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Sample records for binary 1a 1744-361

  1. An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-Mass X-Ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2012-01-01

    We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of (7 +/- 1)×10(exp 17) /sq. cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source

  2. An Fe XXVI Absorption Line in the Persistent Spectrum of the Dipping Low Mass X-ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2009-01-01

    We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power-law (Gamma approx. 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of 7+/-1 x 10(exp 17)/sq cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10(exp 3.6) erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.

  3. RXTE Observations of A1744-361: Correlated Spectral and Timing Behavior

    NASA Technical Reports Server (NTRS)

    Bhattacharyya, Sudip; Strohmayer, Tod E.; Swank, Jean H.; Markwardt, Craig B.

    2007-01-01

    We analyze Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) data of the transient low mass X-ray binary (LMXB) system A1744-361. We explore the X-ray intensity and spectral evolution of the source, perform timing analysis, and find that A1744-361 is a weak LMXB, that shows atoll behavior at high intensity states. The color-color diagram indicates that this LMXB was observed in a low intensity spectrally hard (low-hard) state and in a high intensity banana state. The low-hard state shows a horizontal pattern in the color-color diagram, and the previously reported dipper QPO appears only during this state. We also perform energy spectral analyses, and report the first detection of broad iron emission line and iron absorption edge from A1744-361.

  4. Discovery of a Neutron Star with Spin Frequency 530 Hz in A1744-361

    NASA Technical Reports Server (NTRS)

    Bhattacharyya, Sudip; Strohmayer, Tod E.; Markwardt, Craig B.; Swank, Jean H.; Bhattacharyya, Sudip

    2005-01-01

    We report the detection with the Rossi X-ray Timing Explorer (RXTE) Proportional Counter Array (PCA) of 530 Hz burst oscillations in a thermonuclear (Type I) burst from the transient X-ray source A1744-361. This is only the second burst ever observed from this source, and the first to be seen in any detail. Our results confirm that A1744-361 is a low mass X-ray binary (LMXB) system harboring a rapidly rotating neutron star. The oscillations are first detected along the rising edge of the burst, and show evidence for frequency evolution of a magnitude similar to that seen in other burst sources. The modulation amplitude and its increase with photon energy are also typical of burst oscillations. The lack of any strong indication of photospheric radius expansion during the burst suggests a 9 kpc upper limit of the source distance. We also find energy dependent dips, establishing A1744-361 as a high inclination, dipping LMXB. The timescale between the two episodes of observed dips suggests an orbital period of approx. 97 min. We have also detected a 2 - 4 Hz quasi-periodic-oscillation (QPO) for the first time from this source. This QPO appears consistent with approx. 1 Hz QPOs seen from other high inclination systems. We searched for kilohertz QPOs, and found a suggestive 2.3 sigma feature at 800 Hz in one observation. The frequency, strength and quality factor are consistent with that of a lower frequency kilohertz QPO, but the relatively low significance argues for caution, so we consider this a tentative detection requiring confirmation.

  5. New X-ray Outburst in X1744-361 (A1744-36)

    NASA Astrophysics Data System (ADS)

    Remillard, Ronald A.

    2009-11-01

    The recurrent transient and accreting neutron star, X1744-361, has begun the fourth outburst observed with RXTE (see ATel #1587). The ASM data rate for this source is impeded by the angular proximity of the Sun, but the outburst appears to have begun near MJD 55145. The intensity seems to have leveled off quickly, and the the average flux during the last week is 65(7) mCrab at 2-12 keV. Followup observations are encouraged.

  6. INTEGRAL observes A1744-361 (XTE J1748-361) in hard X-rays

    NASA Astrophysics Data System (ADS)

    Grebenev, S. A.; Goldoni, P.; Schoenfelder, V.; Roques, J.-P.; Sunyaev, R. A.; Courvoisier, T.; Winkler, C.

    2004-04-01

    The X-ray transient A1744-361 (XTE J1748-361) was detected with ISGRI/IBIS on April 7-8, 2004 during the INTEGRAL Galactic Center Deep Exposure observation. The average flux in the 17-45 keV band was equal to 19.8+/-1.6 mCrab (the S/N ratio was 13). The photon spectrum was extending to at least 100 keV. The source was seen neither in March during previous GCDE observations nor in the beginning of April during the Galactic Center Open Program observation (the 3-sigma upper limit was 1.5 mCrab).

  7. (24495) 2001 AV1 - A Suspected Very Wide Binary

    NASA Astrophysics Data System (ADS)

    Stephens, Robert D.; Warner, Brian D.; Aznar Macias, Amadeo; Benishek, Vladimir

    2017-10-01

    We report that asteroid (24495) 2001 AV1 is a binary asteroid. It is another candidate for the special case of very wide binaries. The primary lightcurve has a period of 24.083 ± 0.005 h and an amplitude 0.58 ± 0.05 mag. and the secondary lightcurve has a period of 2.7375 ± 0.0001 h.

  8. NGC 300 X-1 and IC 10 X-1: a new breed of black hole binary?

    NASA Astrophysics Data System (ADS)

    Barnard, R.; Clark, J. S.; Kolb, U. C.

