.3 Fe and Mn concentrations are as high as 9.7 ppb. Extensive metal precipitation ( yellow boy'') occurs within the tunnel and for several hundred meters from the mouth of the tunnel. The combination of near neutral pH and high metal concentration suggest that the drainage is in contact with highly alkaline materials prior to discharge from the tunnel. The geology of the area does not suggest bedrock as the possible source of alkaline material. One hypothesis is that the acidic water is reacting with the concrete tunnel and being neutralized. Data also suggests that the Fe precipitates much quicker than the Mn, resulting in a zonation between Fe-rich and Mn-rich sediments along the length of the drainage.

  8. Rat psychomotor vigilance task with fast response times using a conditioned lick behavior

    PubMed Central

    Walker, Jennifer L.; Walker, Brendan M.; Fuentes, Fernanda Monjaraz; Rector, David M.

    2010-01-01

    Investigations into the physiological mechanisms of sleep control require an animal psychomotor vigilance task (PVT) with fast response times (<300ms). Rats provide a good PVT model since whisker stimulation produces a rapid and robust cortical evoked response, and animals can be trained to lick following stimulation. Our prior experiments used deprivation-based approaches to maximize motivation for operant conditioned responses. However, deprivation can influence physiological and neurobehavioral effects. In order to maintain motivation without water deprivation, we conditioned rats for immobilization and head restraint, then trained them to lick for a 10% sucrose solution in response to whisker stimulation. After approximately 8 training sessions, animals produced greater than 80% correct hits to the stimulus. Over the course of training, reaction times became faster and correct hits increased. Performance in the PVT was examined after 3, 6 and 12 hours of sleep deprivation achieved by gentle handling. A significant decrease in percent correct hits occurred following 6 and 12 hours of sleep deprivation and reaction times increased significantly following 12 hours of sleep deprivation. While behaviorally the animals appeared to be awake, we observed significant increases in EEG delta power prior to misses. The rat PVT with fast response times allows investigation of sleep deprivation effects, time on task and pharmacological agents. Fast response times also allow closer parallel studies to ongoing human protocols. PMID:20696188

  9. FIRST, a fibered aperture masking instrument: Results of the Lick observing campaign

    NASA Astrophysics Data System (ADS)

    Bordwell, Baylee; Duchene, Gaspard; Huby, Elsa; Goebel, Sean; Marchis, Franck; Perrin, Guy; Lacour, Sylvestre; Kotani, Takayuki; Gates, Elinor L.; Choquet, Elodie

    2015-01-01

    FIRST is a prototype instrument aimed at achieving high dynamic range and angular resolution in ground-based images at visible wavelengths near the diffraction limit. FIRST utilizes an aperture masking-like technique that makes use of single-mode fibers and pupil remapping to maximize the area of the telescope mirror in use. While located at Lick observatory in 2011 and 2012, FIRST observed 25 binary systems with the Shane 3m telescope, with separations ranging from 20 to 200 mas, comparable to the 50 mas diffraction limit for our central wavelength. Huby et al. (2013) has reported results for the Capella system that established the utility of FIRST for characterizing stellar binaries using the directly measured spectral flux ratio. Using an improved data analysis pipeline, we obtained closure phase measurements for a majority of the targets observed at Lick, and derived angular separations and spectral flux ratios. From the spectral flux ratios we obtained spectra for the companions over at least 600-850 nm with R~300. Finally, by obtaining results for many binary systems we have better constrained the current performance of FIRST, which has an exciting future ahead at its current location behind SCExAO at the Subaru 8.2 m telescope, where it will eventually become available for general use by the astronomical community.

  10. Gender, culture, and astrophysical fieldwork: Elizabeth Campbell and the Lick Observatory-Crocker eclipse expeditions.

    NASA Astrophysics Data System (ADS)

    Pang, A. S.-K.

    The article is organized as follows. It begins with an overview of women in nineteenth-century American science. It then describes the culture of mountaintop observatories and life on Mount Hamilton. Elizabeth Campbell's unique role in the Crocker-Lick expeditions drew upon her equally unique role in the observatory, and also on the meaning given to women's work in general on the mountain. The bulk of the article focuses on the Campbells and their expeditions to India in 1898, Spain in 1905, and the South Pacific in 1908. The third section compares the Lick Observatory expeditions to those conducted by David Todd of Amherst College. Todd's wife, Mabel Loomis Todd, went into the field several times with her husband, but her place in the field was radically different from Elizabeth Campbell's, a difference that can be ascribed to a combination of local culture and personality. Finally, it compares American expeditions to British expeditions of the period, to see what the absence of British women on expeditions can tell us about the way national scientific styles and cultures affected gender roles in science.

  11. The lick-index calibration of the Gemini multi-object spectrographs

    SciTech Connect

    Puzia, Thomas H.; Miller, Bryan W.; Trancho, Gelys; Basarab, Brett; Mirocha, Jordan T.; Butler, Karen E-mail: bmiller@gemini.edu

    2013-06-01

    We present the calibration of the spectroscopic Lick/IDS standard line-index system for measurements obtained with the Gemini Multi-Object Spectrographs known as GMOS-North and GMOS-South. We provide linear correction functions for each of the 25 standard Lick line indices for the B600 grism and two instrumental setups, one with 0.''5 slit width and 1 × 1 CCD pixel binning (corresponding to ∼2.5 Å spectral resolution) and the other with 0.''75 slit width and 2 × 2 binning (∼4 Å). We find small and well-defined correction terms for the set of Balmer indices Hβ, Hγ {sub A}, and Hδ {sub A} along with the metallicity sensitive indices Fe5015, Fe5270, Fe5335, Fe5406, Mg{sub 2}, and Mgb that are widely used for stellar population diagnostics of distant stellar systems. We find other indices that sample molecular absorption bands, such as TiO{sub 1} and TiO{sub 2}, with very wide wavelength coverage or indices that sample very weak molecular and atomic absorption features, such as Mg{sub 1}, as well as indices with particularly narrow passband definitions, such as Fe4384, Ca4455, Fe4531, Ca4227, and Fe5782, which are less robustly calibrated. These indices should be used with caution.

  12. Homosexual Fellatio: Erect Penis Licking between Male Bonin Flying Foxes Pteropus pselaphon

    PubMed Central

    Sugita, Norimasa

    2016-01-01

    A recent focus of interest has been on the functional significance of genital licking (fellatio and cunnilingus) in relation to sexual selection in Pteropodid bats. In the present paper, a form of fellatio in wild Bonin flying foxes, Pteropus pselaphon, performed between adult males has been reported. During the mating season, adult flying foxes roost in same-sex groups, forming ball-shaped clusters which provide warmth. The female clusters may also contain a few males. Unassociated with allogrooming, same-sex genital licking occurred among males in the all male clusters. As such, male-male fellatio can be considered as homosexual behavior, two functional explanations could account for this behavior; the social bonding and the social tension regulation hypotheses suggested in a previous review. Given that neither the simpler alternative that in all male groups such fellatio may represent misdirected sexual behavior, nor the two previously proposed functional hypotheses were supported by the data, I propose another functional hypothesis. Homosexual fellatio in this species could help males solve inconsistent situations in the roost when there are conflicts between cooperative behavior for social thermoregulation and competition for mating. PMID:27824953

  13. The Lick AGN Monitoring Project 2016: Extending Reverberation Mapping to Higher Luminosity AGNs

    NASA Astrophysics Data System (ADS)

    U, Vivian; LAMP2016 Collaboration

    2017-01-01

    The technique of reverberation mapping has been used to estimate virial black hole masses and, more fundamentally, to probe the broad line region structure in Seyfert I galaxies. Efforts from the previous Lick AGN Monitoring Project (LAMP) campaigns and other studies to date have culminated in a large sample of reverberation mapped AGNs and measurements of their black hole masses, which in turn enabled major improvement to various AGN scaling relations. However, the high-luminosity end of such relations remains poorly constrained; this is because of observational challenges presented by the weaker continuum flux variations and longer time dilation in these sources. To this end, we have initiated a new LAMP2016 campaign to target AGNs with luminosities of 10^44 erg/s, with predicted H-beta lags of ~20 - 60 days or black hole masses of 10^7 - 10^8.5 Msun. Designed to monitor ~20 AGNs biweekly from Spring 2016 through Winter 2017 with the Kast spectrograph on the 3-m Shane Telescope at Lick Observatory, we aim to probe luminosity-dependent trends in broad line region structure and dynamics, improve calibrations for single-epoch estimates of high-redshift quasar black hole masses, and test photoionization models for the radially-stratified structure of the broad line region. In this talk, I will present the overview and scope of LAMP2016 and show preliminary results from our ongoing campaign.

  14. Decreased consumption of sweet fluids in mu opioid receptor knockout mice: a microstructural analysis of licking behavior

    PubMed Central

    Ostlund, Sean B.; Kosheleff, Alisa; Maidment, Nigel T.; Murphy, Niall P.

    2013-01-01

    Summary Rationale Evidence suggests that the palatability of food (i.e., the hedonic impact produced by its sensory features) can promote feeding and may underlie compulsive eating, leading to obesity. Pharmacological studies implicate opioid transmission in the hedonic control of feeding, though these studies often rely on agents lacking specificity for particular opioid receptors. Objectives Here, we investigated the role of mu opioid receptors (MORs) specifically in determining hedonic responses to palatable sweet stimuli. Methods In Experiment 1, licking microstructure when consuming sucrose solution (2 to 20 %) was compared in MOR knockout and wildtype mice as a function of sucrose concentration and level of food deprivation. In Experiment 2, a similar examination was conducted using the palatable but calorie-free stimulus sucralose (0.001 to 1%), allowing study of licking behavior independent of homeostatic variables. Results In Experiment 1, MOR knockout mice exhibited several alterations in sucrose licking. Although wildtype mice exhibited a two-fold increase in the burst length when food deprived, relative to the nondeprived test, this aspect of sucrose licking was generally insensitive to manipulations of food deprivation for MOR knockout mice. Furthermore, during concentration testing, their rate of sucrose licking was less than half that of wildtype mice. During sucralose testing (Experiment 2), MOR knockout mice licked at approximately half the wildtype rate, providing more direct evidence that MOR knockout mice were impaired in processing stimulus palatability. Conclusions These results suggest that transmission through MORs mediates hedonic responses to palatable stimuli, and therefore likely contributes to normal and pathological eating. PMID:23568577

  15. Population Synthesis in the Blue. IV. Accurate Model Predictions for Lick Indices and UBV Colors in Single Stellar Populations

    NASA Astrophysics Data System (ADS)

    Schiavon, Ricardo P.

    2007-07-01

    We present a new set of model predictions for 16 Lick absorption line indices from Hδ through Fe5335 and UBV colors for single stellar populations with ages ranging between 1 and 15 Gyr, [Fe/H] ranging from -1.3 to +0.3, and variable abundance ratios. The models are based on accurate stellar parameters for the Jones library stars and a new set of fitting functions describing the behavior of line indices as a function of effective temperature, surface gravity, and iron abundance. The abundances of several key elements in the library stars have been obtained from the literature in order to characterize the abundance pattern of the stellar library, thus allowing us to produce model predictions for any set of abundance ratios desired. We develop a method to estimate mean ages and abundances of iron, carbon, nitrogen, magnesium, and calcium that explores the sensitivity of the various indices modeled to those parameters. The models are compared to high-S/N data for Galactic clusters spanning the range of ages, metallicities, and abundance patterns of interest. Essentially all line indices are matched when the known cluster parameters are adopted as input. Comparing the models to high-quality data for galaxies in the nearby universe, we reproduce previous results regarding the enhancement of light elements and the spread in the mean luminosity-weighted ages of early-type galaxies. When the results from the analysis of blue and red indices are contrasted, we find good consistency in the [Fe/H] that is inferred from different Fe indices. Applying our method to estimate mean ages and abundances from stacked SDSS spectra of early-type galaxies brighter than L*, we find mean luminosity-weighed ages of the order of ~8 Gyr and iron abundances slightly below solar. Abundance ratios, [X/Fe], tend to be higher than solar and are positively correlated with galaxy luminosity. Of all elements, nitrogen is the more strongly correlated with galaxy luminosity, which seems to indicate

  16. Image improvement from a sodium-layer laser guide star adaptive optics system

    SciTech Connect

    Max, C. E., LLNL

    1997-06-01

    A sodium-layer laser guide star beacon with high-order adaptive optics at Lick Observatory produced a factor of 2.4 intensity increase and a factor of 2 decrease in full width at half maximum for an astronomical point source, compared with image motion compensation alone. Image full widths at half maximum were identical for laser and natural guide stars (0.3 arc seconds). The Strehl ratio with the laser guide star was 65% of that with a natural guide star. This technique should allow ground-based telescopes to attain the diffraction limit, by correcting for atmospheric distortions.

  17. Laser Guide Star Adaptive Optics Polarimetry of Three Herbig Ae/Be Stars

    NASA Astrophysics Data System (ADS)

    Perrin, M. D.; Gavel, D. T.; Gates, E. L.; Graham, J. R.; Kalas, P.; Larwood, J. D.; Lloyd, J. P.; Max, C. E.; Pennington, D. M.

    2003-12-01

    We have obtained high spatial resolution near-IR imaging polarimetry of several Herbig Ae/Be stars using the Laser Guide Star adaptive optics (AO) system at Lick Observatory. We present here our observations of three of these objects: LkHα 198, LkHα 225, and LkHα 233. Herbig Ae/Be stars are young intermediate-mass stars, whose detailed nature is not as well understood as that of the lower-mass T Tauri stars. AO polarimetry enables us to probe circumstellar dust and outflows at high spatial resolution and dynamic range; the use of the Lick Observatory/LLNL laser guide star system enables observations of these distant and heavily visually extincted targets which could not otherwise be observed with AO. We find a bipolar structure ˜ 10 arcsec in extent oriented north-south surrounding LkHα 198, perpendicular to a dark lane suggestive of an edge-on circumstellar disk. The infrared companion 6 arcsec north illuminates nebulosity oriented in the NW-SE direction and may be the best candidate for driving CO outflow in the region. The two stellar components of the binary LkHα 225 show complex circumstellar structures that resemble tidal arms. Our polarimetric observations establish that the material is illuminated in scattered light from LkHa 225 and is thus physically associated with the binary. The observed morphology may be explained by tidal interactions between circumstellar disks during a close encounter of these stars. LkHα 233 presents a narrow, unpolarized lane separating its characteristic X-shaped reflection nebulosity. This dark lane is oriented perpendicular to a jet and the bipolar cavity and may represent an optically thick circumstellar disk that blocks our direct view of the star at wavelengths shorter than 2.2 micron. This work has been supported by the NSF Center for Adaptive Optics.

  18. Estimating bighorn sheep (Ovis Canadensis) abundance using noninvasive sampling at a mineral lick within a national park wilderness area

    Treesearch

    Kathryn A. Schoenecker; Mary Kay Watry; Laura E. Ellison; Michael K. Schwartz; Gordon L. Luikart

    2015-01-01

    Conservation of species requires accurate population estimates. We used genetic markers from feces to determine bighorn sheep abundance for a herd that was hypothesized to be declining and in need of population status monitoring. We sampled from a small but accessible portion of the population’s range where animals naturally congregate at a natural mineral lick to test...

  19. Temporal distributions of schedule-induced licks, magazine entries, and lever presses on fixed- and variable-time schedules.

    PubMed

    Boakes, Robert A; Patterson, Angela E; Kendig, Michael D; Harris, Justin A

    2015-01-01

    In this article, schedule-induced drinking (SID) refers to increased drinking by hungry rats exposed to intermittent delivery of food pellets. Two major accounts of SID differ in their explanation of why such drinking tends be concentrated soon after pellet delivery. Temporal discrimination theories propose that drinking is a form of displacement activity that occurs when a pellet is least likely. Adventitious reinforcement theories propose that drinking is displaced to early in an interpellet interval (IPI) by magazine-directed behavior that occurs toward the end of an IPI. The main aim of this study was to examine the latter response-competition account by recording distributions of both licking and magazine entries as SID developed when pellets were delivered to different groups either on a fixed-time (FT 30 s) or on a variable-time schedule (VT 30 s), as in Experiment 1. Although VT 30-s schedules produced essentially flat distributions of magazine entries, licking still tended to be concentrated early in an IPI. Furthermore, there was no indication (Experiments 1 and 2) that magazine entry distributions developed ahead of licking distributions. Experiment 3 examined distributions of lever presses instead of licks: Initially high rates of lever pressing declined both with response-independent schedules (FT and VT) and when a minimal response-dependency was introduced (recycling conjunctive schedule), yet this response also tended to be most frequent soon after pellet delivery. Overall, the data were generally consistent with temporal conditioning theories.

  20. Measurement of the Lick Indices in Early-Type Galaxies: Line-of-Sight Velocity Distribution Corrections for IC 1459

    NASA Astrophysics Data System (ADS)

    Samurovic, S.

    2009-12-01

    In this paper we analyse the measurements of the absorption line-strength Lick indices in the early-type galaxy IC 1459. We use the long-slit spectra of the elliptical galaxy IC 1459 from which its kinematics had previously been extracted to calculate the Lick indices for the observed spectral region (Mg_2, Fe5270, Fe5335 and H_β). We apply the usual procedure and correct the indices to the Lick spectral resolution and for the zero velocity dispersion. The procedure applied in this paper also corrects to non-Gaussian line-of-sight velocity distribution (LOSVD) observed in this galaxy, especially in its outer parts. The findings of Kuntschner (2004) were tested and it is shown that the departures from the Gaussian LOSVD may indeed cause erroneous determinations of the Lick indices. The impact of the introduction of non-Gaussian LOSVD differs for different indices. For the galaxy IC~1459 it is shown that the iron indices are especially sensitive when the correction due to anistropies is introduced: the corrections for Fe5270 and Fe5335 are ˜ 10 and ˜ 19 percent larger, respectively, than the corrections obtained in case of a pure Gaussian. The corrections for Mg_2 index are shown to be negligible and the corrections of the H_β index due to anisotropies are also small (below ˜ 4 per cent at most).

  1. IV nicotine self-administration in rats using a consummatory operant licking response: sensitivity to serotonergic, glutaminergic and histaminergic drugs.

    PubMed

    Cousins, Vanessa; Rose, Jed E; Levin, Edward D

    2014-10-03

    Tobacco smoking is characterized by repeated self-administration of nicotine by placing the cigarette in the mouth. The repeated hand-to-mouth self-administration is essentially a consummatory act. We recently developed a paradigm in which rats lick one of two spouts to trigger intravenous (IV) delivery of nicotine, which combines a consummatory act with rapid delivery of nicotine to model the act of tobacco smoking. We have found that rats will lick hundreds of times per nicotine infusion. In the current study, using the operant licking nicotine self-administration model with young adult Sprague-Dawley rats (0.03mg/kg/infusion of nicotine), we tested the effect of antagonists of H1 histamine receptors pyrilamine, serotonin (5HT) type 2 receptors ketanserin and N-methyl-d-aspartate (NMDA) glutamate receptors with d-cycloserine as well as an agonist of 5HT2c receptors lorcaserin, in dose ranges that we have found in previous studies to significantly reduce IV nicotine self-administration with the operant lever press operand. The H1 antagonist pyrilamine significantly reduced operant licking for nicotine self-administration. Pyrilamine caused significant reductions in the operant licking paradigm at lower doses (10 and 20mg/kg) than those we previously observed to affect responding in the operant lever press paradigm. In contrast, the 5HT2A and C antagonist ketanserin did not show an effect of reducing nicotine self-administration in the same dose range we had found in a previous study to significantly reduce operant lever press nicotine self-administration. The 5HT2C agonist lorcaserin significantly decreased nicotine self-administration in the licking paradigm at the same dose threshold as with lever press responding. The NMDA glutamate partial agonist d-cycloserine did not produce any change in nicotine self-administration with the licking operand, in contrast to its effect on the classic lever-pressing task. The rat model incorporating consummatory aspects of

  2. Pasteurella multocida infection of a total knee arthroplasty after a "dog lick".

    PubMed

    Heym, B; Jouve, F; Lemoal, M; Veil-Picard, A; Lortat-Jacob, A; Nicolas-Chanoine, M H

    2006-10-01

    The patient we report here underwent a total knee arthroplasty (TKA) which got infected with P. multocida after her dog had licked a small wound at the third toe of the same foot. Despite a correct treatment comprising synovectomy and cleansing, and an active antibiotic treatment for 3 months, the patient was readmitted for persistent infection of the same knee 2 weeks after the end of the antibiotic treatment. Sampling during surgery allowed for the growth of a P. multocida isolate proven by a molecular method to be identical to the previously isolated strain. This recurrent P. multocida infection was treated by a two-step change of the TKA comprising a 2-month period of antibiotic treatment between the two surgical interventions.

  3. Adaptive optics observations of NGC 6240 at the Keck and Lick Observatories

    NASA Astrophysics Data System (ADS)

    Max, C. E.; Whysong, D.; Macintosh, B. A.; Antonucci, R.; Roe, H.

    2000-12-01

    NGC 6240 is a luminous IRAS galaxy, and contains a nuclear starburst that is about 10 million years old. NGC 6240 consists of two merging disk galaxies. It is a LINER, and may host one or two active galactic nuclei. Previous studies have detected high-velocity ionized gas flowing outward in a "superwind," as well as strong molecular hydrogen and [FeII] emission. Here we report on near-IR adaptive optics imaging and spectroscopy of NGC 6240 at the Keck and Lick Observatories. The twin nuclei are clearly resolved in both images and spectra. We report on the spatial distribution and velocity structure of the molecular hydrogen emission, and its implications for potential excitation mechanisms and physical conditions in the emitting gas. This research was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory, University of California, under Contract W-7405-ENG-48.

  4. Geophagy in animals and geology of kudurs (mineral licks): a review of Russian publications.

    PubMed

    Panichev, A M; Golokhvast, K S; Gulkov, A N; Chekryzhov, I Yu

    2013-02-01

    This paper reviews from the geological and biological perspectives the achievements of Russian researchers in the field of geophagy, which have not been published in English. It is focused on publications in Russian language about (1) animal behavior related to geophagy, (2) mineral and chemical composition as well as geological characteristics and biological effects of the earths, eaten by animals in various locations in Russia and neighboring countries. The authors argue that the Russian term "solonetz" (salt lick) is too limiting, as animals consume not just salt but many other minerals too. The more general term "kudur" is used for places where animals eat earths. The geological nature and biological properties of kudurites (the common name given to biologically active mineral-crystal substances consumed by animals) and gastroliths (stones consumed by birds and reptiles) are addressed. On the basis of the reviewed data, the authors propose their own views regarding the causes of geophagy.

  5. ShaneAO: wide science spectrum adaptive optics system for the Lick Observatory

    NASA Astrophysics Data System (ADS)

    Gavel, Donald; Kupke, Renate; Dillon, Daren; Norton, Andrew; Ratliff, Chris; Cabak, Jerry; Phillips, Andrew; Rockosi, Connie; McGurk, Rosalie; Srinath, Srikar; Peck, Michael; Deich, William; Lanclos, Kyle; Gates, John; Saylor, Michael; Ward, Jim; Pfister, Terry

    2014-07-01

    A new high-order adaptive optics system is now being commissioned at the Lick Observatory Shane 3-meter telescope in California. This system uses a high return efficiency sodium beacon and a combination of low and high-order deformable mirrors to achieve diffraction-limited imaging over a wide spectrum of infrared science wavelengths covering 0.8 to 2.2 microns. We present the design performance goals and the first on-sky test results. We discuss several innovations that make this system a pathfinder for next generation AO systems. These include a unique woofer-tweeter control that provides full dynamic range correction from tip/tilt to 16 cycles, variable pupil sampling wavefront sensor, new enhanced silver coatings developed at UC Observatories that improve science and LGS throughput, and tight mechanical rigidity that enables a multi-hour diffraction-limited exposure in LGS mode for faint object spectroscopy science.

  6. Precise Doppler Monitoring of Barnard's Star

    NASA Astrophysics Data System (ADS)

    Choi, Jieun; McCarthy, Chris; Marcy, Geoffrey W.; Howard, Andrew W.; Fischer, Debra A.; Johnson, John A.; Isaacson, Howard; Wright, Jason T.

    2013-02-01

    We present 248 precise Doppler measurements of Barnard's Star (Gl 699), the second nearest star system to Earth, obtained from Lick and Keck Observatories during the 25 years between 1987 and 2012. The early precision was 20 m s-1 but was 2 m s-1 during the last 8 years, constituting the most extensive and sensitive search for Doppler signatures of planets around this stellar neighbor. We carefully analyze the 136 Keck radial velocities spanning 8 years by first applying a periodogram analysis to search for nearly circular orbits. We find no significant periodic Doppler signals with amplitudes above ~2 m s-1, setting firm upper limits on the minimum mass (Msin i) of any planets with orbital periods from 0.1 to 1000 days. Using a Monte Carlo analysis for circular orbits, we determine that planetary companions to Barnard's Star with masses above 2 M ⊕ and periods below 10 days would have been detected. Planets with periods up to 2 years and masses above 10 M ⊕ (0.03 M Jup) are also ruled out. A similar analysis allowing for eccentric orbits yields comparable mass limits. The habitable zone of Barnard's Star appears to be devoid of roughly Earth-mass planets or larger, save for face-on orbits. Previous claims of planets around the star by van de Kamp are strongly refuted. The radial velocity of Barnard's Star increases with time at 4.515 ± 0.002 m s-1 yr-1, consistent with the predicted geometrical effect, secular acceleration, that exchanges transverse for radial components of velocity. Based on observations made at Keck Observatory and Lick Observatory.

  7. Lick-index entanglement and biased diagnostic of stellar populations in galaxies

    NASA Astrophysics Data System (ADS)

    Buzzoni, Alberto

    2015-05-01

    The inherent statistical and operational properties of the Lick-index spectrophotometric system are investigated to facilitate a more appropriate use for astrophysical studies. Non-Gaussian effects in the index standardization procedure suggest that a minimum S/N ratio has to be met by spectral data, such as S/N ≳ 5 px-1 for a spectral resolution R ˜ 2000. In addition, index (re-)definition in terms of narrow-band colour should be preferred over the classical pseudo-equivalent width scheme. The overlapping wavelength range among different indices is also an issue, as it may lead the later ones to correlate beyond any strictly physical relationship. The nested configuration of the Fe5335 and Fe5270 indices, and the so-called Mg complex (including Mg1, Mg2 and Mgb), is analysed, in this context, by assessing the implied bias when joining entangled features into global diagnostic meta-indices, like the perused [MgFe] metallicity tracer. The perturbing effect of [O III]5007 and [N I]5199 forbidden gas emission on Fe5015 and Mgb absorption features is considered, and an updated correction scheme is proposed when using [O III]5007 as a proxy to appraise Hβ residual emission. When applied to the present-day elliptical galaxy population, the revised Hβ scale leads, on average, to 20-30 per cent younger age estimates. Finally, the misleading role of the christening element in Lick-based chemical analyses is illustrated for the striking case of Fe4531. In fact, while iron is nominally the main contributor to the observed feature in high-resolution spectra, we have shown that the maximum responsiveness of the Fe4531 index is actually to titanium abundance.

  8. Arsenic in groundwater of Licking County, Ohio, 2012—Occurrence and relation to hydrogeology

    USGS Publications Warehouse

    Thomas, Mary Ann

    2016-02-23

    Arsenic concentrations were measured in samples from 168 domestic wells in Licking County, Ohio, to document arsenic concentrations in a wide variety of wells and to identify hydrogeologic factors associated with arsenic concentrations in groundwater. Elevated concentrations of arsenic (greater than 10.0 micrograms per liter [µg/L]) were detected in 12 percent of the wells (about 1 in 8). The maximum arsenic concentration of about 44 µg/L was detected in two wells in the same township.A subset of 102 wells was also sampled for iron, sulfate, manganese, and nitrate, which were used to estimate redox conditions of the groundwater. Elevated arsenic concentrations were detected only in strongly reducing groundwater. Almost 20 percent of the samples with iron concentrations high enough to produce iron staining (greater than 300 µg/L) also had elevated concentrations of arsenic.In groundwater, arsenic primarily occurs as two inorganic species—arsenite and arsenate. Arsenic speciation was determined for a subset of nine samples, and arsenite was the predominant species. Of the two species, arsenite is more difficult to remove from water, and is generally considered to be more toxic to humans.Aquifer and well-construction characteristics were compiled from 99 well logs. Elevated concentrations of arsenic (and iron) were detected in glacial and bedrock aquifers but were more prevalent in glacial aquifers. The reason may be that the glacial deposits typically contain more organic carbon than the Paleozoic bedrock. Organic carbon plays a role in the redox reactions that cause arsenic (and iron) to be released from the aquifer matrix. Arsenic concentrations were not significantly different for different types of bedrock (sandstone, shale, sandstone/shale, or other). However, arsenic concentrations in bedrock wells were correlated with two well-construction characteristics; higher arsenic concentrations in bedrock wells were associated with (1) shorter open intervals and

  9. Sodium Laser Guide Star Adaptive Optics Imaging Polarimetry of Herbig Ae/Be Stars

    SciTech Connect

    Perrin, M D; Graham, J R; Lloyd, J P; Kalas, P; Gates, E L; Gavel, D T; Pennington, D M; Max, C E

    2004-01-08

    The future of high-resolution ground-based optical and infrared astronomy requires the successful implementation of laser guide star adaptive optics systems. We present the first science results from the Lick Observatory sodium beacon laser guide star system. By coupling this system to a near-infrared (J;H;Ks bands) dual-channel imaging polarimeter, we achieve very high sensitivity to light scattered in the circumstellar enviroment of Herbig Ae/Be stars on scales of 100-300 AU. Observations of LkH{alpha} 198 reveal a highly polarized, biconical nebula 10 arcseconds in diameter (6000 AU) . We also observe a polarized jet-like feature associated with the deeply embedded source LkH{alpha} 198-IR. The star LkH{alpha} 233 presents a narrow, unpolarized dark lane dividing its characteristic butterfly-shaped polarized reflection nebulosity. This linear structure is oriented perpendicular to an optical jet and bipolar cavity and is consistent with the presence of an optically thick circumstellar disk blocking our direct view of the star. These data suggest that the evolutionary picture developed for the lower-mass T Tauri stars is also relevant to the Herbig Ae/Be stars and demonstrate the ability of laser guide star adaptive optics systems to obtain scientific results competitive with natural guide star adaptive optics or space-based telescopes.

  10. LOSS Revisited. I. Unraveling Correlations Between Supernova Rates and Galaxy Properties, as Measured in a Reanalysis of the Lick Observatory Supernova Search

    NASA Astrophysics Data System (ADS)

    Graur, Or; Bianco, Federica B.; Huang, Shan; Modjaz, Maryam; Shivvers, Isaac; Filippenko, Alexei V.; Li, Weidong; Eldridge, J. J.

    2017-03-01

    Most types of supernovae (SNe) have yet to be connected with their progenitor stellar systems. Here, we reanalyze the 10-year SN sample collected during 1998–2008 by the Lick Observatory Supernova Search (LOSS) in order to constrain the progenitors of SNe Ia and stripped-envelope SNe (SE SNe, i.e., SNe IIb, Ib, Ic, and broad-lined Ic). We matched the LOSS galaxy sample with spectroscopy from the Sloan Digital Sky Survey and measured SN rates as a function of galaxy stellar mass, specific star formation rate, and oxygen abundance (metallicity). We find significant correlations between the SN rates and all three galaxy properties. The SN Ia correlations are consistent with other measurements, as well as with our previous explanation of these measurements in the form of a combination of the SN Ia delay-time distribution and the correlation between galaxy mass and age. The ratio between the SE SN and SN II rates declines significantly in low-mass galaxies. This rules out single stars as SE SN progenitors, and is consistent with predictions from binary-system progenitor models. Using well-known galaxy scaling relations, any correlation between the rates and one of the galaxy properties examined here can be expressed as a correlation with the other two. These redundant correlations preclude us from establishing causality—that is, from ascertaining which of the galaxy properties (or their combination) is the physical driver for the difference between the SE SN and SN II rates. We outline several methods that have the potential to overcome this problem in future works.

  11. Odor-Taste Convergence in the Nucleus of the Solitary Tract of the Awake Freely Licking Rat

    PubMed Central

    Escanilla, Olga D.; Victor, Jonathan D.

    2015-01-01

    Flavor is produced by the integration of taste, olfaction, texture, and temperature, currently thought to occur in the cortex. However, previous work has shown that brainstem taste-related nuclei also respond to multisensory inputs. Here, we test the hypothesis that taste and olfaction interact in the nucleus of the solitary tract (NTS; the first neural relay in the central gustatory pathway) in awake, freely licking rats. Electrophysiological recordings of taste and taste + odor responses were conducted in an experimental chamber following surgical electrode implantation and recovery. Tastants (0.1 m NaCl, 0.1 m sucrose, 0.01 m citric acid, and 0.0001 m quinine) were delivered for five consecutive licks interspersed with five licks of artificial saliva rinse delivered on a VR5 schedule. Odorants were n-amyl acetate (banana), acetic acid (vinegar), octanoic acid (rancid), and phenylethyl alcohol (floral). For each cell, metric space analyses were used to quantify the information conveyed by spike count, by the rate envelope, and by individual spike timing. Results revealed diverse effects of odorants on taste-response magnitude and latency across cells. Importantly, NTS cells were more competent at discriminating taste + odor stimuli versus tastants presented alone for all taste qualities using both rate and temporal coding. The strong interaction of odorants and tastants at the NTS underscores its role as the initial node in the neural circuit that controls food identification and ingestion. PMID:25904782

  12. Stability Analysis of the Planetary System Orbiting Upsilon Andromedae. 2; Simulations Using New Lick Observatory Fits

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Rivera, Eugenio J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    We present results of long-term numerical orbital integrations designed to test the stability of the three-planet system orbiting upsilon Andromedae and short-term integrations to test whether mutual perturbations among the planets can be used to determine planetary masses. Our initial conditions are based on recent fits to the radial velocity data obtained by the planet search group at Lick Observatory. The new fits result in significantly more stable systems than did the initially announced planetary parameters. Our integrations using the 2000 February parameters show that if the system is nearly planar, then it is stable for at least 100 Myr for m(sub f) = 1/sin i less than or = 4. In some stable systems, the eccentricity of the inner planet experiences large oscillations. The relative periastra of the outer two planets' orbits librate about 0 deg. in most of the stable systems; if future observations imply that the periastron longitudes of these planets are very closely aligned at the present epoch, dynamical simulations may provide precise estimates for the masses and orbital inclinations of these two planets.

  13. Modelling reverberation mapping data - II. Dynamical modelling of the Lick AGN Monitoring Project 2008 data set

    NASA Astrophysics Data System (ADS)

    Pancoast, Anna; Brewer, Brendon J.; Treu, Tommaso; Park, Daeseong; Barth, Aaron J.; Bentz, Misty C.; Woo, Jong-Hak

    2014-12-01

    We present dynamical modelling of the broad-line region (BLR) for a sample of five Seyfert 1 galaxies using reverberation mapping data taken by the Lick AGN Monitoring Project in 2008. By modelling the AGN continuum light curve and Hβ line profiles directly, we are able to constrain the geometry and kinematics of the BLR and make a measurement of the black hole mass that does not depend upon the virial factor, f, needed in traditional reverberation mapping analysis. We find that the geometry of the BLR is generally a thick disc viewed close to face-on. While the Hβ emission is found to come preferentially from the far side of the BLR, the mean size of the BLR is consistent with the lags measured with cross-correlation analysis. The BLR kinematics are found to be consistent with either inflowing motions or elliptical orbits, often with some combination of the two. We measure black hole masses of log _{10}(M_ BH/M_{odot })=6.62^{+0.10}_{-0.13} for Arp 151, 7.42^{+0.26}_{-0.27} for Mrk 1310, 7.59^{+0.24}_{-0.21} for NGC 5548, 6.37^{+0.21}_{-0.16} for NGC 6814, and 6.99^{+0.32}_{-0.25} for SBS 1116+583A. The f factors measured individually for each AGN are found to correlate with inclination angle, although not with M BH, L5100, or FWHM/σ of the emission line profile.

  14. Stability Analysis of the Planetary System Orbiting Upsilon Andromedae. 2; Simulations Using New Lick Observatory Fits

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Rivera, Eugenio J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    We present results of long-term numerical orbital integrations designed to test the stability of the three-planet system orbiting upsilon Andromedae and short-term integrations to test whether mutual perturbations among the planets can be used to determine planetary masses. Our initial conditions are based on recent fits to the radial velocity data obtained by the planet search group at Lick Observatory. The new fits result in significantly more stable systems than did the initially announced planetary parameters. Our integrations using the 2000 February parameters show that if the system is nearly planar, then it is stable for at least 100 Myr for m(sub f) = 1/sin i less than or = 4. In some stable systems, the eccentricity of the inner planet experiences large oscillations. The relative periastra of the outer two planets' orbits librate about 0 deg. in most of the stable systems; if future observations imply that the periastron longitudes of these planets are very closely aligned at the present epoch, dynamical simulations may provide precise estimates for the masses and orbital inclinations of these two planets.

  15. Near-Infrared Observations of Neptune's Tropospheric Cloud Layer with the Lick Observatory Adaptive Optics System

    NASA Astrophysics Data System (ADS)

    Roe, Henry G.; Gavel, Donald; Max, Claire; de Pater, Imke; Gibbard, Seran; Macintosh, Bruce; Baines, Kevin H.

    2001-09-01

    We provide one of the first constraints on the combined infrared single-scattering albedo and opacity of Neptune's upper tropospheric cloud layer. For the observations, we used the adaptive optics system on the Lick Observatory's 3 m Shane Telescope (Mount Hamilton, California). The cloud layer is thought to be composed of H2S and extend up to 3.5-4.5 bars. Previously, the single-scattering albedo was measured in the range 0.2-0.94 μm and found to be extremely high (>0.8), but decreasing with increasing wavelength. Assuming an optically thick cloud, we find the best-fit single-scattering albedo of a 3.5 bar layer to be 0.23+0.07-0.08 at 1.27 μm and 0.18+0.03-0.04 at 1.56 μm. Uncertainties in the column density of haze above the cloud layer, and from deconvolution to remove contaminating light scattered by the point-spread function from infrared-bright features, indicate that the cloud could be even darker, but it is unlikely to be brighter than we report. The cloud particles could be brighter than we report if the total near-infrared opacity of the cloud is very low or the cloud's scattering phase function is significantly more forward-scattering at 1.2-1.6 μm than at 0.75 μm.

  16. The lick AGN monitoring project 2011: Fe II reverberation from the outer broad-line region

    SciTech Connect

    Barth, Aaron J.; Cooper, Michael C.; Pancoast, Anna; Treu, Tommaso; Bennert, Vardha N.; Brewer, Brendon J.; Canalizo, Gabriela; Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Clubb, Kelsey I.; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Sand, David J.; Stern, Daniel; Assef, Roberto J.; Woo, Jong-Hak; Bae, Hyun-Jin; Buehler, Tabitha; and others

    2013-06-01

    The prominent broad Fe II emission blends in the spectra of active galactic nuclei have been shown to vary in response to continuum variations, but past attempts to measure the reverberation lag time of the optical Fe II lines have met with only limited success. Here we report the detection of Fe II reverberation in two Seyfert 1 galaxies, NGC 4593 and Mrk 1511, based on data from a program carried out at Lick Observatory in Spring 2011. Light curves for emission lines including Hβ and Fe II were measured by applying a fitting routine to decompose the spectra into several continuum and emission-line components, and we use cross-correlation techniques to determine the reverberation lags of the emission lines relative to V-band light curves. In both cases, the measured lag (τ{sub cen}) of Fe II is longer than that of Hβ, although the inferred lags are somewhat sensitive to the choice of Fe II template used in the fit. For spectral decompositions done using the Fe II template of Véron-Cetty et al., we find τ{sub cen}(Fe II)/τ{sub cen}(Hβ) = 1.9 ± 0.6 in NGC 4593 and 1.5 ± 0.3 in Mrk 1511. The detection of highly correlated variations between Fe II and continuum emission demonstrates that the Fe II emission in these galaxies originates in photoionized gas, located predominantly in the outer portion of the broad-line region.

  17. THE LICK AGN MONITORING PROJECT: PHOTOMETRIC LIGHT CURVES AND OPTICAL VARIABILITY CHARACTERISTICS

    SciTech Connect

    Walsh, Jonelle L.; Bentz, Misty C.; Barth, Aaron J.; Minezaki, Takeo; Sakata, Yu; Yoshii, Yuzuru; Baliber, Nairn; Bennert, Vardha Nicola; Street, Rachel A.; Treu, Tommaso; Li Weidong; Filippenko, Alexei V.; Stern, Daniel; Brown, Timothy M.; Canalizo, Gabriela; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Woo, Jong-Hak

    2009-11-01

    The Lick AGN Monitoring Project targeted 13 nearby Seyfert 1 galaxies with the intent of measuring the masses of their central black holes using reverberation mapping. The sample includes 12 galaxies selected to have black holes with masses roughly in the range 10{sup 6}-10{sup 7} M {sub sun}, as well as the well-studied active galactic nucleus (AGN) NGC 5548. In conjunction with a spectroscopic monitoring campaign, we obtained broadband B and V images on most nights from 2008 February through 2008 May. The imaging observations were carried out by four telescopes: the 0.76 m Katzman Automatic Imaging Telescope, the 2 m Multicolor Active Galactic Nuclei Monitoring telescope, the Palomar 60 inch (1.5 m) telescope, and the 0.80 m Tenagra II telescope. Having well-sampled light curves over the course of a few months is useful for obtaining the broad-line reverberation lag and black hole mass, and also allows us to examine the characteristics of the continuum variability. In this paper, we discuss the observational methods and the photometric measurements, and present the AGN continuum light curves. We measure various variability characteristics of each of the light curves. We do not detect any evidence for a time lag between the B- and V-band variations, and we do not find significant color variations for the AGNs in our sample.

  18. THE LICK AGN MONITORING PROJECT: ALTERNATE ROUTES TO A BROAD-LINE REGION RADIUS

    SciTech Connect

    Greene, Jenny E.; Hood, Carol E.; Barth, Aaron J.; Bentz, Misty C.; Walsh, Jonelle L.; Bennert, Vardha N.; Treu, Tommaso; Filippenko, Alexei V.; Gates, Elinor; Malkan, Matthew A.; Woo, Jong-Hak

    2010-11-01

    It is now possible to estimate black hole (BH) masses across cosmic time, using broad emission lines in active galaxies. This technique informs our views of how galaxies and their central BHs coevolve. Unfortunately, there are many outstanding uncertainties associated with these 'virial' mass estimates. One of these comes from using the accretion luminosity to infer a size for the broad-line region (BLR). Incorporating the new sample of low-luminosity active galaxies from our recent monitoring campaign at Lick Observatory, we recalibrate the radius-luminosity relation with tracers of the accretion luminosity other than the optical continuum. We find that the radius of the BLR scales as the square root of the X-ray and H{beta} luminosities, in agreement with recent optical studies. On the other hand, the scaling appears to be marginally steeper with narrow-line luminosities. This is consistent with a previously observed decrease in the ratio of narrow-line to X-ray luminosity with increasing total luminosity. The radius of the BLR correlates most tightly with H{beta} luminosity, while the X-ray and narrow-line relations both have comparable scatter of a factor of 2. These correlations provide useful alternative virial BH masses in objects with no detectable optical/UV continuum emission, such as high-redshift galaxies with broad emission lines, radio-loud objects, or local active galaxies with galaxy-dominated continua.