    2008-09-01

    Context: IC 10 X-1 has recently been confirmed as a black hole (BH) + Wolf-Rayet (WR) X-ray binary, and NGC 300 X-1 is thought to be. The only other known BH+WR candidate is Cygnus X-3. IC 10 X-1 and NGC 300 X-1 have similar X-ray properties, with 0.3-10 keV luminosities ~1038 erg s-1, and their X-ray lightcurves exhibit orbital periods ~30 h. Aims: We investigate similarities between IC 10 X-1 and NGC 300 X-1, as well as differences between these systems and the known Galactic BH binary systems. Methods: We have examined all four XMM-Newton observations of NGC 300 X-1, as well as the single XMM-Newton observation of IC 10 X-1. For each observation, we extracted lightcurves and spectra from the pn, MOS1 and MOS2 cameras; power density spectra were constructed from the lightcurves, and the X-ray emission spectra were modeled. Results: Each source exhibits power density spectra that are well described by a power law with index, γ, ~1. Such variability is characteristic of turbulence in wind accretion or disc-accreting X-ray binaries (XBs) in the high state. In this state, Galactic XBs with known BH primaries have soft, thermal emission; however the emission spectra of NGC 300 X-1 and IC 10 X-1 in the XMM-Newton observations are predominantly non-thermal. Furthermore, the Observation 1 spectrum of NGC 300 X-1 is strikingly similar to that of IC 10 X-1. Conclusions: The remarkable similarity between the behaviour of NGC 300 X-1 in Observation 1 and that of IC 10 X-1 lends strong evidence for NGC 300 X-1 being a BH+WR binary. Our spectral modeling rules out Bondi-Hoyle accretion onto a neutron star (NS) for NGC 300 X-1, but not a disc-accreting NS+WR system, nor a NS low mass X-ray binary (LMXB) that is merely coincident with the WR. We favour disc accretion for both systems, but cannot exclude Bondi-Hoyle accretion onto a BH. The unusual spectra of NGC 300 X-1 and IC 10 X-1 may be due to these systems existing in a persistently high state, whereas all known BH LMXBs

  9. Brief communication: new Y-chromosome binary markers improve phylogenetic resolution within haplogroup R1a1.

    PubMed

    Pamjav, Horolma; Fehér, Tibor; Németh, Endre; Pádár, Zsolt

    2012-12-01

    Haplogroup R1a1-M198 is a major clade of Y chromosomal haplogroups which is distributed all across Eurasia. To this date, many efforts have been made to identify large SNP-based subgroups and migration patterns of this haplogroup. The origin and spread of R1a1 chromosomes in Eurasia has, however, remained unknown due to the lack of downstream SNPs within the R1a1 haplogroup. Since the discovery of R1a1-M458, this is the first scientific attempt to divide haplogroup R1a1-M198 into multiple SNP-based sub-haplogroups. We have genotyped 217 R1a1-M198 samples from seven different population groups at M458, as well as the Z280 and Z93 SNPs recently identified from the "1000 Genomes Project". The two additional binary markers present an effective tool because now more than 98% of the samples analyzed assign to one of the three sub-haplogroups. R1a1-M458 and R1a1-Z280 were typical for the Hungarian population groups, whereas R1a1-Z93 was typical for Malaysian Indians and the Hungarian Roma. Inner and Central Asia is an overlap zone for the R1a1-Z280 and R1a1-Z93 lineages. This pattern implies that an early differentiation zone of R1a1-M198 conceivably occurred somewhere within the Eurasian Steppes or the Middle East and Caucasus region as they lie between South Asia and Eastern Europe. The detection of the Z93 paternal genetic imprint in the Hungarian Roma gene pool is consistent with South Asian ancestry and amends the view that H1a-M82 is their only discernible paternal lineage of Indian heritage.

  10. GAMMA-RAY OBSERVATIONS OF THE Be/PULSAR BINARY 1A 0535+262 DURING A GIANT X-RAY OUTBURST

    SciTech Connect

    Acciari, V. A.; Benbow, W.; Aliu, E.; Araya, M.; Cui, W.; Finley, J. P.; Arlen, T.; Aune, T.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R.; Bradbury, S. M.; Byrum, K.; Cannon, A.; Collins-Hughes, E.; Cesarini, A.; Ciupik, L.; Duke, C.; Falcone, A. E-mail: cui@purdue.edu

    2011-06-01

    Giant X-ray outbursts, with luminosities of about 10{sup 37} erg s{sup -1}, are observed roughly every five years from the nearby Be/pulsar binary 1A 0535+262. In this article, we present observations of the source with VERITAS at very high energies (VHEs; E >100 GeV) triggered by the X-ray outburst in 2009 December. The observations started shortly after the onset of the outburst and provided comprehensive coverage of the episode, as well as the 111 day binary orbit. No VHE emission is evident at any time. We also examined data from the contemporaneous observations of 1A 0535+262 with the Fermi/Large Area Telescope at high-energy photons (E > 0.1 GeV) and failed to detect the source at GeV energies. The X-ray continua measured with the Swift/X-Ray Telescope and the RXTE/PCA can be well described by the combination of blackbody and Comptonized emission from thermal electrons. Therefore, the gamma-ray and X-ray observations suggest the absence of a significant population of non-thermal particles in the system. This distinguishes 1A 0535+262 from those Be X-ray binaries (such as PSR B1259-63 and LS I +61{sup 0}303) that have been detected at GeV-TeV energies. We discuss the implications of the results on theoretical models.

  11. ETHOS 1: a high-latitude planetary nebula with jets forged by a post-common-envelope binary central star

    NASA Astrophysics Data System (ADS)

    Miszalski, B.; Corradi, R. L. M.; Boffin, H. M. J.; Jones, D.; Sabin, L.; Santander-García, M.; Rodríguez-Gil, P.; Rubio-Díez, M. M.

    2011-05-01

    We report on the discovery of ETHOS 1 (PN G068.1+11.0), the first spectroscopically confirmed planetary nebula (PN) from a survey of the SuperCOSMOS Science Archive for high-latitude PNe. ETHOS 1 stands out as one of the few PNe to have both polar outflows (jets) travelling at 120 ± 10 km s-1 and a close binary central star. The light curve observed with the Mercator Telescope reveals an orbital period of 0.535 d and an extremely large amplitude (0.816 mag) due to irradiation of the companion by a very hot pre-white dwarf. ETHOS 1 further strengthens the long-suspected link between binary central stars of PNe (CSPN) and jets. The Isaac Newton Telescope/Intermediate Dispersion Spectrograph and Very Large Telescope (VLT) FORS spectroscopy of the CSPN reveals weak N III, C III and C IV emission lines seen in other close binary CSPN and suggests that many CSPN with these weak emission lines are misclassified close binaries. We present VLT FORS imaging and Manchester Echelle Spectrometer long-slit observations from which a kinematic model of the nebula is built. An unusual combination of bipolar outflows and a spherical nebula conspires to produce an X-shaped appearance. The kinematic age of the jets (1750 ± 250 yr kpc-1) is found to be more than that of the inner nebula (900 ± 100 yr kpc-1), consistent with previous studies of similar PNe. Emission-line ratios of the jets are found to be consistent with that of reverse-shock models for fast low-ionization emitting regions (FLIERs) in PNe. Further large-scale surveys for close binary CSPN will be required to securely establish whether FLIERs are launched by close binaries. Based on observations made with the Flemish Mercator Telescope and Isaac Newton Telescope of the Observatorio del Roque de Los Muchachos and the VLT at the Paranal Observatory under programs 083.D-0654(A) and 085.D-0629(A).

  12. Finding a 24 Day Orbital Period for the X-Ray Binary 1A 1118-616

    NASA Technical Reports Server (NTRS)

    Staubert, R.; Pottschmidt, K.; Doroshenko, V.; Wilms, J.; Suchy, S.; Rothschild, R.; Santangelo, A.

    2010-01-01

    We report the first determination of the binary period and the orbital ephemeris of the Be X-ray binary containing the pulsar IA 1118-616 (35 years after the discovery of the source). The orbital period is found to be P(sub orb) = 24.0+/-0.4 days. The source was observed by RXTE during its last big X-ray outburst in January 2009, peaking at MJD 54845.4. This outburst was sampled by taking short observations every few days, covering an elapsed time comparable to the orbital period. Using the phase connection technique, pulse arrival time delays could be measured and an orbital solution determined. The data are consistent with a circular orbit, the time of 90 degrees longitude was found to be T,/2 = MJD 54845.37(10), coincident with the peak X-ray flux.

  13. Finding a 24 Day Orbital Period for the X-Ray Binary 1A 1118-616

    NASA Technical Reports Server (NTRS)

    Staubert, R.; Pottschmidt, K.; Doroshenko, V.; Wilms, J.; Suchy, S.; Rothschild, R.; Santangelo, A.

    2010-01-01

    We report the first determination of the binary period and the orbital ephemeris of the Be X-ray binary containing the pulsar IA 1118-616 (35 years after the discovery of the source). The orbital period is found to be P(sub orb) = 24.0+/-0.4 days. The source was observed by RXTE during its last big X-ray outburst in January 2009, peaking at MJD 54845.4. This outburst was sampled by taking short observations every few days, covering an elapsed time comparable to the orbital period. Using the phase connection technique, pulse arrival time delays could be measured and an orbital solution determined. The data are consistent with a circular orbit, the time of 90 degrees longitude was found to be T,/2 = MJD 54845.37(10), coincident with the peak X-ray flux.

  14. LMC X-1: A New Spectral Analysis of the O-star in the Binary and Surrounding Nebula

    NASA Astrophysics Data System (ADS)

    Hyde, E. A.; Russell, D. M.; Ritter, A.; Filipović, M. D.; Kaper, L.; Grieve, K.; O'Brien, A. N.

    2017-09-01

    We provide new observations of the LMC X-1 O star and its extended nebula structure using spectroscopic data from VLT/UVES as well as Hα imaging from the Wide Field Imager on the Max Planck Gesellschaft/European Southern Observatory 2.2 m telescope and ATCA imaging of the 2.1 GHz radio continuum. This nebula is one of the few known to be energized by an X-ray binary. We use a new spectrum extraction technique that is superior to other methods used to obtain both radial velocities and fluxes. This provides an updated spatial velocity of ≃ 21.0 +/- 4.8 km s-1 for the O star. The slit encompasses both the photo-ionized and shock-ionized regions of the nebula. The imaging shows a clear arc-like structure reminiscent of a wind bow shock in between the ionization cone and shock-ionized nebula. The observed structure can be fit well by the parabolic shape of a wind bow shock. If an interpretation of a wind bow shock system is valid, we investigate the N159-O1 star cluster as a potential parent of the system, suggesting a progenitor mass of ˜60 M ⊙ for the black hole. We further note that the radio emission could be non-thermal emission from the wind bow shock, or synchrotron emission associated with the jet-inflated nebula. For both wind- and jet-powered origins, this would represent one of the first radio detections of such a structure.

  15. Circinus X-1: a Laboratory for Studying the Accretion Phenomenon in Compact Binary X-Ray Sources. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Robinson-Saba, J. L.

    1983-01-01

    Observations of the binary X-ray source Circinus X-1 provide samples of a range of spectral and temporal behavior whose variety is thought to reflect a broad continuum of accretion conditions in an eccentric binary system. The data support an identification of three or more X-ray spectral components, probably associated with distinct emission regions.

  16. Binary Plutinos

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.

    2015-08-01

    The Pluto-Charon binary was the first trans-neptunian binary to be identified in 1978. Pluto-Charon is a true binary with both components orbiting a barycenter located between them. The Pluto system is also the first, and to date only, known binary with a satellite system consisting of four small satellites in near-resonant orbits around the common center of mass. Seven other Plutinos, objects in 3:2 mean motion resonance with Neptune, have orbital companions including 2004 KB19 reported here for the first time. Compared to the Cold Classical population, the Plutinos differ in the frequency of binaries, the relative sizes of the components, and their inclination distribution. These differences point to distinct dynamical histories and binary formation processes encountered by Plutinos.