  19. Magnesium deficiency reduces fear-induced conditional lick suppression in mice.

    PubMed

    Bardgett, Mark E; Schultheis, Patrick J; Muzny, Ashley; Riddle, Michael D; Wagge, Jordan R

    2007-03-01

    The consequences of broad-scale alterations in magnesium (Mg2+) levels on learning and memory are poorly understood. We have recently demonstrated that adult male mice maintained on an Mg2+-deficient diet exhibit reduced conditional freezing behavior. The purpose of the present study was to determine if the detrimental effect of Mg2+ deficiency in mice extended to another measure of conditional fear, conditioned lick suppression (CLS), as well as to another form of learning, spatial learning in the swim maze task. Adult male C57Bl/6J mice were provided with a normal or Mg2+-deficient diet and were trained and tested ten days later for conditional fear, using CLS and freezing as indicators of learning. Learning in the swim maze was tested in a separate cohort of mice during days 14-18 of diet exposure. Mg2+-deficient mice showed reduced CLS as well as conditional freezing behavior in comparison to control mice. However, learning in the swim maze task was normal in Mg2+-deficient mice. These studies indicate that the detrimental effects of Mg2+ deficiency extend to other measures of conditional fear but not to all forms of learning.

  20. Progress in Na laser guide star adaptive optics and lessons learned

    NASA Astrophysics Data System (ADS)

    Jones, Katharine J.

    2016-09-01

    Laser beams have long been applied across many disciplines, extending degrees of freedom for purely spatial control to polarization spatial control. Adaptive beam shaping in Na Laser Guide Star approaches will be assessed for progress and lessons learned. Laser Guide Stars based on Rayleigh Scattering at 530 nm is straightforward: simply frequency double a Nd:YAG. For Na Laser Guide Stars, there is no easy way to get 589 nm and is more cotp:plicated. Significate Laser Guide Star Systems include the Starfire Optical Range (SOR), The Lick Laser Gude Star (UC), Caltech/Mt. Palomar, the Keck Laser Guide Star, ESQ VLT, and Gemini South. These will be compared for progress and future developments.

  1. The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-line Light Curves

    NASA Astrophysics Data System (ADS)

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E.; Li, Weidong; Malkan, Matthew A.; Pancoast, Anna; Sand, David J.; Stern, Daniel; Treu, Tommaso; Woo, Jong-Hak; Assef, Roberto J.; Bae, Hyun-Jin; Brewer, Brendon J.; Cenko, S. Bradley; Clubb, Kelsey I.; Cooper, Michael C.; Diamond-Stanic, Aleksandar M.; Hiner, Kyle D.; Hönig, Sebastian F.; Hsiao, Eric; Kandrashoff, Michael T.; Lazarova, Mariana S.; Nierenberg, A. M.; Rex, Jacob; Silverman, Jeffrey M.; Tollerud, Erik J.; Walsh, Jonelle L.

    2015-04-01

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hβ line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Hβ line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad Hβ width and luminosity, demonstrating that the broad-line region “breathes” on short timescales of days to weeks in response to continuum variations. We also find that broad Hβ velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad Hβ velocity shifted by ˜250 km s-1 over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  2. The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-line Light Curves

    NASA Technical Reports Server (NTRS)

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E..; Li, Weidong; Malkan, Matthew A.; Pancoast, Anna; Sand, David J.; hide

    2016-01-01

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hß line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad H beta line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad H beta width and luminosity, demonstrating that the broad-line region "breathes" on short timescales of days to weeks in response to continuum variations. We also find that broad H beta velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad H beta velocity shifted by approximately 250 km s(exp -1) over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  3. THE LICK AGN MONITORING PROJECT 2011: SPECTROSCOPIC CAMPAIGN AND EMISSION-LINE LIGHT CURVES

    SciTech Connect

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Li, Weidong; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Treu, Tommaso; Pancoast, Anna; Sand, David J.; Stern, Daniel; Woo, Jong-Hak; Assef, Roberto J.; Bae, Hyun-Jin; Brewer, Brendon J.; Cenko, S. Bradley; and others

    2015-04-15

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hβ line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Hβ line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad Hβ width and luminosity, demonstrating that the broad-line region “breathes” on short timescales of days to weeks in response to continuum variations. We also find that broad Hβ velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad Hβ velocity shifted by ∼250 km s{sup −1} over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  4. The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-line Light Curves

    NASA Technical Reports Server (NTRS)

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E..; Li, Weidong; Malkan, Matthew A.; Pancoast, Anna; Sand, David J.; Stern, Daniel; Cenko, S. Bradley

    2016-01-01

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hß line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad H beta line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad H beta width and luminosity, demonstrating that the broad-line region "breathes" on short timescales of days to weeks in response to continuum variations. We also find that broad H beta velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad H beta velocity shifted by approximately 250 km s(exp -1) over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  5. The Lick AGN Monitoring Project: Recalibrating Single-epoch Virial Black Hole Mass Estimates

    NASA Astrophysics Data System (ADS)

    Park, Daeseong; Woo, Jong-Hak; Treu, Tommaso; Barth, Aaron J.; Bentz, Misty C.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor; Greene, Jenny E.; Malkan, Matthew A.; Walsh, Jonelle

    2012-03-01

    We investigate the calibration and uncertainties of black hole (BH) mass estimates based on the single-epoch (SE) method, using homogeneous and high-quality multi-epoch spectra obtained by the Lick Active Galactic Nucleus (AGN) Monitoring Project for nine local Seyfert 1 galaxies with BH masses <108 M ⊙. By decomposing the spectra into their AGNs and stellar components, we study the variability of the SE Hβ line width (full width at half-maximum intensity, FWHMHβ or dispersion, σHβ) and of the AGN continuum luminosity at 5100 Å (L 5100). From the distribution of the "virial products" (vprop FWHMHβ 2 L 0.5 5100 or σHβ 2 L 0.5 5100) measured from SE spectra, we estimate the uncertainty due to the combined variability as ~0.05 dex (12%). This is subdominant with respect to the total uncertainty in SE mass estimates, which is dominated by uncertainties in the size-luminosity relation and virial coefficient, and is estimated to be ~0.46 dex (factor of ~3). By comparing the Hβ line profile of the SE, mean, and root-mean-square (rms) spectra, we find that the Hβ line is broader in the mean (and SE) spectra than in the rms spectra by ~0.1 dex (25%) for our sample with FWHMHβ <3000 km s-1. This result is at variance with larger mass BHs where the difference is typically found to be much less than 0.1 dex. To correct for this systematic difference of the Hβ line profile, we introduce a line-width dependent virial factor, resulting in a recalibration of SE BH mass estimators for low-mass AGNs.

  6. THE LICK AGN MONITORING PROJECT 2011: REVERBERATION MAPPING OF MARKARIAN 50

    SciTech Connect

    Barth, Aaron J.; Thorman, Shawn J.; Pancoast, Anna; Bennert, Vardha N.; Sand, David J.; Treu, Tommaso; Brewer, Brendon J.; Li, Weidong; Filippenko, Alexei V.; Cenko, S. Bradley; Clubb, Kelsey I.; Canalizo, Gabriela; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Stern, Daniel; Assef, Roberto J.; Woo, Jong-Hak; Bae, Hyun-Jin; Buehler, Tabitha; and others

    2011-12-10

    The Lick AGN Monitoring Project 2011 observing campaign was carried out over the course of 11 weeks in spring 2011. Here we present the first results from this program, a measurement of the broad-line reverberation lag in the Seyfert 1 galaxy Mrk 50. Combining our data with supplemental observations obtained prior to the start of the main observing campaign, our data set covers a total duration of 4.5 months. During this time, Mrk 50 was highly variable, exhibiting a maximum variability amplitude of a factor of {approx}4 in the U-band continuum and a factor of {approx}2 in the H{beta} line. Using standard cross-correlation techniques, we find that H{beta} and H{gamma} lag the V-band continuum by {tau}{sub cen} = 10.64{sup +0.82}{sub -0.93} and 8.43{sup +1.30}{sub -1.28} days, respectively, while the lag of He II {lambda}4686 is unresolved. The H{beta} line exhibits a symmetric velocity-resolved reverberation signature with shorter lags in the high-velocity wings than in the line core, consistent with an origin in a broad-line region (BLR) dominated by orbital motion rather than infall or outflow. Assuming a virial normalization factor of f = 5.25, the virial estimate of the black hole mass is (3.2 {+-} 0.5) Multiplication-Sign 10{sup 7} M{sub Sun }. These observations demonstrate that Mrk 50 is among the most promising nearby active galaxies for detailed investigations of BLR structure and dynamics.

  7. Comparative Analysis of the Activity Cycles of the Atmospheres of the Sun and of Stars of the Solar-Type

    NASA Astrophysics Data System (ADS)

    Bruevich, E. A.; Bruevich, V. V.; Shimanovskaya, E. V.

    2016-03-01

    The atmospheric activity of the sun and of stars of the solar-type is analyzed using observations from the HK-project at the Mount Wilson Observatory, California, and the Carnegie Planet Search Program at the Keck and Lick Observatories, as well as from the Magellan Planet Search Program at the Las Campanas Observatory. It is shown that a cyclical activity of the stars that is analogous to the 11-year solar activity cycle occurs in stars of spectral classes F, G, and K and is more pronounced in stars of class K. A comparative analysis of the solar-type stars with different levels of chromospheric and coronal activity confirms that the sun is one of the stars with a comparatively low level of atmospheric activity and that these stars have a minimal level of coronal emission and minimal variations in the fluxes of photospheric radiation.

  8. Dopamine on D2-like receptors is involved in reward evaluation in water-deprived rats licking for NaCl and water.

    PubMed

    Canu, Maria Elena; Carta, Davide; Murgia, Emanuele; Serra, Gino; D'Aquila, Paolo S

    2010-08-01

    The analysis of licking microstructure provides measures, size and number of licking bouts, which might reveal, respectively, reward evaluation and behavioural activation. Based on the ability of the dopamine D2-like receptor antagonist raclopride to reduce bout size and to induce an "extinction mimicry effect" on bout number, we suggested that the level of activation of reward-associated responses is updated, or "reboosted", on the basis of a dopamine D2-like receptor-mediated evaluation process occurring during the consummatory transaction with the reward. Here we investigate the effects of the dopamine D2-like receptor antagonist raclopride (0, 25, 125, and 250microg/kg) on the microstructure of licking for water and sodium chloride solutions (0.075M, 0.15M, and 0.3M) in 12h water-deprived rats. In each session, rats were exposed to brief contact tests (1min) for each solution. Bout size, but not bout number, was decreased at the highest NaCl concentration. Raclopride reduced lick number owing to reduced bout size, while bout number was either not affected or even increased depending on the dose. These results are in agreement with the previous observations on sucrose licking, and suggest the involvement of dopamine D2-like receptors in an evaluation process occurring during the consummatory transaction with the reward.

  9. A low-cost solution to measure mouse licking in an electrophysiological setup with a standard analog-to-digital converter.

    PubMed

    Hayar, Abdallah; Bryant, Jeri L; Boughter, John D; Heck, Detlef H

    2006-06-15

    Licking behavior in rodents is widely used to determine fluid consumption in various behavioral contexts and is a typical example of rhythmic movement controlled by internal pattern-generating mechanisms. The measurement of licking behavior by commercially available instruments is based on either tongue protrusion interrupting a light beam or on an electrical signal generated by the tongue touching a metal spout. We report here that licking behavior can be measured with high temporal precision by simply connecting a metal sipper tube to the input of a standard analog/digital (A/D) converter and connecting the animal to ground (via a metal cage floor). The signal produced by a single lick consists of a 100-800 mV dc voltage step, which reflects the metal-to-water junction potential and persists for the duration of the tongue-spout contact. This method does not produce any significant electrical artifacts and can be combined with electrophysiological measurements of single unit activity from neurons involved in the control of the licking behavior.

  10. Spectral energy distribution /119 - 685 nm/ in 16 shell stars and a tentative model for accreting Be stars

    NASA Technical Reports Server (NTRS)

    Plavec, M. J.; Dobias, J. J.; Weiland, J. L.; Stone, R. P. S.

    1982-01-01

    IUE low-dispersion spectra and spectral scans made with the Lick Observatory IDS scanners have been combined for 16 shell stars. Eleven objects can be represented by Kurucz (1979) model atmospheres, although some of them display strong shell-type line spectra. Five among them are known binaries. The six remaining objects display complex spectra. A model involving continuum and line radiation from a hydrogen cloud surrounding the accreting component is proposed. A generalization of this model with optically thick segments of the cloud promises to explain even more exotic objects such as beta Lyrae, W Serpentis and possibly epsilon Aurigae.

  11. Measurement of the reaeration coefficients of the North Fork Licking River at Utica, Ohio by radioactive tracers

    USGS Publications Warehouse

    Hren, Janet

    1983-01-01

    Reaeration coefficients of the North Fork Licking River at Utica, Ohio were measured by the radioactive-tracer method. The tests were conducted on a 2.1-mile reach on September 23 and October 7, 1981, during low-flow conditions. Krypton-85 gas and tritium were the radioopactive tracers, which were used in conjunction with rhodamine-WT dye. The reaertion coefficients determined on September 23 were 3.09 days-1 (subreach 1-2) and 3.32 days-1 (subreach 2-3). On October 7, the values were 2.04 days -1 and 2.23 days-1 respectively.

  12. Licking behaviour induces partial anthelmintic efficacy of ivermectin pour-on formulation in untreated cattle.

    PubMed

    Bousquet-Mélou, Alain; Jacquiet, Philippe; Hoste, Hervé; Clément, Julien; Bergeaud, Jean-Paul; Alvinerie, Michel; Toutain, Pierre-Louis

    2011-04-01

    Licking behaviour in cattle has been reported to account for the disposition of topically administered macrocyclic lactones. However, its impact on anthelmintic efficacy remains to be established. Therefore, we evaluated the impact of ivermectin exchange between cattle on the reduction in the faecal egg count (FEC) after pour-on administration in a group of 10 heifers experimentally infected with Ostertagia ostertagi and Cooperia oncophora. Four treated (500 μg/kg, pour-on) and six untreated animals were put together after treatment and plasma and faecal exposure to ivermectin as well as the FECs were evaluated before and over 40 days after treatment. Ivermectin was detected in plasma and faeces of the six untreated heifers, with maximal exposures two- to three-fold lower than the minimal exposures in treated animals. The interindividual variability of exposure was very high in untreated animals, with a ten-fold difference between the upper and lower limits compared with treated heifers, where there was only a two-fold difference. Anthelmintic efficacy, expressed as an average reduction of the FECs over the experimental period, was maximal in the treated group. In untreated heifers, anthelmintic efficacies ranged from zero to maximal efficacy, with intermediary values between 30% and 80%. The use of a classical pharmacodynamic model demonstrated a clear relationship between exposure and efficacy and enabled us to define the critical plasma or faecal ivermectin concentrations delimiting an exposure window associated with partial anthelmintic efficacy. This range of ivermectin plasma concentrations (0.1-1 ng/mL) could be considered as a potential selection window for anthelmintic resistance. Finally, our results show that macrocyclic lactone exchange between cattle after pour-on administration, resulting from natural grooming behaviour, can significantly impact on anthelmintic efficacy. This raises several issues such as the design of comparative clinical trials and

  13. THE LICK AGN MONITORING PROJECT: RECALIBRATING SINGLE-EPOCH VIRIAL BLACK HOLE MASS ESTIMATES

    SciTech Connect

    Park, Daeseong; Woo, Jong-Hak; Treu, Tommaso; Bennert, Vardha N.; Barth, Aaron J.; Walsh, Jonelle; Bentz, Misty C.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor; Greene, Jenny E.; Malkan, Matthew A.

    2012-03-01

    We investigate the calibration and uncertainties of black hole (BH) mass estimates based on the single-epoch (SE) method, using homogeneous and high-quality multi-epoch spectra obtained by the Lick Active Galactic Nucleus (AGN) Monitoring Project for nine local Seyfert 1 galaxies with BH masses <10{sup 8} M{sub Sun }. By decomposing the spectra into their AGNs and stellar components, we study the variability of the SE H{beta} line width (full width at half-maximum intensity, FWHM{sub H{beta}} or dispersion, {sigma}{sub H{beta}}) and of the AGN continuum luminosity at 5100 A (L{sub 5100}). From the distribution of the 'virial products' ({proportional_to} FWHM{sub H{beta}}{sup 2} L{sup 0.5}{sub 5100} or {sigma}{sub H{beta}}{sup 2} L{sup 0.5}{sub 5100}) measured from SE spectra, we estimate the uncertainty due to the combined variability as {approx}0.05 dex (12%). This is subdominant with respect to the total uncertainty in SE mass estimates, which is dominated by uncertainties in the size-luminosity relation and virial coefficient, and is estimated to be {approx}0.46 dex (factor of {approx}3). By comparing the H{beta} line profile of the SE, mean, and root-mean-square (rms) spectra, we find that the H{beta} line is broader in the mean (and SE) spectra than in the rms spectra by {approx}0.1 dex (25%) for our sample with FWHM{sub H{beta}} <3000 km s{sup -1}. This result is at variance with larger mass BHs where the difference is typically found to be much less than 0.1 dex. To correct for this systematic difference of the H{beta} line profile, we introduce a line-width dependent virial factor, resulting in a recalibration of SE BH mass estimators for low-mass AGNs.

  14. Strange stars

    NASA Technical Reports Server (NTRS)

    Alcock, Charles; Farhi, Edward; Olinto, Angela

    1986-01-01

    Strange matter, a form of quark matter that is postulated to be absolute stable, may be the true ground stage of the hadrons. If this hypothesis is correct, neutron stars may convert to 'strange stars'. The mass-radius relation for strange stars is very different from that of neutron stars; there is no minimum mass, and for mass of 1 solar mass or less, mass is proportional to the cube of the radius. For masses between 1 solar mass and 2 solar masses, the radii of strange stars are about 10 km, as for neutron stars. Strange stars may have an exposed quark surface, which is capable of radiating at rates greatly exceeding the Eddington limit, but has a low emissivity for X-ray photons. The stars may have a thin crust with the same composition as the preneutron drip outer layer of a conventional neutron star crust. Strange stars cool efficiently via neutrino emission.

  15. Stars and Star Myths.

    ERIC Educational Resources Information Center

    Eason, Oliver

    Myths and tales from around the world about constellations and facts about stars in the constellations are presented. Most of the stories are from Greek and Roman mythology; however, a few Chinese, Japanese, Polynesian, Arabian, Jewish, and American Indian tales are also included. Following an introduction, myths are presented for the following 32…

  16. Stars and Star Myths.

    ERIC Educational Resources Information Center

    Eason, Oliver

    Myths and tales from around the world about constellations and facts about stars in the constellations are presented. Most of the stories are from Greek and Roman mythology; however, a few Chinese, Japanese, Polynesian, Arabian, Jewish, and American Indian tales are also included. Following an introduction, myths are presented for the following 32…

  17. The palatability of corn oil and linoleic acid to mice as measured by short-term two-bottle choice and licking tests.

    PubMed

    Yoneda, Takeshi; Saitou, Katsuyoshi; Mizushige, Takafumi; Matsumura, Shigenobu; Manabe, Yasuko; Tsuzuki, Satoshi; Inoue, Kazuo; Fushiki, Tohru

    2007-06-08

    Free fatty acids (FFAs) were reported to be recognized in the oral cavity and possibly involved in fatty foods recognition. To understand the importance of oil recognition in the oral cavity, we investigated the effect of various concentrations of a fatty acid or corn oil on fluid intake as well as mice's preferences in a two-bottle choice test and a licking test. Linoleic acid (LA), which is a main component of corn oil, was used as a representative FFA. In the two-bottle choice test between a pair of different concentrations of corn oil, the mice consistently adopted the higher concentration of corn oil. In the licking test for corn oil, the licking rates for the serial concentration of corn oils (0, 1, 5, 10 and 100%) were increased in a concentration-dependent manner. On the other hand, in the two-bottle test for a pair of different concentrations of LA (0, 0.125, 0.25 and 1%), 0.25% and 1% LA were preferred to mineral oil, but 0.25% and 1% LA were preferred equally in mice. In the licking test for LA, the mice showed the largest number of initial lickings for the 1% LA, while the licking rates for the high concentration of LA decreased. These results suggest that mice could discriminate the concentration of corn oil and LA in the oral cavity. We also suggest that pure corn oil is a highly preferable solution, while an optimal concentration of LA according to the preferences of mice is a low-range concentration (0.25-1%).

  18. Laser guide star adaptive optics imaging polarimetry of Herbig Ae/Be stars

    NASA Astrophysics Data System (ADS)

    Perrin, Marshall D.; Graham, James R.; Kalas, Paul; Lloyd, James P.; Max, Claire E.; Gavel, Donald T.; Pennington, Deanna M.; Gates, Elinor L.

    2004-10-01

    Current and future large telescopes depend critically on laser guide star adaptive optics (LGS AO) to achieve their scientific goals. However, there are still relatively few scientific results reported from existing LGS AO systems. We present some of the first science results from the Lick Observatory sodium beacon LGS AO system. We achieve high sensitivity to light scattered in the circumstellar enviroment of Herbig Ae/Be stars on scales of 100-200 AU by coupling the LGS AO system to a near-infrared (J,H,Ks bands) dual channel imaging polarimeter. We describe the design, implementation, and performance of this instrument. The dominant noise source near bright stars in AO images is a "seeing halo" of uncorrected speckles, and since these speckles are unpolarized, dual-channel polarimetry achieves a significant contrast gain. Our observations reveal a wide range of morphologies, including bipolar nebulosities with and without outflow-evacuated cavities and disk-mediated interaction among members of a binary. These data suggest that the evolutionary picture developed for the lower-mass T Tauri stars is also relevant to the Herbig Ae/Be stars, and demonstrate the ability of LGS AO systems to enhance the scientific capabilities of even modest sized telescopes.

  19. Magnetic cycles of Sun-like stars with different levels of coronal and chromospheric activity — comparison with the Sun

    NASA Astrophysics Data System (ADS)

    Shimanovskaya, Elena; Bruevich, Vasiliy; Bruevich, Elena

    2016-09-01

    The atmospheric activity of the Sun and Sun-like stars is analyzed involving observations from the HK-project at the Mount Wilson Observatory, the California and Carnegie Planet Search Program at the Keck and Lick Observatories and the Magellan Planet Search Program at the Las Campanas Observatory. We show that for stars of F, G and K spectral classes, the cyclic activity, similar to the 11-yr solar cycle, is different: it becomes more prominent in K-stars. Comparative study of Sun-like stars with different levels of chromospheric and coronal activity confirms that the Sun belongs to stars with a low level of chromospheric activity and stands apart among these stars by its minimum level of coronal radiation and minimum level of variations in photospheric flux.

  20. Retired A Stars and Their Companions: Exoplanets Orbiting Three Intermediate-Mass Subgiants

    NASA Astrophysics Data System (ADS)

    Johnson, John Asher; Fischer, Debra A.; Marcy, Geoffrey W.; Wright, Jason T.; Driscoll, Peter; Butler, R. Paul; Hekker, Saskia; Reffert, Sabine; Vogt, Steven S.

    2007-08-01

    We report precision Doppler measurements of three intermediate-mass subgiants obtained at Lick and Keck Observatories. All three stars show variability in their radial velocities consistent with planet-mass companions in Keplerian orbits. We find a planet with a minimum mass MPsini=2.5 MJ in a 351.5 day orbit around HD 192699, a planet with a minimum mass of 2.0 MJ in a 341.1 day orbit around HD 210702, and a planet with a minimum mass of 0.61 MJ in a 297.3 day orbit around HD 175541. Mass estimates from stellar interior models indicate that all three stars were formerly A-type, main-sequence dwarfs with masses ranging from 1.65 to 1.85 Msolar. These three long-period planets would not have been detectable during their stars' main-sequence phases due to the large rotational velocities and stellar jitter exhibited by early-type dwarfs. There are now nine ``retired'' (evolved) A-type stars (M*>1.6 Msolar) with known planets. All nine planets orbit at distances a>=0.78 AU, which is significantly different from the semimajor axis distribution of planets around lower mass stars. Based on observations obtained at the Lick Observatory, which is operated by the University of California, and W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology.

  1. Lick Observatory's Shane telescope adaptive optics system (ShaneAO): research directions and progress

    NASA Astrophysics Data System (ADS)

    Gavel, Donald T.; Kupke, Renate; Rudy, Alexander R.; Srinath, Srikar; Dillon, Daren; Poyneer, Lisa A.

    2016-07-01

    We present a review of the ongoing research activity surrounding the adaptive optics system at the Shane telescope (ShaneAO) particularly the R&D efforts on the technology and algorithms for that will advance AO into wider application for astronomy. We are pursuing the AO challenges for whole sky coverage diffraction-limited correction down to visible science wavelengths. This demands high-order wavefront correction and bright artificial laser beacons. We present recent advancements in the development of MEMS based AO correction, woofer-tweeter architecture, wind-predictive wavefront control algorithms, atmospheric characterization, and a pulsed fiber amplifier guide star laser tuned for optical pumping of the sodium layer. We present the latest on-sky results from the new AO system and present status and experimental plans for the optical pumping guide star laser.

  2. Pulsating Stars

    NASA Astrophysics Data System (ADS)

    Catelan, M.; Smith, H. A.

    2015-03-01

    This book surveys our understanding of stars which change in brightness because they pulsate. Pulsating variable stars are keys to distance scales inside and beyond the Milky Way galaxy. They test our understanding not only of stellar pulsation theory but also of stellar structure and evolution theory. Moreover, pulsating stars are important probes of the formation and evolution of our own and neighboring galaxies. Our understanding of pulsating stars has greatly increased in recent years as large-scale surveys of pulsating stars in the Milky Way and other Local Group galaxies have provided a wealth of new observations and as space-based instruments have studied particular pulsating stars in unprecedented detail.

  3. Effect of the dopamine D1-like receptor antagonist SCH 23390 on the microstructure of ingestive behaviour in water-deprived rats licking for water and NaCl solutions.

    PubMed

    Galistu, Adriana; D'Aquila, Paolo S

    2012-01-18

    The analysis of licking microstructure provides measures, size and number of licking bouts, which might reveal, respectively, reward evaluation and behavioural activation. Based on the different effects of the dopamine D1-like and D2-like receptor antagonists SCH 23390 and raclopride on licking for sucrose, in particular the failure of the former to reduce bout size and the ability of the latter to induce a within-session decrement of bout number resembling either reward devaluation or neuroleptics on instrumental responding, we suggested that activation of reward-associated responses depends on dopamine D1-like receptor stimulation, and its level is updated on the basis of a dopamine D2-like receptor-mediated reward evaluation. Consistent results were obtained in a study examining the effect of dopamine D2-like receptor antagonism in rats licking for NaCl solutions and water. In this study, we examined the effects of the dopamine D1-like receptor antagonist SCH 23390 (0, 10, 20 and 40 μg/kg) on the microstructure of licking for water and sodium chloride solutions (0.075 M, 0.15 M, 0.3 M) in 12 h water deprived rats. Rats were exposed to each solution for 60 s either after the first lick or after 3 min that the animals were placed in the chambers. Bout size, but not bout number, was decreased at the highest NaCl concentration. SCH 23390 produced a decrease of bout number and of lick number mainly due to the decreased number of subjects engaging in licking behaviour, and failed to reduce bout size for Na Cl and water at a dose which increased the latency to the 1st lick but did not affect the intra-bout lick rate. In agreement with previous observations, these results suggest that dopamine D1-like receptors play an important role in the activation of reward-oriented responses.

  4. Four Big-Telescope Planetary Astronomers of the 1920's at Mount Wilson, Yerkes, and Lick Observatories

    NASA Astrophysics Data System (ADS)

    Osterbrock, D. E.

    2002-12-01

    Contrary to current mythology, many professional astronomers tried to do planetary research before World War II, as Ronald Doel and I have previously emphasized. Their difficulty was that once the known planets had been studied with the biggest and best telescopes, spectrographs, and radiometers there was little more they could do until some new instrumental development came along, and these were rare in those years. Two astronomers who observed planets in the 1920's were Frank Ross, of the Yerkes Observatory faculty, with the Mount Wilson 60- and 100-inch telescopes, and William H. Wright, at Lick, with its 36-inch Crossley reflector, which he considered a big telescope. Both were keenly interested in photographic emulsions (Ross had been a research physicist at the Eastman Kodak Laboratory), and when fast new panchromatic films and plates became available in the 1920's they quickly applied them to photographing the planets. Robert J. Trumpler, also at Lick, used its 36-inch refractor in a combination of photographic (in the yellow and red spectral regions) and visual observing to map and describe Martian surface features. All three of them began planetary observing at the close opposition of Mars in 1924; they were all mainline scientists who ultimately were elected to the National Academy of Sciences. All three of them were doing descriptive work, seeing what was there, and none of them had any theoretical ideas to check or disprove. Francis G. Pease, more of a telescope designer and engineer at Mount Wilson, also used its 60- and 100-inch reflectors, chiefly to take photographs of the planets for illustrations in books and magazines. They all used fine-grain photographic plates, but seeing was a problem they could not overcome. Examples of their planetary photographs, papers, and letters will be posted. Ross and Trumpler dropped out of planetary astronomy after 1928, but Wright and Pease continued in it for many years. An interesting sidelight is that Gerard P

  5. Massive Stars

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Villaver, Eva

    2009-11-01

    Participants; Preface Mario Livio and Eva Villaver; 1. High-mass star formation by gravitational collapse of massive cores M. R. Krumholz; 2. Observations of massive star formation N. A. Patel; 3. Massive star formation in the Galactic center D. F. Figer; 4. An X-ray tour of massive star-forming regions with Chandra L. K. Townsley; 5. Massive stars: feedback effects in the local universe M. S. Oey and C. J. Clarke; 6. The initial mass function in clusters B. G. Elmegreen; 7. Massive stars and star clusters in the Antennae galaxies B. C. Whitmore; 8. On the binarity of Eta Carinae T. R. Gull; 9. Parameters and winds of hot massive stars R. P. Kudritzki and M. A. Urbaneja; 10. Unraveling the Galaxy to find the first stars J. Tumlinson; 11. Optically observable zero-age main-sequence O stars N. R. Walborn; 12. Metallicity-dependent Wolf-Raynet winds P. A. Crowther; 13. Eruptive mass loss in very massive stars and Population III stars N. Smith; 14. From progenitor to afterlife R. A. Chevalier; 15. Pair-production supernovae: theory and observation E. Scannapieco; 16. Cosmic infrared background and Population III: an overview A. Kashlinsky.

  6. PRECISE DOPPLER MONITORING OF BARNARD'S STAR

    SciTech Connect

    Choi, Jieun; Marcy, Geoffrey W.; Howard, Andrew W.; Isaacson, Howard; McCarthy, Chris; Fischer, Debra A.; Johnson, John A.; Wright, Jason T.

    2013-02-20

    We present 248 precise Doppler measurements of Barnard's Star (Gl 699), the second nearest star system to Earth, obtained from Lick and Keck Observatories during the 25 years between 1987 and 2012. The early precision was 20 m s{sup -1} but was 2 m s{sup -1} during the last 8 years, constituting the most extensive and sensitive search for Doppler signatures of planets around this stellar neighbor. We carefully analyze the 136 Keck radial velocities spanning 8 years by first applying a periodogram analysis to search for nearly circular orbits. We find no significant periodic Doppler signals with amplitudes above {approx}2 m s{sup -1}, setting firm upper limits on the minimum mass (Msin i) of any planets with orbital periods from 0.1 to 1000 days. Using a Monte Carlo analysis for circular orbits, we determine that planetary companions to Barnard's Star with masses above 2 M {sub Circled-Plus} and periods below 10 days would have been detected. Planets with periods up to 2 years and masses above 10 M {sub Circled-Plus} (0.03 M {sub Jup}) are also ruled out. A similar analysis allowing for eccentric orbits yields comparable mass limits. The habitable zone of Barnard's Star appears to be devoid of roughly Earth-mass planets or larger, save for face-on orbits. Previous claims of planets around the star by van de Kamp are strongly refuted. The radial velocity of Barnard's Star increases with time at 4.515 {+-} 0.002 m s{sup -1} yr{sup -1}, consistent with the predicted geometrical effect, secular acceleration, that exchanges transverse for radial components of velocity.

  7. Commissioning ShARCS: the Shane adaptive optics infrared camera-spectrograph for the Lick Observatory Shane 3-m telescope

    NASA Astrophysics Data System (ADS)

    McGurk, Rosalie; Rockosi, Constance; Gavel, Donald; Kupke, Renate; Peck, Michael; Pfister, Terry; Ward, Jim; Deich, William; Gates, John; Gates, Elinor; Alcott, Barry; Cowley, David; Dillon, Daren; Lanclos, Kyle; Sandford, Dale; Saylor, Mike; Srinath, Srikar; Weiss, Jason; Norton, Andrew

    2014-07-01

    We describe the design and first-light early science performance of the Shane Adaptive optics infraRed Camera- Spectrograph (ShARCS) on Lick Observatory's 3-m Shane telescope. Designed to work with the new ShaneAO adaptive optics system, ShARCS is capable of high-efficiency, diffraction-limited imaging and low-dispersion grism spectroscopy in J, H, and K-bands. ShARCS uses a HAWAII-2RG infrared detector, giving high quantum efficiency (<80%) and Nyquist sampling the diffraction limit in all three wavelength bands. The ShARCS instrument is also equipped for linear polarimetry and is sensitive down to 650 nm to support future visible-light adaptive optics capability. We report on the early science data taken during commissioning.

  8. Pairs and Groups of Genetically Related Long-period Comets and Proposed Identity of the Mysterious Lick Object of 1921

    NASA Astrophysics Data System (ADS)

    Sekanina, Zdenek; Kracht, Rainer

    2016-05-01

    We present the history of investigation of the dynamical properties of pairs and groups of genetically related long-period comets (other than the Kreutz sungrazing system). Members of a comet pair or group move in nearly identical orbits, and their origin as fragments of a common parent comet is unquestionable. The only variable is the time of perihelion passage, which differs considerably from member to member owing primarily to an orbital-momentum increment acquired during breakup. Meter-per-second separation velocities account for gaps of years or tens of years, thanks to the orbital periods of many millennia. The physical properties of individual members may not at all be alike, as illustrated by the trio of C/1988 A1, C/1996 Q1, and C/2015 F3. We exploit orbital similarity to examine whether the enigmatic and as-yet-unidentified object discovered from the Lick Observatory near the Sun at sunset on 1921 August 7 happened to be a member of such a pair and to track down the long-period comet to which it might be genetically related. Our search shows that the Lick object, which could not be a Kreutz sungrazer, was likely a companion to comet C/1847 C1 (Hind), whose perihelion distance was ˜9 R ⊙ and true orbital period was approximately 8300 yr. The gap of 74.4 yr between their perihelion times is consistent with a separation velocity of ˜1 m s-1 which sets the fragments apart following the parent's breakup in a general proximity of perihelion during the previous return to the Sun in the seventh millennium BCE.

  9. Ground-Water Data and Flow Directions in the Vicinity of Swamp Road, Licking County, Ohio, 2006-07

    USGS Publications Warehouse

    Dumouchelle, Denise H.

    2007-01-01

    The Natural Resources Conservation Service (NRCS) is proposing to build a dry dam on the South Fork Licking River to mitigate flood impacts. Concerns have been raised regarding the effects of impounded floodwaters on ground-water conditions in the Swamp Road neighborhood. To obtain a better understanding of existing ground-water conditions, the U.S. Geological Survey, in cooperation with the NRCS, installed three monitoring wells and collected ground-water-quality samples on two occasions from these and four residential wells. In addition, transducers were placed in these seven wells to obtain hourly water-level measurements from August, 2006 to early March, 2007. Intermittent water levels also were measured in another seven residential wells in the area. Water-quality samples were collected in September 2006 and January 2007. Samples were analyzed for nutrients, inorganic elements, and fecal-indicator bacteria. In general, the ground-water quality was very hard with large iron concentrations of 1,700 ?g/L and above. Although the aquifer underlying the Swamp Road area is confined, the continuous water-level records indicate a rapid response to precipitation. Comparison of the well hydrographs with the stage hydrograph for the nearby South Fork Licking River indicates a hydraulic connection between the river and the aquifer. In the vicinity of Swamp Road, the ground-water-flow direction was southeast during the duration of the study. The ground-water-level elevations were above the planned maximum elevation for water impounded by the dam, thus the impounded floodwater should have minimal impact on ground-water conditions along Swamp Road.

  10. CH Stars and Barium Stars

    NASA Astrophysics Data System (ADS)

    Bond, H.; Sion, E.; Murdin, P.

    2000-11-01

    The classical barium (or `Ba II') stars are RED GIANT STARS whose spectra show strong absorption lines of barium, strontium and certain other heavy elements, as well as strong features due to carbon molecules. Together with the related class of CH stars, the Ba II stars were crucial in establishing the existence of neutron-capture reactions in stellar interiors that are responsible for the synt...

  11. T1R2 and T1R3 subunits are individually unnecessary for normal affective licking responses to Polycose: implications for saccharide taste receptors in mice.

    PubMed

    Treesukosol, Yada; Blonde, Ginger D; Spector, Alan C

    2009-04-01

    The T1R2 and T1R3 proteins are expressed in taste receptor cells and form a heterodimer binding with compounds described as sweet by humans. We examined whether Polycose taste might be mediated through this heterodimer by testing T1R2 knockout (KO) and T1R3 KO mice and their wild-type (WT) littermate controls in a series of brief-access taste tests (25-min sessions with 5-s trials). Sucrose, Na-saccharin, and Polycose were each tested for three consecutive sessions with order of presentation varied among subgroups in a Latin-Square manner. Both KO groups displayed blunted licking responses and initiated significantly fewer trials of sucrose and Na-saccharin across a range of concentrations. KO mice tested after Polycose exposure demonstrated some degree of concentration-dependent licking of sucrose, likely attributable to learning related to prior postingestive experience. These results are consistent with prior findings in the literature, implicating the T1R2+3 heterodimer as the principal taste receptor for sweet-tasting ligands, and also provide support for the potential of postingestive experience to influence responding in the KO mice. In contrast, T1R2 KO and T1R3 KO mice displayed concentration-dependent licking responses to Polycose that tracked those of their WT controls and in some cases licked midrange concentrations more; the number of Polycose trials initiated overall did not differ between KO and WT mice. Thus, the T1R2 and T1R3 proteins are individually unnecessary for normal concentration-dependent licking of Polycose to be expressed in a brief-access test. Whether at least one of these T1R protein subunits is necessary for normal Polycose responsiveness remains untested. Alternatively, there may be a novel taste receptor(s) that mediates polysaccharide taste.

  12. T1R2 and T1R3 subunits are individually unnecessary for normal affective licking responses to polycose: implications for saccharide taste receptors in mice

    PubMed Central

    Treesukosol, Yada; Blonde, Ginger D.; Spector, Alan C.

    2009-01-01

    The T1R2 and T1R3 proteins are expressed in taste receptor cells and form a heterodimer binding with compounds described as sweet by humans. We examined whether Polycose taste might be mediated through this heterodimer by testing T1R2 knockout (KO) and T1R3 KO mice and their wild-type (WT) littermate controls in a series of brief-access taste tests (25-min sessions with 5-s trials). Sucrose, Na-saccharin, and Polycose were each tested for three consecutive sessions with order of presentation varied among subgroups in a Latin-Square manner. Both KO groups displayed blunted licking responses and initiated significantly fewer trials of sucrose and Na-saccharin across a range of concentrations. KO mice tested after Polycose exposure demonstrated some degree of concentration-dependent licking of sucrose, likely attributable to learning related to prior postingestive experience. These results are consistent with prior findings in the literature, implicating the T1R2+3 heterodimer as the principal taste receptor for sweet-tasting ligands, and also provide support for the potential of postingestive experience to influence responding in the KO mice. In contrast, T1R2 KO and T1R3 KO mice displayed concentration-dependent licking responses to Polycose that tracked those of their WT controls and in some cases licked midrange concentrations more; the number of Polycose trials initiated overall did not differ between KO and WT mice. Thus, the T1R2 and T1R3 proteins are individually unnecessary for normal concentration-dependent licking of Polycose to be expressed in a brief-access test. Whether at least one of these T1R protein subunits is necessary for normal Polycose responsiveness remains untested. Alternatively, there may be a novel taste receptor(s) that mediates polysaccharide taste. PMID:19158407

  13. Taste coding in the parabrachial nucleus of the pons in awake, freely licking rats and comparison with the nucleus of the solitary tract.

    PubMed

    Weiss, Michael S; Victor, Jonathan D; Di Lorenzo, Patricia M

    2014-04-01

    In the rodent, the parabrachial nucleus of the pons (PbN) receives information about taste directly from the nucleus of the solitary tract (NTS). Here we examined how information about taste quality (sweet, sour, salty, and bitter) is conveyed in the PbN of awake, freely licking rats, with a focus on how this information is transformed from the incoming NTS signals. Awake rats with electrodes in the PbN had free access to a lick spout that delivered taste stimuli (5 consecutive licks; 100 mM NaCl, 10 mM citric acid, 0.01 mM quinine HCl, or 100 mM sucrose and water) or water (as a rinse) on a variable-ratio schedule. To assess temporal coding, a family of metrics that quantifies the similarity of two spike trains in terms of spike count and spike timing was used. PbN neurons (n = 49) were generally broadly tuned across taste qualities with variable response latencies. Some PbN neurons were quiescent during lick bouts, and others, some taste responsive, showed time-locked firing to the lick pattern. Compared with NTS neurons, spike timing played a larger role in signaling taste in the first 2 s of the response, contributing significantly in 78% (38/49) of PbN cells compared with 45% of NTS cells. Also, information from temporal coding increased at a faster rate as the response unfolded over time in PbN compared with NTS. Collectively, these data suggest that taste-related information from NTS converges in the PbN to enable a subset of PbN cells to carry a larger information load.

  14. Taste coding in the parabrachial nucleus of the pons in awake, freely licking rats and comparison with the nucleus of the solitary tract

    PubMed Central

    Weiss, Michael S.; Victor, Jonathan D.