  17. Ultraviolet observations of close-binary and pulsating nuclei of planetary nebulae; Winds and shells around low-mass supergiants; The close-binary nucleus of the planetary nebula HFG-1; A search for binary nuclei of planetary nebulae; UV monitoring of irregularly variable planetary nuclei; and The pulsating nucleus of the planetary nebula Lo 4

    NASA Technical Reports Server (NTRS)

    Bond, Howard E.

    1992-01-01

    A brief summary of the research highlights is presented. The topics covered include the following: binary nuclei of planetary nebulae; other variable planetary nuclei; low-mass supergiants; and other IUE-related research.

  18. 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.

  19. Binary and ternary crystal structure analyses of a novel inhibitor with 17beta-HSD type 1: a lead compound for breast cancer therapy.

    PubMed

    Mazumdar, Mausumi; Fournier, Diane; Zhu, Dao-Wei; Cadot, Christine; Poirier, Donald; Lin, Sheng-Xiang

    2009-12-10

    Oestradiol is a well-characterized sex hormone that stimulates breast cancer and other oestrogen-related diseases. 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) catalyses the last step in the synthesis of oestradiol and androstenediol in breast tumour tissue. The enzyme's high expression and activity after simultaneous blockade of oestrogen receptors and inhibition of aromatase in the tumour shows the necessity for its inhibition as a requirement for breast cancer therapy. In the present paper, we report structures of the binary and ternary complexes of 17beta-HSD1 with a new inhibitor E2B {3-[3',17'beta-dihydroxyestra-1',3',5'(10')-trien-16'beta-methyl]benzamide}, and the enzyme inhibition by the later. The IC50 value for E2B was determined to be 42 nM in T47D cells. Multiple interactions between E2B and the enzyme include hydrogen bonds and hydrophobic interactions, as well as pi-pi interactions. A kinetic study demonstrated that E2B inhibits the enzyme's reduction forming oestradiol from oestrone, with a Ki of 0.9+/-0.15 nM. Such strong inhibition is in agreement with its extensive interaction with the enzyme, suggesting its potential as a lead compound for breast cancer therapy. In fact, this possibility is enhanced by its capacity for cell penetration similar to natural steroids. Such inhibitors that block oestrogen synthesis to suppress the sulfatase pathway producing oestradiol can be used in adjuvant therapies with oestrogen receptor blockade, opening a new orientation of breast cancer treatment.

  20. Binary Planets

    NASA Astrophysics Data System (ADS)

    Ryan, Keegan; Nakajima, Miki; Stevenson, David J.

    2014-11-01

    Can a bound pair of similar mass terrestrial planets exist? We are interested here in bodies with a mass ratio of ~ 3:1 or less (so Pluto/Charon or Earth/Moon do not qualify) and we do not regard the absence of any such discoveries in the Kepler data set to be significant since the tidal decay and merger of a close binary is prohibitively fast well inside of 1AU. SPH simulations of equal mass “Earths” were carried out to seek an answer to this question, assuming encounters that were only slightly more energetic than parabolic (zero energy). We were interested in whether the collision or near collision of two similar mass bodies would lead to a binary in which the two bodies remain largely intact, effectively a tidal capture hypothesis though with the tidal distortion being very large. Necessarily, the angular momentum of such an encounter will lead to bodies separated by only a few planetary radii if capture occurs. Consistent with previous work, mostly by Canup, we find that most impacts are disruptive, leading to a dominant mass body surrounded by a disk from which a secondary forms whose mass is small compared to the primary, hence not a binary planet by our adopted definition. However, larger impact parameter “kissing” collisions were found to produce binaries because the dissipation upon first encounter was sufficient to provide a bound orbit that was then rung down by tides to an end state where the planets are only a few planetary radii apart. The long computational times for these simulation make it difficult to fully map the phase space of encounters for which this outcome is likely but the indications are that the probability is not vanishingly small and since planetary encounters are a plausible part of planet formation, we expect binary planets to exist and be a non-negligible fraction of the larger orbital radius exoplanets awaiting discovery.

  1. Search for Binary Trojans

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.; Grundy, W. M.; Ryan, E. L.; Benecchi, S. D.

    2015-11-01

    We have reexamined 41 Trojan asteroids observed with the Hubble Space Telescope (HST) to search for unresolved binaries. We have identified one candidate binary with a separation of 53 milliarcsec, about the width of the diffraction limited point-spread function (PSF). Sub-resolution-element detection of binaries is possible with HST because of the high signal-to-noise ratio of the observations and the stability of the PSF. Identification and confirmation of binary Trojans is important because a Trojan Tour is one of five possible New Frontiers missions. A binary could constitute a potentially high value target because of the opportunity to study two objects and to test models of the primordial nature of binaries. The potential to derive mass-based physical information from the binary orbit could yield more clues to the origin of Trojans.

  2. PHOEBE: PHysics Of Eclipsing BinariEs

    NASA Astrophysics Data System (ADS)

    Prsa, Andrej; Matijevic, Gal; Latkovic, Olivera; Vilardell, Francesc; Wils, Patrick

    2011-06-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program (Wilson & Devinney 1971). This introductory paper overviews most important scientific extensions (incorporating observational spectra of eclipsing binaries into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining and proper treatment of the reddening), numerical innovations (suggested improvements to WD's Differential Corrections method, the new Nelder & Mead's downhill Simplex method) and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability.

  3. X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; van den Heuvel, Edward Peter Jacobus

    1997-01-01

    Preface; 1. The properties of X-ray binaries, N. E. White, F. Nagase and A. N. Parmar; 2. Optical and ultraviolet observations of X-ray binaries J. van Paradijs and J. E. McClintock; 3. Black-hole binaries Y. Tanaka and W. H. G. Lewin; 4. X-ray bursts Walter H. G. Lewin, Jan Van Paradijs and Ronald E. Taam; 5. Millisecond pulsars D. Bhattacharya; 6. Rapid aperiodic variability in binaries M. van der Klis; 7. Radio properties of X-ray binaries R. M. Hjellming and X. Han; 8. Cataclysmic variable stars France Anne-Dominic Córdova; 9. Normal galaxies and their X-ray binary populations G. Fabbiano; 10. Accretion in close binaries Andrew King; 11. Formation and evolution of neutron stars and black holes in binaries F. Verbunt and E. P. J. van den Heuvel; 12. The magnetic fields of neutron stars and their evolution D. Bhattacharya and G. Srinivasan; 13. Cosmic gamma-ray bursts K. Hurley; 14. A catalogue of X-ray binaries Jan van Paradijs; 15. A compilation of cataclysmic binaries with known or suspected orbital periods Hans Ritter and Ulrich Kolb; References; Index.

  4. Sequential binary collision ionization mechanisms

    NASA Astrophysics Data System (ADS)

    van Boeyen, R. W.; Watanabe, N.; Doering, J. P.; Moore, J. H.; Coplan, M. A.; Cooper, J. W.

    2004-03-01

    Fully differential cross sections for the electron-impact ionization of the magnesium 3s orbital have been measured in a high-momentum-transfer regime wherein the ionization mechanisms can be accurately described by simple binary collision models. Measurements where performed at incident-electron energies from 400 to 3000 eV, ejected-electron energies of 62 eV, scattering angle of 20 °, and momentum transfers of 2 to 5 a.u. In the out-of-plane geometry of the experiment the cross section is observed far off the Bethe ridge. Both first- and second-order processes can be clearly distinguished as previously observed by Murray et al [Ref. 1] and Schulz et al [Ref. 2]. Owing to the relatively large momentum of the ejected electron, the second order processes can be modeled as sequential binary collisions involving a binary elastic collision between the incident electron and ionic core and a binary knock-out collision between the incident electron and target electron. At low incident-electron energies the cross section for both first and second order processes are comparable, while at high incident energies second-order processes dominate. *Supported by NSF under grant PHY-99-87870. [1] A. J. Murray, M. B. J. Woolf, and F. H. Read J. Phys. B 25, 3021 (1992). [2] M. Schulz, R. Moshammer, D. Fischer, H. Kollmus, D. H. Madison. S. Jones and J. Ullrich, Nature 422, 48 (2003).

  5. VLSI binary updown counter

    NASA Technical Reports Server (NTRS)

    Truong, Trieu-Kie (Inventor); Hsu, In-Shek (Inventor); Reed, Irving S. (Inventor)

    1989-01-01

    A pipeline binary updown counter is comprised of simple stages that may be readily replicated. Each stage is defined by the Boolean logic equation: A(sub n)(t) = A(sub n)(t - 1) exclusive OR (U AND P(sub n)) inclusive OR (D AND Q(sub n)), where A(sub n)(t) denotes the value of the nth bit at time t. The input to the counter has three values represented by two binary signals U and D such that if both are zero, the input is zero, if U = 0 and D = 1, the input is -1 and if U = 1 and D = 0, the input is +1. P(sub n) represents a product of A(sub k)'s for 1 is less than or equal to k is less than or equal to -1, while Q(sub n) represents the product of bar A's for 1 is less than or equal to K is less than or equal to n - 1, where bar A(sub k) is the complement of A(sub k) and P(sub n) and Q(sub n) are expressed as the following two equations: P(sub n) = A(sub n - 1) A(sub n - 2)...A(sub 1) and Q(sub n) = bar A(sub n - 1) bar A(sub n - 2)...bar A(sub 1), which can be written in recursive form as P(sub n) = P(sub n - 1) AND bar A(sub n - 1) and Q(sub n) = Q(sub n - 1) AND bar A(sub n - 1) with the initial values P(sub 1) = 1 and Q(sub 1) = 1.

  6. Case A Binary Evolution

    SciTech Connect

    Nelson, C A; Eggleton, P P

    2001-03-28

    We undertake a comparison of observed Algol-type binaries with a library of computed Case A binary evolution tracks. The library consists of 5500 binary tracks with various values of initial primary mass M{sub 10}, mass ratio q{sub 0}, and period P{sub 0}, designed to sample the phase-space of Case A binaries in the range -0.10 {le} log M{sub 10} {le} 1.7. Each binary is evolved using a standard code with the assumption that both total mass and orbital angular momentum are conserved. This code follows the evolution of both stars until the point where contact or reverse mass transfer occurs. The resulting binary tracks show a rich variety of behavior which we sort into several subclasses of Case A and Case B. We present the results of this classification, the final mass ratio and the fraction of time spent in Roche Lobe overflow for each binary system. The conservative assumption under which we created this library is expected to hold for a broad range of binaries, where both components have spectra in the range G0 to B1 and luminosity class III - V. We gather a list of relatively well-determined observed hot Algol-type binaries meeting this criterion, as well as a list of cooler Algol-type binaries where we expect significant dynamo-driven mass loss and angular momentum loss. We fit each observed binary to our library of tracks using a {chi}{sup 2}-minimizing procedure. We find that the hot Algols display overall acceptable {chi}{sup 2}, confirming the conservative assumption, while the cool Algols show much less acceptable {chi}{sup 2} suggesting the need for more free parameters, such as mass and angular momentum loss.