    2013-01-01

    In the rodent, the parabrachial nucleus of the pons (PbN) receives information about taste directly from the nucleus of the solitary tract (NTS). Here we examined how information about taste quality (sweet, sour, salty, and bitter) is conveyed in the PbN of awake, freely licking rats, with a focus on how this information is transformed from the incoming NTS signals. Awake rats with electrodes in the PbN had free access to a lick spout that delivered taste stimuli (5 consecutive licks; 100 mM NaCl, 10 mM citric acid, 0.01 mM quinine HCl, or 100 mM sucrose and water) or water (as a rinse) on a variable-ratio schedule. To assess temporal coding, a family of metrics that quantifies the similarity of two spike trains in terms of spike count and spike timing was used. PbN neurons (n = 49) were generally broadly tuned across taste qualities with variable response latencies. Some PbN neurons were quiescent during lick bouts, and others, some taste responsive, showed time-locked firing to the lick pattern. Compared with NTS neurons, spike timing played a larger role in signaling taste in the first 2 s of the response, contributing significantly in 78% (38/49) of PbN cells compared with 45% of NTS cells. Also, information from temporal coding increased at a faster rate as the response unfolded over time in PbN compared with NTS. Collectively, these data suggest that taste-related information from NTS converges in the PbN to enable a subset of PbN cells to carry a larger information load. PMID:24381029

  15. Absolute Spectrophotometry of 237 Open Cluster Stars

    NASA Astrophysics Data System (ADS)

    Clampitt, L.; Burstein, D.

    1994-12-01

    We present absolute spectrophotometry of 237 stars in 7 nearby open clusters: Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, and M 39. The observations were taken using the Wampler single-channel scanner (Wampler 1966) on the Crossley 0.9m telescope at Lick Observatory from July 1973 through December 1974. 21 bandpasses spanning the spectral range 3500 Angstroms to 7780 Angstroms were observed for each star, with bandwiths ranging from 32Angstroms to 64 Angstroms. Data are standardized to the Hayes--Latham (1975) system. Our measurements are compared to filter colors on the Johnson BV, Stromgren ubvy, and Geneva U V B_1 B_2 V_1 G systems, as well as to spectrophotometry of a few stars published by Gunn, Stryker & Tinsley and in the Spectrophotometric Standards Catalog (Adelman; as distributed by the NSSDC). Both internal and external comparisons to the filter systems indicate a formal statistical accuracy per bandpass of 0.01 to 0.02 mag, with apparent larger ( ~ 0.03 mag) differences in absolute calibration between this data set and existing spectrophotometry. These data will comprise part of the spectrophotometry that will be used to calibrate the Beijing-Arizona-Taipei-Connecticut Color Survey of the Sky (see separate paper by Burstein et al. at this meeting).

  16. Rotational Velocities of Field Blue Horizontal Branch Stars

    NASA Astrophysics Data System (ADS)

    Weafer, V. K.; Fulbright, J. P.

    2001-12-01

    This study is motivated by interest in the much-debated ``second-parameter" problem. Deep mixing, driven by angular momentum, has been proposed as a second parameter controlling horizontal-branch colour morphology (Sweigart & Mengel 1979). Observations of low-metallicity field giant stars show little evidence of deep mixing (Kraft 1994, Wallerstein et al. 1997, Gratton et al. 2000). We therefore expect that field horizontal branch stars may show little evidence of rotation. We have used high-resolution spectra from Keck and Lick observatories to find the projected rotational velocity (v sin i) of 44 blue (-0.04 <= B-V <= 0.20) horizontal branch stars in the halo field. Selected Fe and Ti absorption lines were co-added in velocity space to create an average line profile for each star. To find v sin i, the average profile was compared to similarly-averaged synthesised lines. We have compared the v sin i values of the sample to those of the blue horizontal branch stars in the second-parameter globular-cluster pair, M3 and M13 (Peterson et al. 1995). Although further work is needed to completely establish the velocity distribution of the sample, we have found that the sample has rotational velocities more similar to M13 than to M3, with at least 5 stars showing v sin i > = 25 km/s.

  17. Massive binary stars as a probe of massive star formation

    NASA Astrophysics Data System (ADS)

    Kiminki, Daniel C.

    2010-10-01

    Massive stars are among the largest and most influential objects we know of on a sub-galactic scale. Binary systems, composed of at least one of these stars, may be responsible for several types of phenomena, including type Ib/c supernovae, short and long gamma ray bursts, high-velocity runaway O and B-type stars, and the density of the parent star clusters. Our understanding of these stars has met with limited success, especially in the area of their formation. Current formation theories rely on the accumulated statistics of massive binary systems that are limited because of their sample size or the inhomogeneous environments from which the statistics are collected. The purpose of this work is to provide a higher-level analysis of close massive binary characteristics using the radial velocity information of 113 massive stars (B3 and earlier) and binary orbital properties for the 19 known close massive binaries in the Cygnus OB2 Association. This work provides an analysis using the largest amount of massive star and binary information ever compiled for an O-star rich cluster like Cygnus OB2, and compliments other O-star binary studies such as NGC 6231, NGC 2244, and NGC 6611. I first report the discovery of 73 new O or B-type stars and 13 new massive binaries by this survey. This work involved the use of 75 successful nights of spectroscopic observation at the Wyoming Infrared Observatory in addition to observations obtained using the Hydra multi-object spectrograph at WIYN, the HIRES echelle spectrograph at KECK, and the Hamilton spectrograph at LICK. I use these data to estimate the spectrophotometric distance to the cluster and to measure the mean systemic velocity and the one-sided velocity dispersion of the cluster. Finally, I compare these data to a series of Monte Carlo models, the results of which indicate that the binary fraction of the cluster is 57 +/- 5% and that the indices for the power law distributions, describing the log of the periods, mass

  18. Neutron Stars

    NASA Technical Reports Server (NTRS)

    Cottam, J.

    2007-01-01

    Neutron stars were discovered almost 40 years ago, and yet many of their most fundamental properties remain mysteries. There have been many attempts to measure the mass and radius of a neutron star and thereby constrain the equation of state of the dense nuclear matter at their cores. These have been complicated by unknown parameters such as the source distance and burning fractions. A clean, straightforward way to access the neutron star parameters is with high-resolution spectroscopy. I will present the results of searches for gravitationally red-shifted absorption lines from the neutron star atmosphere using XMM-Newton and Chandra.

  19. Desing of a Laser Guide Star System for the Keck II Telescope

    SciTech Connect

    Friedman, H.W.; Erbert, G.V.; Kuklo, T.; Thompson, G.R.; Wong, N.J.; Gavel, D.T.; Salmon, J.T.; Feldman, M.

    1997-09-11

    A laser guide star system similar to that deployed at the Lick Observatory has been designed for the Keck II 10 m telescope on Mauna Kea, Hawaii. The subaperature size on the primary is comparable to that at Lick, and at the same observational wavelength centered about the K band, so that the average power requirements of the laser system are also comparable, at about 20 W. One major difference is that the seeing at Mauna Kea is about a factor of two better than at Lick so that the spot diameter requirements are smaller and this can give rise to reduced back scatter resulting from saturation effects in the sodium layer. To reduce the peak flux in the sodium layer and obtain a smaller spot diameter, the output beam diameter has been increased along with the repetition rate of the laser. As with the Lick laser system, a dye laser is pumped by a series of frequency doubled YAG lasers which are remotely located and coupled to the dye laser on the telescope by optical fibers. The laser system has a full set of beam control optics as well as launch telescope and safety systems. A computer system couples the laser system to the User Interface and Supervisory Control system of the main telescope. The laser system is due to be shipped to Keck during the fall of 1997 where it will be integrated with the telescope at Mauna Kea. The Adaptive Optics and Optics Bench systems will be integrated first and be ready for integration with the laser in the summer of 1998. 1 ref., 8 figs.

  20. Star Polymers.

    PubMed

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  1. Radio stars

    NASA Astrophysics Data System (ADS)

    Hjellming, Robert M.

    The state of knowledge on continuum radio emission from the stars is considered. Fundamental radio emission process and stellar radiative transfer are reviewed, and solar radio emission is examined. Flare stars and active binaries are addressed, and stellar winds and cataclysmic variables are considered. Radio-emitting X-ray binaries are discussed.

  2. Radio stars.

    PubMed

    Hjellming, R M; Wade, C M

    1971-09-17

    Up to the present time six classes of radio stars have been established. The signals are almost always very faint and drastically variable. Hence their discovery has owed as much to serendipity as to the highly sophisticated equipment and techniques that have been used. When the variations are regular, as with the pulsars, this characteristic can be exploited very successfully in the search for new objects as well as in the detailed study of those that are already known. The detection of the most erratically variable radio stars, the flare stars and the x-ray stars, is primarily a matter of luck and patience. In the case of the novas, one at least knows where and oughly when to look for radio emission. A very sensitive interferometer is clearly the best instrument to use in the initial detection of a radio star. The fact that weak background sources are frequently present makes it essential to prove that the position of a radio source agrees with that of a star to within a few arc seconds. The potential of radio astronomy for the study of radio stars will not be realized until more powerful instruments than those that are available today can be utilized. So far, we have been able to see only the most luminous of the radio stars.

  3. Precise radial velocities of giant stars. VIII. Testing for the presence of planets with CRIRES infrared radial velocities

    NASA Astrophysics Data System (ADS)

    Trifonov, Trifon; Reffert, Sabine; Zechmeister, Mathias; Reiners, Ansgar; Quirrenbach, Andreas

    2015-10-01

    Context. We have been monitoring 373 very bright (V ≤ 6 mag) G and K giants with high precision optical Doppler spectroscopy for more than a decade at Lick Observatory. Our goal was to discover planetary companions around those stars and to better understand planet formation and evolution around intermediate-mass stars. However, in principle, long-term, g-mode nonradial stellar pulsations or rotating stellar features, such as spots, could effectively mimic a planetary signal in the radial velocity data. Aims: Our goal is to compare optical and infrared radial velocities for those stars with periodic radial velocity patterns and to test for consistency of their fitted radial velocity semiamplitudes. Thereby, we distinguish processes intrinsic to the star from orbiting companions as reason for the radial velocity periodicity observed in the optical. Methods: Stellar spectra with high spectral resolution have been taken in the H-band with the CRIRES near-infrared spectrograph at ESO's VLT for 20 stars of our Lick survey. Radial velocities are derived using many deep and stable telluric CO2 lines for precise wavelength calibration. Results: We find that the optical and near-infrared radial velocities of the giant stars in our sample are consistent. We present detailed results for eight stars in our sample previously reported to have planets or brown dwarf companions. All eight stars passed the infrared test. Conclusions: We conclude that the planet hypothesis provides the best explanation for the periodic radial velocity patterns observed for these giant stars. Based on observations collected at the European Southern Observatory, Chile, under program IDs 088.D-0132, 089.D-0186, 090.D-0155 and 091.D-0365.Appendix A is available in electronic form at http://www.aanda.org

  4. Spectrophotometry of 237 Stars in 7 Open Clusters

    NASA Astrophysics Data System (ADS)

    Clampitt, Lori; Burstein, David

    1997-08-01

    Spectrophotometry is presented for 237 stars in 7 nearby open clusters: Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, and M39. The observations were taken by Lee McDonald and David Burstein using the Wampler single-channel scanner on the Crossley 0.9m telescope at Lick Observatory from July 1973 through December 1974. Sixteen bandpasses spanning the spectral range 3500 Angstroms to 7780 Angstroms were observed for each star, with bandwidths 32Angstroms, 48 Angstroms or 64 Angstroms. Data are standardized to the Hayes-Latham system to mutual accuracy of 0.016 mag per passband. The accuracy of the spectrophotometry is assessed in three ways on a star-by-star basis. First, comparisons are made with previously published spectrophotometry for 19 stars observed in common. Second, (B-V) colors and uvby colors are compared for 236 stars and 221 stars, respectively. Finally, comparsions are made for 200 main sequence stars to the spectral synthesis models of Kurucz, fixing log g = 4.0 and [Fe/H] = 0.0, and only varying effective temperature. The accuracy of tests using uvby colors and the Kurucz models are shown to track each other closely, yielding an accuracy estimate (1 sigma ) of 0.01 mag for the 13 colors formed from bandpasses longward of the Balmer jump, and 0.02 mag for the 3 colors formed from the three bandpasses below the Balmer jump. In contrast, larger scatter is found relative to the previously published spectrophotometry of Bohm-Vitense & Johnson (16 stars in common) and Gunn & Stryker (3 stars). We also show that the scatter in the fits of the spectrophotometric colors and the uvby filter colors is a reasonable way to identify the observations of which specific stars are accurate to 1 sigma , 2 sigma , .... As such, the residuals from both the filter color fits and the Kurucz model fits are tabulated for each star where it was possible to make a comparison, so users of these data can choose stars according to the accuracy of the data

  5. VizieR Online Data Catalog: Super-metal-rich stars (Buzzoni+, 2001)

    NASA Astrophysics Data System (ADS)

    Buzzoni, A.; Chavez, M.; Malagnini, M. L.; Morossi, C.

    2002-01-01

    We present Lick spectral indices for a complete sample of 139 candidate super-metal-rich stars of different luminosity classes (MK type from I to V). For 91 of these stars we were able to identify, in an accompanying paper, the fundamental atmosphere parameters. This confirms that at least 2/3 of the sample consists of stars with [Fe/H] in excess of +0.1 dex. Optical indices for both observations and fiducial synthetic spectra have been calibrated to the Lick system according to Worthey et al. (1994, Cat. ) and include the FeI indices of Fe5015, Fe5270, and Fe5335 and the MgI and MgH indices of Mg2 and Mgb at 5180Å. The internal accuracy of the observations is found to be σ(Fe5015)=10.32Å, σ(Fe5270)=10.19Å, σ(Fe5335)=10.22Å, σ(Mg2)=10.004mag, and σ(Mgb)=10.19Å. This is about a factor of 2 better than the corresponding theoretical indices from the synthetic spectra, the latter being a consequence of the intrinsic limitations in the input physics, as discussed by Chavez et al. (1997, Cat. ). (1 data file).

  6. RESULTS OF THE LICK OBSERVATORY SUPERNOVA SEARCH FOLLOW-UP PHOTOMETRY PROGRAM: BVRI LIGHT CURVES OF 165 TYPE Ia SUPERNOVAE

    SciTech Connect

    Ganeshalingam, Mohan; Li Weidong; Filippenko, Alexei V.; Anderson, Carmen; Foster, Griffin; Griffith, Christopher V.; Joubert, Niels; Leja, Joel; Macomber, Brent; Pritchard, Tyler; Thrasher, Patrick; Winslow, Dustin; Gates, Elinor L.; Grigsby, Bryant J.; Lowe, Thomas B.

    2010-10-15

    We present BVRI light curves of 165 Type Ia supernovae (SNe Ia) from the Lick Observatory Supernova Search follow-up photometry program from 1998 through 2008. Our light curves are typically well sampled (cadence of 3-4 days) with an average of 21 photometry epochs. We describe our monitoring campaign and the photometry reduction pipeline that we have developed. Comparing our data set to that of Hicken et al., with which we have 69 overlapping supernovae (SNe), we find that as an ensemble the photometry is consistent, with only small overall systematic differences, although individual SNe may differ by as much as 0.1 mag, and occasionally even more. Such disagreement in specific cases can have significant implications for combining future large data sets. We present an analysis of our light curves which includes template fits of light-curve shape parameters useful for calibrating SNe Ia as distance indicators. Assuming the B - V color of SNe Ia at 35 days past maximum light can be presented as the convolution of an intrinsic Gaussian component and a decaying exponential attributed to host-galaxy reddening, we derive an intrinsic scatter of {sigma} = 0.076 {+-} 0.019 mag, consistent with the Lira-Phillips law. This is the first of two papers, the second of which will present a cosmological analysis of the data presented herein.

  7. Implications for Planet Formation and Evolution Processes from AO Imaging of Kepler Planet Candidate Host Stars

    NASA Astrophysics Data System (ADS)

    Wolfgang, Angie; Laughlin, G. P.

    2013-01-01

    The Kepler Mission, a search for transits of solar-type stars by potentially habitable Earth-sized planets, has made enormous advances in the study of extrasolar planets over the last three years. With 1790 candidate planetary systems discovered in its first 16 months of data, Kepler promises to answer one of the most fundamental questions posed in exoplanetary research: what does the "typical" planetary system look like, if such a thing exists at all? The answer to this question provides insight into the relative importance of various processes at work in sculpting planetary systems and refines our understanding of our own place in the Galactic planetary census. Here I present high resolution imaging of the most recent Kepler planet candidate host stars observed with the Shane 3m laser guide star adaptive optics system at Lick Observatory, and I investigate the additional insight such information can provide for questions of planetary origin and evolution.

  8. Manganese Abundances in Globular Cluster and Halo Field Stars

    NASA Astrophysics Data System (ADS)

    Sobeck, J. S.; Simmerer, J. A.; Fulbright, J. P.; Sneden, C.; Kraft, R. P.; Ivans, I. I.

    2004-05-01

    We have derived Mn abundances for more than 100 stars in nine Galactic globular clusters: M3, M4, M5, M10, M13, M15, M71, Pal5 and NGC 7006. In addition, Mn abundance determinations have been made for a comparable number of halo field stars possessing an overlapping range of metallicities and stellar parameters. The spectra of the cluster giants were obtained as a part of the Lick-Texas investigations into globular cluster chemistry. The spectra of the field stars are a part of a large study by Simmerer et al. (2004, ApJ, submitted). Data were collected at the McDonald, Lick ,and Keck Observatories and were analyzed using the synthetic spectra of the 6000 Å Mn I triplet. Hyperfine structure parameters were included in the synthetic spectra computations. It is well known that metal-poor field stars possess [Mn/Fe] ratios approximately a factor of two lower than solar values (Wallerstein et al. 1963, Gratton et al.1989, McWilliam et al. 1997). Our analysis shows that for the metallicity range -0.5 > [Fe/H] > -2.8 field stars have a mean relative abundance of <[Mn/Fe]> = -0.28±0.01 (sigma = 0.08), a value esssentially identical to that of the nine globular clusters: <[Mn/Fe]> = -0.28±0.01 (sigma = 0.12). It is evident that [Mn/Fe] ratios of metal-poor stars do not depend upon their environment. Our Mn abundance results viewed in conjunction with the globular cluster Cu abundances of Simmerer et al. (2003) suggest the following possibilities: one, the production of these elements is extremely metallicity-dependent or two, these elements were manufactured in the Galactic halo prior to cluster formation. Ongoing support from NSF, currently through grants AST-0307495 to CS and AST-0098453 to RPK, is gratefully acknowledged. Research for III is currently supported by NASA through Hubble Fellowship grant HST-HF-01151.01-A from the Space Telescope Science Institute.

  9. Revisiting the Lick Observatory Supernova Search Volume-limited Sample: Updated Classifications and Revised Stripped-envelope Supernova Fractions

    NASA Astrophysics Data System (ADS)

    Shivvers, Isaac; Modjaz, Maryam; Zheng, WeiKang; Liu, Yuqian; Filippenko, Alexei V.; Silverman, Jeffrey M.; Matheson, Thomas; Pastorello, Andrea; Graur, Or; Foley, Ryan J.; Chornock, Ryan; Smith, Nathan; Leaman, Jesse; Benetti, Stefano

    2017-05-01

    We re-examine the classifications of supernovae (SNe) presented in the Lick Observatory Supernova Search (LOSS) volume-limited sample with a focus on the stripped-envelope SNe. The LOSS volume-limited sample, presented by Leaman et al. and Li et al., was calibrated to provide meaningful measurements of SN rates in the local universe; the results presented therein continue to be used for comparisons to theoretical and modeling efforts. Many of the objects from the LOSS sample were originally classified based upon only a small subset of the data now available, however, and recent studies have both updated some subtype distinctions and improved our ability to perform robust classifications, especially for stripped-envelope SNe. We re-examine the spectroscopic classifications of all events in the LOSS volume-limited sample (180 SNe and SN impostors) and update them if necessary. We discuss the populations of rare objects in our sample including broad-lined SNe Ic, Ca-rich SNe, SN 1987A-like events (we identify SN 2005io as SN 1987A-like here for the first time), and peculiar subtypes. The relative fractions of SNe Ia, SNe II, and stripped-envelope SNe in the local universe are not affected, but those of some subtypes are. Most significantly, after discussing the often unclear boundary between SNe Ib and Ic when only noisy spectra are available, we find a higher SN Ib fraction and a lower SN Ic fraction than calculated by Li et al.: spectroscopically normal SNe Ib occur in the local universe 1.7 ± 0.9 times more often than do normal SNe Ic.

  10. On the robustness of the Hβ Lick index as a cosmic clock in passive early-type galaxies

    NASA Astrophysics Data System (ADS)

    Concas, Alice; Pozzetti, L.; Moresco, M.; Cimatti, A.

    2017-06-01

    We examine the Hβ Lick index in a sample of ˜24 000 massive (log(M/M_{⊙})>10.75) and passive early-type galaxies extracted from the Sloan Digital Sky Survey at z < 0.3, in order to assess the reliability of this index to constrain the epoch of formation and age evolution of these systems. We further investigate the possibility of exploiting this index as `cosmic chronometer', i.e. to derive the Hubble parameter from its differential evolution with redshift, hence constraining cosmological models independently of other probes. We find that the Hβ strength increases with redshift as expected in passive evolution models, and shows at each redshift weaker values in more massive galaxies. However, a detailed comparison of the observed index with the predictions of stellar population synthesis models highlights a significant tension, with the observed index being systematically lower than expected. By analysing the stacked spectra, we find a weak [N II] λ6584 emission line (not detectable in the single spectra) that anti-correlates with the mass, which can be interpreted as a hint of the presence of ionized gas. We estimated the correction of the Hβ index by the residual emission component exploiting different approaches, but find it very uncertain and model dependent. We conclude that, while the qualitative trends of the observed Hβ-z relations are consistent with the expected passive and downsizing scenario, the possible presence of ionized gas even in the most massive and passive galaxies prevents us to use this index for a quantitative estimate of the age evolution and for cosmological applications.

  11. THE LICK AGN MONITORING PROJECT 2011: DYNAMICAL MODELING OF THE BROAD-LINE REGION IN Mrk 50

    SciTech Connect

    Pancoast, Anna; Brewer, Brendon J.; Treu, Tommaso; Bennert, Vardha N.; Sand, David J.; Barth, Aaron J.; Cooper, Michael C.; Canalizo, Gabriela; Filippenko, Alexei V.; Li, Weidong; Cenko, S. Bradley; Clubb, Kelsey I.; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Stern, Daniel; Assef, Roberto J.; Woo, Jong-Hak; Bae, Hyun-Jin; Buehler, Tabitha; and others

    2012-07-20

    We present dynamical modeling of the broad-line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9.6{sup +1.2}{sub -0.9} light days, a width of the BLR of 6.9{sup +1.2}{sub -1.1} light days, and a disk opening angle of 25 {+-} 10 deg above the plane. We also constrain the inclination angle to be 9{sup +7}{sub -5} deg, close to face-on. Finally, the black hole mass of Mrk 50 is inferred to be log{sub 10}(M{sub BH}/M{sub Sun }) = 7.57{sup +0.44}{sub -0.27}. By comparison to the virial black hole mass estimate from traditional reverberation mapping analysis, we find the normalizing constant (virial coefficient) to be log{sub 10} f = 0.78{sup +0.44}{sub -0.27}, consistent with the commonly adopted mean value of 0.74 based on aligning the M{sub BH}-{sigma}* relation for active galactic nuclei and quiescent galaxies. While our dynamical model includes the possibility of a net inflow or outflow in the BLR, we cannot distinguish between these two scenarios.

  12. Limits on Planetary Companions from Doppler Surveys of Nearby Stars

    NASA Astrophysics Data System (ADS)

    Howard, Andrew W.; Fulton, Benjamin J.

    2016-11-01

    Most of our knowledge of planets orbiting nearby stars comes from Doppler surveys. For spaced-based, high-contrast imaging missions, nearby stars with Doppler-discovered planets are attractive targets. The known orbits tell imaging missions where and when to observe, and the dynamically determined masses provide important constraints for the interpretation of planetary spectra. Quantifying the set of planet masses and orbits that could have been detected will enable more efficient planet discovery and characterization. We analyzed Doppler measurements from Lick and Keck Observatories by the California Planet Survey. We focused on stars that are likely targets for three space-based planet imaging mission concepts studied by NASA—WFIRST-AFTA, Exo-C, and Exo-S. The Doppler targets are primarily F8 and later main sequence stars, with observations spanning 1987-2014. We identified 76 stars with Doppler measurements from the prospective mission target lists. We developed an automated planet search and a methodology to estimate the pipeline completeness using injection and recovery tests. We applied this machinery to the Doppler data and computed planet detection limits for each star as a function of planet minimum mass and semimajor axis. For typical stars in the survey, we are sensitive to approximately Saturn-mass planets inside of 1 au, Jupiter-mass planets inside of ˜3 au, and our sensitivity declines out to ˜10 au. For the best Doppler targets, we are sensitive to Neptune-mass planets in 3 au orbits. Using an idealized model of Doppler survey completeness, we forecast the precision of future surveys of non-ideal Doppler targets that are likely targets of imaging missions. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by NASA, the University of California, and the University of Hawaii.

  13. Symbiotic stars

    NASA Technical Reports Server (NTRS)

    Kafatos, M.; Michalitsianos, A. G.

    1984-01-01

    The physical characteristics of symbiotic star systems are discussed, based on a review of recent observational data. A model of a symbiotic star system is presented which illustrates how a cool red-giant star is embedded in a nebula whose atoms are ionized by the energetic radiation from its hot compact companion. UV outbursts from symbiotic systems are explained by two principal models: an accretion-disk-outburst model which describes how material expelled from the tenuous envelope of the red giant forms an inwardly-spiralling disk around the hot companion, and a thermonuclear-outburst model in which the companion is specifically a white dwarf which superheats the material expelled from the red giant to the point where thermonuclear reactions occur and radiation is emitted. It is suspected that the evolutionary course of binary systems is predetermined by the initial mass and angular momentum of the gas cloud within which binary stars are born. Since red giants and Mira variables are thought to be stars with a mass of one or two solar mass, it is believed that the original cloud from which a symbiotic system is formed can consist of no more than a few solar masses of gas.

  14. Van Gogh's Starry Nights, Lincoln's Moon, Shakespeare's Stars, and More: Tales of Astronomy in Art, History, and Literature

    NASA Astrophysics Data System (ADS)

    Olson, Donald W.

    2009-01-01

    How do astronomical methods make it possible to calculate dates and times for Vincent van Gogh's night-sky paintings? Why is there a blood-red sky in Edvard Munch's The Scream? How can the 18.6-year cycle of the lunar nodes and the Moon's declination on the night of August 29-30, 1857, explain a long-standing mystery about Abraham Lincoln's honesty in the murder case known as the almanac trial? Why is a bright star described in Act 1, Scene 1, of Hamlet? There is a long tradition of astronomical methods employed to analyze works of art, to understand historical events, and to elucidate passages in literature. Both Edmond Halley and George Biddell Airy calculated lunar phases and tide tables in attempts to determine the landing beach where Julius Caesar invaded Britain in 55 B.C. Henry Norris Russell computed configurations of Jupiter and Saturn to determine a date for a 14th-century celestial event mentioned in Chaucer's Troilus and Criseyde. In this tradition, our Texas State group has published a series of articles in Sky & Telescope over the last two decades, applying astronomy to art, history, and literature. Don Osterbrock worked with us 3 years ago when my students and I calculated dates for moonrise photographs taken by Ansel Adams in Yosemite National Park. The peaks of the Sierra Nevada crest in Yosemite are more than 125 miles from Lick Observatory, but the mountains can become visible from Lick on clear winter days and were photographed from there on early infrared-sensitive plates during the 1920s and 1930s. As we tested our topographic software by identifying the peaks that appear in the Lick plates, it was a pleasure to come to know Don, a former director of Lick Observatory and the person in whose honor this talk is dedicated.

  15. Photometric Observations of 6000 Stars in the Cygnus Field

    NASA Technical Reports Server (NTRS)

    Borucki, W.; Caldwell, D.; Koch, D.; Jenkins, J.; Ninkov, Z.

    1999-01-01

    A small photometer to detect transits by extrasolar planets has been assembled and is being tested at Lick Observatory on Mt. Hamilton, California. The Vulcan photometer is constructed from a 30 cm focal length, F/2.5 AeroEktar reconnaissance lens and Photometrics PXL16800 CCD camera. A spectral filter is used to confine the pass band from 480 to 763 mn. It simultaneously monitors 6000 stars brighter than 12th magnitude within a single star field in the galactic plane. When the data are folded and phased to discover low amplitude transits, the relative precision of one-hour samples is about 1 part per thousand (10 x l0(exp -3)) for many of the brighter stars. This precision is sufficient to find jovian-size planets orbiting solar-like stars, which have signal amplitudes from 5 to 30 x l0(exp -3) depending on the inflation of the planet and the size of the star. Based on the frequency of giant inner-planets discovered by Doppler-velocity method, one or two planets should be detectable in a rich star field. The goal of the observations is to obtain the sizes of giant extrasolar planets in short-period orbits and to combine these with masses determined from Doppler velocity measurements to determine the densities of these planets. A further goal is to compare the measured planetary diameters with those predicted from theoretical models. From August 10 through September 30 of 1998, a forty nine square degree field in the Cygnus constellation centered at RA and DEC of 19 hr 47 min, +36 deg 55 min was observed. Useful data were obtained on twenty-nine nights. Nearly fifty stars showed some evidence of transits with periods between 0.3 and 8 days. Most had amplitudes too large to be associated with planetary transits. However, several stars showed low amplitude transits. The data for several transits of each of these two stars have been folded and been folded into 30 minute periods. Only Cygl433 shows any evidence of a flattened bottom that is expected when a small object

  16. Stellar Companions to Stars with Planets

    NASA Astrophysics Data System (ADS)

    Patience, J.; White, R. J.; Ghez, A. M.; McCabe, C.; McLean, I. S.; Larkin, J. E.; Prato, L.; Kim, Sungsoo S.; Lloyd, J. P.; Liu, M. C.; Graham, J. R.; Macintosh, B. A.; Gavel, D. T.; Max, C. E.; Bauman, B. J.; Olivier, S. S.; Wizinowich, P.; Acton, D. S.

    2002-12-01

    A combination of high-resolution and wide-field imaging reveals two binary stars and one triple star system among the sample of the first 11 stars with planets detected by radial velocity variations. High-resolution speckle or adaptive optics (AO) data probe subarcsecond scales down to the diffraction limit of the Keck 10 m or the Lick 3 m, and direct images or AO images are sensitive to a wider field, extending to 10" or 38", depending on the camera. One of the binary system-HD 114762-was not previously known to be a spatially resolved multiple system; additional data taken with the combination of Keck adaptive optics and NIRSPEC are used to characterize the new companion. The second binary system-τ Boo-was a known multiple with two conflicting orbital solutions; the current data will help constrain the discrepant estimates of periastron time and separation. Another target-16 Cyg B-was a known common proper motion binary, but the current data resolve a new third component, close to the wide companion 16 Cyg A. Both the HD 114762 and 16 Cyg B systems harbor planets in eccentric orbits, while the τ Boo binary contains an extremely close planet in a tidally circularized orbit. Although the sample is currently small, the proportion of binary systems is comparable to that measured in the field over a similar separation range. Incorporating the null result from another companion search project lowers the overall fraction of planets in binary systems, but the detections in our survey reveal that planets can form in binaries separated by less than 50 AU.

  17. Chameleon stars

    SciTech Connect

    Dzhunushaliev, Vladimir; Folomeev, Vladimir; Singleton, Douglas

    2011-10-15

    We consider a gravitating spherically symmetric configuration consisting of a scalar field nonminimally coupled to ordinary matter in the form of a perfect fluid. For this system we find static, regular, asymptotically flat solutions for both relativistic and nonrelativistic cases. It is shown that the presence of the nonminimal interaction leads to substantial changes both in the radial matter distribution of the star and in the star's total mass. A simple stability test indicates that, for the choice of parameters used in the paper, the solutions are unstable.

  18. Rainbow's stars

    NASA Astrophysics Data System (ADS)

    Garattini, Remo; Mandanici, Gianluca

    2017-01-01

    In recent years, a growing interest in the equilibrium of compact astrophysical objects like white dwarf and neutron stars has been manifested. In particular, various modifications due to Planck-scale energy effects have been considered. In this paper we analyze the modification induced by gravity's rainbow on the equilibrium configurations described by the Tolman-Oppenheimer-Volkoff (TOV) equation. Our purpose is to explore the possibility that the rainbow Planck-scale deformation of space-time could support the existence of different compact stars.

  19. A pre-partum lift in ewe nutrition from a high-energy lick or maize or by grazing Lotus uliginosus pasture, increases colostrum production and lamb survival.

    PubMed

    Banchero, G E; Quintans, G; Lindsay, D R; Milton, J T B

    2009-08-01

    This experiment tested the hypothesis that a lift in the nutrition of ewes, before lambing, to increase colostrum production would enhance lamb survival. In all, 261 mature Corriedale ewes, each with a single fetus from a synchronised mating, grazed native pasture to day 130 after mating; at which point they were weighed, condition scored and allocated to graze either native pasture or a pasture dominant with Lotus uliginosus. Five days later (14 days before the expected start of lambing) the ewes were allocated to one of four treatments and fed: (i) native pasture alone, (ii) native pasture plus a commercial high-energy lick, (iii) L. uliginosus pasture alone or (iv) L. uliginosus pasture plus whole maize. The weight, viscosity and concentration of components and immunoglobulin G in the colostrum that had accumulated at parturition, were measured for 10 ewes in each treatment. The lambs that survived to 20 days of age from the 221 ewes that were not milked, were recorded. The ewes supplemented with the lick or maize grain and those that grazed the L. uliginosus pasture alone accumulated two to three times more colostrum at birth than the ewes that grazed native pasture alone (396, 635 and 662 g v. 206 g; P < 0.01). The colostrum from the ewes that grazed only native pasture was more viscous (lower score) than that from the ewes supplemented with the lick or maize grain or the ewes that grazed the L. uliginosus pasture alone (scores of 4.1 v. 6.2, 6.5 and 6.4, P < 0.001) and, not surprisingly, the concentration of lactose in the colostrum of the ewes fed only native pasture was also much lower (1.1% v. 3.0%, 2.8% and 2.6%; P < 0.001)he survival of lambs from the ewes fed only native pasture was less than that of the lambs from ewes fed native pasture plus the commercial lick (81.8% v. 95.5%; P < 0.05) or the L. uliginosus pasture alone (92.4%, P < 0.05), and also tended to be lower than that for lambs born to ewes fed L. uliginosus pasture plus maize (91.8%, P = 0

  20. The Lick AGN Monitoring Project: Broad-line Region Radii and Black Hole Masses from Reverberation Mapping of Hβ

    NASA Astrophysics Data System (ADS)

    Bentz, Misty C.; Walsh, Jonelle L.; Barth, Aaron J.; Baliber, Nairn; Bennert, Vardha Nicola; Canalizo, Gabriela; Filippenko, Alexei V.; Ganeshalingam, Mohan; Gates, Elinor L.; Greene, Jenny E.; Hidas, Marton G.; Hiner, Kyle D.; Lee, Nicholas; Li, Weidong; Malkan, Matthew A.; Minezaki, Takeo; Sakata, Yu; Serduke, Frank J. D.; Silverman, Jeffrey M.; Steele, Thea N.; Stern, Daniel; Street, Rachel A.; Thornton, Carol E.; Treu, Tommaso; Wang, Xiaofeng; Woo, Jong-Hak; Yoshii, Yuzuru

    2009-11-01

    We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~106-107 M sun and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hβ emission. We present here the light curves for all the objects in this sample and the subsequent Hβ time lags for the nine objects where these measurements were possible. The Hβ lag time is directly related to the size of the broad-line region (BLR) in AGNs, and by combining the Hβ lag time with the measured width of the Hβ emission line in the variable part of the spectrum, we determine the virial mass of the central supermassive black hole in these nine AGNs. The absolute calibration of the black hole masses is based on the normalization derived by Onken et al., which brings the masses determined by reverberation mapping into agreement with the local M BH-σsstarfrelationship for quiescent galaxies. We also examine the time lag response as a function of velocity across the Hβ line profile for six of the AGNs. The analysis of four leads to rather ambiguous results with relatively flat time lags as a function of velocity. However, SBS 1116+583A exhibits a symmetric time lag response around the line center reminiscent of simple models for circularly orbiting BLR clouds, and Arp 151 shows an asymmetric profile that is most easily explained by a simple gravitational infall model. Further investigation will be necessary to fully understand the constraints placed on the physical models of the BLR by the velocity-resolved response in these objects.

  1. THE LICK AGN MONITORING PROJECT: BROAD-LINE REGION RADII AND BLACK HOLE MASSES FROM REVERBERATION MAPPING OF Hbeta

    SciTech Connect

    Bentz, Misty C.; Walsh, Jonelle L.; Barth, Aaron J.; Baliber, Nairn; Bennert, Vardha Nicola; Greene, Jenny E.; Hidas, Marton G.; Canalizo, Gabriela; Hiner, Kyle D.; Filippenko, Alexei V.; Ganeshalingam, Mohan; Lee, Nicholas; Li, Weidong; Serduke, Frank J. D.; Silverman, Jeffrey M.; Steele, Thea N.; Gates, Elinor L.; Malkan, Matthew A.; Minezaki, Takeo; Sakata, Yu

    2009-11-01

    We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range approx10{sup 6}-10{sup 7} M {sub sun} and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hbeta emission. We present here the light curves for all the objects in this sample and the subsequent Hbeta time lags for the nine objects where these measurements were possible. The Hbeta lag time is directly related to the size of the broad-line region (BLR) in AGNs, and by combining the Hbeta lag time with the measured width of the Hbeta emission line in the variable part of the spectrum, we determine the virial mass of the central supermassive black hole in these nine AGNs. The absolute calibration of the black hole masses is based on the normalization derived by Onken et al., which brings the masses determined by reverberation mapping into agreement with the local M {sub BH}-sigma{sub *}relationship for quiescent galaxies. We also examine the time lag response as a function of velocity across the Hbeta line profile for six of the AGNs. The analysis of four leads to rather ambiguous results with relatively flat time lags as a function of velocity. However, SBS 1116+583A exhibits a symmetric time lag response around the line center reminiscent of simple models for circularly orbiting BLR clouds, and Arp 151 shows an asymmetric profile that is most easily explained by a simple gravitational infall model. Further investigation will be necessary to fully understand the constraints placed on the physical models of the BLR by the velocity-resolved response

  2. THE LICK AGN MONITORING PROJECT: THE M {sub BH}-{sigma}{sub *} RELATION FOR REVERBERATION-MAPPED ACTIVE GALAXIES

    SciTech Connect

    Woo, Jong-Hak; Treu, Tommaso; Bennert, Vardha N.; Barth, Aaron J.; Walsh, Jonelle L.; Bentz, Misty C.; Wright, Shelley A.; Filippenko, Alexei V.; Li, Weidong; Martini, Paul; Canalizo, Gabriela; Gates, Elinor; Greene, Jenny; Malkan, Matthew A.; Stern, Daniel; Minezaki, Takeo

    2010-06-10

    To investigate the black hole mass versus stellar velocity dispersion (M {sub BH}-{sigma}{sub *}) relation of active galaxies, we measured the velocity dispersions of a sample of local Seyfert 1 galaxies, for which we have recently determined black hole masses using reverberation mapping. For most objects, stellar velocity dispersions were measured from high signal-to-noise ratio optical spectra centered on the Ca II triplet region ({approx}8500 A), obtained at the Keck, Palomar, and Lick Observatories. For two objects, in which the Ca II triplet region was contaminated by nuclear emission, the measurement was based on high-quality H-band spectra obtained with the OH-Suppressing Infrared Imaging Spectrograph at the Keck-II telescope. Combining our new measurements with data from the literature, we assemble a sample of 24 active galaxies with stellar velocity dispersions and reverberation-based black hole mass measurements in the range of black hole mass 10{sup 6} < M {sub BH}/M {sub sun} < 10{sup 9}. We use this sample to obtain reverberation-mapping constraints on the slope and intrinsic scatter of the M {sub BH}-{sigma}{sub *} relation of active galaxies. Assuming a constant virial coefficient f for the reverberation-mapping black hole masses, we find a slope {beta} = 3.55 {+-} 0.60 and the intrinsic scatter {sigma}{sub int} = 0.43 {+-} 0.08 dex in the relation log(M {sub BH}/M {sub sun}) = {alpha} + {beta} log({sigma}{sub *}/200 km s{sup -1}), which are consistent with those found for quiescent galaxies. We derive an updated value of the virial coefficient f by finding the value which places the reverberation masses in best agreement with the M {sub BH}-{sigma}{sub *} relation of quiescent galaxies; using the quiescent M {sub BH}-{sigma}{sub *} relation determined by Gueltekin et al., we find log f = 0.72{sup +0.09} {sub -0.10} with an intrinsic scatter of 0.44 {+-} 0.07 dex. No strong correlations between f and parameters connected to the physics of accretion

  3. Star Power

    ScienceCinema

    None

    2016-07-12

    The U.S. Department of Energy's Princeton Plasma Physics Laboratory has released ''Star Power,'' a new informational video that uses dramatic and beautiful images and thought-provoking interviews to highlight the importance of the Laboratory's research into magnetic fusion.

  4. Morning Star

    NASA Image and Video Library

    2013-03-04

    Dawn on Saturn is greeted across the vastness of interplanetary space by the morning star, Venus, in this image from NASA Cassini spacecraft. Venus appears just off the edge of the planet directly above the white streak of Saturn G ring.

  5. Star Power

    SciTech Connect

    2014-10-17

    The U.S. Department of Energy's Princeton Plasma Physics Laboratory has released ''Star Power,'' a new informational video that uses dramatic and beautiful images and thought-provoking interviews to highlight the importance of the Laboratory's research into magnetic fusion.

  6. The Lick-Carnegie exoplanet survey: Gliese 687 b—A Neptune-mass planet orbiting a nearby red dwarf

    SciTech Connect

    Burt, Jennifer; Vogt, Steven S.; Hanson, Russell; Rivera, Eugenio J.; Laughlin, Gregory; Meschiari, Stefano; Henry, Gregory W.

    2014-07-10

    Precision radial velocities from the Automated Planet Finder (APF) and Keck/HIRES reveal an Msin (i) = 18 ± 2 M{sub ⊕} planet orbiting the nearby M3V star GJ 687. This planet has an orbital period P = 38.14 days and a low orbital eccentricity. Our Strömgren b and y photometry of the host star suggests a stellar rotation signature with a period of P = 60 days. The star is somewhat chromospherically active, with a spot filling factor estimated to be several percent. The rotationally induced 60 day signal, however, is well separated from the period of the radial velocity variations, instilling confidence in the interpretation of a Keplerian origin for the observed velocity variations. Although GJ 687 b produces relatively little specific interest in connection with its individual properties, a compelling case can be argued that it is worthy of remark as an eminently typical, yet at a distance of 4.52 pc, a very nearby representative of the galactic planetary census. The detection of GJ 687 b indicates that the APF telescope is well suited to the discovery of low-mass planets orbiting low-mass stars in the as yet relatively un-surveyed region of the sky near the north celestial pole.