  7. Binary Galaxies in Clusters

    NASA Astrophysics Data System (ADS)

    Ip, Peter Shun Sang

    1994-01-01

    CCD images of the binary-rich clusters of galaxies A373, A408, A667, A890, and A1250 taken at the Canada-France-Hawaii telescope show that about half the binary galaxies' are actually star-galaxy or star-star pairs. These clusters are not binary-rich. N-body simulations are used to study the effect of static cluster potentials on binary and single galaxies. The softening procedure is discussed in detail. Since Plummer softening is not self-consistent, and since the force laws for various other density models are similar to each other, uniform-density softening is used. The choice of the theoretical galaxy model in terms of the potential at various locations. A fixed cluster potential cannot stabilize binary galaxies against merger, but can disrupt even quite tightly bound binaries. A moderately good predictor of whether a binary merges or disrupts is the mean torque over a quarter of the initial binary period. But the dynamics of the situation is quite complicated, and depends on an interplay between the motion of the binary through the cluster and the absorption of orbital energy by the galaxies. There is also a substantial amount of mass loss. Simulations of single galaxies in cluster show that this mass loss is due mainly to the cluster potential, and not to an interplay between the merging binary and the cluster. This mass loss is driven partially by virial equilibrium responding to the initial tidal truncation by the cluster. Besides verifying some general results of mass loss from satellite systems in the tidal field of larger bodies, it was found that the galaxy loses mass at an exponential rate.

  8. Taming the binaries

    NASA Astrophysics Data System (ADS)

    Pourbaix, D.

    2008-07-01

    Astrometric binaries are both a gold mine and a nightmare. They are a gold mine because they are sometimes the unique source of orbital inclination for spectroscopic binaries, thus making it possible for astrophysicists to get some clues about the mass of the often invisible secondary. However, this is an ideal situation in the sense that one benefits from the additional knowledge that it is a binary for which some orbital parameters are somehow secured (e.g. the orbital period). On the other hand, binaries are a nightmare, especially when their binary nature is not established yet. Indeed, in such cases, depending on the time interval covered by the observations compared to the orbital period, either the parallax or the proper motion can be severely biased if the successive positions of the binary are modelled assuming it is a single star. With large survey campaigns sometimes monitoring some stars for the first time ever, it is therefore crucial to design robust reduction pipelines in which such troublesome objects are quickly identified and either removed or processed accordingly. Finally, even if an object is known not to be a single star, the binary model might turn out not to be the most appropriate for describing the observations. These different situations will be covered.

  9. Cool Star Binaries with ALEXIS

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.

    1998-01-01

    We proposed to search for high-temperature, flare-produced Fe XXIII line emission from active cool star binary systems using the ALEXIS all-sky survey. Previous X-ray transient searches with ARIEL V and HEAO-1, and subsequent shorter duration monitoring with the GINGA and EXOSAT satellites demonstrated that active binaries can produce large (EM approximately equals 10(exp 55-56/cu cm) X-ray flares lasting several hours or longer. Hot plasma from these flares at temperatures of 10(exp 7)K or more should produce Fe XXIII line emission at lambda = 132.8 A, very near the peak response of ALEXIS telescopes 1A and 2A. Our primary goals were to estimate flare frequency for the largest flares in the active binary systems, and, if the data permitted, to derive a distribution of flare energy vs. frequency for the sample as a whole. After a long delay due to the initial problems with the ALEXIS attitude control, the heroic efforts on the part of the ALEXIS satellite team enabled us to carry out this survey. However, the combination of the higher than expected and variable background in the ALEXIS detectors, and the lower throughput of the ALEXIS telescopes resulted in no convincing detections of large flares from the active binary systems. In addition, vignetting-corrected effective exposure times from the ALEXIS aspect solution were not available prior to the end of this contract; therefore, we were unable to convert upper limits measured in ALEXIS counts to the equivalent L(sub EUV).

  10. Binary Minor Planets

    NASA Astrophysics Data System (ADS)

    Richardson, Derek C.; Walsh, Kevin J.

    2006-05-01

    A review of observations and theories regarding binary asteroids and binary trans-Neptunian objects [collectively, binary minor planets (BMPs)] is presented. To date, these objects have been discovered using a combination of direct imaging, lightcurve analysis, and radar. They are found throughout the Solar System, and present a challenge for theorists modeling their formation in the context of Solar System evolution. The most promising models invoke rotational disruption for the smallest, shortest-lived objects (the asteroids nearest to Earth), consistent with the observed fast rotation of these bodies; impacts for the larger, longer-lived asteroids in the main belt, consistent with the range of size ratios of their components and slower rotation rates; and mutual capture for the distant, icy, trans-Neptunian objects, consistent with their large component separations and near-equal sizes. Numerical simulations have successfully reproduced key features of the binaries in the first two categories; the third remains to be investigated in detail.

  11. Binaries in globular clusters

    NASA Technical Reports Server (NTRS)

    Hut, Piet; Mcmillan, Steve; Goodman, Jeremy; Mateo, Mario; Phinney, E. S.; Pryor, Carlton; Richer, Harvey B.; Verbunt, Frank; Weinberg, Martin

    1992-01-01

    Recent observations have shown that globular clusters contain a substantial number of binaries most of which are believed to be primordial. We discuss different successful optical search techniques, based on radial-velocity variables, photometric variables, and the positions of stars in the color-magnitude diagram. In addition, we review searches in other wavelengths, which have turned up low-mass X-ray binaries and more recently a variety of radio pulsars. On the theoretical side, we give an overview of the different physical mechanisms through which individual binaries evolve. We discuss the various simulation techniques which recently have been employed to study the effects of a primordial binary population, and the fascinating interplay between stellar evolution and stellar dynamics which drives globular-cluster evolution.