  7. The Lick-Carnegie Exoplanet Survey: Gliese 687 b—A Neptune-mass Planet Orbiting a Nearby Red Dwarf

    NASA Astrophysics Data System (ADS)

    Burt, Jennifer; Vogt, Steven S.; Butler, R. Paul; Hanson, Russell; Meschiari, Stefano; Rivera, Eugenio J.; Henry, Gregory W.; Laughlin, Gregory

    2014-07-01

    Precision radial velocities from the Automated Planet Finder (APF) and Keck/HIRES reveal an Msin (i) = 18 ± 2 M ⊕ planet orbiting the nearby M3V star GJ 687. This planet has an orbital period P = 38.14 days and a low orbital eccentricity. Our Strömgren b and y photometry of the host star suggests a stellar rotation signature with a period of P = 60 days. The star is somewhat chromospherically active, with a spot filling factor estimated to be several percent. The rotationally induced 60 day signal, however, is well separated from the period of the radial velocity variations, instilling confidence in the interpretation of a Keplerian origin for the observed velocity variations. Although GJ 687 b produces relatively little specific interest in connection with its individual properties, a compelling case can be argued that it is worthy of remark as an eminently typical, yet at a distance of 4.52 pc, a very nearby representative of the galactic planetary census. The detection of GJ 687 b indicates that the APF telescope is well suited to the discovery of low-mass planets orbiting low-mass stars in the as yet relatively un-surveyed region of the sky near the north celestial pole.

  8. Supersolar metallicity in G0-G3 main-sequence stars with V < 15

    NASA Astrophysics Data System (ADS)

    López-Valdivia, R.; Bertone, E.; Chávez, M.; Tapia-Schiavon, C.; Hernández-Águila, J. B.; Valdés, J. R.; Chavushyan, V.

    2014-11-01

    The basic stellar atmospheric parameters (effective temperature, surface gravity and global metallicity) were determined simultaneously for a sample of 233 stars, limited in magnitude (V < 15), with spectral types between G0 and G3 and luminosity class V (main sequence). The analysis was based on spectroscopic observations collected at the Observatorio Astrofísico Guillermo Haro and using a set of Lick-like indices defined in the spectral range 3800-4800 Å. An extensive set of indices computed in a grid of theoretical spectra was used as a comparison tool in order to determine the photospheric parameters. The method was validated by matching the results from spectra of the asteroids Vesta and Ceres with the Sun parameters. The main results were as follows: (i) the photospheric parameters were determined for the first time for 213 objects in our sample and (ii) a sample of 20 new super-metal-rich star candidates was found.

  9. A survey study of energy distribution in component stars of Algol-type binary systems

    NASA Astrophysics Data System (ADS)

    Dobias, Jan Joseph

    A study survey of Algol-type binary systems was undertaken in order to investigate radiative flux distributions of their component stars. For hot primaries low-dispersion ultraviolet spectra, made with the International Ultraviolet Explorer (IUD) satellite, are combined at comparable phases with optical spectrophotometric scans, made at Lick Observatory, and then matched with a least-square method to Kurucz model atmospheres. Cooler secondaries are classified by matching their optical flux distributions, observed at totality, to standard stars. Results show that the U Sagittae system consists of a B7.5V-IV star while the secondary is matched by a G4III IV standard. The RW Tauri system consists of a B8V primary, while the secondary is matched by a KOIII standard. The UV spectrum of the primary in RY Geminorum matches that of an AOV standard. The secondary in RY GEM is KOIV. The system of RS Cephei consists of B9.7Ve and G8III-IV stars. The system of RW Persei consists of B9.6e and K2(+ or - 2)IV-III stars. The system of RX Geminorum consists of AOV or AOIII and K2(+ or - 2) stars. Finally, in Beta Lyrae the primary appears to be a B8.5-B9II-Ib object.

  10. The Selective Serotonin Reuptake Inhibitor Paroxetine Decreases Breakpoint of Rats Engaging in a Progressive Ratio Licking Task for Sucrose and Quinine Solutions

    PubMed Central

    2013-01-01

    Increased serotonergic activity has been shown to reduce motivation to ingest, which may involve, in part, gustatory processes. Here, we examined the effect of paroxetine, a selective serotonin reuptake inhibitor, on appetitive responding for a preferred and an avoided taste solution using a progressive ratio (PR) task in which licking was employed as the operant. Male Sprague-Dawley rats (n = 8/taste stimulus) were trained to respond for a concentration series of sucrose or quinine on fixed and PR schedules of reinforcement. Performance for sucrose was assessed while the rats were partially food- and water-restricted and nondeprived, and performance for water and quinine was assessed while the rats were water-deprived. Then, the rats were injected with vehicle (10% dimethyl sulfoxide, 1mL/kg intraperitoneal [ip], −1h) or paroxetine (5mg/kg), and their responding on a PR schedule for sucrose measured when the rats were nondeprived or for water and quinine when the rats were water-deprived. Paroxetine decreased breakpoint, which was defined as the number of operant (e.g., dry) licks in the final reinforced ratio, for water, quinine, and sucrose. This demonstrates that a general systemic increase in serotonergic activity decreases the appetitive-based responses to both preferred and nonpreferred fluids under different deprivation states. PMID:23254343

  11. The selective serotonin reuptake inhibitor paroxetine decreases breakpoint of rats engaging in a progressive ratio licking task for sucrose and quinine solutions.

    PubMed

    Mathes, Clare M; Gregson, Jillian R; Spector, Alan C

    2013-03-01

    Increased serotonergic activity has been shown to reduce motivation to ingest, which may involve, in part, gustatory processes. Here, we examined the effect of paroxetine, a selective serotonin reuptake inhibitor, on appetitive responding for a preferred and an avoided taste solution using a progressive ratio (PR) task in which licking was employed as the operant. Male Sprague-Dawley rats (n = 8/taste stimulus) were trained to respond for a concentration series of sucrose or quinine on fixed and PR schedules of reinforcement. Performance for sucrose was assessed while the rats were partially food- and water-restricted and nondeprived, and performance for water and quinine was assessed while the rats were water-deprived. Then, the rats were injected with vehicle (10% dimethyl sulfoxide, 1mL/kg intraperitoneal [ip], -1h) or paroxetine (5mg/kg), and their responding on a PR schedule for sucrose measured when the rats were nondeprived or for water and quinine when the rats were water-deprived. Paroxetine decreased breakpoint, which was defined as the number of operant (e.g., dry) licks in the final reinforced ratio, for water, quinine, and sucrose. This demonstrates that a general systemic increase in serotonergic activity decreases the appetitive-based responses to both preferred and nonpreferred fluids under different deprivation states.

  12. Converting neutron stars into strange stars

    NASA Technical Reports Server (NTRS)

    Olinto, A. V.

    1991-01-01

    If strange matter is formed in the interior of a neutron star, it will convert the entire neutron star into a strange star. The proposed mechanisms are reviewed for strange matter seeding and the possible strange matter contamination of neutron star progenitors. The conversion process that follows seeding and the recent calculations of the conversion timescale are discussed.

  13. Barnard’s Star: Planets or Pretense

    NASA Astrophysics Data System (ADS)

    Bartlett, Jennifer L.; Ianna, P. A.

    2014-01-01

    Barnard’s Star remains popular with planet hunters because it is not only an extremely near, high proper motion star, but also the object of early planet-detection claims. In 1963, van de Kamp explained perturbations in its proper motion by the presence of a planet. In 1969, he produced another single-planet solution and a two-planet solution to the astrometric wobbles detected. At least 19 studies have failed to confirm his results using a range of techniques, including radial velocity, direct imaging, and speckle interferometry. However, most of them lacked the sensitivity to detect the planets he described, including astrometric studies at the McCormick and Naval Observatories. However, radial-velocity monitoring of Barnard’s Star at Lick and Keck Observatories from 1987 through 2012 appears to have ruled out such planets. Based upon observations made at the Sproul Observatory between 1916 and 1962, van de Kamp claimed that Barnard’s Star had a planet with about 1.6 times the mass of Jupiter and an orbital period of 24 years. After accounting for instrumentation effects that might have been partially responsible for his initial results, he continued to assert that this red dwarf had two planets. In his 1982 analysis of ~20,000 exposures collected between 1938 and 1981, he calculated that two planets with 0.7- and 0.5-Jupiter masses in 12- and 20-year orbits, respectively, orbited the second-closest stellar system to our own. Starting in 1995, the dramatic successes of radial velocity searches for extrasolar planets drove van de Kamp’s unsubstantiated claims from popular consciousness. Although many low-mass stellar companions were discovered through astrometry, the technique has been less successful for planets: “The Extrasolar Planets Encyclopaedia” identifies one such discovery out of the 997 planets listed on 2013 September 23. Although Barnard’s Star has lost its pretensions to hosting the first extrasolar planets known, its intrinsic

  14. Star clusters

    NASA Astrophysics Data System (ADS)

    Labhardt, Lukas; Binggeli, Bruno

    Star clusters are at the heart of astronomy, being key objects for our understanding of stellar evolution and galactic structure. Observations with the Hubble Space Telescope and other modern equipment have revealed fascinating new facts about these galactic building blocks. This book provides two comprehensive and up-to-date, pedagogically designed reviews on star clusters by two well-known experts in the field. Bruce Carney presents our current knowledge of the relative and absolute ages of globular clusters and the chemical history of our Galaxy. Bill Harris addresses globular clusters in external galaxies and their use as tracers of galaxy formation and cosmic distance indicators. The book is written for graduate students as well as professionals in astronomy and astrophysics.

  15. An Astrometric Companion to the Nearby Metal-Poor, Low-Mass Star LHS 1589

    NASA Astrophysics Data System (ADS)

    Lépine, Sébastien; Rich, R. Michael; Shara, Michael M.; Cruz, Kelle L.; Skemer, Andrew

    2007-10-01

    We report the discovery of a companion to the high proper motion star LHS 1589, a nearby high-velocity, low-mass subdwarf. The companion (LHS 1589B) is located 0.224''+/-0.004'' to the southwest of the primary (LHS 1589A), and is 0.5 mag fainter than the primary in the Ks band. The pair was resolved with the IRCAL infrared camera at Lick Observatory, operating with the Laser Guide Star Adaptive Optics system. A low-resolution spectrum of the unresolved pair obtained at the MDM observatory shows the source to be consistent with a cool subdwarf of spectral subtype sdK7.5. A photometric distance estimate places the metal-poor system at a distance d=81+/-18 pc from the Sun. We also measure a radial velocity Vrad=67+/-8 km s-1, which, together with the proper motion and estimated distance, suggests that the pair is roaming the inner Galactic halo on a highly eccentric orbit. With a projected orbital separation s=18.1+/-4.8 AU, and a crude estimate of the system's total mass, we estimate the orbital period of the system to be in the range 75 yr stars. Based on observations performed with the Laser Guide Star Adaptive Optics system at the Lick Observatory, operated by the University of California system. Based on observations conducted at the MDM observatory, operated jointly by the University of Michigan, Dartmouth College, the Ohio State University, Columbia University, and the University of Ohio.

  16. VizieR Online Data Catalog: The Washington Visual Double Star Catalog (Mason+ 2001-2014)

    NASA Astrophysics Data System (ADS)

    Mason, B. D.; Wycoff, G. L.; Hartkopf, W. I.; Douglass, G. G.; Worley, C. E.

    2016-11-01

    The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS; Jeffers and van den Bos, Publ. Lick Obs. 21). Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. The WDS is continually updated as published data become available. Prior to this, three major updates have been published (Worley and Douglass 1984, "Washington Visual Double Star Catalog, 1984.0", U.S. Naval Observatory, Washington; Worley and Douglass 1997A&AS..125..523W, Cat. I/237; Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ....122.3466M; and Mason et al. 2006.5). The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. Is is maintained by the US Naval Observatory, and represents the world's principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of the systems. (3 data files).

  17. VizieR Online Data Catalog: The Washington Visual Double Star Catalog (Mason+ 2001-2014)

    NASA Astrophysics Data System (ADS)

    Mason, B. D.; Wycoff, G. L.; Hartkopf, W. I.; Douglass, G. G.; Worley, C. E.

    2015-11-01

    The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS; Jeffers and van den Bos, Publ. Lick Obs. 21). Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. The WDS is continually updated as published data become available. Prior to this, three major updates have been published (Worley and Douglass 1984, "Washington Visual Double Star Catalog, 1984.0", U.S. Naval Observatory, Washington; Worley and Douglass 1997A&AS..125..523W, Cat. I/237; Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ....122.3466M; and Mason et al. 2006.5). The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. Is is maintained by the US Naval Observatory, and represents the world's principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of the systems. (3 data files).

  18. VizieR Online Data Catalog: The Washington Visual Double Star Catalog (Mason+ 2001-2014)

    NASA Astrophysics Data System (ADS)

    Mason, B. D.; Wycoff, G. L.; Hartkopf, W. I.; Douglass, G. G.; Worley, C. E.

    2017-03-01

    The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS; Jeffers and van den Bos, Publ. Lick Obs. 21). Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. The WDS is continually updated as published data become available. Prior to this, three major updates have been published (Worley and Douglass 1984, "Washington Visual Double Star Catalog, 1984.0", U.S. Naval Observatory, Washington; Worley and Douglass 1997A&AS..125..523W, Cat. I/237; Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ....122.3466M; and Mason et al. 2006.5). The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. Is is maintained by the US Naval Observatory, and represents the world's principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of the systems. (3 data files).

  19. VizieR Online Data Catalog: The Washington Visual Double Star Catalog (Mason+ 2001-2014)

    NASA Astrophysics Data System (ADS)

    Mason, B. D.; Wycoff, G. L.; Hartkopf, W. I.; Douglass, G. G.; Worley, C. E.

    2014-11-01

    The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS; Jeffers and van den Bos, Publ. Lick Obs. 21). Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. The WDS is continually updated as published data become available. Prior to this, three major updates have been published (Worley and Douglass 1984, "Washington Visual Double Star Catalog, 1984.0", U.S. Naval Observatory, Washington; Worley and Douglass 1997A&AS..125..523W, Cat. I/237; Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ....122.3466M; and Mason et al. 2006.5). The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. Is is maintained by the US Naval Observatory, and represents the world's principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of the systems. (3 data files).

  20. VizieR Online Data Catalog: The Washington Visual Double Star Catalog (Mason+ 2001-2013)

    NASA Astrophysics Data System (ADS)

    Mason, B. D.; Wycoff, G. L.; Hartkopf, W. I.; Douglass, G. G.; Worley, C. E.

    2013-11-01

    The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS; Jeffers and van den Bos, Publ. Lick Obs. 21). Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. The WDS is continually updated as published data become available. Prior to this, three major updates have been published (Worley and Douglass 1984, "Washington Visual Double Star Catalog, 1984.0", U.S. Naval Observatory, Washington; Worley and Douglass 1997A&AS..125..523W, Cat. I/237; Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ....122.3466M; and Mason et al. 2006.5). The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. Is is maintained by the US Naval Observatory, and represents the world's principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of the systems. (3 data files).

  1. VizieR Online Data Catalog: The Washington Visual Double Star Catalog (Mason+ 2001-2012)

    NASA Astrophysics Data System (ADS)

    Mason, B. D.; Wycoff, G. L.; Hartkopf, W. I.; Douglass, G. G.; Worley, C. E.

    2012-11-01

    The Washington Visual Double Star Catalog (WDS) is the successor to the Index Catalogue of Visual Double Stars, 1961.0 (IDS; Jeffers and van den Bos, Publ. Lick Obs. 21). Three earlier double star catalogs in XXth century, those by Burnham (BDS, 1906, "General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), Innes (SDS, 1927, "Southern Double Star Catalogue -19 to -90 degrees", Union Observatory, Johannesburg, South Africa), and Aitken (ADS, 1932 "New General Catalogue of Double Stars within 121 degrees of the North Pole", Carnegie Institution of Washington), each covered only a portion of the sky. Both the IDS and the WDS cover the entire sky, and the WDS is intended to contain all known visual double stars for which at least one differential measure has been published. The WDS is continually updated as published data become available. Prior to this, three major updates have been published (Worley and Douglass 1984, "Washington Visual Double Star Catalog, 1984.0", U.S. Naval Observatory, Washington; Worley and Douglass 1997A&AS..125..523W, Cat. I/237; Mason, Wycoff, Hartkopf, Douglass and Worley 2001AJ....122.3466M; and Mason et al. 2006.5). The Washington Double Star Catalog (WDS) has seen numerous changes since the last major release of the catalog. The application of many techniques and considerable industry over the past few years has yielded significant gains in both the number of systems and the number of measures. Is is maintained by the US Naval Observatory, and represents the world's principal database of astrometric double and multiple star information. The WDS contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of the systems. (3 data files).

  2. RETIRED A STARS AND THEIR COMPANIONS. III. COMPARING THE MASS-PERIOD DISTRIBUTIONS OF PLANETS AROUND A-TYPE STARS AND SUN-LIKE STARS

    SciTech Connect

    Bowler, Brendan P.; Johnson, John Asher; Liu, Michael C.; Marcy, Geoffrey W.; Peek, Kathryn M. G.; Henry, Gregory W.; Fischer, Debra A.; Clubb, Kelsey I.; Reffert, Sabine; Schwab, Christian; Lowe, Thomas B.

    2010-01-20

    We present an analysis of approx5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass (IM) subgiants (1.5 approx< M{sub *}/M{sub sun}approx< 2.0) with the goal of measuring the occurrence rate of Jovian planets around (evolved) A-type stars and comparing the distributions of their orbital and physical characteristics to those of planets around Sun-like stars. We provide updated orbital solutions incorporating new radial velocity measurements for five known planet-hosting stars in our sample; uncertainties in the fitted parameters are assessed using a Markov-Chain Monte Carlo method. The frequency of Jovian planets interior to 3 AU is 26{sup +9}{sub -8}%, which is significantly higher than the 5%-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to left brace0.2, 0.3, 0.5, 0.6, 1.3right brace M{sub Jup} within left brace0.1, 0.3, 0.6, 1.0, 3.0right brace AU. To compare the properties of planets around IM stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN propor to M {sup a}lpha P {sup b}eta dlnMdlnP, the observed planet frequency, and the detection limits we derived. We find that the values of alpha and beta for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4sigma level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (approx50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets.

  3. IUE observations of pre-main-sequence stars. I - Mg II and Ca II resonance line fluxes for T Tauri stars

    NASA Technical Reports Server (NTRS)

    Giampapa n, M. S.

    1981-01-01

    IUE satellite and Lick 3 m reflector image tube scanner measurements of the Mg II and Ca II resonance lines in a sample of T Tauri stars are the basis of a discussion of the Mg II h and k line emission and the Ca II H and K line emission, within the context of stellar chromospheres. Corroborative evidence is presented for the chromospheric origin of these resonance lines, and chromospheric radiative loss rates in the Mg II and Ca II resonance lines are derived. It is found that the degree of nonradiative heating present in the outer atmospheres of T Tauri stars generally exceeds that of the RS CVn systems, as well as the dMe stars and other active chromospheric dwarfs, and it is inferred that the surfaces of such pre-main sequence stars are covered by regions similar to solar plages. The mean chromospheric electron density of T Tauri stars is determined as 10 to the 11th/cu cm.

  4. Christmas star.

    NASA Astrophysics Data System (ADS)

    Biała, J.

    There are continuous attempts to identify the legendary Christmas Star with a real astronomical event accompanying the birth of Jesus from Nazareth. Unfortunately, the date of birth is difficult to establish on the basis of historical records with better accuracy than a few years. During that period a number of peculiar astronomical events were observed and it seem to be impossible to identify the right one unambiguously.

  5. Exceptional Stars

    NASA Astrophysics Data System (ADS)

    Kulkarni, S. R.; Hansen, B.; van Kerkwijk, M.; Phinney, E. S.

    2005-12-01

    As part of our Interdisciplinary Scientist effort (PI, Kulkarni) for the Space Interferometry Mission (SIM) we proposed an investigation with SIM of a number of exceptional stars. With SIM we plan to observe dozens of nearby white dwarfs and search for planets surviving the evolution away from the main sequence as well as (newly formed) planets formed in the circumbinary disks of post-AGB binaries or as a result of white dwarf mergers. We propose to measure the proper motion of a sample of X-ray binaries and Be star binaries with the view of understanding the originof high latitude objects and inferring natal kicks and pre-supernova orbits. We plan to observe several compact object binaries to determine the mass of the compact star. Of particular importance is the proposed observation of SS 433 (for which we propose to use the spectrometer on SIM to measure the proper motion of the emission line clumps embedded in the relativistic jets). Separately we are investigating the issue of frame tie between SIM and the ecliptic frame (by observing binary millisecond pulsars with SIM; the position of these objects is very well determined by pulsar timing) and the degree to which highly precise visibility amplitude measurements can be inverted to infer binary parameters.

  6. Neutron Stars

    NASA Astrophysics Data System (ADS)

    van den Heuvel, Ed

    Radio pulsars are unique laboratories for a wide range of physics and astrophysics. Understanding how they are created, how they evolve and where we find them in the Galaxy, with or without binary companions, is highly constraining of theories of stellar and binary evolution. Pulsars' relationship with a recently discovered variety of apparently different classes of neutron stars is an interesting modern astrophysical puzzle which we consider in Part I of this review. Radio pulsars are also famous for allowing us to probe the laws of nature at a fundamental level. They act as precise cosmic clocks and, when in a binary system with a companion star, provide indispensable venues for precision tests of gravity. The different applications of radio pulsars for fundamental physics will be discussed in Part II. We finish by making mention of the newly discovered class of astrophysical objects, the Fast Radio Bursts, which may or may not be related to radio pulsars or neutron stars, but which were discovered in observations of the latter.

  7. Binary stars.

    PubMed

    Paczynacuteski, B

    1984-07-20

    Most stars in the solar neighborhood are either double or multiple systems. They provide a unique opportunity to measure stellar masses and radii and to study many interesting and important phenomena. The best candidates for black holes are compact massive components of two x-ray binaries: Cygnus X-1 and LMC X-3. The binary radio pulsar PSR 1913 + 16 provides the best available evidence for gravitational radiation. Accretion disks and jets observed in close binaries offer a very good testing ground for models of active galactic nuclei and quasars.

  8. KSC-2012-1551

    NASA Image and Video Library

    2012-02-23

    ORLANDO, Fla. -- Visitors enter the Orange County Convention Center in Orlando, Fla., for the NBA All-Star Jam Session. Representatives from NASA's Kennedy Space Center in Florida were available to highlight some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

  9. KSC-2012-1554

    NASA Image and Video Library

    2012-02-23

    ORLANDO, Fla. -- Inside the Orange County Convention Center in Orlando, Fla., representatives from NASA's Kennedy Space Center in Florida speak to attendees visiting the NBA All-Star Jam Session. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

  10. KSC-2012-1552

    NASA Image and Video Library

    2012-02-23

    ORLANDO, Fla. -- At NASA's exhibit inside the Orange County Convention Center in Orlando, Fla., visitors to the NBA All-Star Jam Session participate in hands-on educational activities to learn more about how science plays into sports. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

  11. KSC-2012-1556

    NASA Image and Video Library

    2012-02-23

    ORLANDO, Fla. -- Representatives from NASA's Kennedy Space Center in Florida talk to visitors attending the NBA All-Star Jam Session at the Orange County Convention Center in Orlando, Fla. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

  12. KSC-2012-1553

    NASA Image and Video Library

    2012-02-23

    ORLANDO, Fla. -- Inside the Orange County Convention Center in Orlando, Fla., representatives from NASA's Kennedy Space Center in Florida speak to attendees visiting the NBA All-Star Jam Session. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

  13. True-sky demonstration of an autonomous star tracker

    NASA Astrophysics Data System (ADS)

    van Bezooijen, Roelof W.

    1994-07-01

    An autonomous star tracker (AST) is basically a `star field in, attitude out' device capable of determining its attitude without requiring any a priori attitude knowledge. In addition to this attitude acquisition capability, an AST can perform attitude updates autonomously and is able to provide its attitude `continuously' while tracking a star field. The Lockheed Palo Alto Research Laboratory is developing a reliable, low-cost, miniature AST that has a one arcsec overall accuracy, weighs less than 1.5 kg, consumes less than 7 watts of power, and is sufficiently sensitive to be used at all sky locations. The device performs attitude acquisition in a fraction of a second and outputs its attitude at a 10 Hz rate when operating in its tracking mode. Besides providing the functionality needed for future advanced attitude control and navigation systems, an AST also improves spacecraft reliability, mass, power, cost, and operating expenses. The AST comprises a-thermalized, refractive optics, a frame-transfer CCD with a sensitive area of 1024 by 1024 pixels, camera electronics implemented with application- specific integrated circuits, a compact single board computer with a radiation hard 32 bit RISC processor, and an all-sky guide star database. Star identification is performed by a memory- efficient and highly robust algorithm that finds the largest group of observed stars matching a group of guide stars. An important milestone has recently been achieved with the validation of the attitude acquisition capability through correct and rapid identification of all 704 true-sky star fields obtained at the Lick Observatory, using an uncalibrated prototype AST with a 512 by 1024 pixel frame-transfer CCD and a 50 mm f/1.2 lens that provided an effective 6.5 by 13.2 degree field of view. The overlapping fields cover 47% of the sky, including both rich and sparse areas. The paper contains a description of the AST, a summary of the functions enabled or improved by the device, an

  14. Three Temperate Neptunes Orbiting Nearby Stars

    NASA Astrophysics Data System (ADS)

    Fulton, Benjamin J.; Howard, Andrew W.; Weiss, Lauren M.; Sinukoff, Evan; Petigura, Erik A.; Isaacson, Howard; Hirsch, Lea; Marcy, Geoffrey W.; Henry, Gregory W.; Grunblatt, Samuel K.; Huber, Daniel; von Braun, Kaspar; Boyajian, Tabetha S.; Kane, Stephen R.; Wittrock, Justin; Horch, Elliott P.; Ciardi, David R.; Howell, Steve B.; Wright, Jason T.; Ford, Eric B.

    2016-10-01

    We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD 42618 b has a minimum mass of 15.4 ± 2.4 {M}\\oplus , a semimajor axis of 0.55 au, an equilibrium temperature of 337 K, and is the first planet discovered to orbit the solar analogue host star, HD 42618. We also discover new planets orbiting the known exoplanet host stars HD 164922 and HD 143761 (ρ CrB). The new planet orbiting HD 164922 has a minimum mass of 12.9 ± 1.6 {M}\\oplus and orbits interior to the previously known Jovian mass planet orbiting at 2.1 au. HD 164922 c has a semimajor axis of 0.34 au and an equilibrium temperature of 418 K. HD 143761 c orbits with a semimajor axis of 0.44 au, has a minimum mass of 25 ± 2 {M}\\oplus , and is the warmest of the three new planets with an equilibrium temperature of 445 K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time was granted for this project by the University of Hawai‘i, the University of California, and NASA.

  15. The Evolving Mixture of Barium Isotopes in Milky Way Halo Stars

    NASA Astrophysics Data System (ADS)

    Choudhury, Zareen; Kirby, E. N.; Guhathakurta, P.

    2014-01-01

    Heavy metals in stars form through one of two types of neutron capture processes: the rapid r-process or slower s-process. The fraction of odd and even barium isotopes in stars can indicate which process predominantly contributed to a star’s heavy metals, since odd barium isotopes predominantly form through the r-process and even barium isotopes through the s-process. The “stellar model” predicts that older stars contain comparable amounts of odd and even barium isotopes, while the “classical model” states that they almost exclusively contain odd isotopes. This study investigated these competing models by analyzing high-resolution spectra of twelve Milky Way stars. These spectra were analyzed for the first time in this study. To quantify r- and s-process enrichment, we measured the odd barium isotope fraction in the stars by fitting models to the stars’ spectra. Generating models involved measuring the stars’ Doppler shift, resolution, and barium abundance. To reduce error margins we optimized resolution and barium abundance measurements by enhancing existing techniques through several rounds of revisions. Our results support the stellar model of heavy metal enrichment, and our proposed optimizations will enable future researchers to obtain a deeper understanding of chemical enrichment in the Universe. This research was supported by the Science Internship Program at the University of California Santa Cruz, Lick Observatory, and the National Science Foundation.

  16. Star-to-Star Abundance Variations among Bright Giants in the Mildly Metal-poor Globular Cluster M4

    NASA Astrophysics Data System (ADS)

    Ivans, Inese I.; Sneden, Christopher; Kraft, Robert P.; Suntzeff, Nicholas B.; Smith, Verne V.; Langer, G. Edward; Fulbright, Jon P.

    1999-09-01

    We present a chemical composition analysis of 36 giants in the nearby mildly metal-poor (<[Fe/H]>=-1.18) ``CN-bimodal'' globular cluster M4. The stars were observed at the Lick and McDonald Observatories using high-resolution échelle spectrographs and at the Cerro Tololo Inter-American Observatory using the multiobject spectrometer. Confronted with a cluster having interstellar extinction that is large and variable across the cluster face, we combined traditional spectroscopic abundance methods with modifications to the line depth ratio technique pioneered by Gray to determine the atmospheric parameters of our stars. We derive a total-to-selective extinction ratio of 3.4+/-0.4 and an average reddening of 0.33+/-0.01, which is significantly lower than that estimated by using the dust maps made by Schlegel and coworkers. We determine abundance ratios typical of halo field and cluster stars for scandium, titanium, vanadium, nickel, and europium with star-to-star variations in these elements of less than +/-0.1. Silicon, aluminum, barium, and lanthanum are overabundant with respect to what is seen in other globular clusters of similar metallicity. These overabundances confirm the results of an earlier study by Brown & Wallerstein based on a much smaller sample of M4 giants. Superposed on the primordial abundance distribution is evidence for the existence of proton capture synthesis of carbon, oxygen, neon, and magnesium. We recover some of the C, N, O, Na, Mg, and Al abundance swings and correlations found in other more metal-poor globular clusters, but the range of variation is muted. In the case of Mg and Al, this is compatible with the idea that the Al enhancements are derived from the destruction of ^25,26Mg, not ^24Mg. We determine that the C+N+O abundance sum is constant to within the observational errors and agrees with the C+N+O total that might be expected for M4 stars at birth. The asymptotic giant branch (AGB) stars in M4 have C, N, and O

  17. Pasteurella multocida non-native joint infection after a dog lick: A case report describing a complicated two-stage revision and a comprehensive review of the literature

    PubMed Central

    Philip W, Lam; Page, Andrea V

    2015-01-01

    Prosthetic joint infections (PJIs) are commonly caused by pathogens such as Staphylococcus aureus and coagulase-negative staphylococci; however, other microbial etiologies and specific risk factors are increasingly recognized. Pasteurella multocida is a Gram-negative coccobacillus that is part of the normal oral flora in many animals, and is particularly common in dogs and cats. PJIs caused by P multocida have been reported only rarely in the literature and typically occur in the context of an animal bite or scratch. The present article describes a P multocida joint infection that occurred after a dog lick and complicated a two-stage revision arthroplasty. A comprehensive review of the literature regarding P multocida PJIs follows. PMID:26361490

  18. Pasteurella multocida non-native joint infection after a dog lick: A case report describing a complicated two-stage revision and a comprehensive review of the literature.

    PubMed

    Lam, Philip W; Page, Andrea V

    2015-01-01

    Prosthetic joint infections (PJIs) are commonly caused by pathogens such as Staphylococcus aureus and coagulase-negative staphylococci; however, other microbial etiologies and specific risk factors are increasingly recognized. Pasteurella multocida is a Gram-negative coccobacillus that is part of the normal oral flora in many animals, and is particularly common in dogs and cats. PJIs caused by P multocida have been reported only rarely in the literature and typically occur in the context of an animal bite or scratch. The present article describes a P multocida joint infection that occurred after a dog lick and complicated a two-stage revision arthroplasty. A comprehensive review of the literature regarding P multocida PJIs follows.

  19. Observations of comet P/Shoemaker-Levy 9 impact on Jupiter from Lick Obseravtory using a high resolution speckle imaging camera

    SciTech Connect

    Max, C.; Gavel, D.; Johansson, E.; Sherwood, B.; Liu, M.; Bradford, B.

    1996-03-15

    During the week of the impacts of Comet Shoemaker-Levy 9 into Jupiter, we used a speckle imaging camera mounted on the Lick Observatory 3 meter Telescope to record a continuous stream of images of the planet. Because the speckle imaging technique compensates for atmospheric blurring, the resulting images were most likely the highest resolution of any taken from the ground. These images compliment the Hubble Space Telescope data by covering time periods when Hubble was not observing Jupiter. We collected full planet 1024 by 1024 pixel CCD images taken 20 per minute for 4 hours per night over 6 nights July 15 to 22. Only a portion of this raw data has been reduced to high resolution images to date.

  20. Ice Stars

    NASA Image and Video Library

    2017-09-27

    Ice Stars - August 4th, 2002 Description: Like distant galaxies amid clouds of interstellar dust, chunks of sea ice drift through graceful swirls of grease ice in the frigid waters of Foxe Basin near Baffin Island in the Canadian Arctic. Sea ice often begins as grease ice, a soupy slick of tiny ice crystals on the ocean's surface. As the temperature drops, grease ice thickens and coalesces into slabs of more solid ice. Credit: USGS/NASA/Landsat 7 To learn more about the Landsat satellite go to: landsat.gsfc.nasa.gov/ 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 Join us on Facebook

  1. Studies of bipolar nebulae. VII - The exciting star of OH 0739-14 /equals OH 231.8 plus 4.2/

    NASA Technical Reports Server (NTRS)

    Cohen, M.

    1981-01-01

    A spectral classification for the exciting star of the bipolar reflection nebula OH 0739-14, which has also been observed to be an OH/H2O maser source, is obtained from the spectrum of the nebulosity in the range 6000-9000 A. Spectrophotometry of the visible nebula was obtained with the Cassegrain image-tube scanner on the Lick Observatory 3-m telescope at a resolution of approximately 7 A. The red spectrum is found to be distinguished by TiO absorption at the bandheads at 8206, 8303, 8432, 8442 and 8452 A and VO in the 7400 and 7900 A regions. On the basis of the depths of these bandheads and the K I 7699 A and Ca II infrared triplet, OH 0739-14 is determined to be of spectral type M9 III. The underlying star thus represents the coolest known star to occur in a bipolar system.

  2. Performances of four photometry softwares in very dense stellar fields

    NASA Astrophysics Data System (ADS)

    Dubout-Crillon, R.; Llebaria, A.

    2002-06-01

    We assess the relative performances of the softwares DAOPHOT, DAOPHOT/ ALLSTAR, CAPELLA, SEXTRACTOR for stellar fields with irregular backgrounds and asymmetric PSFs. The first three packages use PSF fit- tings, the fourth performs fixed aperture photometry and a small aperture was used in order to minimize the contaminating fluxes. A typical extragalactic stellar field has been used to built synthetic counterparts in order to test the photometric accuracy with respect to the blend extent. The results show in which cases DAOPHOT, DAOPHOT/ ALLSTAR and SEXTRACTOR overestimate the fluxes of blended stars. SEXTRACTOR results dispersions are near the ALLSTAR ones, but as we can expect, systematic overestimation appears for the severely blended stars. For stars merged in the wings of brighter stars, CAPELLA reaches the best accuracy. For isolated and moderately blended stars, ALLSTAR, CAPELLA and SEXTRACTOR results are near.

  3. O stars and Wolf-Rayet stars

    NASA Technical Reports Server (NTRS)

    Conti, Peter S.; Underhill, Anne B.; Jordan, Stuart (Editor); Thomas, Richard (Editor)

    1988-01-01

    Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented.

  4. The Stellar Populations of Nuclei, Globular Clusters, and Stars in dE Galaxies in Virgo and Fornax

    NASA Astrophysics Data System (ADS)

    Whitfield Miller, Bryan; Hyazinth Puzia, Thomas; Hilker, Michael; Sanchez-Janssen, Ruben; Kissler-Patig, Markus

    2015-08-01

    We present ages and metallicities for globular clusters, nuclei, and underlying stars in nucleated dwarf elliptical galaxies (dE,N) in the Virgo and Fornax Cluster based on Lick/IDS index measurements and SSP models. Gemini/GMOS spectroscopy shows that the globular clusters are mostly old and metal-poor, very similar to the globular clusters in the Milky Way halo. The nuclei and underlying stars tend to be more metal-rich than the globular clusters and have a wide range of ages. The [α/Fe] ratios for both the globular clusters and nuclei range between 0.0 and 0.3. Formation scenarios for globular clusters and nuclei will be discussed.

  5. Lifestyles of the Stars.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Cocoa Beach, FL. John F. Kennedy Space Center.

    Some general information on stars is provided in this National Aeronautics and Space Administration pamphlet. Topic areas briefly discussed are: (1) the birth of a star; (2) main sequence stars; (3) red giants; (4) white dwarfs; (5) neutron stars; (6) supernovae; (7) pulsars; and (8) black holes. (JN)

  6. Egyptian "Star Clocks"

    NASA Astrophysics Data System (ADS)

    Symons, Sarah

    Diagonal, transit, and Ramesside star clocks are tables of astronomical information occasionally found in ancient Egyptian temples, tombs, and papyri. The tables represent the motions of selected stars (decans and hour stars) throughout the Egyptian civil year. Analysis of star clocks leads to greater understanding of ancient Egyptian constellations, ritual astronomical activities, observational practices, and pharaonic chronology.

  7. Magnetic Fields in Stars

    NASA Astrophysics Data System (ADS)

    Landstreet, J.; Murdin, P.

    2000-11-01

    Magnetism—the force that deflects the needle of a compass—and magnetic fields have been found in some hundreds of stars during the past 50 yr. Magnetic fields have been detected in T Tauri stars and other pre-main-sequence stars, several types of main sequence stars, white dwarfs and neutron stars. We now know a number of methods by which such magnetic fields may be detected, we are in the proces...

  8. Neutron Stars and NuSTAR

    NASA Astrophysics Data System (ADS)

    Bhalerao, Varun

    2012-05-01

    My thesis centers around the study of neutron stars, especially those in massive binary systems. To this end, it has two distinct components: the observational study of neutron stars in massive binaries with a goal of measuring neutron star masses and participation in NuSTAR, the first imaging hard X-ray mission, one that is extremely well suited to the study of massive binaries and compact objects in our Galaxy. The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing high energy X-ray telescope to orbit. NuSTAR has an order-of-magnitude better angular resolution and has two orders of magnitude higher sensitivity than any currently orbiting hard X-ray telescope. I worked to develop, calibrate, and test CdZnTe detectors for NuSTAR. I describe the CdZnTe detectors in comprehensive detail here - from readout procedures to data analysis. Detailed calibration of detectors is necessary for analyzing astrophysical source data obtained by the NuSTAR. I discuss the design and implementation of an automated setup for calibrating flight detectors, followed by calibration procedures and results. Neutron stars are an excellent probe of fundamental physics. The maximum mass of a neutron star can put stringent constraints on the equation of state of matter at extreme pressures and densities. From an astrophysical perspective, there are several open questions in our understanding of neutron stars. What are the birth masses of neutron stars? How do they change in binary evolution? Are there multiple mechanisms for the formation of neutron stars? Measuring masses of neutron stars helps answer these questions. Neutron stars in high-mass X-ray binaries have masses close to their birth mass, providing an opportunity to disentangle the role of "nature" and "nurture" in the observed mass distributions. In 2006, masses had been measured for only six such objects, but this small sample showed the greatest diversity in masses

  9. O stars and Wolf-Rayet stars.

    NASA Astrophysics Data System (ADS)

    Baade, D.; Conti, P. S.; Divan, L.; Garmany, C. D.; Henrichs, H. F.; Kudritzki, R. P.; Pauldrach, A.; Prévot-Burnichon, M.-L.; Puls, J.; Underhill, A. B.; Thomas, R. N.

    Contents: Perspective (R. N. Thomas).Part I. Introduction (L. Divan, M.-L. Prévot-Burnichon).1. Introducing the O and Wolf-Rayet stars.Part II. One perspective on O, Of, and Wolf-Rayet stars emphasizing winds and mass loss, with remarks on environment and evolution:2. Overview of O, Of, and Wolf-Rayet populations (P. S. Conti). 3. Intrinsic stellar parameters (P. S. Conti, D. Baade). 4. Stellar winds: (a) Introduction (P. S. Conti). (b) Mass loss from O stars (C. D. Garmany). (c) Mass loss in Wolf-Rayetstars (P. S. Conti). (d) Radiation-driven winds of hot luminous stars (R. P. Kudritzki, A. Pauldrach, J. Puls). (e) Intrinsic variability in ultraviolet spectra of early-type stars: the discrete absorption lines (H. Henrichs). 5. Environments and evolution (P. S. Conti).Part III. Another perspective on O, Of, and Wolf-Rayet stars, emphasizing model atmospheres and possibilities for atmospheric heating (A. B. Underhill): 6. Understanding the O and Wolf-Rayet stars. 7. Model Atmospheres and the theoryof spectra for O and Wolf-Rayet stars. 8. The physics of the mantles of hot stars. 9. Summary of processes influencing the spectra of O andWolf-Rayet stars.

  10. An X-ray and Optical Spectroscopic Study of the Perplexing Star RZ Piscium

    NASA Astrophysics Data System (ADS)

    Punzi, Kristina Marie; Kastner, Joel H.; Melis, Carl; Zuckerman, Ben M.

    2017-01-01

    The evolutionary status of the "anti-flare" variable star RZ Psc is ambiguous; both pre- and post-main sequence models have been proposed. RZ Psc shows evidence for gaseous and dusty circumstellar material in the form of emission lines and an infrared excess; its space velocities suggest that it is young, but it does not appear to be a member of a known association of young stars. We report the results of X-ray observations of RZ Psc with XMM-Newton, as well as high-resolution optical spectroscopy of the star obtained at the Lick and Keck observatories. The XMM-Newton imaging spectroscopy establishes that RZ Psc is highly X-ray-luminous, while the optical spectroscopy confirms that the star is G-type and has low surface gravity. The nearly saturated stellar activity and X-ray plasma properties of RZ Psc are indicative of pre-main sequence status, but are also consistent with those of rapidly rotating first-ascent giants. The optical spectroscopy yields evidence for radial velocity variability, hinting at the possibility that RZ Psc is a spectroscopic binary system. Further observations of RZ Psc and its field are necessary to break the age degeneracy and to confirm its close binary status. This research is supported in part by NASA Astrophysics Data Analysis program grant NNX16AG13G to RIT.