  12. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  13. From Binaries to Triples

    NASA Astrophysics Data System (ADS)

    Freismuth, T.; Tokovinin, A.

    2002-12-01

    About 10% of all binary systems are close binaries (P<1000 days). Among those with P<10d, over 40% are known to belong to higher-multiplicity systems (triples, quadruples, etc.). Do ALL close systems have tertiary companions? For a selection of 12 nearby, and apparently "single" close binaries with solar-mass dwarf primary components from the 8-th catalogue of spectroscopic binary orbits, images in the B and R filters were taken at the CTIO 0.9m telescope and suitable tertiary candidates were be identified on color-magnitude diagrams (CMDs). Of the 12 SBs, four were found to have tertiary candidates: HD 67084, HD 120734, HD 93486, and VV Mon. However, none of these candidates were found to be common proper motion companions. Follow up observations using adaptive optics reveal a companion to HD 148704. Future observations are planned.

  14. Binary technetium halides

    NASA Astrophysics Data System (ADS)

    Johnstone, Erik Vaughan

    In this work, the synthetic and coordination chemistry as well as the physico-chemical properties of binary technetium (Tc) chlorides, bromides, and iodides were investigated. Resulting from these studies was the discovery of five new binary Tc halide phases: alpha/beta-TcCl3, alpha/beta-TcCl 2, and TcI3, and the reinvestigation of the chemistries of TcBr3 and TcX4 (X = Cl, Br). Prior to 2009, the chemistry of binary Tc halides was poorly studied and defined by only three compounds, i.e., TcF6, TcF5, and TcCl4. Today, ten phases are known (i.e., TcF6, TcF5, TcCl4, TcBr 4, TcBr3, TcI3, alpha/beta-TcCl3 and alpha/beta-TcCl2) making the binary halide system of Tc comparable to those of its neighboring elements. Technetium binary halides were synthesized using three methods: reactions of the elements in sealed tubes, reactions of flowing HX(g) (X = Cl, Br, and I) with Tc2(O2CCH3)4Cl2, and thermal decompositions of TcX4 (X = Cl, Br) and alpha-TcCl 3 in sealed tubes under vacuum. Binary Tc halides can be found in various dimensionalities such as molecular solids (TcF6), extended chains (TcF5, TcCl4, alpha/beta-TcCl2, TcBr 3, TcI3), infinite layers (beta-TcCl3), and bidimensional networks of clusters (alpha-TcCl3); eight structure-types with varying degrees of metal-metal interactions are now known. The coordination chemistry of Tc binary halides can resemble that of the adjacent elements: molybdenum and ruthenium (beta-TcCl3, TcBr3, TcI 3), rhenium (TcF5, alpha-TcCl3), platinum (TcCl 4, TcBr4), or can be unique (alpha-TcCl2 and beta-TcCl 2) in respect to other known transition metal binary halides. Technetium binary halides display a range of interesting physical properties that are manifested from their electronic and structural configurations. The thermochemistry of binary Tc halides is extensive. These compounds can selectively volatilize, decompose, disproportionate, or convert to other phases. Ultimately, binary Tc halides may find application in the nuclear fuel

  15. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  16. Learning binary matroid ports

    SciTech Connect

    Coullard, C.; Hellerstein, L.

    1994-12-31

    Given a binary matroid M specified by a port oracle, we can in polynomial number of calls to the oracle construct a binary representation for M. For general matroids, we can in polynomial number of calls to a port oracle determine whether a given subset is independent (that is, we can simulate an independence oracle with a port oracle). The work is related to a theorem of Lehman on matroid ports, and is motivated by issues in computational learning theory.

  17. Binary-Symmetry Detection

    NASA Technical Reports Server (NTRS)

    Lopez, Hiram

    1987-01-01

    Transmission errors for zeros and ones tabulated separately. Binary-symmetry detector employs psuedo-random data pattern used as test message coming through channel. Message then modulo-2 added to locally generated and synchronized version of test data pattern in same manner found in manufactured test sets of today. Binary symmetrical channel shows nearly 50-percent ones to 50-percent zeroes correspondence. Degree of asymmetry represents imbalances due to either modulation, transmission, or demodulation processes of system when perturbed by noise.

  18. 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...

  19. Scattering from binary optics

    NASA Technical Reports Server (NTRS)

    Ricks, Douglas W.

    1993-01-01

    There are a number of sources of scattering in binary optics: etch depth errors, line edge errors, quantization errors, roughness, and the binary approximation to the ideal surface. These sources of scattering can be systematic (deterministic) or random. In this paper, scattering formulas for both systematic and random errors are derived using Fourier optics. These formulas can be used to explain the results of scattering measurements and computer simulations.

  20. Solar System binaries

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.

    The discovery of binaries in each of the major populations of minor bodies in the solar system is propelling a rapid growth of heretofore unattainable physical information. The availability of mass and density constraints for minor bodies opens the door to studies of internal structure, comparisons with meteorite samples, and correlations between bulk-physical and surface-spectral properties. The number of known binaries is now more than 70 and is growing rapidly. A smaller number have had the extensive followup observations needed to derive mass and albedo information, but this list is growing as well. It will soon be the case that we will know more about the physical parameters of objects in the Kuiper Belt than has been known about asteroids in the Main Belt for the last 200 years. Another important aspect of binaries is understanding the mechanisms that lead to their formation and survival. The relative sizes and separations of binaries in the different minor body populations point to more than one mechanism for forming bound pairs. Collisions appear to play a major role in the Main Belt. Rotational and/or tidal fission may be important in the Near Earth population. For the Kuiper Belt, capture in multi-body interactions may be the preferred formation mechanism. However, all of these conclusions remain tentative and limited by observational and theoretical incompleteness. Observational techniques for identifying binaries are equally varied. High angular resolution observations from space and from the ground are critical for detection of the relatively distant binaries in the Main Belt and the Kuiper Belt. Radar has been the most productive method for detection of Near Earth binaries. Lightcurve analysis is an independent technique that is capable of exploring phase space inaccessible to direct observations. Finally, spacecraft flybys have played a crucial paradigm-changing role with discoveries that unlocked this now-burgeoning field.