  11. THE FREQUENCY OF HOT JUPITERS ORBITING NEARBY SOLAR-TYPE STARS

    SciTech Connect

    Wright, J. T.; Marcy, G. W.; Howard, A. W.; Johnson, John Asher; Morton, T. D.; Fischer, D. A.

    2012-07-10

    We determine the fraction of F, G, and K dwarfs in the solar neighborhood hosting hot Jupiters as measured by the California Planet Survey from the Lick and Keck planet searches. We find the rate to be 1.2% {+-} 0.38%, which is consistent with the rate reported by Mayor et al. from the HARPS and CORALIE radial velocity (RV) surveys. These numbers are more than double the rate reported by Howard et al. for Kepler stars and the rate of Gould et al. from the OGLE-III transit search; however, due to small number statistics these differences are of only marginal statistical significance. We explore some of the difficulties in estimating this rate from the existing RV data sets and comparing RV rates to rates from other techniques.

  12. CCD star trackers

    NASA Technical Reports Server (NTRS)

    Goss, W. C.

    1975-01-01

    The application of CCDs to star trackers and star mappers is considered. Advantages and disadvantages of silicon CCD star trackers are compared with those of image dissector star trackers. It is concluded that the CCD has adequate sensitivity for most single star tracking tasks and is distinctly superior in multiple star tracking or mapping applications. The signal and noise figures of several current CCD configurations are discussed. The basic structure of the required signal processing is described, and it is shown that resolution in excess of the number of CCD elements may be had by interpolation.

  13. The Millennium Star Atlas

    NASA Astrophysics Data System (ADS)

    Sinnott, R. W.

    1997-08-01

    Derived from Hipparcos and Tycho observations, the Millennium Star Atlas is a set of 1548 charts covering the entire sky to about magnitude 11. It stands apart from all previous printed atlases in completeness to magnitude 10 and in uniformity around the sky. The generous chart scale has made possible a number of innovations never before seen in a star atlas: arrows on high-proper-motion stars, double-star ticks conveying separation and position angle for a specific modern epoch, distance labels for nearby stars, and variable stars coded by amplitude, period, and type. Among the nonstellar objects plotted, more than 8000 galaxies are shown with aspect ratio and orientation.

  14. VizieR Online Data Catalog: Star Formation in Early-type galaxies (Longhetti+ 1998)

    NASA Astrophysics Data System (ADS)

    Longhetti, M.; Rampazzo, R.; Bressan, A.; Chiosi, C.

    1998-03-01

    The paper is the first of a series (Longhetti et al., 1998A&AS..130..267L, 1998b (Paper III) in press) dedicated to the study of the star formation history in early-type galaxies which show fine structures and/or interaction signatures. It presents nuclear line-strength indices for a sample composed of 21 shell galaxies, from the Malin & Carter (1983ApJ...274..534M) southern survey, and 30 members of isolated interacting pairs, from the Reduzzi & Rampazzo (1995ApL....30....1R) catalogue, located in low density environments. The spectral range covers 3700Å<λ<5700Å at 2.1ÅFWHM resolution. We measure 16 red (λ>4200Å) indices defined by the Lick Group. Measures have been transformed into the Lick-IDS ``standard'' system. The procedure has been tested on a set of 5 elliptical galaxies selected from the Gonzalez (1993, Ph.D. thesis) sample. We derive also three blue (λ<4200) indices, namely {DELTA}(4000Å) defined by Hamilton (1985ApJ...297..371H), H+K(CaII) and Hdelta/FeI defined by Rose (1984AJ.....89.1238R, 1985AJ.....90.1927R). Blue indices are correlated to the age of the last starburst occurred in a galaxy (Leonardi & Rose, 1996AJ....111..182L). The indices determination, the estimate of the measurement errors and the correction for the galaxies velocity dispersions are discussed in detail. In the Appendix A we present the indices for a set of hot stars (T>10000K) which may be used for extending, toward high temperatures, Worthey (1992, Ph.D. Thesis) fitting functions. (12 data files).

  15. A case of Appalachian endemism: Revision of the Cambarus robustus complex (Decapoda: Cambaridae) in the Kentucky and Licking River basins of Kentucky, USA, with the description of three new species.

    PubMed

    Loughman, Zachary J; Henkanaththegedara, Sujan M; Fetzner, James W; Thoma, Roger F

    2017-05-24

    The amazing levels of freshwater biodiversity found in the Appalachian Mountains of the eastern United States are among the highest recorded globally. Localized endemics make up much of this diversity, with numerous fish, freshwater mussels, salamanders and crayfish often being restricted to a single watershed, and in some instances, subwatersheds. Much of this diversity is the product of the processes of vicariance and historical stream drainage patterns. Herein, we describe three new crayfish species, all previously members of the Cambarus robustus complex, which occur in the Appalachian portion of the Kentucky and Licking river basins in Kentucky, USA. All three species differ from each other morphologically, genetically, and zoogeographically, fulfilling the requirements of the integrated species concept. Cambarus guenteri occurs in the southern tributaries of the Kentucky River mainstem as well as throughout the South Fork Kentucky River. Cambarus taylori is a narrow endemic, which only occurs in the Middle Fork Kentucky River. Cambarus hazardi, which has the widest distribution of the three new species, occurs in the North Fork Kentucky River, Red River, and upper reaches of the Licking River basin. Stream piracy events between the Cumberland and South Fork Kentucky River, as well as the Licking, Red and North Fork Kentucky rivers, are theorized to be important in the evolution of this complex. Cambarus guenteri is proposed as currently stable, though both C. taylori and C. hazardi are considered imperiled at this time due to habitat destruction throughout both of their respective ranges.

  16. Artificial rearing inhibits apoptotic cell death through action on pro-apoptotic signaling molecules during brain development: replacement licking partially reverses these effects.

    PubMed

    Chatterjee-Chakraborty, Munmun; Chatterjee, Diptendu

    2010-08-12

    Early life stress associated with being reared without mother, siblings, and nest affects the formation of neuronal networks during rat development. Prior work shows that in comparison to mother-reared male rats, artificial rearing results in elevated numbers of neurons in adulthood and reduced apoptosis during the first postnatal week. Replacement with stroking stimulation, designed to simulate mothers' licking, reversed these effects in most brain areas. The present communication explored the effects of early rearing manipulations on signaling proteins. Male rats were reared until postnatal day 7 either in an artificial-feeding paradigm (AR) or with their mothers (MR). AR animals received different amounts of maternal-like stimulation using a soft paintbrush. Brains were extracted and prepared for molecular assays of 1) apoptosis and 2) pro and anti-apoptotic proteins on day 7 of postnatal life. Results showed that stimulation of the AR pups reversed the effects of artificial rearing on apoptosis in a dose dependent manner; low and very high levels of stimulation were without effect whereas moderate levels of stimulation produced effects on apoptosis similar to effects seen in mother-reared controls. Moreover, this artificial rearing effect and the pattern of reversal with stroking were also found for levels of pro-apoptotic Bax protein, the ratio of Bax/Bcl-2 and levels of activated caspase-3 which we believe mediates programmed cell death.

  17. Massive Star Makes Waves

    NASA Image and Video Library

    2012-12-18

    The giant star Zeta Ophiuchi, a young, large and hot star located around 370 light-years away, is having a hocking effect on the surrounding dust clouds in this infrared image from NASA Spitzer Space Telescope.

  18. Sloshing Star Goes Supernova

    NASA Image and Video Library

    2014-02-19

    NuSTAR has provided the first observational evidence in support of a theory that says exploding stars slosh around before detonating. That theory, referred to as mild asymmetries, is shown here in a simulation by Christian Ott.

  19. Assembly Line of Stars

    NASA Image and Video Library

    2010-05-06

    This image from NASA Herschel, in the constellation of Vulpecula, shows an entire assembly line of newborn stars. The diffuse glow reveals the widespread cold reservoir of raw material that our Milky Way galaxy has in stock for building stars.

  20. Star formation: Cosmic feast

    NASA Astrophysics Data System (ADS)

    Scaringi, Simone

    2017-03-01

    Low-mass stars form through a process known as disk accretion, eating up material that orbits in a disk around them. It turns out that the same mechanism also describes the formation of more massive stars.

  1. Star formation: Cosmic feast

    NASA Astrophysics Data System (ADS)

    Scaringi, Simone

    2016-11-01

    Low-mass stars form through a process known as disk accretion, eating up material that orbits in a disk around them. It turns out that the same mechanism also describes the formation of more massive stars.

  2. Astrophysics: Stars fight back

    NASA Astrophysics Data System (ADS)

    Hopkins, Philip F.

    2014-12-01

    Galaxies contain fewer stars than predicted. The discovery of a massive galactic outflow of molecular gas in a compact galaxy, which forms stars 100 times faster than the Milky Way, may help to explain why. See Letter p.68

  3. AgSTAR Accomplishments

    EPA Pesticide Factsheets

    Showcases AgSTAR's accomplishments reducing greenhouse gas emissions in the agriculture sector. Through outreach, education, training, and other tools, AgSTAR continues to help evaluate, construct, and maintain anaerobic digesters on livestock farms.

  4. Star Formation in Galaxies

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Topics addressed include: star formation; galactic infrared emission; molecular clouds; OB star luminosity; dust grains; IRAS observations; galactic disks; stellar formation in Magellanic clouds; irregular galaxies; spiral galaxies; starbursts; morphology of galactic centers; and far-infrared observations.

  5. Intrinsically variable stars

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, Erika; Querci, Monique

    1987-01-01

    The characteristics of intrinsically variable stars are examined, reviewing the results of observations obtained with the IUE satellite since its launch in 1978. Selected data on both medium-spectral-class pulsating stars (Delta Cep stars, W Vir stars, and related groups) and late-type variables (M, S, and C giants and supergiants) are presented in spectra, graphs, and tables and described in detail. Topics addressed include the calibration of the the period-luminosity relation, Cepheid distance determination, checking stellar evolution theory by the giant companions of Cepheids, Cepheid masses, the importance of the hydrogen convection zone in Cepheids, temperature and abundance estimates for Population II pulsating stars, mass loss in Population II Cepheids, SWP and LWP images of cold giants and supergiants, temporal variations in the UV lines of cold stars, C-rich cold stars, and cold stars with highly ionized emission lines.

  6. White Dwarf Stars

    NASA Image and Video Library

    1999-12-01

    Peering deep inside a cluster of several hundred thousand stars, NASA Hubble Space Telescope has uncovered the oldest burned-out stars in our Milky Way Galaxy, giving astronomers a fresh reading on the age of the universe.

  7. Another Death Star?

    NASA Image and Video Library

    2012-12-03

    Although Mimas holds the unofficial designation of Death Star moon, Tethys is seen here also vaguely resembling the space station from Star Wars. Apparently, Tethys doesnt want Mimas to have all the fun!

  8. Intrinsically variable stars

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, Erika; Querci, Monique

    1987-01-01

    The characteristics of intrinsically variable stars are examined, reviewing the results of observations obtained with the IUE satellite since its launch in 1978. Selected data on both medium-spectral-class pulsating stars (Delta Cep stars, W Vir stars, and related groups) and late-type variables (M, S, and C giants and supergiants) are presented in spectra, graphs, and tables and described in detail. Topics addressed include the calibration of the the period-luminosity relation, Cepheid distance determination, checking stellar evolution theory by the giant companions of Cepheids, Cepheid masses, the importance of the hydrogen convection zone in Cepheids, temperature and abundance estimates for Population II pulsating stars, mass loss in Population II Cepheids, SWP and LWP images of cold giants and supergiants, temporal variations in the UV lines of cold stars, C-rich cold stars, and cold stars with highly ionized emission lines.

  9. Precise radial velocities of giant stars. IX. HD 59686 Ab: a massive circumstellar planet orbiting a giant star in a 13.6 au eccentric binary system

    NASA Astrophysics Data System (ADS)

    Ortiz, Mauricio; Reffert, Sabine; Trifonov, Trifon; Quirrenbach, Andreas; Mitchell, David S.; Nowak, Grzegorz; Buenzli, Esther; Zimmerman, Neil; Bonnefoy, Mickaël; Skemer, Andy; Defrère, Denis; Lee, Man Hoi; Fischer, Debra A.; Hinz, Philip M.

    2016-10-01

    Context. For over 12 yr, we have carried out a precise radial velocity (RV) survey of a sample of 373 G- and K-giant stars using the Hamilton Échelle Spectrograph at the Lick Observatory. There are, among others, a number of multiple planetary systems in our sample as well as several planetary candidates in stellar binaries. Aims: We aim at detecting and characterizing substellar and stellar companions to the giant star HD 59686 A (HR 2877, HIP 36616). Methods: We obtained high-precision RV measurements of the star HD 59686 A. By fitting a Keplerian model to the periodic changes in the RVs, we can assess the nature of companions in the system. To distinguish between RV variations that are due to non-radial pulsation or stellar spots, we used infrared RVs taken with the CRIRES spectrograph at the Very Large Telescope. Additionally, to characterize the system in more detail, we obtained high-resolution images with LMIRCam at the Large Binocular Telescope. Results: We report the probable discovery of a giant planet with a mass of mp sin i = 6.92-0.24+0.18 MJup orbiting at ap = 1.0860-0.0007+0.0006 au from the giant star HD 59686 A. In addition to the planetary signal, we discovered an eccentric (eB = 0.729-0.003+0.004) binary companion with a mass of mB sin i = 0.5296-0.0008+0.0011 M⊙ orbiting at a close separation from the giant primary with a semi-major axis of aB = 13.56-0.14+0.18 au. Conclusions: The existence of the planet HD 59686 Ab in a tight eccentric binary system severely challenges standard giant planet formation theories and requires substantial improvements to such theories in tight binaries. Otherwise, alternative planet formation scenarios such as second-generation planets or dynamical interactions in an early phase of the system's lifetime need to be seriously considered to better understand the origin of this enigmatic planet. Based on observations collected at the Lick Observatory, University of California.Based on observations collected at the

  10. Chromospheres of Coronal Stars

    NASA Technical Reports Server (NTRS)

    Linsky, Jeffrey L.; Wood, Brian E.

    1996-01-01

    We summarize the main results obtained from the analysis of ultraviolet emission line profiles of coronal late-type stars observed with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope. The excellent GHRS spectra provide new information on magnetohydrodynamic phenomena in the chromospheres and transition regions of these stars. One exciting new result is the discovery of broad components in the transition region lines of active stars that we believe provide evidence for microflare heating in these stars.

  11. Dibaryons in neutron stars

    NASA Technical Reports Server (NTRS)

    Olinto, Angela V.; Haensel, Pawel; Frieman, Joshua A.

    1991-01-01

    The effects are studied of H-dibaryons on the structure of neutron stars. It was found that H particles could be present in neutron stars for a wide range of dibaryon masses. The appearance of dibaryons softens the equations of state, lowers the maximum neutron star mass, and affects the transport properties of dense matter. The parameter space is constrained for dibaryons by requiring that a 1.44 solar mass neutron star be gravitationally stable.

  12. America's Star Libraries

    ERIC Educational Resources Information Center

    Lyons, Ray; Lance, Keith Curry

    2009-01-01

    "Library Journal"'s new national rating of public libraries, the "LJ" Index of Public Library Service, identifies 256 "star" libraries. It rates 7,115 public libraries. The top libraries in each group get five, four, or three Michelin guide-like stars. All included libraries, stars or not, can use their scores to learn from their peers and improve…

  13. America's Star Libraries

    ERIC Educational Resources Information Center

    Lyons, Ray; Lance, Keith Curry

    2009-01-01

    "Library Journal"'s new national rating of public libraries, the "LJ" Index of Public Library Service, identifies 256 "star" libraries. It rates 7,115 public libraries. The top libraries in each group get five, four, or three Michelin guide-like stars. All included libraries, stars or not, can use their scores to learn from their peers and improve…

  14. Seeing Stars in Serpens

    NASA Image and Video Library

    2006-12-08

    Infant stars are glowing gloriously in this image of the Serpens star-forming region, captured by NASA Spitzer Space Telescope. The reddish-pink dots are baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create it.

  15. THE LICK-CARNEGIE EXOPLANET SURVEY: A URANUS-MASS FOURTH PLANET FOR GJ 876 IN AN EXTRASOLAR LAPLACE CONFIGURATION

    SciTech Connect

    Rivera, Eugenio J.; Laughlin, Gregory; Vogt, Steven S.; Meschiari, Stefano; Haghighipour, Nader

    2010-08-10

    Continued radial velocity (RV) monitoring of the nearby M4V red dwarf star GJ 876 with Keck/High Resolution Echelle Spectrograph has revealed the presence of a Uranus-mass fourth planetary companion in the system. The new planet has a mean period of P{sub e} = 126.6 days (over the 12.6-year baseline of the RV observations), and a minimum mass of m{sub e} sin i{sub e} = 12.9 {+-} 1.7 M {sub +}. The detection of the new planet has been enabled by significant improvements to our RV data set for GJ 876. The data have been augmented by 36 new high-precision measurements taken over the past five years. In addition, the precision of all of the Doppler measurements have been significantly improved by the incorporation of a high signal-to-noise template spectrum for GJ 876 into the analysis pipeline. Implementation of the new template spectrum improves the internal rms errors for the velocity measurements taken during 1998-2005 from 4.1 m s{sup -1} to 2.5 m s{sup -1}. Self-consistent, N-body fits to the RV data set show that the four-planet system has an invariable plane with an inclination relative to the plane of the sky of i = 59.{sup 0}5. The fit is not significantly improved by the introduction of a mutual inclination between the planets 'b' and 'c', but the new data do confirm a non-zero eccentricity, e{sub d} = 0.207 {+-} 0.055 for the innermost planet, 'd'. In our best-fit coplanar model, the mass of the new component is m{sub e} = 14.6 {+-} 1.7 M {sub +}. Our best-fitting model places the new planet in a three-body resonance with the previously known giant planets (which have mean periods of P{sub c} = 30.4 and P{sub b} = 61.1 days). The critical argument, {psi}{sub Laplace} = {lambda} {sub c} - 3{lambda} {sub b} + 2{lambda} {sub e}, for the Laplace resonance librates with an amplitude of {Delta}{psi}{sub Laplace} = 40{sup 0} {+-} 13{sup 0} about {psi}{sub Laplace} = 0{sup 0}. Numerical integration indicates that the four-planet system is stable for at least a

  16. Modeling Mid-Ultraviolet Spectra. I. Temperatures of Metal-poor Stars

    NASA Astrophysics Data System (ADS)

    Peterson, Ruth C.; Dorman, Ben; Rood, Robert T.

    2001-09-01

    Determining the properties of remote globular clusters and elliptical galaxies using evolutionary population synthesis requires a library of reliable model stellar fluxes. Empirical libraries are limited to spectra of stars in the solar neighborhood, with nearly solar abundances and abundance ratios. We report here a first step toward providing a flux library that includes nonsolar abundances, based on calculations from first principles that are calibrated empirically. Because the mid-ultraviolet spectrum of an old stellar system is dominated by the contribution from its main-sequence turnoff stars, we have started by modeling these. We have calculated mid-ultraviolet spectra for the Sun and nine nearby, near-main-sequence stars spanning metallicities from less than 1/100 solar to greater than solar, encompassing a range of light-element-abundance enhancements. We first determined temperatures of eight of the stars by analyzing optical echelle spectra together with the mid-ultraviolet. Both could be matched at the same time only when models with no convective overshoot were adopted and only when an approximate chromosphere was incorporated near the surface of relatively metal-rich models. Extensive modifications to mid-UV line parameters were also required, notably the manual assignment of approximate identifications for mid-UV lines missing from laboratory line lists. Without recourse to additional missing opacity, these measures suffice to reproduce in detail almost the entire mid-UV spectrum of solar-temperature stars up to 1/10 solar metallicity and the region from 2900 to 3100 Å throughout the entire metallicity range. Ramifications for abundance determinations in individual metal-poor stars and for age-metallicity determinations of old stellar systems are briefly discussed, with emphasis on the predictive power of the calculations. Based on observations obtained with the Hubble Space Telescope of the Space Telescope Science Institute, under contract with the

  17. Who Really Coined the Word Supernova? Who First Predicted Neutron Stars?

    NASA Astrophysics Data System (ADS)

    Osterbrock, D. E.

    2001-12-01

    The answer to both questions is Walter Baade and Fritz Zwicky. They used the word and postulated that the remnants could be neutron stars in the abstract of their joint paper ``Supernovae and Cosmic Rays," presented orally by Zwicky at an American Physical Society meeting at Stanford in December 1933. The abstract was published in the Physical Review in early 1934, and was a condensation of their two joint papers in PNAS in 1934. The concept that there is a special class of ``much more luminous novae" (Lundmark 1923), which we today call supernovae, was put forward by Knut Lundmark (1920), who called them ``giant novae," and independently by Heber D. Curtis (1921). Hubble (1929) referred to them as ``exceptional novae," and Baade (1929), writing in German, as ``Hauptnovae" (chief novae). According to a review article by Zwicky (1940), he and Baade introduced the term supernovae in seminars and an astrophysics course at Caltech in 1931. Lundmark (1933) actually first published the word (as ``super-Novae") in a paper dated December 31, 1932 but published in 1933. He was at Lick and Mount Wilson during the fall and winter of 1932-33, and it is much more probable that he heard it there than that he coined it himself. In their abstract and PNAS papers Baade and Zwicky ``advanced the view" that supernovae represent the collapse of ``ordinary stars into neutron stars," because that gave about the right total energy released in the outburst. Many physicists believe that Lev Landau (1932) had introduced this concept, but actually his paper is about relativistically degenerate stars and does not mention neutrons, neutron stars, nor a density. Freeman Dyson (1971) in his published lectures on neutron stars and pulsars correctly credited the concept to Baade and Zwicky (1934). Extracts from these and other related papers will be posted.

  18. A Star Close Encounter

    NASA Image and Video Library

    2006-10-03

    The potential planet-forming disk (or "protoplanetary disk") of a sun-like star is being violently ripped away by the powerful winds of a nearby hot O-type star in this image from NASA's Spitzer Space Telescope. At up to 100 times the mass of sun-like stars, O stars are the most massive and energetic stars in the universe. The O star can be seen to the right of the image, as the large orange spot with the white center. To the left, the comet-like structure is actually a neighboring solar system that is being destroyed by the O star's powerful winds and intense ultraviolet light. In a process called "photoevaporation," immense output from the O star heats up the nearby protoplanetary disk so much that gas and dust boil off, and the disk can no longer hold together. Photon (or light) blasts from the O star then strip the potential planet-forming disk off its neighbor star by blowing away evaporated material. This effect is illustrated in the smaller system's comet-like structure. The system is located about 2,450 light-years away in the star-forming cloud IC 1396. The image was taken with Spitzer's multiband imaging photometer instrument at 24 microns. The picture is a pseudo-color stretch representing intensity. Yellow and white represent hot areas, whereas purple and blue represent relatively cooler, fainter regions.

  19. Star field simulator

    NASA Technical Reports Server (NTRS)

    1985-01-01

    A Star Field Simulator has been developed to serve as a source of radiation for the ASTRO Star Tracker. The star tracker and simulator are components of a motion compensation test facility located at Marshall Space Flight Center in Huntsville, Alabama. Preflight tests and simulations using various levels of guide stars are performed in the test facility to establish performance of the motion compensation system before being used in a flight environment. The ASTRO Star Tracker operates over a wide dynamic range of irradiance corresponding to visual stellar magnitudes of -0.8 to 8. A minimum of three simulated guide stars with variable magnitudes are needed to fully test the Star Tracker performance under simulated mission conditions.

  20. Spectrophotometry of Symbiotic Stars

    NASA Astrophysics Data System (ADS)

    Boyd, David

    2017-06-01

    Symbiotic stars are fascinating objects - complex binary systems comprising a cool red giant star and a small hot object, often a white dwarf, both embedded in a nebula formed by a wind from the giant star. UV radiation from the hot star ionises the nebula producing a range of emission lines. These objects have composite spectra with contributions from both stars plus the nebula and these spectra can change on many timescales. Being moderately bright, they lend themselves well to amateur spectroscopy. This paper describes the symbiotic star phenomenon, shows how spectrophotometry can be used to extract astrophysically useful information about the nature of these systems, and gives results for three symbiotic stars based on the author's observations.

  1. Ponderable soliton stars

    NASA Technical Reports Server (NTRS)

    Chiu, Hong-Yee

    1990-01-01

    The theory of Lee and Pang (1987), who obtained solutions for soliton stars composed of zero-temperature fermions and bosons, is applied here to quark soliton stars. Model soliton stars based on a simple physical model of the proton are computed, and the properties of the solitons are discussed, including the important problem of the existence of a limiting mass and thus the possible formation of black holes of primordial origin. It is shown that there is a definite mass limit for ponderable soliton stars, so that during cooling a soliton star might reach a stage beyond which no equilibrium configuration exists and the soliton star probably will collapse to become a black hole. The radiation of ponderable soliton stars may alter the short-wavelength character of the cosmic background radiation, and may be observed as highly redshifted objects at z of about 100,000.

  2. CHEMICAL ABUNDANCE ANTICORRELATIONS IN GLOBULAR CLUSTER STARS: THE EFFECT ON CLUSTER INTEGRATED SPECTRA

    SciTech Connect

    Coelho, P.; Percival, S. M.; Salaris, M. E-mail: smp@astro.livjm.ac.uk

    2011-06-10

    It is widely accepted that individual Galactic globular clusters harbor two coeval generations of stars, the first one born with the 'standard' {alpha}-enhanced metal mixture observed in field halo objects and the second one characterized by an anticorrelated CNONa abundance pattern overimposed on the first generation, {alpha}-enhanced metal mixture. We have investigated with appropriate stellar population synthesis models how this second generation of stars affects the integrated spectrum of a typical metal-rich Galactic globular cluster, like 47 Tuc, focusing our analysis on the widely used Lick-type indices. We find that the only indices appreciably affected by the abundance anticorrelations are Ca4227, G4300, CN{sub 1}, CN{sub 2}, and NaD. The age-sensitive Balmer line, Fe line, and the [MgFe] indices widely used to determine age, Fe, and total metallicity of extragalactic systems are largely insensitive to the second generation population. Enhanced He in second generation stars affects also the Balmer line indices of the integrated spectra, through the change of the turnoff temperature and-with the assumption that the mass-loss history of both stellar generations is the same-the horizontal branch morphology of the underlying isochrones.

  3. Ages and Metallicities of the Nuclei and Field Stars of Dwarf Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Henderson, Scott; Miller, B. W.; Harris, W.; Lotz, J. M.

    2007-12-01

    We present preliminary ages and metallicities for six nucleated dwarf elliptical galaxies (dE,N) in the Fornax Cluster based on Lick/IDS index measurements and SSP models. Employing IRAF and IDL routines we have successfully extracted high signal-to-noise (S/N >= 30 per Å) Gemini GMOS-S spectra of both galactic nuclei and field star regions. Extracted spectrum have a wavelength range of 3,700 Å to 6,500 Å with a resolution of 4 Å. We fit our data with empirical chemo-evolutionary models to determine radial velocity along with Hb and [MgFe]' line indices. We then compare our measurements to current SSP model predictions by Bruzual & Charlot (2003) to determine age and metallicity. Results suggest that the dE nuclei have intermediate ages ( 5 Gyr) and less than solar metallicities ([Fe/H] <= -0.64dex). Comparing nuclei and dE field star spectra, we find evidence that in general the nuclei have undergone more recent star formation. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: The National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

  4. Spectroscopic study of formation, evolution and interaction of M31 and M33 with star clusters

    NASA Astrophysics Data System (ADS)

    Fan, Zhou; Yang, Yanbin

    2016-02-01

    The recent studies show that the formation and evolution process of the nearby galaxies are still unclear. By using the Canada France Hawaii Telescope (CFHT) 3.6m telescope, the PanDAS shows complicated substructures (dwarf satellite galaxies, halo globular clusters, extended clusters, star streams, etc.) in the halo of M31 to ~150 kpc from the center of galaxy and M31-M33 interaction has been studied. In our work, we would like to investigate formation, evolution and interaction of M31 and M33, which are the nearest two spiral galaxies in Local Group. The star cluster systems of the two galaxies are good tracers to study the dynamics of the substructures and the interaction. Since 2010, the Xinglong 2.16m, Lijiang 2.4m and MMT 6.5m telescopes have been used for our spectroscopic observations. The radial velocities and Lick absorption-line indices can thus be measured with the spectroscopy and then ages, metallicities and masses of the star clusters can be fitted with the simple stellar population models. These parameters could be used as the input physical parameters for numerical simulations of M31-M33 interaction.

  5. Taste coding of complex naturalistic taste stimuli and traditional taste stimuli in the parabrachial pons of the awake, freely licking rat.

    PubMed

    Sammons, Joshua D; Weiss, Michael S; Victor, Jonathan D; Di Lorenzo, Patricia M

    2016-07-01

    Several studies have shown that taste-responsive cells in the brainstem taste nuclei of rodents respond to sensory qualities other than gustation. Such data suggest that cells in the classical gustatory brainstem may be better tuned to respond to stimuli that engage multiple sensory modalities than to stimuli that are purely gustatory. Here, we test this idea by recording the electrophysiological responses to complex, naturalistic stimuli in single neurons in the parabrachial pons (PbN, the second neural relay in the central gustatory pathway) in awake, freely licking rats. Following electrode implantation and recovery, we presented both prototypical and naturalistic taste stimuli and recorded the responses in the PbN. Prototypical taste stimuli (NaCl, sucrose, citric acid, and caffeine) and naturalistic stimuli (clam juice, grape juice, lemon juice, and coffee) were matched for taste quality and intensity (concentration). Umami (monosodium glutamate + inosine monophosphate) and fat (diluted heavy cream) were also tested. PbN neurons responded to naturalistic stimuli as much or more than to prototypical taste stimuli. Furthermore, they convey more information about naturalistic stimuli than about prototypical ones. Moreover, multidimensional scaling analyses showed that across unit responses to naturalistic stimuli were more widely separated than responses to prototypical taste stimuli. Interestingly, cream evoked a robust and widespread response in PbN cells. Collectively, these data suggest that natural foods are more potent stimulators of PbN cells than purely gustatory stimuli. Probing PbN cells with pure taste stimuli may underestimate the response repertoire of these cells. Copyright © 2016 the American Physiological Society.

  6. An RR Lyrae survey with the Lick astrograph. V - A survey of three fields at intermediate latitudes towards the galactic anticenter

    NASA Astrophysics Data System (ADS)

    Kinman, T. D.; Mahaffey, C. T.; Wirtanen, C. A.

    1982-02-01

    Photometric data, positions, and finding charts are given for 62 variables in three astrograph fields covering 84 square degrees at galactic latitudes - 18°, +26°, and +36° towards the anticenter. These variables have mean photographic magnitudes in the range 11.2 < mpg < 17.9. Nineteen of these are RR Lyrae stars of the type ab stars. Photoelectric observations are given for all the RR Lyrae stars and their B - V colors at minimum light are used in a discussion of the extinctions in these fields. Spectroscopic observations of 26 of the variables (predominantly the RR Lyrae stars) are described in an accompanying paper by Butler, Kemper, Kraft, and Suntzeff (1982). It is found that the RR Lyrae stars in these anticenter fields and at the north galactic pole show a significant deficiency of very metal-poor members (with [Fe/H] < - 1.6) if compared with samples of globular clusters or a sample of nearby subdwarfs, and the reasons are discussed. Despite this disadvantage, the absolute brightness of the RR Lyrae stars and their characteristic light variations which enable them to be recognized with a high degree of completeness at great distances, continue to make them important tracers of the structure of the galactic halo.

  7. Massive Compact Stars as Quark Stars

    NASA Astrophysics Data System (ADS)

    Rodrigues, Hilário; Barbosa Duarte, Sérgio; de Oliveira, José Carlos T.

    2011-03-01

    High-mass compact stars have been reported recently in the literature, providing strong constraints on the properties of the ultra dense matter beyond the saturation nuclear density. In view of these results, the calculations of quark star or hybrid star equilibrium structure must be compatible with the provided observational data. But since the equations of state used in describing quark matter are in general too soft in comparison with the equation of states used to describe the hadronic or nuclear matter, the calculated quark star models presented in the literature are in general not suitable to explain the stability of highly-compact massive objects. In this work, we present the calculations of a spherically symmetric quark star structure by using an equation of state that takes into account the superconducting color-flavor locked phase of the strange quark matter. In addition, some fundamental aspects of QCD (asymptotic freedom and confinement) are considered by means of a phenomenological description of the deconfined quark phase, the density-dependent quark mass model. The quark matter behavior introduced by this model stiffens the corresponding equation of state. We thus investigate the influence of this model on the mass-radius diagram of quark stars. We obtain massive quark stars due to the stiffness of the equation of state, when a reasonable parameterization of the color superconducting gap is used. Models of quark stars enveloped by a nucleonic crust composed of a nuclear lattice embedded in an electron gas, with nuclei close to neutron drip line, are also discussed.

  8. Star Clusters within FIRE

    NASA Astrophysics Data System (ADS)

    Perez, Adrianna; Moreno, Jorge; Naiman, Jill; Ramirez-Ruiz, Enrico; Hopkins, Philip F.

    2017-01-01

    In this work, we analyze the environments surrounding star clusters of simulated merging galaxies. Our framework employs Feedback In Realistic Environments (FIRE) model (Hopkins et al., 2014). The FIRE project is a high resolution cosmological simulation that resolves star forming regions and incorporates stellar feedback in a physically realistic way. The project focuses on analyzing the properties of the star clusters formed in merging galaxies. The locations of these star clusters are identified with astrodendro.py, a publicly available dendrogram algorithm. Once star cluster properties are extracted, they will be used to create a sub-grid (smaller than the resolution scale of FIRE) of gas confinement in these clusters. Then, we can examine how the star clusters interact with these available gas reservoirs (either by accreting this mass or blowing it out via feedback), which will determine many properties of the cluster (star formation history, compact object accretion, etc). These simulations will further our understanding of star formation within stellar clusters during galaxy evolution. In the future, we aim to enhance sub-grid prescriptions for feedback specific to processes within star clusters; such as, interaction with stellar winds and gas accretion onto black holes and neutron stars.

  9. Dark stars: a review.

    PubMed

    Freese, Katherine; Rindler-Daller, Tanja; Spolyar, Douglas; Valluri, Monica

    2016-06-01

    Dark stars are stellar objects made (almost entirely) of hydrogen and helium, but powered by the heat from dark matter annihilation, rather than by fusion. They are in hydrostatic and thermal equilibrium, but with an unusual power source. Weakly interacting massive particles (WIMPs), among the best candidates for dark matter, can be their own antimatter and can annihilate inside the star, thereby providing a heat source. Although dark matter constitutes only [Formula: see text]0.1% of the stellar mass, this amount is sufficient to power the star for millions to billions of years. Thus, the first phase of stellar evolution in the history of the Universe may have been dark stars. We review how dark stars come into existence, how they grow as long as dark matter fuel persists, and their stellar structure and evolution. The studies were done in two different ways, first assuming polytropic interiors and more recently using the MESA stellar evolution code; the basic results are the same. Dark stars are giant, puffy (∼10 AU) and cool (surface temperatures  ∼10 000 K) objects. We follow the evolution of dark stars from their inception at  ∼[Formula: see text] as they accrete mass from their surroundings to become supermassive stars, some even reaching masses  >[Formula: see text] and luminosities  >[Formula: see text], making them detectable with the upcoming James Webb Space Telescope. Once the dark matter runs out and the dark star dies, it may collapse to a black hole; thus dark stars may provide seeds for the supermassive black holes observed throughout the Universe and at early times. Other sites for dark star formation may exist in the Universe today in regions of high dark matter density such as the centers of galaxies. The current review briefly discusses dark stars existing today, but focuses on the early generation of dark stars.

  10. Dark stars: a review

    NASA Astrophysics Data System (ADS)

    Freese, Katherine; Rindler-Daller, Tanja; Spolyar, Douglas; Valluri, Monica

    2016-06-01

    Dark stars are stellar objects made (almost entirely) of hydrogen and helium, but powered by the heat from dark matter annihilation, rather than by fusion. They are in hydrostatic and thermal equilibrium, but with an unusual power source. Weakly interacting massive particles (WIMPs), among the best candidates for dark matter, can be their own antimatter and can annihilate inside the star, thereby providing a heat source. Although dark matter constitutes only ≲ 0.1% of the stellar mass, this amount is sufficient to power the star for millions to billions of years. Thus, the first phase of stellar evolution in the history of the Universe may have been dark stars. We review how dark stars come into existence, how they grow as long as dark matter fuel persists, and their stellar structure and evolution. The studies were done in two different ways, first assuming polytropic interiors and more recently using the MESA stellar evolution code; the basic results are the same. Dark stars are giant, puffy (˜10 AU) and cool (surface temperatures  ˜10 000 K) objects. We follow the evolution of dark stars from their inception at  ˜1{{M}⊙} as they accrete mass from their surroundings to become supermassive stars, some even reaching masses  >{{10}6}{{M}⊙} and luminosities  >{{10}10}{{L}⊙} , making them detectable with the upcoming James Webb Space Telescope. Once the dark matter runs out and the dark star dies, it may collapse to a black hole; thus dark stars may provide seeds for the supermassive black holes observed throughout the Universe and at early times. Other sites for dark star formation may exist in the Universe today in regions of high dark matter density such as the centers of galaxies. The current review briefly discusses dark stars existing today, but focuses on the early generation of dark stars.

  11. STAR in CTO PCI: When is STAR not a star?

    PubMed

    Hira, Ravi S; Dean, Larry S

    2016-04-01

    Subintimal tracking and reentry (STAR) has been used as a bailout strategy and involves an uncontrolled dissection and recanalization into the distal lumen to reestablish vessel patency. In the current study, thrombolysis in myocardial infarction (TIMI) flow < 3 was the only variable which they found to be significantly associated with restenosis and reocclusion after stent placement. It may be reasonable to consider second generation drug eluting stent placement in patients receiving STAR that have TIMI 3 flow, however, this should only be done if there is no compromise of major side branches. If unsure, we recommend to perform balloon angioplasty without stenting. © 2016 Wiley Periodicals, Inc.

  12. The First Stars

    NASA Astrophysics Data System (ADS)

    Yoshida, Naoki

    2010-10-01

    The standard cosmological model predicts that the first cosmological objects are formed when the age of the universe is a few hundred million years. Recent theoretical studies and numerical simulations consistently suggest that the first objects are very massive primordial stars. We introduce the key physics and explain why the first stars are thought to be massive, rather than to be low-mass stars. The state-of-the-art simulations include all the relevant atomic and molecular physics to follow the thermal evolution of a prestellar gas cloud to very high ``stellar'' densities. Evolutionary calculations of the primordial stars suggest the formation of massive blackholes in the early universe. Finally, we show the results from high-resolution simulations of star formation in a low-metallicity gas. Vigorous fragmentation is triggered in a star-forming gas cloud at a metallicity of as low as Z = 10-5Zsolar.

  13. Equilibrium Star Cluster Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan C.; Krumholz, Mark R.; McKee, Christopher F.

    2006-04-01

    We argue that rich star clusters take at least several local dynamical times to form and so are quasi-equilibrium structures during their assembly. Observations supporting this conclusion include morphologies of star-forming clumps, momentum flux of protostellar outflows from forming clusters, age spreads of stars in the Orion Nebula cluster (ONC) and other clusters, and the age of a dynamical ejection event from the ONC. We show that these long formation timescales are consistent with the expected star formation rate in turbulent gas, as recently evaluated by Krumholz & McKee. Finally, we discuss the implications of these timescales for star formation efficiencies, the disruption of gas by stellar feedback, mass segregation of stars, and the longevity of turbulence in molecular clumps.

  14. Age-Defying Star

    NASA Image and Video Library

    2016-08-29

    An age-defying star called IRAS 19312+1950 exhibits features characteristic of a very young star and a very old star. The object stands out as extremely bright inside a large, chemically rich cloud of material, as shown in this image from NASA's Spitzer Space Telescope. IRAS 19312+1950 is the bright red star in the center of this image. A NASA-led team of scientists thinks the star -- which is about 10 times as massive as our sun and emits about 20,000 times as much energy -- is a newly forming protostar. That was a big surprise, because the region had not been known as a stellar nursery before. But the presence of a nearby interstellar bubble, which indicates the presence of a recently formed massive star, also supports this idea. http://photojournal.jpl.nasa.gov/catalog/PIA20914

  15. Toward Understanding the B[e] Phenomenon. II. New Galactic FS CMa Stars

    NASA Astrophysics Data System (ADS)

    Miroshnichenko, A. S.; Manset, N.; Kusakin, A. V.; Chentsov, E. L.; Klochkova, V. G.; Zharikov, S. V.; Gray, R. O.; Grankin, K. N.; Gandet, T. L.; Bjorkman, K. S.; Rudy, R. J.; Lynch, D. K.; Venturini, C. C.; Mazuk, S.; Puetter, R. C.; Perry, R. B.; Levato, H.; Grosso, M.; Bernabei, S.; Polcaro, V. F.; Viotti, R. F.; Norci, L.; Kuratov, K. S.

    2007-12-01

    FS CMa stars form a group of objects with the B[e] phenomenon that were previously known as unclassified B[e] stars or B[e] stars with warm dust (B[e]WD) until recently. They exhibit strong emission-line spectra and strong IR excesses, most likely due to recently formed circumstellar dust. These properties have been suggested to be due to ongoing or recent rapid mass exchange in binary systems with hot primaries and various types of secondaries. The first paper of this series reported an analysis of the available information about previously known Galactic objects with the B[e] phenomenon, the initial selection of the FS CMa group objects, and a qualitative explanation of their properties. This paper reports the results of our new search for more FS CMa objects in the IRAS Point Source Catalog. We present new photometric criteria for identifying FS CMa stars as well as the first results of our observations of nine new FS CMa group members. With this addition, the FS CMa group has now 40 members, becoming the largest among the dust-forming hot star groups. We also present nine objects with no evidence for the B[e] phenomenon, but with newly discovered spectral line emission and/or strong IR excesses. Partially based on data obtained at the 6 m BTA Telescope of the Russian Academy of Sciences, 3.6 m Canada-France-Hawaii Telescope, 3 m Shane Telescope of the Lick Observatory, 2.7 m Harlan J. Smith and 2.1 m Otto Struve Telescopes of the McDonald Observatory, 2.1 m telescope of the San Pedro Martir Observatory, 1.5 m telescope of the Loiano Observatory, and 0.8 m telescope of the Dark Sky Observatory.

  16. SIRTF and star formation

    NASA Technical Reports Server (NTRS)

    Shu, Frank H.

    1988-01-01

    Four problems in the field of star formation that can be attacked to advantage with SIRTF are discussed: (1) the patterns of star formation in spiral galaxies, (2) the physical mechanism for bimodal star formation, (3) the nature of bipolar outflows from young stellar objects, and (4) the birth of brown dwarfs. In each case, SIRTF can provide the crucial combination of high angular resolution with great sensitivity over a broad range of wavelengths that is needed to address the relevant issues.

  17. Strange nonchaotic stars.

    PubMed

    Lindner, John F; Kohar, Vivek; Kia, Behnam; Hippke, Michael; Learned, John G; Ditto, William L

    2015-02-06

    The unprecedented light curves of the Kepler space telescope document how the brightness of some stars pulsates at primary and secondary frequencies whose ratios are near the golden mean, the most irrational number. A nonlinear dynamical system driven by an irrational ratio of frequencies generically exhibits a strange but nonchaotic attractor. For Kepler's "golden" stars, we present evidence of the first observation of strange nonchaotic dynamics in nature outside the laboratory. This discovery could aid the classification and detailed modeling of variable stars.

  18. The Theatre of stars

    NASA Astrophysics Data System (ADS)

    Cavedon, M.; Peri, F.

    Planetariums are special instruments in education and didactics of Astronomy and Astrophysics. Since 1930 the Planetarium of Milan, the most important planetarium in Italy, has played a fundamental role in outreach to the public. Italian tradition always preferred didactics in ``live'' lessons. Now technology expands the potential of the star projector and the theatre of stars is a real window on the universe, where you can travel among the stars and galaxies, to reach the boundaries of space and time.

  19. Nagyszombat and the stars

    NASA Astrophysics Data System (ADS)

    Zsoldos, E.

    Péter Pázmány, founder of the University of Nagyszombat, considered stars in terms inherited from medieval times. The theses, connected to the university graduation, soon left this definition, and imagined stars as made from sublunar elements. The 1753 decree of the Empress Maria Theresia ordered university professors to publish textbooks. These textbooks, together with the theses showed a definite improvement, defining stars according to contemporary knowledge.

  20. Assessing the fundamental limits of multiple star formation: An imaging search for the lowest mass stellar companions to intermediate-mass stars

    NASA Astrophysics Data System (ADS)

    Duchene, Gaspard; Tzern Oon, Jner; Kantorski, Patrick; De Rosa, Robert J.; Thomas, Sandrine; Patience, Jennifer; Pueyo, Laurent; Nielsen, Eric L.; Konopacky, Quinn M.

    2017-01-01

    Stellar binaries are a common byproduct of star formation and therefore inform us on the processes of collapse and fragmentation of prestellar cores. While multiplicity surveys generally reveal an extensive diversity of multiple systems, with broad ranges of semi-major axis, mass ratio and eccentricities, one remarkable feature that was identified in the last two decades is the so-called brown dwarf desert, i.e., the apparent paucity of (non-planetary) substellar companions to solar-type stars. This "desert" was primarily identified among spectroscopic binaries but also appears to be a significant feature of wider, visual binaries. The physical origin of this feature has not been fully accounted for but is likely established during the formation of the systems. One way to shed new light on this question is to study the frequency of low-mass stellar companions to intermediate-mass star (late-B type, or 3-5 Msun), as those form through a similar, albeit scaled-up, mechanism as solar-type stars. Here we present preliminary results from two adaptive-optics based surveys to search for such multiple systems. Specifically, we are using the new ShaneAO system on the Lick3m telescope (~100 stars observed to date) and the Gemini Planet Imager (45 stars observed). We are targeting stars located both in open clusters and scattered in the Galactic field to search for potential evidence of dynamic evolution. To identify candidate low-mass companions as close in to target stars, we use advanced point spread function (PSF) subtraction algorithms, specifically implementations of the LOCI and KLIP algorithms. In the case of the ShaneAO observations, which do not allow for field rotation, we use LOCI in combination with Reference Differential Imaging (ADI), using our library of science images as input for PSF subtraction. In this contribution, we will discuss the potential of ShaneAO to reveal faint, subarcsecond companions in this context and present candidate companions from both

  1. Strangeon and Strangeon Star

    NASA Astrophysics Data System (ADS)

    Xiaoyu, Lai; Renxin, Xu

    2017-06-01

    The nature of pulsar-like compact stars is essentially a central question of the fundamental strong interaction (explained in quantum chromo-dynamics) at low energy scale, the solution of which still remains a challenge though tremendous efforts have been tried. This kind of compact objects could actually be strange quark stars if strange quark matter in bulk may constitute the true ground state of the strong-interaction matter rather than 56Fe (the so-called Witten’s conjecture). From astrophysical points of view, however, it is proposed that strange cluster matter could be absolutely stable and thus those compact stars could be strange cluster stars in fact. This proposal could be regarded as a general Witten’s conjecture: strange matter in bulk could be absolutely stable, in which quarks are either free (for strange quark matter) or localized (for strange cluster matter). Strange cluster with three-light-flavor symmetry is renamed strangeon, being coined by combining “strange nucleon” for the sake of simplicity. A strangeon star can then be thought as a 3-flavored gigantic nucleus, and strangeons are its constituent as an analogy of nucleons which are the constituent of a normal (micro) nucleus. The observational consequences of strangeon stars show that different manifestations of pulsarlike compact stars could be understood in the regime of strangeon stars, and we are expecting more evidence for strangeon star by advanced facilities (e.g., FAST, SKA, and eXTP).

  2. Delta Scuti stars: Theory

    NASA Technical Reports Server (NTRS)

    Guzik, J. A.

    1998-01-01

    The purpose of asteroseismology is not only to derive the internal structure of individual stars from their observed oscillation frequencies, but also to test and extend one's understanding of the physics of matter under the extremes of temperature, density, and pressure found in stellar interiors. In this review, the author hopes to point out what one can learn about the Sun by studying (delta) Scuti stars, as well as what one can learn about stars more massive or evolved than the Sun. He discusses some of the difficulties in theoretical approaches to asteroseismology for (delta) Scuti stars, using FG Vir, (delta) Scuti, and CD-24(degree) 7599 as examples.

  3. Massive soliton stars

    NASA Astrophysics Data System (ADS)

    Chiu, Hong-Yee

    1990-05-01

    The structure of nontopological solutions of Einstein field equations as proposed by Friedberg, Lee, and Pang (1987) is examined. This analysis incorporates finite temperature effects and pair creation. Quarks are assumed to be the only species that exist in interior of soliton stars. The possibility of primordial creation of soliton stars in the incomplete decay of the degenerate vacuum in early universe is explored. Because of dominance of pair creation inside soliton stars, the luminosity of soliton stars is not determined by its radiative transfer characteristics, and the surface temperature of soliton stars can be the same as its interior temperature. It is possible that soliton stars are intense X-ray radiators at large distances. Soliton stars are nearly 100 percent efficient energy converters, converting the rest energy of baryons entering the interior into radiation. It is possible that a sizable number of baryons may also be trapped inside soliton stars during early epochs of the universe. In addition, if soliton stars exist they could assume the role played by massive black holes in galactic centers.

  4. Massive soliton stars

    NASA Technical Reports Server (NTRS)

    Chiu, Hong-Yee

    1990-01-01

    The structure of nontopological solutions of Einstein field equations as proposed by Friedberg, Lee, and Pang (1987) is examined. This analysis incorporates finite temperature effects and pair creation. Quarks are assumed to be the only species that exist in interior of soliton stars. The possibility of primordial creation of soliton stars in the incomplete decay of the degenerate vacuum in early universe is explored. Because of dominance of pair creation inside soliton stars, the luminosity of soliton stars is not determined by its radiative transfer characteristics, and the surface temperature of soliton stars can be the same as its interior temperature. It is possible that soliton stars are intense X-ray radiators at large distances. Soliton stars are nearly 100 percent efficient energy converters, converting the rest energy of baryons entering the interior into radiation. It is possible that a sizable number of baryons may also be trapped inside soliton stars during early epochs of the universe. In addition, if soliton stars exist they could assume the role played by massive black holes in galactic centers.

  5. Delta Scuti stars: Theory

    SciTech Connect

    Guzik, J.A.

    1998-03-01

    The purpose of asteroseismology is not only to derive the internal structure of individual stars from their observed oscillation frequencies, but also to test and extend one`s understanding of the physics of matter under the extremes of temperature, density, and pressure found in stellar interiors. In this review, the author hopes to point out what one can learn about the Sun by studying {delta} Scuti stars, as well as what one can learn about stars more massive or evolved than the Sun. He discusses some of the difficulties in theoretical approaches to asteroseismology for {delta} Scuti stars, using FG Vir, {delta} Scuti, and CD-24{degree} 7599 as examples.

  6. Introduction to neutron stars

    SciTech Connect

    Lattimer, James M.

    2015-02-24

    Neutron stars contain the densest form of matter in the present universe. General relativity and causality set important constraints to their compactness. In addition, analytic GR solutions are useful in understanding the relationships that exist among the maximum mass, radii, moments of inertia, and tidal Love numbers of neutron stars, all of which are accessible to observation. Some of these relations are independent of the underlying dense matter equation of state, while others are very sensitive to the equation of state. Recent observations of neutron stars from pulsar timing, quiescent X-ray emission from binaries, and Type I X-ray bursts can set important constraints on the structure of neutron stars and the underlying equation of state. In addition, measurements of thermal radiation from neutron stars has uncovered the possible existence of neutron and proton superfluidity/superconductivity in the core of a neutron star, as well as offering powerful evidence that typical neutron stars have significant crusts. These observations impose constraints on the existence of strange quark matter stars, and limit the possibility that abundant deconfined quark matter or hyperons exist in the cores of neutron stars.

  7. Ecospheres around binary stars

    NASA Astrophysics Data System (ADS)

    Deka, B.

    2011-01-01

    Scientific investigations concerning ecospheres of other stars are very important for understanding the posibilities of existence and evolution of extraterrestrial life. In several last years astronomers discovered hundreds of extrasolar planets. Identification of stars with ecospheres is the first step in selecting those planets which could be inhabited. Usually an ecosphere of a single star is considered but it may also exist in planetary systems with two suns. This possibility is very promising in search for life on other planets as more that 60 % of stars reside in binary or multiple systems.

  8. Massive soliton stars

    NASA Technical Reports Server (NTRS)

    Chiu, Hong-Yee

    1990-01-01

    The structure of nontopological solutions of Einstein field equations as proposed by Friedberg, Lee, and Pang (1987) is examined. This analysis incorporates finite temperature effects and pair creation. Quarks are assumed to be the only species that exist in interior of soliton stars. The possibility of primordial creation of soliton stars in the incomplete decay of the degenerate vacuum in early universe is explored. Because of dominance of pair creation inside soliton stars, the luminosity of soliton stars is not determined by its radiative transfer characteristics, and the surface temperature of soliton stars can be the same as its interior temperature. It is possible that soliton stars are intense X-ray radiators at large distances. Soliton stars are nearly 100 percent efficient energy converters, converting the rest energy of baryons entering the interior into radiation. It is possible that a sizable number of baryons may also be trapped inside soliton stars during early epochs of the universe. In addition, if soliton stars exist they could assume the role played by massive black holes in galactic centers.

  9. Charged Proca stars

    NASA Astrophysics Data System (ADS)

    Landea, Ignacio Salazar; García, Federico

    2016-11-01

    In this paper, we study gauged solutions associated with a massive vector field representing a spin-1 condensate, namely, the Proca field. We focus on regular spherically symmetric solutions which we construct either using a self-interaction potential or general relativity in order to glue the solutions together. We start generating nongravitating solutions—so-called Proca Q -balls and charged Proca Q -balls. Then we turn on backreaction on the metric, allowing gravity to hold together the Proca condensate, to study the so-called Proca stars, charged Proca stars, Proca Q -stars, and charged Proca Q -stars.

  10. Delta Scuti stars: Theory

    NASA Technical Reports Server (NTRS)

    Guzik, J. A.

    1998-01-01

    The purpose of asteroseismology is not only to derive the internal structure of individual stars from their observed oscillation frequencies, but also to test and extend one's understanding of the physics of matter under the extremes of temperature, density, and pressure found in stellar interiors. In this review, the author hopes to point out what one can learn about the Sun by studying (delta) Scuti stars, as well as what one can learn about stars more massive or evolved than the Sun. He discusses some of the difficulties in theoretical approaches to asteroseismology for (delta) Scuti stars, using FG Vir, (delta) Scuti, and CD-24(degree) 7599 as examples.

  11. Strange Nonchaotic Stars

    NASA Astrophysics Data System (ADS)

    Lindner, John F.; Kohar, Vivek; Kia, Behnam; Hippke, Michael; Learned, John G.; Ditto, William L.

    2015-08-01

    Exploiting the unprecedented capabilities of the planet-hunting Kepler space telescope, which stared at 150 000 stars for four years, we discuss recent evidence that certain stars dim and brighten in complex patterns with fractal features. Such stars pulsate at primary and secondary frequencies whose ratios are near the famous golden mean, the most irrational number. A nonlinear system driven by an irrational ratio of frequencies is generically attracted toward a “strange” behavior that is geometrically fractal without displaying the “butterfly effect” of chaos. Strange nonchaotic attractors have been observed in laboratory experiments and have been hypothesized to describe the electrochemical activity of the brain, but a bluish white star 16 000 light years from Earth in the constellation Lyra may manifest, in the scale-free distribution of its minor frequency components, the first strange nonchaotic attractor observed in the wild. The recognition of stellar strange nonchaotic dynamics may improve the classification of these stars and refine the physical modeling of their interiors. We also discuss nonlinear analysis of other RR Lyrae stars in Kepler field of view and discuss some toy models for modeling these stars.References: 1) Hippke, Michael, et al. "Pulsation period variations in the RRc Lyrae star KIC 5520878." The Astrophysical Journal 798.1 (2015): 42.2) Lindner, John F., et al. "Strange nonchaotic stars." Phys. Rev. Lett. 114, 054101 (2015)

  12. Combinations of 148 navigation stars and the star tracker

    NASA Technical Reports Server (NTRS)

    Duncan, R.

    1980-01-01

    The angular separation of all star combinations for 148 nav star on the onboard software for space transportation system-3 flight and following missions is presented as well as the separation of each pair that satisfies the viewing constraints of using both star trackers simultaneously. Tables show (1) shuttle star catalog 1980 star position in M 1950 coordinates; (2) two star combination of 148 nav stars; and (3) summary of two star-combinations of the star tracker 5 deg filter. These 148 stars present 10,875 combinations. For the star tracker filters of plus or minus 5 deg, there are 875 combinations. Formalhaut (nav star 26) has the best number of combinations, which is 33.

  13. Star formation history of early-type galaxies in low density environments. I. Nuclear line-strength indices

    NASA Astrophysics Data System (ADS)

    Longhetti, M.; Rampazzo, R.; Bressan, A.; Chiosi, C.

    1998-06-01

    This paper is the first of a series \\cite[(Longhetti et al. 1997a,b)]{lon97} dedicated to the study of the star formation history in early-type galaxies which show fine structures and/or signatures of interaction. It presents nuclear line-strength indices for a sample composed of 21 shell galaxies, from the \\cite[Malin & Carter (1983)]{mal83} southern survey, and 30 members of isolated interacting pairs, from the \\cite[Reduzzi & Rampazzo (1995)]{red95} catalogue, located in low density environments. The spectral range covers 3700 Angstroms < lambda < 5700 Angstroms at 2.1 Angstroms FWHM resolution. We measure 16 red (lambda > 4200 Angstroms) indices defined by the Lick Group. Measures have been transformed into the Lick-IDS ``standard'' system. The procedure has been tested on a set of 5 elliptical galaxies selected from the \\cite[Gonzalez (1993)]{gon93} sample. We derive also three blue (lambda < 4200) indices, namely Delta (4000 Angstroms) defined by \\cite[Hamilton (1985)]{ham85}, H+K(CaII) and Hdelta /FeI defined by \\cite[Rose (1984, 1985)]{ros84}. Blue indices are correlated to the age of the last starburst occurred in a galaxy \\cite[(Leonardi & Rose 1996)]{leo96}. The determination of these indices, the estimate of the measurement errors and the correction for the galaxies velocity dispersions are discussed in detail. In the Appendix A we present the indices for a set of hot stars (T> 10000 K) which may be used for extending W92 fitting functions toward high temperatures. Based on observations obtained at ESO, La Silla, Chile. Tables 1-8 are also available in electronic form at CDS and Tables 9-15 are only available in electronic form at CDS: via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  14. GLOBAL STAR FORMATION REVISITED

    SciTech Connect

    Silk, Joseph; Norman, Colin E-mail: norman@stsci.edu

    2009-07-20

    A general treatment of disk star formation is developed from a dissipative multiphase model, with the dominant dissipation due to cloud collisions. The Schmidt-Kennicutt (SK) law emerges naturally for star-forming disks and starbursts. We predict that there should be an inverse correlation between Tully-Fisher law and SK law residuals. The model is extended to include a multiphase treatment of supernova feedback that leads to a turbulent pressure-regulated generalization of the star formation law and is applicable to gas-rich starbursts. Enhanced pressure, as expected in merger-induced star formation, enhances star formation efficiency. An upper limit is derived for the disk star formation rate in starbursts that depends on the ratio of global ISM to cloud pressures. We extend these considerations to the case where the interstellar gas pressure in the inner galaxy is dominated by outflows from a central active galactic nucleus (AGN). During massive spheroid formation, AGN-driven winds trigger star formation, resulting in enhanced supernova feedback and outflows. The outflows are comparable to the AGN-boosted star formation rate and saturate in the super-Eddington limit. Downsizing of both SMBH and spheroids is a consequence of AGN-driven positive feedback. Bondi accretion feeds the central black hole with a specific accretion rate that is proportional to the black hole mass. AGN-enhanced star formation is mediated by turbulent pressure and relates spheroid star formation rate to black hole accretion rate. The relation between black hole mass and spheroid velocity dispersion has a coefficient (Salpeter time to gas consumption time ratio) that provides an arrow of time. Highly efficient, AGN-boosted star formation can occur at high redshift.

  15. Stars Brewing in Cygnus X

    NASA Image and Video Library

    2012-01-10

    A bubbling cauldron of star birth is highlighted in this image from NASA Spitzer Space Telescope. Massive stars have blown bubbles, or cavities, in the dust and gas -- a violent process that triggers both the death and birth of stars.

  16. Cooking up the First Stars

    NASA Image and Video Library

    2011-11-10

    Scientists are simulating how the very first stars in our universe were born. The stars we see today formed out of collapsing clouds of gas and dust. In the very early universe, however, the stars had fewer ingredients available.

  17. Observations of FK Comae stars

    NASA Technical Reports Server (NTRS)

    Bopp, B. W.

    1981-01-01

    Observations on the FK Comae stars are described. FK Com, UZ Lib and HD 199178 are compared and related as a group of stars. The crucial observational tests of the proposed evolutionary status of these stars are noted.

  18. Neutron Star Compared to Manhattan

    NASA Image and Video Library

    A pulsar is a neutron star, the crushed core of a star that has exploded. Neutron stars crush half a million times more mass than Earth into a sphere no larger than Manhattan, as animated in this s...

  19. Star Trek in the Schools

    ERIC Educational Resources Information Center

    Journal of Aerospace Education, 1977

    1977-01-01

    Describes specific educational programs for using the Star Trek TV program from kindergarten through college. For each grade level lesson plans, ideas for incorporating Star Trek into future classes, and reports of specific programs utilizing Star Trek are provided. (SL)

  20. Hybrid stars that masquerade as neutron stars

    SciTech Connect

    Mark Paris; Mark Alford; Matt Braby; Sanjay Reddy

    2004-11-01

    We show that a hybrid (nuclear + quark matter) star can have a mass-radius relationship very similar to that predicted for a star made of purely nucleonic matter. We show this for a generic parameterization of the quark matter equation of state, and also for an MIT bag model, each including a phenomenological correction based on gluonic corrections to the equation of state. We obtain hybrid stars as heavy as 2 M{sub solar} for reasonable values of the bag model parameters. For nuclear matter, we use the equation of state calculated by Akmal, Pandharipande, and Ravenhall using many-body techniques. Both mixed and homogeneous phases of nuclear and quark matter are considered.

  1. Stars and Flowers, Flowers and Stars

    NASA Astrophysics Data System (ADS)

    Minti, Hari

    2012-12-01

    The author, a graduated from the Bucharest University (1964), actually living and working in Israel, concerns his book to variable stars and flowers, two domains of his interest. The analogies includes double stars, eclipsing double stars, eclipses, Big Bang. The book contains 34 chapters, each of which concerns various relations between astronomy and other sciences and pseudosciences such as Psychology, Religion, Geology, Computers and Astrology (to which the author is not an adherent). A special part of the book is dedicated to archeoastronomy and ethnoastronomy, as well as to history of astronomy. Between the main points of interest of these parts: ancient sanctuaries in Sarmizegetusa (Dacia), Stone Henge(UK) and other. The last chapter of the book is dedicated to flowers. The book is richly illustrated. It is designed for a wide circle of readers.

  2. Nuclear Star Clusters

    NASA Astrophysics Data System (ADS)

    Neumayer, Nadine

    2017-03-01

    The centers of galaxies host two distinct, compact components: massive black holes and nuclear star clusters. Nuclear star clusters are the densest stellar systems in the universe, with masses of ~ 107M⊙ and sizes of ~ 5pc. They are almost ubiquitous at the centres of nearby galaxies with masses similar to, or lower than the Milky Way. Their occurrence both in spirals and dwarf elliptical galaxies appears to be a strong function of total galaxy light or mass. Nucleation fractions are up to 100% for total galaxy magnitudes of M B = -19mag or total galaxy luminosities of about L B = 1010 L ⊙ and falling nucleation fractions for both smaller and higher galaxy masses. Although nuclear star clusters are so common, their formation mechanisms are still under debate. The two main formation scenarios proposed are the infall and subsequent merging of star clusters and the in-situ formation of stars at the center of a galaxy. Here, I review the state-of-the-art of nuclear star cluster observations concerning their structure, stellar populations and kinematics. These observations are used to constrain the proposed formation scenarios for nuclear star clusters. Constraints from observations show, that likely both cluster infall and in-situ star formation are at work. The relative importance of these two mechanisms is still subject of investigation.

  3. Dusty Dead Star

    NASA Image and Video Library

    2010-03-29

    A composite image from NASA Chandra and Spitzer space telescopes shows the dusty remains of a collapsed star, a supernova remnant called G54.1+0.3. The white source at the center is a dead star called a pulsar.

  4. Magnetized Compact Stars

    NASA Astrophysics Data System (ADS)

    Pérez Martínez, Aurora; González Felipe, Ricardo; Manreza Paret, Daryel

    2015-01-01

    The magnetized color flavor locked matter phase can be more stable than the unpaired phase, thus becoming the ground state inside neutron stars. In the presence of a strong magnetic field, there exist an anisotropy in the pressures. We estimate the mass-radius relation of magnetized compact stars taking into account the parallel and perpendicular (to the magnetic field) pressure components.

  5. Star System Bonanza Illustration

    NASA Image and Video Library

    2014-02-27

    This illustration shows the unusual orbit of planet Kepler-413b around a close pair of orange and red dwarf stars. The planet 66-day orbit is tilted 2.5 degrees with respect to the plane of the binary stars orbit.

  6. Observing Double Stars

    NASA Astrophysics Data System (ADS)

    Genet, Russell M.; Fulton, B. J.; Bianco, Federica B.; Martinez, John; Baxter, John; Brewer, Mark; Carro, Joseph; Collins, Sarah; Estrada, Chris; Johnson, Jolyon; Salam, Akash; Wallen, Vera; Warren, Naomi; Smith, Thomas C.; Armstrong, James D.; McGaughey, Steve; Pye, John; Mohanan, Kakkala; Church, Rebecca

    2012-05-01

    Double stars have been systematically observed since William Herschel initiated his program in 1779. In 1803 he reported that, to his surprise, many of the systems he had been observing for a quarter century were gravitationally bound binary stars. In 1830 the first binary orbital solution was obtained, leading eventually to the determination of stellar masses. Double star observations have been a prolific field, with observations and discoveries - often made by students and amateurs - routinely published in a number of specialized journals such as the Journal of Double Star Observations. All published double star observations from Herschel's to the present have been incorporated in the Washington Double Star Catalog. In addition to reviewing the history of visual double stars, we discuss four observational technologies and illustrate these with our own observational results from both California and Hawaii on telescopes ranging from small SCTs to the 2-meter Faulkes Telescope North on Haleakala. Two of these technologies are visual observations aimed primarily at published "hands-on" student science education, and CCD observations of both bright and very faint doubles. The other two are recent technologies that have launched a double star renaissance. These are lucky imaging and speckle interferometry, both of which can use electron-multiplying CCD cameras to allow short (30 ms or less) exposures that are read out at high speed with very low noise. Analysis of thousands of high speed exposures allows normal seeing limitations to be overcome so very close doubles can be accurately measured.

  7. Hyperons in neutron stars

    SciTech Connect

    Glendenning, N.K.

    1986-04-01

    Generalized beta equilibrium involving nucleons, hyperons, and isobars is examined for neutron star matter. The hyperons produce a considerable softening of the equation of state. It is shown that the observed masses of neutron stars can be used to settle a recent controversy concerning the nuclear compressibility. Compressibilities less than 200 MeV are incompatible with observed masses. 7 refs., 9 figs.

  8. ENERGY STAR Certified Televisions

    EPA Pesticide Factsheets

    Certified models meet all ENERGY STAR requirements as listed in the Version 7.0 ENERGY STAR Program Requirements for Televisions that are effective as of October 30, 2015. A detailed listing of key efficiency criteria are available at https://www.energystar.gov/index.cfm?c=tv_vcr.pr_crit_tv_vcr.

  9. How do stars form

    NASA Astrophysics Data System (ADS)

    Tscharnuter, W. M.

    1980-02-01

    Modes and model concept of star formation are reviewed, beginning with the theory of Kant (1755), via Newton's exact mathematical formulation of the laws of motion, his recognition of the universal validity of general gravitation, to modern concepts and hypotheses. Axisymmetric and spherically symmetric collapse models are discussed, and the origin of double and multiple star systems is examined.

  10. Science Through ARts (STAR)

    NASA Technical Reports Server (NTRS)

    Kolecki, Joseph; Petersen, Ruth; Williams, Lawrence

    2002-01-01

    Science Through ARts (STAR) is an educational initiative designed to teach students through a multidisciplinary approach to learning. This presentation describes the STAR pilot project, which will use Mars exploration as the topic to be integrated. Schools from the United Kingdom, Japan, the United States, and possibly eastern Europe are expected to participate in the pilot project.

  11. Science through ARts (STAR)

    ERIC Educational Resources Information Center

    Densmore, Marycay; Kolecki, Joseph C.; Miller, Allan; Petersen, Ruth; Terrell, Mike

    2005-01-01

    Science Through ARts (STAR) is a free, international, cross-curricular program thematically aligned with "The Vision for Space Exploration," a framework of goals and objectives published by NASA in February 2004. Through the STAR program, students in grades 5 through 12 are encouraged to apply their knowledge in creative ways as they approach a…

  12. Nebraska STARS: Achieving Results

    ERIC Educational Resources Information Center

    Roschewski, Pat; Isernhagen, Jody; Dappen, Leon

    2006-01-01

    In 2000, the state of Nebraska passed legislation requiring the assessment of student performance on content standards, but its requirements were very different from those of any other state. Nebraska created what has come to be known as STARS (School-based Teacher-led Assessment and Reporting System). Under STARS, each of Nebraska's nearly 500…

  13. Nebraska STARS: Achieving Results

    ERIC Educational Resources Information Center

    Roschewski, Pat; Isernhagen, Jody; Dappen, Leon

    2006-01-01

    In 2000, the state of Nebraska passed legislation requiring the assessment of student performance on content standards, but its requirements were very different from those of any other state. Nebraska created what has come to be known as STARS (School-based Teacher-led Assessment and Reporting System). Under STARS, each of Nebraska's nearly 500…

  14. Science through ARts (STAR)

    ERIC Educational Resources Information Center

    Densmore, Marycay; Kolecki, Joseph C.; Miller, Allan; Petersen, Ruth; Terrell, Mike

    2005-01-01

    Science Through ARts (STAR) is a free, international, cross-curricular program thematically aligned with "The Vision for Space Exploration," a framework of goals and objectives published by NASA in February 2004. Through the STAR program, students in grades 5 through 12 are encouraged to apply their knowledge in creative ways as they approach a…

  15. Modeling rapidly rotating stars

    NASA Astrophysics Data System (ADS)

    Rieutord, M.

    2006-06-01

    We review the quest of modeling rapidly rotating stars during the past 40 years and detail the challenges to be taken up by models facing new data from interferometry, seismology, spectroscopy... We then present the progress of the ESTER project aimed at giving a physically self-consistent model for the structure and evolution of rapidly rotating stars.

  16. Star spot location estimation using Kalman filter for star tracker.

    PubMed

    Liu, Hai-bo; Yang, Jian-kun; Wang, Jiong-qi; Tan, Ji-chun; Li, Xiu-jian

    2011-04-20

    Star pattern recognition and attitude determination accuracy is highly dependent on star spot location accuracy for the star tracker. A star spot location estimation approach with the Kalman filter for a star tracker has been proposed, which consists of three steps. In the proposed approach, the approximate locations of the star spots in successive frames are predicted first; then the measurement star spot locations are achieved by defining a series of small windows around each predictive star spot location. Finally, the star spot locations are updated by the designed Kalman filter. To confirm the proposed star spot location estimation approach, the simulations based on the orbit data of the CHAMP satellite and the real guide star catalog are performed. The simulation results indicate that the proposed approach can filter out noises from the measurements remarkably if the sampling frequency is sufficient.

  17. Young Star HD 141569

    NASA Image and Video Library

    2017-01-30

    This image shows the dusty disk of planetary material surrounding the young star HD 141569, located 380 light-years away from Earth. It was taken using the vortex coronagraph on the W.M. Keck Observatory. The vortex suppressed light from the star in the center, revealing light from the innermost ring of planetary material around the star (blue). The disk around the star, made of olivine particles, extends from 23 to 70 astronomical units from the star. By comparison, Uranus is over 19 astronomical units from our sun, and Neptune about 30 astronomical units. One astronomical unit is the distance between Earth and our sun. http://photojournal.jpl.nasa.gov/catalog/PIA21090

  18. The Carbon Star Phenomenon

    NASA Astrophysics Data System (ADS)

    Wing, Robert F.

    2000-06-01

    The atmospheres of many stars have chemical compositions that are significantly different from that of the interstellar medium from which they are formed. This symposium considered all kinds of late-type stars showing altered compositions, the carbon stars being simply the best-known of these. All stages of stellar evolution from the main sequence to the ejection of a planetary nebula were considered, with emphasis on the changes that occur on the asymptotic giant branch. The spectroscopic properties of the photospheres and circumstellar envelopes of chemically-peculiar red giant stars, their origins via single-star evolution or mass transfer in binary systems, and the methods currently used to study them were all discussed in detail. This volume includes the full texts of papers given orally at the symposium and abstracts of the posters. Link: http://www.wkap.nl/book.htm/0-7923-6347-7

  19. Producing Runaway Stars

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-07-01

    How are the hypervelocity stars weve observed in our galaxy produced? A recent study suggests that these escapees could be accelerated by a massive black hole in the center of the Large Magellanic Cloud.A Black Hole SlingshotSince their discovery in 2005, weve observed dozens of candidate hypervelocity stars stars whose velocity in the rest frame of our galaxy exceeds the local escape velocity of the Milky Way. These stars present a huge puzzle: how did they attain these enormous velocities?One potential explanation is known as the Hills mechanism. In this process, a stellar binary is disrupted by a close encounter with a massive black hole (like those thought to reside at the center of every galaxy). One member of the binary is flung out of the system as a result of the close encounter, potentially reaching very large velocities.A star-forming region known as LHA 120-N 11, located within the LMC. Some binary star systems within the LMC might experience close encounters with a possible massive black hole at the LMCs center. [ESA/NASA/Hubble]Blame the LMC?Usually, discussions of the Hills mechanism assume that Sagittarius A*, the supermassive black hole at the center of the Milky Way, is the object guilty of accelerating the hypervelocity stars weve observed. But what if the culprit isnt Sgr A*, but a massive black hole at the center of the Large Magellanic Cloud (LMC), one of the Milky Ways satellite galaxies?Though we dont yet have evidence of a massive black hole at the center of the LMC, the dwarf galaxy is large enough to potentially host one as large as 100,000 solar masses. Assuming that it does, two scientists at the University of Cambridge, Douglas Boubert and Wyn Evans, have now modeled how this black hole might tear apart binary star systems and fling hypervelocity stars around the Milky Way.Models for AccelerationBoubert and Evans determined that the LMCs hypothetical black hole could easily eject stars at ~100 km/s, which is the escape velocity of the

  20. TYCHO star recognition

    NASA Astrophysics Data System (ADS)

    Halbwachs, J. L.; Hog, E.; Bastian, U.; Schwekendiek, P.; Schwekendiek, P.

    1992-05-01

    The observations of the first year of mission of the Tycho program will be used for revising the Tycho Input Catalogue (TIC). The Tycho Input Catalogue Revision essentially defines the list of objects in the final Tycho output catalogs. This paper describes the mathematical and practical details of this revision process. The stars will be recognized with three different processes, according to their distances from the positions in the TIC. The main process concerns the stars closer than 6 arcsec to the T/C positions; stars with separations between 6 and 20 arcsec are recognized too, but the threshold in detection is slightly brighter than in the main process. Stars absent from the input catalog could also be recognized, but with an even higher threshold in detection. An assessment based on about 85 hours of actual Hipparcos observations is presented. It points to a Tycho Input Catalogue Revision containing about 1 million stars.

  1. Neutron stars - General review

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.; Canuto, V.

    1974-01-01

    A review is presented of those properties of neutron stars upon which there is general agreement and of those areas which currently remain in doubt. Developments in theoretical physics of neutron star interiors are summarized with particular attention devoted to hyperon interactions and the structure of interior layers. Determination of energy states and the composition of matter is described for successive layers, beginning with the surface and proceeding through the central region into the core. Problems encountered in determining the behavior of matter in the ultra-high density regime are discussed, and the effects of the magnetic field of a neutron star are evaluated along with the behavior of atomic structures in the field. The evolution of a neutron star is outlined with discussion centering on carbon detonation, cooling, vibrational damping, rotation, and pulsar glitches. The role of neutron stars in cosmic-ray propagation is considered.

  2. How Stars Form

    NASA Astrophysics Data System (ADS)

    McKee, Christopher F.

    2017-01-01

    Stars are the atoms of the universe. The process by which stars form is at the nexus of astrophysics since they are believed to be responsible for the re-ionization of the universe, they created the heavy elements, they play a central role in the formation and evolution of galaxies, and their formation naturally leads to the formation of planets. Whereas early work on star formation was based on the assumption that it is a quiescent process, it is now believed that turbulence plays a dominant role. In this overview, I shall discuss the evolution of our understanding of how stars form and current ideas about the stellar initial mass function and the rate of star formation.

  3. Activity Cycles in Stars

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    Starspots and stellar activity can be detected in other stars using high precision photometric and spectrometric measurements. These observations have provided some surprises (starspots at the poles - sunspots are rarely seen poleward of 40 degrees) but more importantly they reveal behaviors that constrain our models of solar-stellar magnetic dynamos. The observations reveal variations in cycle characteristics that depend upon the stellar structure, convection zone dynamics, and rotation rate. In general, the more rapidly rotating stars are more active. However, for stars like the Sun, some are found to be inactive while nearly identical stars are found to be very active indicating that periods like the Sun's Maunder Minimum (an inactive period from 1645 to 1715) are characteristic of Sun-like stars.

  4. Gaia and Variable Stars

    NASA Astrophysics Data System (ADS)

    Udalski, A.; Soszyński, I.; Skowron, D. M.; Skowron, J.; Pietrukowicz, P.; Mróz, P.; Poleski, R.; Szymański, M. K.; Kozłowski, S.; Wyrzykowski, Ł.; Ulaczyk, K.; Pawlak, M.

    2016-12-01

    We present a comparison of the Gaia DR1 samples of pulsating variable stars - Cepheids and RR Lyr type - with the OGLE Collection of Variable Stars aiming at the characterization of the Gaia mission performance in the stellar variability domain. Out of 575 Cepheids and 2322 RR Lyr candidates from the Gaia DR1 samples located in the OGLE footprint in the sky, 559 Cepheids and 2302 RR Lyr stars are genuine pulsators of these types. The number of misclassified stars is low indicating reliable performance of the Gaia data pipeline. The completeness of the Gaia DR1 samples of Cepheids and RR Lyr stars is at the level of 60-75% as compared to the OGLE Collection dataset. This level of completeness is moderate and may limit the applicability of the Gaia data in many projects.

  5. Catch a Star!

    NASA Astrophysics Data System (ADS)

    2006-11-01

    ESO and the European Association for Astronomy Education are launching today the 2007 edition of 'Catch a Star!', their international astronomy competition for school students. Now in its fifth year, the competition offers students the chance to win a once-in-a-lifetime trip to ESO's flagship observatory in Chile, as well as many other prizes. Students are invited to 'become astronomers' and embark on a journey to explore the Universe. ESO PR Photo 42/06 The competition includes separate categories - 'Catch a Star Researchers' and 'Catch a Star Adventurers' - to ensure that every student, whatever their level, has the chance to enter and win exciting prizes. For the artistically minded, 'Catch a Star!' also includes an artwork competition, 'Catch a Star Artists'. "'Catch a Star!' offers a unique opportunity for students to learn more about astronomy and about the methods scientists use to discover new things about the Universe", said Douglas Pierce-Price, Education Officer at ESO. In teams, students choose an astronomical topic to study and produce an in-depth report. An important part of the project for 'Catch a Star Researchers' is to think about how ESO's telescopes or a telescope of the future can contribute to their investigations of the subject. As well as the top prize - a trip to one of ESO's observatory sites in Chile - visits to observatories in Germany, Austria and Spain, and many other prizes are also available to be won. 'Catch a Star Researchers' winners will be chosen by an international jury, and 'Catch a Star Adventurers' will be awarded further prizes by lottery. Entries for 'Catch a Star Artists' will be displayed on the web and winners chosen with the help of a public online vote. The first editions of 'Catch a Star!' have attracted several hundred entries from more than 25 countries worldwide. Previous winning entries have included "Star clusters and the structure of the Milky Way" (Budapest, Hungary), "Vega" (Acqui Terme, Italy) and "Venus

  6. Dense Axion Stars

    NASA Astrophysics Data System (ADS)

    Mohapatra, Abhishek; Braaten, Eric; Zhang, Hong

    2016-03-01

    If the dark matter consists of axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound Bose-Einstein condensates of axions. In the previously known axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. If the axion mass energy is mc2 =10-4 eV, these dilute axion stars have a maximum mass of about 10-14M⊙ . We point out that there are also dense axion stars in which gravity is balanced by the mean-field pressure of the axion condensate. We study axion stars using the leading term in a systematically improvable approximation to the effective potential of the nonrelativistic effective field theory for axions. Using the Thomas-Fermi approximation in which the kinetic pressure is neglected, we find a sequence of new branches of axion stars in which gravity is balanced by the mean-field interaction energy of the axion condensate. If mc2 =10-4 4 eV, the first branch of these dense axion stars has mass ranging from about 10-11M⊙ toabout M⊙.

  7. Dense Axion Stars.

    PubMed

    Braaten, Eric; Mohapatra, Abhishek; Zhang, Hong

    2016-09-16

    If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about 10^{-14}M_{⊙} if the axion mass is 10^{-4}  eV. We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about 10^{-20}M_{⊙} to about M_{⊙}. If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.

  8. Heartbeat Stars Artist Concept

    NASA Image and Video Library

    2016-10-21

    This artist's concept depicts "heartbeat stars," which have been detected by NASA's Kepler Space Telescope and others. The illustration shows two heartbeat stars swerving close to one another in their closest approach along their highly elongated orbits around one another. The mutual gravitation of the two stars would cause the stars themselves to become slightly ellipsoidal in shape. A third, more distant star in the system is shown in the upper left. Astronomers speculate that such unseen companions may exist in some of these heartbeat star systems, and could be responsible for maintaining these oddly stretched-out orbits. The overlaid curve depicts the inferred cyclic change in velocities in one such system, called KIC 9965691, looking something like the graph of an electrocardiogram (hence the name "heartbeat stars"). The solid points represent measurements made by the HIRES instrument at the W.M. Keck Observatory, and the curve is the best fit model for the motions of this system. http://photojournal.jpl.nasa.gov/catalog/PIA21075

  9. From stars to nuclei

    NASA Astrophysics Data System (ADS)

    Meynet, G.

    2008-04-01

    We recall the basic physical principles governing the evolution of stars with some emphasis on the role played by the nuclear reactions. We argue that in general it is not possible from observations of stars to deduce constraints on the nuclear reaction rates. This is the reason why precise measurements of nuclear reaction rates are a necessity in order to make progresses in stellar physics, nucleosynthesis and chemical evolution of galaxies. There are however some stars which provides useful constraints on nuclear processes. The Wolf-Rayet stars of the WN type present at their surface CNO equilibrium patterns. There is also the particular case of the abundance of 22Ne at the surface of WC stars. The abundance of this element is a measure of the initial CNO content. Very interestingly, recent determinations of its abundance at the surface of WC stars tend to confirm that massive stars in the solar neighborhood have initial metallicities in agreement with the Asplund et al. [1] solar abundances.

  10. Neutron star evolutionary sequences

    NASA Technical Reports Server (NTRS)

    Richardson, M. B.; Van Horn, H. M.; Ratcliff, K. F.; Malone, R. C.

    1982-01-01

    Detailed numerical calculations which are solutions of the full set of general relativistic equations describing the evolution of a spherical star are presented, for the case of the evolution of neutron stars that are cooling over the central temperatures range of 10 to the 10th to 10 to the 7th K. The effects of nucleon superfluidity in the inner crust and core are included, and models are constructed with and without a pion condensate at high densities. It is found that the localized neutrino cooling which dominates the early evolution of neutron stars is so rapid that heat transport within the star cannot keep pace, and temperature distribution is not isothermal. The residual contraction of the neutron star during the early cooling phase contributes little to the heat budget of the star, and most of the gravitational energy released raises the Fermi energy of the degenerate nucleons. It is concluded that since calculations with and without pion condensate are consistent with the upper limits of current observations, these are not sufficient in distinguishing between the various models of neutron star cooling.

  11. Starspots on A stars

    NASA Astrophysics Data System (ADS)

    Balona, L. A.

    2017-05-01

    Rotation modulation of Kepler light curves in mid-A to late-B stars is shown to be present. This is demonstrated by the high correlation of projected rotational velocities with photometric frequencies in 30 stars. The time-frequency diagrams show stochastic variations in all respects similar to those in spotted cool stars. This disposes of any explanation in terms of binary proximity effects. More than half of the sample of stars with effective temperatures in the range of 8300-12 000 K show rotational modulation, indicating that starspots are the rule rather than the exception among A stars. The periodograms of a subset of these stars show a characteristic pattern in which a broad peak is flanked by a sharp peak at a slightly higher frequency. It is demonstrated that the sharp peak has the same width as the spectral window, indicating a stable period over the duration of the 4-yr Kepler observations. It is speculated that this might be a signature of a reflection effect in a non-transiting planet. These observations suggest that the presence of localized magnetic fields in A and B stars and that current views of radiative stellar envelopes need to be revised.

  12. Pseudosynchronization of Heartbeat Stars

    NASA Astrophysics Data System (ADS)

    Zimmerman, Mara; Thompson, Susan E.; Hambleton, Kelly; Fuller, Jim; Shporer, Avi; Isaacson, Howard T.; Howard, Andrew; Kurtz, Donald

    2016-01-01

    A type of eccentric binary star that undergoes extreme dynamic tidal forces, known as Heartbeat stars, were discovered by the Kepler Mission. As the two stars pass through periastron, the tidal distortion causes unique brightness variations. Short period, eccentric binary stars, like these, are theorized to pseudosynchronize, or reach a rotational frequency that matches the weighted average orbital angular velocity of the system. This pseudosynchronous rate, as predicted by Hut (1981), depends on the binary's orbital period and eccentricity. We tested whether sixteen heartbeat stars have pseudosynchronized. We measure the rotation rate from obvious spot signatures in the light curve. We measure the eccentricity by fitting the light curve using PHOEBE and are actively carrying out a radial velocity monitoring program with Keck/HIRES in order to improve these orbital parameters. Our initial results show that while most heartbeat stars appear to have pseudosynchronized we find stars with rotation frequencies both longer and shorter than this rate. We thank the SETI Institute REU program, the NSF, and the Kepler Guest Observer Program for making this work possible.

  13. Dense Axion Stars

    NASA Astrophysics Data System (ADS)

    Braaten, Eric; Mohapatra, Abhishek; Zhang, Hong

    2016-09-01

    If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about 10-14M⊙ if the axion mass is 10-4 eV . We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about 10-20M⊙ to about M⊙ . If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.

  14. Highly-evolved stars

    NASA Technical Reports Server (NTRS)

    Heap, S. R.

    1981-01-01

    The ways in which the IUE has proved useful in studying highly evolved stars are reviewed. The importance of high dispersion spectra for abundance analyses of the sd0 stars and for studies of the wind from the central star of NGC 6543 and the wind from the 0 type component of Vela X-1 is shown. Low dispersion spectra are used for absolute spectrophotometry of the dwarf nova, Ex Hya. Angular resolution is important for detecting and locating UV sources in globular clusters.

  15. Superradiance in stars

    NASA Astrophysics Data System (ADS)

    Cardoso, Vitor; Brito, Richard; Rosa, João L.

    2015-06-01

    It has long been known that dissipation is a crucial ingredient in the superradiant amplification of wave packets off rotating objects. We show that, once appropriate dissipation mechanisms are included, stars are also prone to superradiance and superradiant instabilities. In particular, ultralight dark matter with small interaction cross section with the star material or self-annihilation can trigger a superradiant instability. On long time scales, the instability strips the star of most of its angular momentum. Whether or not new stationary configurations surrounded by scalar condensates exist remains to be seen.

  16. STARs in the CNS.

    PubMed

    Ehrmann, Ingrid; Fort, Philippe; Elliott, David J

    2016-08-15

    STAR (signal transduction and activation of RNA) proteins regulate splicing of target genes that have roles in neural connectivity, survival and myelination in the vertebrate nervous system. These regulated splicing targets include mRNAs such as the Neurexins (Nrxn), SMN2 (survival of motor neuron) and MAG (myelin-associated glycoprotein). Recent work has made it possible to identify and validate STAR protein splicing targets in vivo by using genetically modified mouse models. In this review, we will discuss the importance of STAR protein splicing targets in the CNS (central nervous system). © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  17. Infrared spectroscopy of stars

    NASA Technical Reports Server (NTRS)

    Merrill, K. M.; Ridgway, S. T.

    1979-01-01

    This paper reviews applications of IR techniques in stellar classification, studies of stellar photospheres, elemental and isotopic abundances, and the nature of remnant and ejected matter in near-circumstellar regions. Qualitative IR spectral classification of cool and hot stars is discussed, along with IR spectra of peculiar composite star systems and of obscured stars, and IR characteristics of stellar populations. The use of IR spectroscopy in theoretical modeling of stellar atmospheres is examined, IR indicators of stellar atmospheric composition are described, and contributions of IR spectroscopy to the study of stellar recycling of interstellar matter are summarized. The future of IR astronomy is also considered.

  18. The Automated Planet Finder's detection of a 6-planet system orbiting the bright, nearby star HD219134

    NASA Astrophysics Data System (ADS)

    Burt, Jennifer; Laughlin, Greg; Meschiari, Stefano; Vogt, Steve; Butler, R. Paul

    2015-12-01

    The Automated Planet Finder (APF) is the newest facility at Lick Observatory, comprised of a 2.4m telescope coupled with the high-resolution Levy echelle spectrograph. Purpose built for exoplanet detection and characterization, 80% of the telescope's observing time is dedicated to these science goals. The APF has demonstrated 1 m/s radial velocity precision on bright, RV standard stars and performs with the same speed-on-sky as Keck/HIRES when observing M-dwarfs.The APF has contributed to the detection of four planetary systems in its first two years of scientific operations. Our most recent detection is that of a 6-planet system around the bright (V=5.5), nearby (d=6.5pc), K3V star HD219134. The planets in this system have masses ranging from 3.5 to108 MEarth, with orbital periods from 3 to 2247 days. An independent detection of the inner 4 planets in this system by the HARPS-N team has shown that the 3d planet transits the star, making this system ideal for follow-up observations.I will discuss the APF's detections to date, highlighting HD219134, as well as the overall performance results of the telescope and our future observing strategy.

  19. Mass loss of massive stars

    NASA Astrophysics Data System (ADS)

    Martins, F.

    2015-12-01

    In this contribution we review the properties of the winds of massive stars. We focus on OB stars, red supergiants, Luminous Blue Variables (LBVs) and Wolf-Rayet stars. For each type of star, we summarize the main wind properties and we give a brief description of the physical mechanism(s) responsible for mass loss.

  20. R Coronae Borealis stars

    NASA Astrophysics Data System (ADS)

    Skuljan, Ljiljana; Cottrell, Peter L.

    2004-05-01

    In the last ten years a significant step forward has been made toward a better understanding of the evolutionary status and unusual nature of the R Coronae Borealis (RCB) stars, a rare class of hydrogen-poor and carbon-rich variable stars. More detailed abundance analyses of the majority of RCB stars, and objects related to them, have become available in the last couple of years. In addition to this, recent theoretical studies of the most popular evolutionary models (`Double Degenerate' and `Final Flash')provide a new insight into the origin of these stars. Regarding the nature of the RCB declines, more observations from the light maxima and the decline phase are now available, including more data from space. However, the characteristics of the various emission lines appearing during the RCB declines, and the nature of their emitting regions, are still not entirely understood.

  1. Tabby's Star (Illustration)

    NASA Image and Video Library

    2017-10-04

    This illustration depicts a hypothetical uneven ring of dust orbiting KIC 8462852, also known as Boyajian's Star or Tabby's Star. Astronomers have found the dimming of the star over long periods appears to be weaker at longer infrared wavelengths of light and stronger at shorter ultraviolet wavelengths. Such reddening is characteristic of dust particles and inconsistent with more fanciful "alien megastructure" concepts, which would evenly dim all wavelengths of light. By studying observations from NASA's Spitzer and Swift telescopes, as well as the Belgian AstroLAB IRIS observatory, the researchers have been able to better constrain the size of the dust particles. This places them within the range found in dust disks orbiting stars, and larger than the particles typically found in interstellar dust. The system is portrayed with a couple of comets, consistent with previous studies that have found evidence for cometary activity within the system. https://photojournal.jpl.nasa.gov/catalog/PIA22081

  2. Winds from cool stars

    NASA Technical Reports Server (NTRS)

    Dupree, A. K.

    1995-01-01

    Spectral observations of cool stars enable study of the presence and character of winds and the mass loss process in objects with effective temperatures, gravities, and atmospheric compositions which differ from that of the Sun. A wealth of recent spectroscopic measurements from the Hubble Space Telescope, and the Extreme Ultraviolet Explorer complement high resolution ground-based measures in the optical and infrared spectral regions. Such observations when combined with realistic semi-empirical atmospheric modeling allow us to estimate the physical conditions in the atmospheres and winds of many classes of cool stars. Line profiles support turbulent heating and mass motions. In low gravity stars, evidence is found for relatively fast (approximately 200 km s(exp -1)), warm winds with rapid acceleration occurring in the chromosphere. In some cases outflows commensurate with stellar escape velocities are present. Our current understanding of cool star winds will be reviewed including the implications of stellar observations for identification of atmospheric heating and acceleration processes.

  3. Cosmology with hypervelocity stars

    SciTech Connect

    Loeb, Abraham

    2011-04-01

    In the standard cosmological model, the merger remnant of the Milky Way and Andromeda (Milkomeda) will be the only galaxy remaining within our event horizon once the Universe has aged by another factor of ten, ∼ 10{sup 11} years after the Big Bang. After that time, the only extragalactic sources of light in the observable cosmic volume will be hypervelocity stars being ejected continuously from Milkomeda. Spectroscopic detection of the velocity-distance relation or the evolution in the Doppler shifts of these stars will allow a precise measurement of the vacuum mass density as well as the local matter distribution. Already in the near future, the next generation of large telescopes will allow photometric detection of individual stars out to the edge of the Local Group, and may target the ∼ 10{sup 5±1} hypervelocity stars that originated in it as cosmological tracers.

  4. Chaotic Star Birth

    NASA Image and Video Library

    2005-11-15

    Located 1,000 light years from Earth in the constellation Perseus, a reflection nebula called NGC 1333 epitomizes the beautiful chaos of a dense group of stars being born. This image is from NASA Spitzer Space Telescope.

  5. Cooling of neutron stars

    NASA Technical Reports Server (NTRS)

    Pethick, C. J.

    1992-01-01

    It is at present impossible to predict the interior constitution of neutron stars based on theory and results from laboratory studies. It has been proposed that it is possible to obtain information on neutron star interiors by studying thermal radiation from their surfaces, because neutrino emission rates, and hence the temperature of the central part of a neutron star, depend on the properties of dense matter. The theory predicts that neutron stars cool relatively slowly if their cores are made up of nucleons, and cool faster if the matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been questioned by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.

  6. Cooling of neutron stars

    NASA Technical Reports Server (NTRS)

    Pethick, C. J.

    1992-01-01

    It is at present impossible to predict the interior constitution of neutron stars based on theory and results from laboratory studies. It has been proposed that it is possible to obtain information on neutron star interiors by studying thermal radiation from their surfaces, because neutrino emission rates, and hence the temperature of the central part of a neutron star, depend on the properties of dense matter. The theory predicts that neutron stars cool relatively slowly if their cores are made up of nucleons, and cool faster if the matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been questioned by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.

  7. Guide star probabilities

    NASA Technical Reports Server (NTRS)

    Soneira, R. M.; Bahcall, J. N.

    1981-01-01

    Probabilities are calculated for acquiring suitable guide stars (GS) with the fine guidance system (FGS) of the space telescope. A number of the considerations and techniques described are also relevant for other space astronomy missions. The constraints of the FGS are reviewed. The available data on bright star densities are summarized and a previous error in the literature is corrected. Separate analytic and Monte Carlo calculations of the probabilities are described. A simulation of space telescope pointing is carried out using the Weistrop north galactic pole catalog of bright stars. Sufficient information is presented so that the probabilities of acquisition can be estimated as a function of position in the sky. The probability of acquiring suitable guide stars is greatly increased if the FGS can allow an appreciable difference between the (bright) primary GS limiting magnitude and the (fainter) secondary GS limiting magnitude.

  8. Magnetospheres of massive stars

    NASA Astrophysics Data System (ADS)

    Küker, M.

    We study the interaction of line-driven winds from massive stars with the magnetic field rooted in these stars by carrying out numerical simulations using the Nirvana MHD code in 2D in spherical polar coordinates. The code's adaptive mesh refinement feature allows high spatial resolution across the whole simulation box. We study both O and Wolf-Rayet stars for a range of magnetic field strengths from weak to strong as measured by the confinement parameter. For weak fields our simulations show that the initially dipolar field opens up far away from the star and a thin disk-like structure forms in the equatorial plane of the magnetic field. For stronger fields the disk is disrupted close to the stellar surface and closed field lines persist at low latitudes. For very strong fields a pronounced magnetosphere forms where the gas is forced to move along the field lines and eventually falls back to the stellar surface.

  9. Discovery of variable stars

    NASA Technical Reports Server (NTRS)

    Kurochkin, N. Y.

    1973-01-01

    Instrumented methods of discovering variable stars are reviewed, specifically the blink comparator, color contrast method, positive-negative method, and television method. Among the empirical methods discussed, the Van Gent method is the most important.

  10. Planets Around Neutron Stars

    NASA Technical Reports Server (NTRS)

    Wolszczan, Alexander; Kulkarni, Shrinivas R; Anderson, Stuart B.

    2003-01-01

    The objective of this proposal was to continue investigations of neutron star planetary systems in an effort to describe and understand their origin, orbital dynamics, basic physical properties and their relationship to planets around normal stars. This research represents an important element of the process of constraining the physics of planet formation around various types of stars. The research goals of this project included long-term timing measurements of the planets pulsar, PSR B1257+12, to search for more planets around it and to study the dynamics of the whole system, and sensitive searches for millisecond pulsars to detect further examples of old, rapidly spinning neutron stars with planetary systems. The instrumentation used in our project included the 305-m Arecibo antenna with the Penn State Pulsar Machine (PSPM), the 100-m Green Bank Telescope with the Berkeley- Caltech Pulsar Machine (BCPM), and the 100-m Effelsberg and 64-m Parkes telescopes equipped with the observatory supplied backend hardware.

  11. Conformally symmetric relativistic star

    NASA Astrophysics Data System (ADS)

    Rahaman, Farook; Maharaj, Sunil D.; Sardar, Iftikar Hossain; Chakraborty, Koushik

    2017-03-01

    We investigate whether compact stars having Tolman-like interior geometry admit conformal symmetry. Taking anisotropic pressure along the two principal directions within the compact object, we obtain physically relevant quantities such as transverse and radial pressure, density and redshift function. We study the equation of state (EOS) for the matter distribution inside the star. From the relation between pressure and density function of the constituent matter, we explore the nature and properties of the interior matter. The redshift function and compactness parameter are found to be physically reasonable. The matter inside the star satisfies the null, weak and strong energy conditions. Finally, we compare the masses and radii predicted from the model with corresponding values in some observed stars.

  12. Dark Wombs of Stars

    NASA Image and Video Library

    2009-10-02

    This image from the Herschel Observatory, a European Space Agency mission, reveals some of the coldest and darkest material in our galaxy. The yellow filaments show the coldest dust dotted with the youngest embryonic stars.

  13. Catch a Star 2008!

    NASA Astrophysics Data System (ADS)

    2007-10-01

    ESO and the European Association for Astronomy Education have just launched the 2008 edition of 'Catch a Star', their international astronomy competition for school students. Now in its sixth year, the competition offers students the chance to win a once-in-a-lifetime trip to ESO's flagship observatory in Chile, as well as many other prizes. CAS logo The competition includes separate categories - 'Catch a Star Researchers' and 'Catch a Star Adventurers' - to ensure that every student, whatever their level, has the chance to enter and win exciting prizes. In teams, students investigate an astronomical topic of their choice and write a report about it. An important part of the project for 'Catch a Star Researchers' is to think about how ESO's telescopes such as the Very Large Telescope (VLT) or future telescopes such as the Atacama Large Millimeter/submillimeter Array (ALMA) and the European Extremely Large Telescope (E-ELT) could contribute to investigations of the topic. Students may also include practical activities such as observations or experiments. For the artistically minded, 'Catch a Star' also offers an artwork competition, 'Catch a Star Artists'. Last year, hundreds of students from across Europe and beyond took part in 'Catch a Star', submitting astronomical projects and artwork. "'Catch a Star' gets students thinking about the wonders of the Universe and the science of astronomy, with a chance of winning great prizes. It's easy to take part, whether by writing about astronomy or creating astronomically inspired artwork," said Douglas Pierce-Price, Education Officer at ESO. As well as the top prize - a trip to ESO's Very Large Telescope in Chile - visits to observatories in Austria and Spain, and many other prizes, can also be won. 'Catch a Star Researchers' winners will be chosen by an international jury, and 'Catch a Star Adventurers' will be awarded further prizes by lottery. Entries for 'Catch a Star Artists' will be displayed on the web and winners

  14. Sounds of a Star

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Acoustic Oscillations in Solar-Twin "Alpha Cen A" Observed from La Silla by Swiss Team Summary Sound waves running through a star can help astronomers reveal its inner properties. This particular branch of modern astrophysics is known as "asteroseismology" . In the case of our Sun, the brightest star in the sky, such waves have been observed since some time, and have greatly improved our knowledge about what is going on inside. However, because they are much fainter, it has turned out to be very difficult to detect similar waves in other stars. Nevertheless, tiny oscillations in a solar-twin star have now been unambiguously detected by Swiss astronomers François Bouchy and Fabien Carrier from the Geneva Observatory, using the CORALIE spectrometer on the Swiss 1.2-m Leonard Euler telescope at the ESO La Silla Observatory. This telescope is mostly used for discovering exoplanets (see ESO PR 07/01 ). The star Alpha Centauri A is the nearest star visible to the naked eye, at a distance of a little more than 4 light-years. The new measurements show that it pulsates with a 7-minute cycle, very similar to what is observed in the Sun . Asteroseismology for Sun-like stars is likely to become an important probe of stellar theory in the near future. The state-of-the-art HARPS spectrograph , to be mounted on the ESO 3.6-m telescope at La Silla, will be able to search for oscillations in stars that are 100 times fainter than those for which such demanding observations are possible with CORALIE. PR Photo 23a/01 : Oscillations in a solar-like star (schematic picture). PR Photo 23b/01 : Acoustic spectrum of Alpha Centauri A , as observed with CORALIE. Asteroseismology: listening to the stars ESO PR Photo 23a/01 ESO PR Photo 23a/01 [Preview - JPEG: 357 x 400 pix - 96k] [Normal - JPEG: 713 x 800 pix - 256k] [HiRes - JPEG: 2673 x 3000 pix - 2.1Mb Caption : PR Photo 23a/01 is a graphical representation of resonating acoustic waves in the interior of a solar-like star. Red and blue

  15. Astro STARS Camp

    NASA Image and Video Library

    2011-06-28

    Tom Nicolaides, an aerospace technologist in the Engineering & Test Directorate at Stennis Space Center, looks on as 2011 Astro STARS participants take turns gazing at the sun through a special telescope. The sun-gazing activity was part of the Astro STARS (Spaceflight, Technology, Astronomy & Robotics at Stennis) camp for 13-to-15-year-olds June 27 - July 1. The weeklong science and technology camp is held each year onsite at the rocket engine test facility.

  16. Chaotic Star Birth

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Click on the image for Poster VersionClick on the image for IRAS 4B Inset

    Located 1,000 light years from Earth in the constellation Perseus, a reflection nebula called NGC 1333 epitomizes the beautiful chaos of a dense group of stars being born. Most of the visible light from the young stars in this region is obscured by the dense, dusty cloud in which they formed. With NASA's Spitzer Space Telescope, scientists can detect the infrared light from these objects. This allows a look through the dust to gain a more detailed understanding of how stars like our sun begin their lives.

    The young stars in NGC 1333 do not form a single cluster, but are split between two sub-groups. One group is to the north near the nebula shown as red in the image. The other group is south, where the features shown in yellow and green abound in the densest part of the natal gas cloud. With the sharp infrared eyes of Spitzer, scientists can detect and characterize the warm and dusty disks of material that surround forming stars. By looking for differences in the disk properties between the two subgroups, they hope to find hints of the star and planet formation history of this region.

    The knotty yellow-green features located in the lower portion of the image are glowing shock fronts where jets of material, spewed from extremely young embryonic stars, are plowing into the cold, dense gas nearby. The sheer number of separate jets that appear in this region is unprecedented. This leads scientists to believe that by stirring up the cold gas, the jets may contribute to the eventual dispersal of the gas cloud, preventing more stars from forming in NGC 1333.

    In contrast, the upper portion of the image is dominated by the infrared light from warm dust, shown as red.

  17. Star of Bethlehem

    NASA Astrophysics Data System (ADS)

    Hughes, D.; Murdin, P.

    2001-07-01

    The biblical Star of Bethlehem, which heralded the birth of Jesus Christ, is only mentioned in the Gospel of St Matthew 2. The astrologically significant 7 bc triple conjunction of Jupiter and Saturn in the constellation of Pisces is the most likely candidate, although a comet/nova in 5 bc and a comet in 4 bc cannot be ruled out. There is also the possibility that the star was simply fictitious....

  18. A messy star factory

    NASA Image and Video Library

    2014-12-15

    This sprinkle of cosmic glitter is a blue compact dwarf galaxy known as Markarian 209. Galaxies of this type are blue-hued, compact in size, gas-rich, and low in heavy elements. They are often used by astronomers to study star formation, as their conditions are similar to those thought to exist in the early Universe. Markarian 209 in particular has been studied extensively. It is filled with diffuse gas and peppered with star-forming regions towards its core. This image captures it undergoing a particularly dramatic burst of star formation, visible as the lighter blue cloudy region towards the top right of the galaxy. This clump is filled with very young and hot newborn stars. This galaxy was initially thought to be a young galaxy undergoing its very first episode of star formation, but later research showed that Markarian 209 is actually very old, with an almost continuous history of forming new stars. It is thought to have never had a dormant period — a period during which no stars were formed — lasting longer than 100 million years. The dominant population of stars in Markarian 209 is still quite young, in stellar terms, with ages of under 3 million years. For comparison, the Sun is some 4.6 billion years old, and is roughly halfway through its expected lifespan. The observations used to make this image were taken using Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys, and span the ultraviolet, visible, and infrared parts of the spectrum. A scattering of other bright galaxies can be seen across the frame, including the bright golden oval that could, due to a trick of perspective, be mistaken as part of Markarian 209 but is in fact a background galaxy. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Nick Rose. Links: Nick Rose’s Hidden Treasures entry on Flickr

  19. Matter accreting neutron stars

    NASA Technical Reports Server (NTRS)

    Meszaros, P.

    1981-01-01

    Some of the fundamental neutron star parameters, such as the mass and the magnetic field strength, were experimentally determined in accreting neutron star systems. Some of the relevant data and the models used to derive useful information from them, are reviewed concentrating mainly on X-ray pulsars. The latest advances in our understanding of the radiation mechanisms and the transfer in the strongly magnetized polar cap regions are discussed.

  20. Bubbly Little Star

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In this processed Spitzer Space Telescope image, baby star HH 46/47 can be seen blowing two massive 'bubbles.' The star is 1,140 light-years away from Earth.

    The infant star can be seen as a white spot toward the center of the Spitzer image. The two bubbles are shown as hollow elliptical shells of bluish-green material extending from the star. Wisps of green in the image reveal warm molecular hydrogen gas, while the bluish tints are formed by starlight scattered by surrounding dust.

    These bubbles formed when powerful jets of gas, traveling at 200 to 300 kilometers per second, or about 120 to 190 miles per second, smashed into the cosmic cloud of gas and dust that surrounds HH 46/47. The red specks at the end of each bubble show the presence of hot sulfur and iron gas where the star's narrow jets are currently crashing head-on into the cosmic cloud's gas and dust material.

    Whenever astronomers observe a star, or snap a stellar portrait, through the lens of any telescope, they know that what they are seeing is slightly blurred. To clear up the blurring in Spitzer images, astronomers at the Jet Propulsion Laboratory developed an image processing technique for Spitzer called Hi-Res deconvolution.

    This process reduces blurring and makes the image sharper and cleaner, enabling astronomers to see the emissions around forming stars in greater detail. When scientists applied this image processing technique to the Spitzer image of HH 46/47, they were able to see winds from the star and jets of gas that are carving the celestial bubbles.

    This infrared image is a three-color composite, with data at 3.6 microns represented in blue, 4.5 and 5.8 microns shown in green, and 24 microns represented as red.

  1. Chaotic Star Birth

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Click on the image for Poster VersionClick on the image for IRAS 4B Inset

    Located 1,000 light years from Earth in the constellation Perseus, a reflection nebula called NGC 1333 epitomizes the beautiful chaos of a dense group of stars being born. Most of the visible light from the young stars in this region is obscured by the dense, dusty cloud in which they formed. With NASA's Spitzer Space Telescope, scientists can detect the infrared light from these objects. This allows a look through the dust to gain a more detailed understanding of how stars like our sun begin their lives.

    The young stars in NGC 1333 do not form a single cluster, but are split between two sub-groups. One group is to the north near the nebula shown as red in the image. The other group is south, where the features shown in yellow and green abound in the densest part of the natal gas cloud. With the sharp infrared eyes of Spitzer, scientists can detect and characterize the warm and dusty disks of material that surround forming stars. By looking for differences in the disk properties between the two subgroups, they hope to find hints of the star and planet formation history of this region.

    The knotty yellow-green features located in the lower portion of the image are glowing shock fronts where jets of material, spewed from extremely young embryonic stars, are plowing into the cold, dense gas nearby. The sheer number of separate jets that appear in this region is unprecedented. This leads scientists to believe that by stirring up the cold gas, the jets may contribute to the eventual dispersal of the gas cloud, preventing more stars from forming in NGC 1333.

    In contrast, the upper portion of the image is dominated by the infrared light from warm dust, shown as red.

  2. Bubbly Little Star

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In this processed Spitzer Space Telescope image, baby star HH 46/47 can be seen blowing two massive 'bubbles.' The star is 1,140 light-years away from Earth.

    The infant star can be seen as a white spot toward the center of the Spitzer image. The two bubbles are shown as hollow elliptical shells of bluish-green material extending from the star. Wisps of green in the image reveal warm molecular hydrogen gas, while the bluish tints are formed by starlight scattered by surrounding dust.

    These bubbles formed when powerful jets of gas, traveling at 200 to 300 kilometers per second, or about 120 to 190 miles per second, smashed into the cosmic cloud of gas and dust that surrounds HH 46/47. The red specks at the end of each bubble show the presence of hot sulfur and iron gas where the star's narrow jets are currently crashing head-on into the cosmic cloud's gas and dust material.

    Whenever astronomers observe a star, or snap a stellar portrait, through the lens of any telescope, they know that what they are seeing is slightly blurred. To clear up the blurring in Spitzer images, astronomers at the Jet Propulsion Laboratory developed an image processing technique for Spitzer called Hi-Res deconvolution.

    This process reduces blurring and makes the image sharper and cleaner, enabling astronomers to see the emissions around forming stars in greater detail. When scientists applied this image processing technique to the Spitzer image of HH 46/47, they were able to see winds from the star and jets of gas that are carving the celestial bubbles.

    This infrared image is a three-color composite, with data at 3.6 microns represented in blue, 4.5 and 5.8 microns shown in green, and 24 microns represented as red.

  3. Spectroscopic Binary Stars

    NASA Astrophysics Data System (ADS)

    Batten, A.; Murdin, P.

    2000-11-01

    Historically, spectroscopic binary stars were binary systems whose nature was discovered by the changing DOPPLER EFFECT or shift of the spectral lines of one or both of the component stars. The observed Doppler shift is a combination of that produced by the constant RADIAL VELOCITY (i.e. line-of-sight velocity) of the center of mass of the whole system, and the variable shift resulting from the o...

  4. ENERGY STAR Certified Products - Lighting

    EPA Pesticide Factsheets

    This data set contains a simplified list of all currently certified ENERGY STAR Lighting models with basic model information collected across all product categories including ENERGY STAR Unique IDs, ENERGY STAR partners, model names and numbers, and brand names. Learn more about ENERGY STAR products at www.energystar.gov/products. A full list of ENERGY STAR specifications can be found at www.energystar.gov/specifications.

  5. Radio emission from binary stars

    NASA Technical Reports Server (NTRS)

    Dulk, G. A.

    1986-01-01

    This paper reviews the radio emission from binary star systems - the emission processes that occur, the characteristics of the binary systems inferred from the radio observations, and the reasons for the activity. Several classes of binary stars are described including those with two main sequence stars, those with one normal star and a white dwarf, and those containing a neutron star or a black hole.

  6. Seeing Stars in Serpens

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Infant stars are glowing gloriously in this infrared image of the Serpens star-forming region, captured by NASA's Spitzer Space Telescope.

    The reddish-pink dots are baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create it. A dusty disk of cosmic debris, or 'protoplanetary disk,' that may eventually form planets, surrounds the infant stars.

    Wisps of green throughout the image indicate the presence of carbon rich molecules called polycyclic aromatic hydrocarbons. On Earth, these molecules can be found on charred barbecue grills and in automobile exhaust. Blue specks sprinkled throughout the image are background stars in our Milky Way galaxy.

    The Serpens star-forming region is located approximately 848 light-years away in the Serpens constellation.

    The image is a three-channel, false-color composite, where emission at 4.5 microns is blue, emission at 8.0 microns is green, and 24 micron emission is red.

  7. Young Stars with SALT

    NASA Astrophysics Data System (ADS)

    Riedel, Adric R.; Alam, Munazza K.; Rice, Emily L.; Cruz, Kelle L.; Henry, Todd J.

    2017-05-01

    We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77 systems. All of these dwarfs are low-proper-motion southern hemisphere objects and were identified in a nearby star survey with a demonstrated sensitivity to young stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph on the South African Large Telescope, we have determined radial velocities, H-alpha, lithium 6708 Å, and potassium 7699 Å equivalent widths linked to age and activity, and spectral types for all of our targets. Combined with astrometric information from literature sources, we identify 44 young stars. Eighteen are previously known members of moving groups within 100 pc of the Sun. Twelve are new members, including one member of the TW Hydra moving group, one member of the 32 Orionis moving group, 9 members of Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We also find 14 young star systems that are not members of any known groups. The remaining 33 star systems do not appear to be young. This appears to be evidence of a new population of nearby young stars not related to the known nearby young moving groups. Based on observations made with the Southern African Large Telescope (SALT).

  8. Seeing Stars in Serpens

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Infant stars are glowing gloriously in this infrared image of the Serpens star-forming region, captured by NASA's Spitzer Space Telescope.

    The reddish-pink dots are baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create it. A dusty disk of cosmic debris, or 'protoplanetary disk,' that may eventually form planets, surrounds the infant stars.

    Wisps of green throughout the image indicate the presence of carbon rich molecules called polycyclic aromatic hydrocarbons. On Earth, these molecules can be found on charred barbecue grills and in automobile exhaust. Blue specks sprinkled throughout the image are background stars in our Milky Way galaxy.

    The Serpens star-forming region is located approximately 848 light-years away in the Serpens constellation.

    The image is a three-channel, false-color composite, where emission at 4.5 microns is blue, emission at 8.0 microns is green, and 24 micron emission is red.

  9. Star formation around isolated T Tauri stars?

    NASA Astrophysics Data System (ADS)

    Hoff, W.; Pfau, W.; Henning, T.

    1996-02-01

    The authors want to present their search for young stellar objects around the two isolated T Tau stars TW Hya (Rucinski and Krautter 1983) and CoD -29°8887 (de la Reza et al. 1989). From the known spectroscopic features of these objects, TW Hya is to be classified as a classical T Tau star (CTTS), but it is not associated with a dark cloud region like all other known CTTSs. The same situation turns out for the weak-line T Tau star (WTTS) CoD -29°8887. One possible explanation for their isolated position is that they have formed from small dark clouds or globules, which were later destroyed. The authors carried out two ROSAT PSPC observations pointing at TW Hya and CoD -29°8887 and used a source detection procedure considering all the standard ROSAT energy bands to test this hypothesis. Spectroscopic follow-up observations were made for 24 possible T Tauri candidates, but there are no further low-mass young stellar objects in the vicinity of the two targets. The study shows that the objects are definitely not formed in a cluster at the positions of the objects.

  10. Collapsing Enormous Stars

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    One of the big puzzles in astrophysics is how supermassive black holes (SMBHs) managed to grow to the large sizes weve observed in the very early universe. In a recent study, a team of researchers examines the possibility that they were formed by the direct collapse of supermassive stars.Formation MysterySMBHs billions of times as massive as the Sun have been observed at a time when the universe was less than a billion years old. But thats not enough time for a stellar-mass black hole to grow to SMBH-size by accreting material so another theory is needed to explain the presence of these monsters so early in the universes history. A new study, led by Tatsuya Matsumoto (Kyoto University, Japan), poses the following question: what if supermassive stars in the early universe collapsed directly into black holes?Previous studies of star formation in the early universe have suggested that, in the hot environment of these primordial times, stars might have been able to build up mass much faster than they can today. This could result in early supermassive stars roughly 100,000 times more massive than the Sun. But if these early stars end their lives by collapsing to become massive black holes in the same way that we believe massive stars can collapse to form stellar-mass black holes today this should result in enormously violent explosions. Matusmoto and collaborators set out to model this process, to determine what we would expect to see when it happens!Energetic BurstsThe authors modeled the supermassive stars prior to collapse and then calculated whether a jet, created as the black hole grows at the center of the collapsing star, would be able to punch out of the stellar envelope. They demonstrated that the process would work much like the widely-accepted collapsar model of massive-star death, in which a jet successfully punches out of a collapsing star, violently releasing energy in the form of a long gamma-ray burst (GRB).Because the length of a long GRB is thought to

  11. Hot Subluminous Stars

    NASA Astrophysics Data System (ADS)

    Heber, U.

    2016-08-01

    Hot subluminous stars of spectral type B and O are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. Most hot subdwarf stars are chemically highly peculiar and provide a laboratory to study diffusion processes that cause these anomalies. The most obvious anomaly lies with helium, which may be a trace element in the atmosphere of some stars (sdB, sdO) while it may be the dominant species in others (He-sdB, He-sdO). Strikingly, the distribution in the Hertzsprung-Russell diagram of He-rich versus He-poor hot subdwarf stars of the globular clusters ω Cen and NGC 2808 differ from that of their field counterparts. The metal-abundance patterns of hot subdwarfs are typically characterized by strong deficiencies of some lighter elements as well as large enrichments of heavy elements. A large fraction of sdB stars are found in close binaries with white dwarf or very low-mass main sequence companions, which must have gone through a common-envelope (CE) phase of evolution. Because the binaries are detached they provide a clean-cut laboratory to study this important but yet poorly understood phase of stellar evolution. Hot subdwarf binaries with sufficiently massive white dwarf companions are viable candidate progenitors of type Ia supernovae both in the double degenerate as well as in the single degenerate scenario as helium donors for double detonation supernovae. The hyper-velocity He-sdO star US 708 may be the surviving donor of such a double detonation supernova. Substellar companions to sdB stars have also been found. For HW Vir systems the companion mass distribution extends from the stellar into the brown dwarf regime. A giant planet to the acoustic-mode pulsator V391 Peg was the first discovery of a planet that survived the red giant evolution of its host star. Evidence for Earth-size planets to two pulsating sdB stars have been reported and circumbinary giant planets or brown dwarfs have been found around HW

  12. Wolf-Rayet Stars

    NASA Astrophysics Data System (ADS)

    Hamann, Wolf-Rainer; Sander, Andreas; Todt, Helge

    Nearly 150 years ago, the French astronomers Charles Wolf and Georges Rayet described stars with very conspicuous spectra that are dominated by bright and broad emission lines. Meanwhile termed Wolf-Rayet Stars after their discoverers, those objects turned out to represent important stages in the life of massive stars. As the first conference in a long time that was specifically dedicated to Wolf-Rayet stars, an international workshop was held in Potsdam, Germany, from 1.-5. June 2015. About 100 participants, comprising most of the leading experts in the field as well as as many young scientists, gathered for one week of extensive scientific exchange and discussions. Considerable progress has been reported throughout, e.g. on finding such stars, modeling and analyzing their spectra, understanding their evolutionary context, and studying their circumstellar nebulae. While some major questions regarding Wolf-Rayet stars still remain open 150 years after their discovery, it is clear today that these objects are not just interesting stars as such, but also keystones in the evolution of galaxies. These proceedings summarize the talks and posters presented at the Potsdam Wolf-Rayet workshop. Moreover, they also include the questions, comments, and discussions emerging after each talk, thereby giving a rare overview not only about the research, but also about the current debates and unknowns in the field. The Scientific Organizing Committee (SOC) included Alceste Bonanos (Athens), Paul Crowther (Sheffield), John Eldridge (Auckland), Wolf-Rainer Hamann (Potsdam, Chair), John Hillier (Pittsburgh), Claus Leitherer (Baltimore), Philip Massey (Flagstaff), George Meynet (Geneva), Tony Moffat (Montreal), Nicole St-Louis (Montreal), and Dany Vanbeveren (Brussels).

  13. Models of symbiotic stars

    NASA Technical Reports Server (NTRS)

    Friedjung, Michael

    1993-01-01

    One of the most important features of symbiotic stars is the coexistence of a cool spectral component that is apparently very similar to the spectrum of a cool giant, with at least one hot continuum, and emission lines from very different stages of ionization. The cool component dominates the infrared spectrum of S-type symbiotics; it tends to be veiled in this wavelength range by what appears to be excess emission in D-type symbiotics, this excess usually being attributed to circumstellar dust. The hot continuum (or continua) dominates the ultraviolet. X-rays have sometimes also been observed. Another important feature of symbiotic stars that needs to be explained is the variability. Different forms occur, some variability being periodic. This type of variability can, in a few cases, strongly suggest the presence of eclipses of a binary system. One of the most characteristic forms of variability is that characterizing the active phases. This basic form of variation is traditionally associated in the optical with the veiling of the cool spectrum and the disappearance of high-ionization emission lines, the latter progressively appearing (in classical cases, reappearing) later. Such spectral changes recall those of novae, but spectroscopic signatures of the high-ejection velocities observed for novae are not usually detected in symbiotic stars. However, the light curves of the 'symbiotic nova' subclass recall those of novae. We may also mention in this connection that radio observations (or, in a few cases, optical observations) of nebulae indicate ejection from symbiotic stars, with deviations from spherical symmetry. We shall give a historical overview of the proposed models for symbiotic stars and make a critical analysis in the light of the observations of symbiotic stars. We describe the empirical approach to models and use the observational data to diagnose the physical conditions in the symbiotics stars. Finally, we compare the results of this empirical

  14. Compact Star Time Scales

    NASA Astrophysics Data System (ADS)

    Swank, J. H.

    1996-12-01

    A major goal of RXTE is to investigate the fastest timing signals from compact stars, especially neutron stars and black holes. Signals have now been found from many (at least nine) low mass X-ray binaries containing neutron stars in the frequency range (100-1200 Hz) expected for the rotation period of the neutron star after being spun up by accretion over a long period. The kilohertz frequency domain for these sources is simpler than the domain of oscillations below about 50 Hz in that a few isolated features can dominate over white noise. However there are three main features to consider (not all present at the same time) and at least two are quasiperiodic with varying widths and frequencies. Several models are pitting their predictions against the behavior of these features, but the bursters, especially, appear to be revealing the neutron stars's spin. It is consistent with our beliefs that no black hole candidate has shown the same complex of signals, although at least one QPO frequency of a few hundred Hz could be expected in black hole candidates by analogy to the 67 Hz observed from GRS 1915+105. The observations also provide critical tests of the interpretions of the lower frequency (5-50 Hz) QPO and the variable noise seen in both low magnetic field neutron stars and black hole candidates. The kilohertz features have not been seen from the accreting pulsars with relatively high magnetic fields, but high luminosity pulsars (such as last year's transient, GRO J1744-28) reveal signatures of the dynamic interaction between the accretion flow, the magnetic field, and perhaps the neutron star surface in addition to their coherent pulsations.

  15. Life Cycle of Stars

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In this stunning picture of the giant galactic nebula NGC 3603, the crisp resolution of NASA's Hubble Space Telescope captures various stages of the life cycle of stars in one single view. To the upper left of center is the evolved blue supergiant called Sher 25. The star has a unique circumstellar ring of glowing gas that is a galactic twin to the famous ring around the supernova 1987A. The grayish-bluish color of the ring and the bipolar outflows (blobs to the upper right and lower left of the star) indicates the presence of processed (chemically enriched) material. Near the center of the view is a so-called starburst cluster dominated by young, hot Wolf-Rayet stars and early O-type stars. A torrent of ionizing radiation and fast stellar winds from these massive stars has blown a large cavity around the cluster. The most spectacular evidence for the interaction of ionizing radiation with cold molecular-hydrogen cloud material are the giant gaseous pillars to the right of the cluster. These pillars are sculptured by the same physical processes as the famous pillars Hubble photographed in the M16 Eagle Nebula. Dark clouds at the upper right are so-called Bok globules, which are probably in an earlier stage of star formation. To the lower left of the cluster are two compact, tadpole-shaped emission nebulae. Similar structures were found by Hubble in Orion, and have been interpreted as gas and dust evaporation from possibly protoplanetary disks (proplyds). This true-color picture was taken on March 5, 1999 with the Wide Field Planetary Camera 2.

  16. Star Caught Smoking

    NASA Astrophysics Data System (ADS)

    2007-08-01

    VLTI Snapshots Dusty Puff Around Variable Star Using ESO's Very Large Telescope Interferometer, astronomers from France and Brazil have detected a huge cloud of dust around a star. This observation is further evidence for the theory that such stellar puffs are the cause of the repeated extreme dimming of the star. ESO PR Photo 34a/07 ESO PR Photo 34a/07 Dust Cloud in a R CrB Star (Artist's Impression) R Coronae Borealis stars are supergiants exhibiting erratic variability. Named after the first star that showed such behaviour [1], they are more than 50 times larger than our Sun. R Coronae Borealis stars can see their apparent brightness unpredictably decline to a thousandth of their nominal value within a few weeks, with the return to normal light levels being much slower. It has been accepted for decades that such fading could be due to obscuration of the stellar surface by newly formed dusty clouds. This 'Dust Puff Theory' suggests that mass is lost from the R Coronae Borealis (or R CrB for short) star and then moves away until the temperature is low enough for carbon dust to form. If the newly formed dust cloud is located along our line-of-sight, it eclipses the star. As the dust is blown away by the star's strong light, the 'curtain' vanishes and the star reappears. RY Sagittarii is the brightest member in the southern hemisphere of this family of weird stars. Located about 6,000 light-years away towards the constellation of Sagittarius (The Archer), its peculiar nature was discovered in 1895 by famous Dutch astronomer Jacobus Cornelius Kapteyn. In 2004, near-infrared adaptive optics observations made with NACO on ESO's Very Large Telescope allowed astronomers Patrick de Laverny and Djamel Mékarnia to clearly detect the presence of clouds around RY Sagittarii. This was the first direct confirmation of the standard scenario explaining the light variations of R CrB stars by the presence of heterogeneities in their envelope surrounding the star. ESO PR Photo 32e

  17. Fingerprinting Nearby Star Suspects

    NASA Astrophysics Data System (ADS)

    Henry, Todd J.; Bean, Jacob; Golimowski, Dave; Jao, Wei-Chun; Subasavage, John; Walkowicz, Lucianne

    2002-02-01

    To identify and characterize the Sun's neighbors, we propose to obtain red spectra (5300-9900+ Å) for suspected nearby red, brown, and white dwarfs. These spectra play an important role in a new parallax effort initiated as part of a small telescope consortium operating at CTIO. This new effort, CTIOPI2, will be an expansion of the highly successful CTIOPI effort - an NOAO Surveys Program in which we are measuring parallaxes for more than 200 southern nearby stars. Both are carried out under the RECONS (Research Consortium on Nearby Stars) effort based at Georgia State U., Johns Hopkins U., and U. Virginia. During RECONS' two previous CTIO spectroscopic observing runs, we had two partly cloudy nights in Feb 1998, and three rainy nights in Jul 2001. Nonetheless, from the earlier run's meager data we have identified six new stars within 25 pc, two of which lie within 10 pc. High quality spectra for these new nearby stars are being provided to the fundamental database of the NASA/NSF NStars Project. This proposal is similar to our previous proposal, 2001A-0270, although we now include three new samples of stars that are being examined for CTIOPI2 targets. These samples are being used for both PhD (Jao, Subasavage) and undergraduate senior (Bean, Walkowicz) theses.

  18. Circulation of Stars

    NASA Astrophysics Data System (ADS)

    Boitani, P.

    2016-01-01

    Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

  19. Apollo Project- star projector

    NASA Technical Reports Server (NTRS)

    1964-01-01

    The specially designed star projector used in the Projection Planetarium. From A.W. Vogeley, 'Piloted Space-Flight Simulation at Langley Research Center,' Paper presented at the American Society of Mechanical Engineers, 1966 Winter Meeting, New York, NY, November 27 - December 1, 1966. 'Another approach to the scene-generation problem is the point-light-source projection technique. This technique has been used in the Langley Projection Planetarium,... to study Apollo launch-abort problems. This method was very effective in providing the required horizon-to-horizon view of Florida as seen from about 100,000 feet.' 'This projector operates on a concept developed by Spitz. It consists of a point-light source reflecting off a centrally located highly reflective sphere which directs the light outward through the many holes representing the stars. The size of the holes is varied to vary star magnitude. The star images are brought into focus on the inside of the planetarium by lenses glued to the surface of the projector and the diameter of the projection sphere govern the focal length required for these lenses. Although this type of projector does not have the precision required for the study of navigation problems it is very adequate for pilot control problems such as rendezvous where the star field is primarily used as an attitude reference.'

  20. Nursery of New Stars

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This is a Hubble Space Telescope image (right) of a vast nebula called NGC 604, which lies in the neighboring spiral galaxy M33, located 2.7 million light-years away in the constellation Triangulum. This is a site where new stars are being born in a spiral arm of the galaxy. Though such nebulae are common in galaxies, this one is particularly large, nearly 1,500 light-years across. The nebula is so vast it is easily seen in ground-based telescopic images (left). At the heart of NGC 604 are over 200 hot stars, much more massive than our Sun (15 to 60 solar masses). They heat the gaseous walls of the nebula making the gas fluoresce. Their light also highlights the nebula's three-dimensional shape, like a lantern in a cavern. By studying the physical structure of a giant nebula, astronomers may determine how clusters of massive stars affect the evolution of the interstellar medium of the galaxy. The nebula also yields clues to its star formation history and will improve understanding of the starburst process when a galaxy undergoes a 'firestorm' of star formation. The image was taken on January 17, 1995 with Hubble's Wide Field and Planetary Camera 2. Separate exposures were taken in different colors of light to study the physical properties of the hot gas (17,000 degrees Fahrenheit, 10,000 degrees Kelvin

  1. Origin of Neutron Stars

    NASA Astrophysics Data System (ADS)

    Brecher, K.

    1999-12-01

    The origin of the concept of neutron stars can be traced to two brief, incredibly insightful publications. Work on the earlier paper by Lev Landau (Phys. Z. Sowjetunion, 1, 285, 1932) actually predated the discovery of neutrons. Nonetheless, Landau arrived at the notion of a collapsed star with the density of a nucleus (really a "nucleus star") and demonstrated (at about the same time as, and independent of, Chandrasekhar) that there is an upper mass limit for dense stellar objects of about 1.5 solar masses. Perhaps even more remarkable is the abstract of a talk presented at the December 1933 meeting of the American Physical Society published by Walter Baade and Fritz Zwicky in 1934 (Phys. Rev. 45, 138). It followed the discovery of the neutron by just over a year. Their report, which was about the same length as the present abstract: (1) invented the concept and word supernova; (2) suggested that cosmic rays are produced by supernovae; and (3) in the authors own words, proposed "with all reserve ... the view that supernovae represent the transitions from ordinary stars to neutron stars (italics), which in their final stages consist of extremely closely packed neutrons." The abstract by Baade and Zwicky probably contains the highest density of new, important (and correct) ideas in high energy astrophysics ever published in a single paper. In this talk, we will discuss some of the facts and myths surrounding these two publications.

  2. Condensate dark matter stars

    SciTech Connect

    Li, X.Y.; Harko, T.; Cheng, K.S. E-mail: harko@hkucc.hku.hk

    2012-06-01

    We investigate the structure and stability properties of compact astrophysical objects that may be formed from the Bose-Einstein condensation of dark matter. Once the critical temperature of a boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Therefore we model the dark matter inside the star as a Bose-Einstein condensate. In the condensate dark matter star model, the dark matter equation of state can be described by a polytropic equation of state, with polytropic index equal to one. We derive the basic general relativistic equations describing the equilibrium structure of the condensate dark matter star with spherically symmetric static geometry. The structure equations of the condensate dark matter stars are studied numerically. The critical mass and radius of the dark matter star are given by M{sub crit} ≈ 2(l{sub a}/1fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2}M{sub s}un and R{sub crit} ≈ 1.1 × 10{sup 6}(l{sub a}/1 fm){sup 1/2}(m{sub χ}/1 GeV){sup −3/2} cm respectively, where l{sub a} and m{sub χ} are the scattering length and the mass of dark matter particle, respectively.

  3. Characterizing Retired A Stars

    NASA Astrophysics Data System (ADS)

    Ghezzi, Luan; Johnson, John

    2015-08-01

    A complete understanding of the formation and evolution of planetary systems depends on the precise characterization of the planets and their host stars. The stellar mass is particularly important because it might influence the planet occurrence and it is used to constrain the planetary masses, thus providing information about the systems' architectures. Single FGK stars on the main sequence usually have precise masses estimated from evolutionary tracks, but the results of this method for subgiants and giants have recently been called into question. In this work, we describe the ongoing efforts to precisely constrain the masses of evolved stars using benchmark subgiants and giants from the literature as well as the sample of retired A stars observed by the California Planet Search survey. Different input atmospheric parameters (from excitation and ionization equilibria, spectral synthesis, interferometry and photometry) and methods (evolutionary tracks, asteroseismology and lithium abundances) are used to critically evaluate the stellar masses and its uncertainties. Preliminary results are discussed and suggest that current mass determinations for evolved stars do not present any significant systematic errors.

  4. Four new Delta Scuti stars

    NASA Technical Reports Server (NTRS)

    Schutt, R. L.

    1991-01-01

    Four new Delta Scuti stars are reported. Power, modified into amplitude, spectra, and light curves are used to determine periodicities. A complete frequency analysis is not performed due to the lack of a sufficient time base in the data. These new variables help verify the many predictions that Delta Scuti stars probably exist in prolific numbers as small amplitude variables. Two of these stars, HR 4344 and HD 107513, are possibly Am stars. If so, they are among the minority of variable stars which are also Am stars.

  5. Blurred Star Image Processing for Star Sensors under Dynamic Conditions

    PubMed Central

    Zhang, Weina; Quan, Wei; Guo, Lei

    2012-01-01

    The precision of star point location is significant to identify the star map and to acquire the aircraft attitude for star sensors. Under dynamic conditions, star images are not only corrupted by various noises, but also blurred due to the angular rate of the star sensor. According to different angular rates under dynamic conditions, a novel method is proposed in this article, which includes a denoising method based on adaptive wavelet threshold and a restoration method based on the large angular rate. The adaptive threshold is adopted for denoising the star image when the angular rate is in the dynamic range. Then, the mathematical model of motion blur is deduced so as to restore the blurred star map due to large angular rate. Simulation results validate the effectiveness of the proposed method, which is suitable for blurred star image processing and practical for attitude determination of satellites under dynamic conditions. PMID:22778666

  6. Collapse of axion stars

    SciTech Connect

    Eby, Joshua; Leembruggen, Madelyn; Suranyi, Peter; Wijewardhana, L. C. R.

    2016-12-15

    Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leading-order expansion of the axion potential. Here, heavier states are susceptible to gravitational collapse. Inclusion of higher-order interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leading-order expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present in the full potential, providing evidence that such objects do not form black holes. In the last moments of collapse, the binding energy of the axion star grows rapidly, and we provide evidence that a large amount of its energy is lost through rapid emission of relativistic axions.

  7. GRACE star camera noise

    NASA Astrophysics Data System (ADS)

    Harvey, Nate

    2016-08-01

    Extending results from previous work by Bandikova et al. (2012) and Inacio et al. (2015), this paper analyzes Gravity Recovery and Climate Experiment (GRACE) star camera attitude measurement noise by processing inter-camera quaternions from 2003 to 2015. We describe a correction to star camera data, which will eliminate a several-arcsec twice-per-rev error with daily modulation, currently visible in the auto-covariance function of the inter-camera quaternion, from future GRACE Level-1B product releases. We also present evidence supporting the argument that thermal conditions/settings affect long-term inter-camera attitude biases by at least tens-of-arcsecs, and that several-to-tens-of-arcsecs per-rev star camera errors depend largely on field-of-view.

  8. Heavy Metal Stars

    NASA Astrophysics Data System (ADS)

    2001-08-01

    La Silla Telescope Detects Lots of Lead in Three Distant Binaries Summary Very high abundances of the heavy element Lead have been discovered in three distant stars in the Milky Way Galaxy . This finding strongly supports the long-held view that roughly half of the stable elements heavier than Iron are produced in common stars during a phase towards the end of their life when they burn their Helium - the other half results from supernova explosions. All the Lead contained in each of the three stars weighs about as much as our Moon. The observations show that these "Lead stars" - all members of binary stellar systems - have been more enriched with Lead than with any other chemical element heavier than Iron. This new result is in excellent agreement with predictions by current stellar models about the build-up of heavy elements in stellar interiors. The new observations are reported by a team of Belgian and French astronomers [1] who used the Coude Echelle Spectrometer on the ESO 3.6-m telescope at the La Silla Observatory (Chile). PR Photo 26a/01 : A photo of HD 196944 , one of the "Lead stars". PR Photo 26b/01 : A CES spectrum of HD 196944 . The build-up of heavy elements Astronomers and physicists denote the build-up of heavier elements from lighter ones as " nucleosynthesis ". Only the very lightest elements (Hydrogen, Helium and Lithium [2]) were created at the time of the Big Bang and therefore present in the early universe. All the other heavier elements we now see around us were produced at a later time by nucleosynthesis inside stars. In those "element factories", nuclei of the lighter elements are smashed together whereby they become the nuclei of heavier ones - this process is known as nuclear fusion . In our Sun and similar stars, Hydrogen is being fused into Helium. At some stage, Helium is fused into Carbon, then Oxygen, etc. The fusion process requires positively charged nuclei to move very close to each other before they can unite. But with increasing

  9. Giant star seismology

    NASA Astrophysics Data System (ADS)

    Hekker, S.; Christensen-Dalsgaard, J.

    2017-06-01

    The internal properties of stars in the red-giant phase undergo significant changes on relatively short timescales. Long near-uninterrupted high-precision photometric timeseries observations from dedicated space missions such as CoRoT and Kepler have provided seismic inferences of the global and internal properties of a large number of evolved stars, including red giants. These inferences are confronted with predictions from theoretical models to improve our understanding of stellar structure and evolution. Our knowledge and understanding of red giants have indeed increased tremendously using these seismic inferences, and we anticipate that more information is still hidden in the data. Unraveling this will further improve our understanding of stellar evolution. This will also have significant impact on our knowledge of the Milky Way Galaxy as well as on exo-planet host stars. The latter is important for our understanding of the formation and structure of planetary systems.

  10. Neutron star crusts

    NASA Technical Reports Server (NTRS)

    Lorenz, C. P.; Ravenhall, D. G.; Pethick, C. J.

    1993-01-01

    We calculate properties of neutron star matter at subnuclear densities using an improved nuclear Hamiltonian. Nuclei disappear and the matter becomes uniform at a density of about 0.6n(s), where n(s) of about 0.16/cu fm is the saturation density of nuclear matter. As a consequence, the mass of matter in the crusts of neutron stars is only about half as large as previously estimated. In about half of that crustal mass, nuclear matter occurs in shapes very different from the roughly spherical nuclei familiar at lower densities. The thinner crust and the unusual nuclear shape have important consequences for theories of the rotational and thermal evolution of neutron stars, especialy theories of glitches.

  11. Collapse of axion stars

    DOE PAGES

    Eby, Joshua; Leembruggen, Madelyn; Suranyi, Peter; ...

    2016-12-15

    Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leading-order expansion of the axion potential. Here, heavier states are susceptible to gravitational collapse. Inclusion of higher-order interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leading-order expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present inmore » the full potential, providing evidence that such objects do not form black holes. In the last moments of collapse, the binding energy of the axion star grows rapidly, and we provide evidence that a large amount of its energy is lost through rapid emission of relativistic axions.« less

  12. Extensive Lesions in the Gustatory Cortex in the Rat Do Not Disrupt the Retention of a Presurgically Conditioned Taste Aversion and Do Not Impair Unconditioned Concentration-Dependent Licking of Sucrose and Quinine

    PubMed Central

    2014-01-01

    Although damage to gustatory cortex (GC) in the rat has been reported to severely impair, if not eliminate, retention of a presurgically conditioned taste aversion (CTA), it has equivocal effects on taste preference as measured by intake tests. Because intake tests can be influenced by nongustatory (e.g., postingestive) factors, we employed the brief-access taste test to assess the effects of ibotenic acid–induced lesions targeting the GC on unconditioned licking to a sucrose and then a quinine concentration series in a specialized lickometer. As a functional lesion assessment, a presurgical CTA to 0.1M NaCl was established in thirsty rats by following 15-min intake with intraperitoneal administration of either LiCl (or NaCl for control) on 2 occasions. Both conditioned sham-operated (SHAM) rats and rats with histologically confirmed extensive damage to the GC (GCX) avoided a NaCl concentration series relative to unconditioned controls in a postsurgical brief-access CTA test, with no difference between the surgical groups in their responses to NaCl or similar concentrations of KCl. GCX rats also did not differ from SHAM rats in the EC50 of concentration–response functions for sucrose or quinine. Clearly, the critical cortical area required for the retention of a presurgical CTA falls outside of the extensive area of damage, which was well centered within the conventionally defined gustatory zone of the insular cortex. The absence of an effect on unconditioned responsiveness to sucrose and quinine suggests that the damaged region is also unnecessary for the normal expression of affective licking responses to tastants. PMID:24226296

  13. General Relativity&Compact Stars

    SciTech Connect

    Glendenning, Norman K.

    2005-08-16

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10{sup 14} times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed.

  14. Spectroscopic study of extended star clusters in dwarf galaxy NGC 6822

    SciTech Connect

    Hwang, Narae; Kim, Sang Chul; Park, Hong Soo; Lee, Myung Gyoon; Lim, Sungsoon; Hodge, Paul W.; Weisz, Daniel; Miller, Bryan

    2014-03-01

    We present a spectroscopic study of the four extended star clusters (ESCs) in NGC 6822 based on the data obtained with the Gemini Multi-Object Spectrograph on the Gemini-South 8.1 m telescope. The radial velocities derived from the spectra range from –61.2 ± 20.4 km s{sup –1} (for C1) to –115.34 ± 57.9 km s{sup –1} (for C4) and, unlike the intermediate-age carbon stars, they do not display any sign of systematic rotation around NGC 6822. The ages and metallicities derived using the Lick indices show that the ESCs are old (≥8 Gyr) and metal poor ([Fe/H] ≲ –1.5). NGC 6822 is found to have both metal poor ([Fe/H] ≈–2.0) and metal rich ([Fe/H] ≈–0.9) star clusters within 15' (2 kpc) from the center, whereas only metal poor clusters are observed in the outer halo with r ≥ 20'(2.6 kpc). The kinematics, old ages, and low metallicities of ESCs suggest that ESCs may have accreted into the halo of NGC 6822. Based on the velocity distribution of ESCs, we have determined the total mass and the mass-to-light ratio of NGC 6822: M{sub N6822}=7.5{sub −0.1}{sup +4.5}×10{sup 9} M{sub ⊙} and (M/L){sub N6822}=75{sub −1}{sup +45}(M/L){sub ⊙}. It shows that NGC 6822 is one of the most dark matter dominated dwarf galaxies in the Local Group.

  15. Pulsating Star Mystery Solved

    NASA Astrophysics Data System (ADS)

    2010-11-01

    By discovering the first double star where a pulsating Cepheid variable and another star pass in front of one another, an international team of astronomers has solved a decades-old mystery. The rare alignment of the orbits of the two stars in the double star system has allowed a measurement of the Cepheid mass with unprecedented accuracy. Up to now astronomers had two incompatible theoretical predictions of Cepheid masses. The new result shows that the prediction from stellar pulsation theory is spot on, while the prediction from stellar evolution theory is at odds with the new observations. The new results, from a team led by Grzegorz Pietrzyński (Universidad de Concepción, Chile, Obserwatorium Astronomiczne Uniwersytetu Warszawskiego, Poland), appear in the 25 November 2010 edition of the journal Nature. Grzegorz Pietrzyński introduces this remarkable result: "By using the HARPS instrument on the 3.6-metre telescope at ESO's La Silla Observatory in Chile, along with other telescopes, we have measured the mass of a Cepheid with an accuracy far greater than any earlier estimates. This new result allows us to immediately see which of the two competing theories predicting the masses of Cepheids is correct." Classical Cepheid Variables, usually called just Cepheids, are unstable stars that are larger and much brighter than the Sun [1]. They expand and contract in a regular way, taking anything from a few days to months to complete the cycle. The time taken to brighten and grow fainter again is longer for stars that are more luminous and shorter for the dimmer ones. This remarkably precise relationship makes the study of Cepheids one of the most effective ways to measure the distances to nearby galaxies and from there to map out the scale of the whole Universe [2]. Unfortunately, despite their importance, Cepheids are not fully understood. Predictions of their masses derived from the theory of pulsating stars are 20-30% less than predictions from the theory of the

  16. Really Hot Stars

    NASA Astrophysics Data System (ADS)

    2003-04-01

    Spectacular VLT Photos Unveil Mysterious Nebulae Summary Quite a few of the most beautiful objects in the Universe are still shrouded in mystery. Even though most of the nebulae of gas and dust in our vicinity are now rather well understood, there are some which continue to puzzle astronomers. This is the case of a small number of unusual nebulae that appear to be the subject of strong heating - in astronomical terminology, they present an amazingly "high degree of excitation". This is because they contain significant amounts of ions, i.e., atoms that have lost one or more of their electrons. Depending on the atoms involved and the number of electrons lost, this process bears witness to the strength of the radiation or to the impact of energetic particles. But what are the sources of that excitation? Could it be energetic stars or perhaps some kind of exotic objects inside these nebulae? How do these peculiar objects fit into the current picture of universal evolution? New observations of a number of such unusual nebulae have recently been obtained with the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). In a dedicated search for the origin of their individual characteristics, a team of astronomers - mostly from the Institute of Astrophysics & Geophysics in Liège (Belgium) [1] - have secured the first detailed, highly revealing images of four highly ionized nebulae in the Magellanic Clouds, two small satellite galaxies of our home galaxy, the Milky Way, only a few hundred thousand light-years away. In three nebulae, they succeeded in identifying the sources of energetic radiation and to eludicate their exceptional properties: some of the hottest, most massive stars ever seen, some of which are double. With masses of more than 20 times that of the Sun and surface temperatures above 90 000 degrees, these stars are truly extreme. PR Photo 09a/03: Nebula around the hot star AB7 in the SMC. PR Photo 09b/03: Nebula near the hot Wolf-Rayet star BAT99

  17. American Urban Star Fest

    NASA Astrophysics Data System (ADS)

    Pazmino, John

    2003-12-01

    Over the last couple of decades New York City implemented, and continues to carry out, several schemes of eradicating luminous graffiti. One result has been the gradual recovery of the natural night sky. By 1994 the normal clear sky transparency over Manhattan deepened to fourth magnitude and has been slowly creeping deeper, until in 2002 it is at magnitude 4 to 4.5. In the spring of 1995, during some lazing on a Manhattan rooftop under a sky full of stars, several New York astronomers hatched the idea of letting the whole people celebrate the renewed starry sky. In due course they, through the Amateur Astronomers Association, engaged the New York City Parks Department and the Urban Park Rangers in an evening of quiet picnicking to enjoy the stars in their natural sky. Thus the Urban Star Fest was born. The event thrilled about 3,000 visitors in Central Park's Sheep Meadow on Saturday 30 September 1995. This year's Fest, the eighth in the series demonstrated the City's upper skyline of stars on Saturday 5 October 2002 to about 2,200 enthused visitors. Although the Fest is always noted as cancelable for inclement weather, so far, it has convened every year, with attendance ranging from 4,000 down to a mere 1,000, this latter being under the smoke plume of the World Trade Center in 2001. Despite this swing in attendance, the American Urban Star Fest is America's largest regularly scheduled public astronomy event. Of course, special occasions, like comets or eclipses, can and do attract far larger interest both in the city and elsewhere. The presentation shows the setup and program of the American Urban Star Fest, to illustrate how the general public can actively become aware of the night sky and see for themselves the result of their very own efforts at removing light pollution--and note where improvement is yet to come.

  18. Weighing the Smallest Stars

    NASA Astrophysics Data System (ADS)

    2005-01-01

    VLT Finds Young, Very Low Mass Objects Are Twice As Heavy As Predicted Summary Thanks to the powerful new high-contrast camera installed at the Very Large Telescope, photos have been obtained of a low-mass companion very close to a star. This has allowed astronomers to measure directly the mass of a young, very low mass object for the first time. The object, more than 100 times fainter than its host star, is still 93 times as massive as Jupiter. And it appears to be almost twice as heavy as theory predicts it to be. This discovery therefore suggests that, due to errors in the models, astronomers may have overestimated the number of young "brown dwarfs" and "free floating" extrasolar planets. PR Photo 03/05: Near-infrared image of AB Doradus A and its companion (NACO SDI/VLT) A winning combination A star can be characterised by many parameters. But one is of uttermost importance: its mass. It is the mass of a star that will decide its fate. It is thus no surprise that astronomers are keen to obtain a precise measure of this parameter. This is however not an easy task, especially for the least massive ones, those at the border between stars and brown dwarf objects. Brown dwarfs, or "failed stars", are objects which are up to 75 times more massive than Jupiter, too small for major nuclear fusion processes to have ignited in its interior. To determine the mass of a star, astronomers generally look at the motion of stars in a binary system. And then apply the same method that allows determining the mass of the Earth, knowing the distance of the Moon and the time it takes for its satellite to complete one full orbit (the so-called "Kepler's Third Law"). In the same way, they have also measured the mass of the Sun by knowing the Earth-Sun distance and the time - one year - it takes our planet to make a tour around the Sun. The problem with low-mass objects is that they are very faint and will often be hidden in the glare of the brighter star they orbit, also when viewed

  19. Computational astrophysics: Pulsating stars

    NASA Astrophysics Data System (ADS)

    Davis, C. G.

    The field of computational astrophysics in pulsating star studies has grown considerably since the advent of the computer. Initially calculations were done on the IBM 704 with 32K of memory and now we use the CRAY YMP computers with considerably more memory. Our early studies were for models of pulsating stars using a 1D Lagrangian hydrodynamic code (SPEC) with radiation diffusion. The radiative transfer was treated in the equilibrium diffusion approximation and the hydrodynamics was done utilizing the approximation of artificial viscosity. The early calculations took many hours of 704 CPU time. Early in 1965 we decided to improve on the usual treatment of the radiative transfer used in our codes by utilizing the method of moments, the so-called variable Eddington approximation. In this approximation the material energy field is uncoupled from the radiation energy field and the angular dependence is introduced through the Eddington factor. A multigroup frequency dependent method may also be applied. The Eddington factor is determined by snapshots of the stars structure utilizing a y-line approximation. The full radiative transfer approximation appears necessary in order to understand the light curves for W Virginia stars and may be important for the light curves of RR Lyrae stars. A detailed radiative transfer method does not appear to be necessary for the understanding of Cepheid light curves. A recent improvement to our models for pulsating stars is in the use of an adaptive mesh scheme to resolve the sharp features in the nonlinear hydrodynamic structure. From these improved structures, better analysis of the radius, velocity, and light curves could be obtained.

  20. Morphodynamics of star dunes

    NASA Astrophysics Data System (ADS)

    Zhang, D.; Narteau, C.; Rozier, O.; Courrech du Pont, S.

    2012-04-01

    Star dunes are among the biggest and the most impressive dunes in Earth sand seas. Nonetheless, they remain poorly studied, probably because of their apparent complexity. They are massive pyramidal dunes with interlaced arms whose slip faces are oriented in various directions. Being large, they can integrate wind properties over a wide range of time scales. Thus, they are observed for wind regimes with multiple directions, and may result from the amalgamation of dunes or from the development of arms on a well-established dune pattern. In both cases, the roles of wind directional variability and secondary flow have been emphasized but not precisely quantified. Here, we report simulations where the star dune shape results from a a combination of longitudinal dunes, which form the star dune arms. These arms may radiate and so interact with the other dunes in the field. This mass exchange, controlled by the morphodynamics of star dunes arms, must play an important role in the large-scale arrangement of star dunes networks. We first demonstrate that star dune arms orientation maximizes the flux in the direction of crests. This is opposed to the usually admit dunes orientation, which maximizes the sediment transport perpendicular to the crest. Indeed, depending on sand availability, dunes development results from the growth of a wave on a sand bed or from a net transport of sediment, which grows and extends an isolated longitudinal dune over a non-erodible soil. These two different mechanisms lead to two different modes of crests orientation. Then, we show that the propagating arms reach a stationary state characterized by constant width, height and growth rate. These are controlled by the frequency at which the wind changes direction. Arm width and height increase, whereas the propagation speed decreases with a decreasing frequency. These morphodynamics properties are helpful to assess from pattern observation the variability of wind directionality over several time

  1. A Real Shooting Star

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of A Real Shooting Star

    This artist's animation illustrates a star flying through our galaxy at supersonic speeds, leaving a 13-light-year-long trail of glowing material in its wake. The star, named Mira (pronounced my-rah) after the latin word for 'wonderful,' sheds material that will be recycled into new stars, planets and possibly even life. NASA's Galaxy Evolution Explorer discovered the long trail of material behind Mira during its survey of the entire sky in ultraviolet light.

    The animation begins by showing a close-up of Mira -- a red-giant star near the end of its life. Red giants are red in color and extremely bloated; for example, if a red giant were to replace our sun, it would engulf everything out to the orbit of Mars. They constantly blow off gas and dust in the form of stellar winds, supplying the galaxy with molecules, such as oxygen and carbon, that will make their way into new solar systems. Our sun will mature into a red giant in about 5 billion years.

    As the animation pulls out, we can see the enormous trail of material deposited behind Mira as it hurls along between the stars. Like a boat traveling through water, a bow shock, or build up of gas, forms ahead of the star in the direction of its motion. Gas in the bow shock is heated and then mixes with the cool hydrogen gas in the wind that is blowing off Mira. This heated hydrogen gas then flows around behind the star, forming a turbulent wake.

    Why does the trailing hydrogen gas glow in ultraviolet light? When it is heated, it transitions into a higher-energy state, which then loses energy by emitting ultraviolet light - a process known as fluorescence.

    Finally, the artist's rendering gives way to the actual ultraviolet image taken by the Galaxy Evolution Explorer

    Mira is located 350 light-years from Earth in the constellation Cetus, otherwise known as the whale. Coincidentally, Mira

  2. Synthetic guide star generation

    DOEpatents

    Payne, Stephen A.; Page, Ralph H.; Ebbers, Christopher A.; Beach, Raymond J.

    2004-03-09

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  3. Neutrinos from neutron stars

    NASA Technical Reports Server (NTRS)

    Helfand, D. J.

    1979-01-01

    A calculation of the flux of ultra-high energy neutrinos from galactic neutron stars is presented. The calculation is used to determine the number of point sources detectable at the sensitivity threshold of a proposed deep underwater muon and neutrino detector array. The detector array would have a point source detection threshold of about 100 eV/sq cm-sec. Analysis of neutrino luminosities and the number of detectable sources suggests that the deep underwater detector may make a few discoveries. In particular, a suspected neutron star in the Cyg X-3 source seems a promising target for the deep underwater array.

  4. A Real Shooting Star

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of A Real Shooting Star

    This artist's animation illustrates a star flying through our galaxy at supersonic speeds, leaving a 13-light-year-long trail of glowing material in its wake. The star, named Mira (pronounced my-rah) after the latin word for 'wonderful,' sheds material that will be recycled into new stars, planets and possibly even life. NASA's Galaxy Evolution Explorer discovered the long trail of material behind Mira during its survey of the entire sky in ultraviolet light.

    The animation begins by showing a close-up of Mira -- a red-giant star near the end of its life. Red giants are red in color and extremely bloated; for example, if a red giant were to replace our sun, it would engulf everything out to the orbit of Mars. They constantly blow off gas and dust in the form of stellar winds, supplying the galaxy with molecules, such as oxygen and carbon, that will make their way into new solar systems. Our sun will mature into a red giant in about 5 billion years.

    As the animation pulls out, we can see the enormous trail of material deposited behind Mira as it hurls along between the stars. Like a boat traveling through water, a bow shock, or build up of gas, forms ahead of the star in the direction of its motion. Gas in the bow shock is heated and then mixes with the cool hydrogen gas in the wind that is blowing off Mira. This heated hydrogen gas then flows around behind the star, forming a turbulent wake.

    Why does the trailing hydrogen gas glow in ultraviolet light? When it is heated, it transitions into a higher-energy state, which then loses energy by emitting ultraviolet light - a process known as fluorescence.

    Finally, the artist's rendering gives way to the actual ultraviolet image taken by the Galaxy Evolution Explorer

    Mira is located 350 light-years from Earth in the constellation Cetus, otherwise known as the whale. Coincidentally, Mira

  5. A Star on Earth

    ScienceCinema

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2016-07-12

    At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

  6. Synthetic guide star generation

    DOEpatents

    Payne, Stephen A [Castro Valley, CA; Page, Ralph H [Castro Valley, CA; Ebbers, Christopher A [Livermore, CA; Beach, Raymond J [Livermore, CA

    2008-06-10

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  7. The neutron star zoo

    NASA Astrophysics Data System (ADS)

    Harding, Alice K.

    2013-12-01

    Neutron stars are a very diverse population, both in their observational and their physical properties. They prefer to radiate most of their energy at X-ray and gamma-ray wavelengths. But whether their emission is powered by rotation, accretion, heat, magnetic fields or nuclear reactions, they are all different species of the same animal whose magnetic field evolution and interior composition remain a mystery. This article will broadly review the properties of inhabitants of the neutron star zoo, with emphasis on their high-energy emission.

  8. The Drifting Star

    NASA Astrophysics Data System (ADS)

    2008-04-01

    By studying in great detail the 'ringing' of a planet-harbouring star, a team of astronomers using ESO's 3.6-m telescope have shown that it must have drifted away from the metal-rich Hyades cluster. This discovery has implications for theories of star and planet formation, and for the dynamics of our Milky Way. ESO PR Photo 09a/08 ESO PR Photo 09a/08 Iota Horologii The yellow-orange star Iota Horologii, located 56 light-years away towards the southern Horologium ("The Clock") constellation, belongs to the so-called "Hyades stream", a large number of stars that move in the same direction. Previously, astronomers using an ESO telescope had shown that the star harbours a planet, more than 2 times as large as Jupiter and orbiting in 320 days (ESO 12/99). But until now, all studies were unable to pinpoint the exact characteristics of the star, and hence to understand its origin. A team of astronomers, led by Sylvie Vauclair from the University of Toulouse, France, therefore decided to use the technique of 'asteroseismology' to unlock the star's secrets. "In the same way as geologists monitor how seismic waves generated by earthquakes propagate through the Earth and learn about the inner structure of our planet, it is possible to study sound waves running through a star, which forms a sort of large, spherical bell," says Vauclair. The 'ringing' from this giant musical instrument provides astronomers with plenty of information about the physical conditions in the star's interior. And to 'listen to the music', the astronomers used one of the best instruments available. The observations were conducted in November 2006 during 8 consecutive nights with the state-of-the-art HARPS spectrograph mounted on the ESO 3.6-m telescope at La Silla. Up to 25 'notes' could be identified in the unique dataset, most of them corresponding to waves having a period of about 6.5 minutes. These observations allowed the astronomers to obtain a very precise portrait of Iota Horologii: its

  9. The DQ Herculis stars

    NASA Technical Reports Server (NTRS)

    Patterson, Joseph

    1994-01-01

    We review the properties of the DQ Herculis stars: cataclysmic variables containing an accreting, magnetic, rapidly rotating white dwarf. These stars are characterized by strong X-ray emission, high-excitation spectra, and very stable optical and X-ray pulsations in their light curves. There is considerable resemblance to their more famous cousins, the AM Herculis stars, but the latter class is additionally characterized by spin-orbit synchronism and the presence of strong circular polarization. We list eighteen stars passing muster as certain or very likely DQ Her stars. The rotational periods range from 33 s to 2.0 hr. Additional periods can result when the rotating searchlight illuminates other structures in the binary. A single hypothesis explains most of the observed properties: magnetically channeled accretion within a truncated disk. Some accretion flow still seems to proceed directly to the magnetosphere, however. The white dwarfs' magnetic moments are in the range 10(sup 32) - 10(sup 34) G cc, slightly weaker than in AM Her stars but with some probable overlap. The more important reason why DQ Hers have broken synchronism is probably their greater accretion rate and orbital separation. The observed L(sub x)/L(sub V) values are surprisingly low for a radially accreting white dwarf, suggesting that most of the accretion energy is not radiated in a strong shock above the magnetic pole. The fluxes can be more satisfactorily explained if most of the radial infall energy manages to bypass the shock and deposit itse lf directly in the white dwarf photosphere, where it should emerge as extreme ultraviolet (EUV) radiation. This also provides an adequate source of ionizing photons to power the high-excitation optical and UV emission lines. This is probably the DQ Her analog to the famous 'soft X-ray excess' in AM Her stars. However, unlike the AM Her case, this radiation has not been directly observed, so the analogy must not (yet) be embraced too firmly. There is

  10. The most magnetic stars

    NASA Astrophysics Data System (ADS)

    Wickramasinghe, Dayal T.; Tout, Christopher A.; Ferrario, Lilia

    2014-01-01

    Observations of magnetic A, B and O stars show that the poloidal magnetic flux per unit mass Φp/M appears to have an upper bound of approximately 10-6.5 G cm2 g-1. A similar upper bound to the total flux per unit mass is found for the magnetic white dwarfs even though the highest magnetic field strengths at their surfaces are much larger. For magnetic A and B stars, there also appears to be a well-defined lower bound below which the incidence of magnetism declines rapidly. According to recent hypotheses, both groups of stars may result from merging stars and owe their strong magnetism to fields generated by a dynamo mechanism as they merge. We postulate a simple dynamo that generates magnetic field from differential rotation. We limit the growth of magnetic fields by the requirement that the poloidal field stabilizes the toroidal and vice versa. While magnetic torques dissipate the differential rotation, toroidal field is generated from poloidal by an Ω dynamo. We further suppose that mechanisms that lead to the decay of toroidal field lead to the generation of poloidal. Both poloidal and toroidal fields reach a stable configuration which is independent of the size of small initial seed fields but proportional to the initial differential rotation. We pose the hypothesis that strongly magnetic stars form from the merging of two stellar objects. The highest fields are generated when the merge introduces differential rotation that amounts to critical break-up velocity within the condensed object. Calibration of a simplistic dynamo model with the observed maximum flux per unit mass for main-sequence stars and white dwarfs indicates that about 1.5 × 10-4 of the decaying toroidal flux must appear as poloidal. The highest fields in single white dwarfs are generated when two degenerate cores merge inside a common envelope or when two white dwarfs merge by gravitational-radiation angular momentum loss. Magnetars are the most magnetic neutron stars. Though these are

  11. Star cluster dynamics.

    PubMed

    Vesperini, Enrico

    2010-02-28

    Dynamical evolution plays a key role in shaping the current properties of star clusters and star cluster systems. A detailed understanding of the effects of evolutionary processes is essential to be able to disentangle the properties that result from dynamical evolution from those imprinted at the time of cluster formation. In this review, I focus my attention on globular clusters, and review the main physical ingredients driving their early and long-term evolution, describe the possible evolutionary routes and show how cluster structure and stellar content are affected by dynamical evolution.

  12. VPP Star recognition

    NASA Image and Video Library

    2011-06-09

    Stennis Space Center Deputy Director Rick Gilbrech (right) accepts a plaque designating the test facility as a Voluntary Protection Program Star site. Presenting the plaque is Clyde Payne, area director for the Occupational Safety and Health Administration in Jackson, Miss. OSHA established VPP in 1982 as a proactive safety management model to recognize excellence in safety and health. Since then, more than 2,000 organizations have been designated VPP Star sites. To reach that goal, an organization must demonstrate comprehensive and successful safety and health management programs in the workplace.

  13. A Star on Earth

    SciTech Connect

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2014-03-05

    At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

  14. NuSTAR Briefing

    NASA Image and Video Library

    2012-05-30

    Yunjin Kim, NuSTAR project manager at the Jet Propulsion Laborartory (JPL), talks about NASA's Spectroscopic Telescope Array (NuStar) during a briefing, Wednesday, May 30, 2012, at NASA Headquarters in Washington. Imaging light in the high-energy, short-wavelength X-ray range, the telescope will aim to study how black holes form and evolve along with galaxies. The instrument, packed aboard an Orbital Sciences Pegasus XL rocket is set to launch from a plane in midair no earlier than June 13 from Kwajalein Atoll in the Marshall Islands. Photo Credit: (NASA/Paul E. Alers)

  15. Digital Standard Star Tracker.

    NASA Astrophysics Data System (ADS)

    McQuerry, J. P., Jr.

    The Digital Standard Star Tracker (DSST) is an electro-optical instrument which provides position data used for precise attitude determination. The new DSST design uses flight-proven optical and sensor components from the BASD/NASA Standard Star Tracker (SST) programs while incorporating digital electronics techniques to improve producibility and reliability. This design approach has resulted in a new instrument capable of ≤ 10 arc second calibrated accuracy with 50 percent of the electrical components and only 10 percent of the electrical assemblies used in the SST.

  16. Digital Standard Star Tracker

    NASA Astrophysics Data System (ADS)

    McQuerry, J. P., Jr.

    The Digital Standard Star Tracker (DSST) is an electro-optical instrument which provides position data used for precise attitude determination. The new DSST design uses flight-proven optical and sensor components from the BASD/NASA Standard Star Tracker (SST) programs while incorporating digital electronics techniques to improve producibility and reliability. This design approach has resulted in a new instrument capable of less than 10 arc second calibrated accuracy with 50 percent of the electrical components and only 10 percent of the electrical assemblies used in the SST.

  17. Interferometric star tracking.

    PubMed

    Decou, A B

    1974-02-01

    A new star-tracking technique based on interferometry is described and analyzed in detail. A heuristic comparison is made with traditional star-tracking methods that demonstrates several advantages in the interferometric approach for very high accuracy systems. A detailed error analysis is performed on several versions of the system that use all solid-state detection. One such system is shown to have a potential accuracy of +/-0.01 sec of arc using a small optical system and state-of-the-art components. Applications of the new system in large orbiting astronomical observatories and deep space laser communications systems are also discussed.

  18. Dead Star Warps Light of Red Star Artist Animation

    NASA Image and Video Library

    2013-04-04

    This artist concept depicts an ultra-dense dead star, called a white dwarf, passing in front of a small red star. NASA planet-hunting Kepler was able to detect gravitational lensing by measuring a strangely subtle dip in the star brightness.

  19. Stellar Dynamical Processes in Massive Star and Star Cluster Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan; Eyer, L.

    2009-01-01

    We study how high precision astrometric measurements by SIM and GAIA of stars involved in dynamical ejection events from star clusters can constrain theories of massive star and star cluster formation. We focus on the Orion Nebula Cluster (ONC). First, we investigate the scientific potential associated with an accurate measurement of the distance and proper motion of Theta 1 Ori C, which is the most massive star in the cluster and was recently involved (about 4000 years ago) in the ejection of a B star: the Becklin-Neugebauer (BN) star. The motion of the BN star has taken it close to a massive protostar, known as source I, where it appears to have influenced the accretion and outflow activity, most likely by a tidal interaction with the accretion disk. An accurate proper motion measurement of Theta 1 Ori C will constrain BN's initial motion, allowing us to search for deflections caused by the gravitational potential of the massive protostar. Second, we search the Hipparcos catalog for candidate runaway stars, i.e. that have been dynamically ejected from the cluster over the course of the last several Myr. SIM and GAIA observations of these stars will be needed to confirm their origin from the ONC. The results of this study will constrain the star cluster formation timescale and the statistics of the population of ejected stars. JCT acknowledges support from from NSF CAREER grant AST-0645412 and a grant from NASA for SIM Science Studies.

  20. Magnetic Fields of Nondegenerate Stars

    NASA Astrophysics Data System (ADS)

    Donati, J.-F.; Landstreet, J. D.

    2009-09-01

    Magnetic fields are present in a wide variety of stars throughout the HR diagram and play a role at basically all evolutionary stages, from very-low-mass dwarfs to very massive stars, and from young star-forming molecular clouds and protostellar accretion discs to evolved giants/supergiants and magnetic white dwarfs/neutron stars. These fields range from a few μG (e.g., in molecular clouds) to TG and more (e.g., in magnetic neutron stars); in nondegenerate stars in particular, they feature large-scale topologies varying from simple nearly axisymmetric dipoles to complex nonaxsymmetric structures, and from mainly poloidal to mainly toroidal topologies. After recalling the main techniques of detecting and modeling stellar magnetic fields, we review the existing properties of magnetic fields reported in cool, hot, and young nondegenerate stars and protostars, and discuss our understanding of the origin of these fields and their impact on the birth and life of stars.