  1. Binary optics at Hughes Danbury Optical Systems

    NASA Technical Reports Server (NTRS)

    Logue, James; Power, Michael

    1993-01-01

    An overview of binary optics development at Hughes Danbury Optical Systems is presented. Design software used for mask design is presented. A brief discussion of fabrication follows. Two examples of actual projects are used to highlight the discussion: (1) a large aspheric lens; and (2) a set of grating and lenslet arrays.

  2. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, G.P.; Zhao, J.; Feng, Z.

    1996-12-03

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered. 3 figs.

  3. Binary and Millisecond Pulsars.

    PubMed

    Lorimer, Duncan R

    2008-01-01

    We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5 M⊙, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44) orbit around an unevolved companion.

  4. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, Gerald P.; Zhao, Jianmin; Feng, Zhen

    1996-01-01

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered.

  5. Binary catalogue of exoplanets

    NASA Astrophysics Data System (ADS)

    Schwarz, Richard; Bazso, Akos; Zechner, Renate; Funk, Barbara

    2016-02-01

    Since 1995 there is a database which list most of the known exoplanets (The Extrasolar Planets Encyclopaedia at http://exoplanet.eu/). With the growing number of detected exoplanets in binary and multiple star systems it became more important to mark and to separate them into a new database, which is not available in the Extrasolar Planets Encyclopaedia. Therefore we established an online database (which can be found at: http://www.univie.ac.at/adg/schwarz/multiple.html) for all known exoplanets in binary star systems and in addition for multiple star systems, which will be updated regularly and linked to the Extrasolar Planets Encyclopaedia. The binary catalogue of exoplanets is available online as data file and can be used for statistical purposes. Our database is divided into two parts: the data of the stars and the planets, given in a separate list. We describe also the different parameters of the exoplanetary systems and present some applications.

  6. Binary and Millisecond Pulsars.

    PubMed

    Lorimer, Duncan R

    2005-01-01

    We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1700. There are now 80 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 103 pulsars in 24 of the Galactic globular clusters. Recent highlights have been the discovery of the first ever double pulsar system and a recent flurry of discoveries in globular clusters, in particular Terzan 5.

  7. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1996-01-01

    We present preliminary results of our implementation of a novel electrophoresis separation technique: Binary Oscillatory Cross flow Electrophoresis (BOCE). The technique utilizes the interaction of two driving forces, an oscillatory electric field and an oscillatory shear flow, to create an active binary filter for the separation of charged species. Analytical and numerical studies have indicated that this technique is capable of separating proteins with electrophoretic mobilities differing by less than 10%. With an experimental device containing a separation chamber 20 cm long, 5 cm wide, and 1 mm thick, an order of magnitude increase in throughput over commercially available electrophoresis devices is theoretically possible.

  8. Identification list of binaries

    NASA Astrophysics Data System (ADS)

    Malkov,, O.; Karchevsky,, A.; Kaygorodov, P.; Kovaleva, D.

    The Identification List of Binaries (ILB) is a star catalogue constructed to facilitate cross-referencing between different catalogues of binary stars. As of 2015, it comprises designations for approximately 120,000 double/multiple systems. ILB contains star coordinates and cross-references to the Bayer/Flemsteed, DM (BD/CD/CPD), HD, HIP, ADS, WDS, CCDM, TDSC, GCVS, SBC9, IGR (and some other X-ray catalogues), PSR designations, as well as identifications in the recently developed BSDB system. ILB eventually became a part of the BDB stellar database.

  9. Beam scanning binary logic

    NASA Astrophysics Data System (ADS)

    Itoh, Hideo; Mukai, Seiji; Watanabe, Masanobu; Mori, Masahiko; Yajima, Hiroyoshi

    1990-07-01

    A beam-scanning laser diode (BSLD) is presently applied to a novel optoelectronic logic operation, designated 'beam-scanning binary logic' (BSBL), that covers the implementation of both the basic logic gates and a spatial code encoder for photodetection, while allowing a greater reduction of the number of active devices than ordinary binary logic operations. BSBL executes multifunctional logic operations simultaneously. The data connections between logic gates in BSLD are flexible, due to the ability to electrically control both output power and laser-beam direction.

  10. T Tauri Spectroscopic Binaries

    NASA Astrophysics Data System (ADS)

    Dudorov, A. E.; Eretnova, O. V.

    2017-06-01

    The Hertzsprung-Russell diagram, the excess radius-age, and the eccentricity-period relations are constructed for double-lined spectroscopic T Tauri binaries. The masses and the ages of the classical T Tauri and the weak-line T Tauri stars are compared. All components of T Tauri stars have the excess radius in comparison with initial Main Sequence stars of corresponding mass. The younger the star the more excess radius it has. The overwhelming majority of close binaries (P<10d) have eccentricity near to zero. The fraction of quadruple systems in our sample are higher than for Main Sequence stars.

  11. Binary coding for hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Chang, Chein-I.; Chang, Chein-Chi; Lin, Chinsu

    2004-10-01

    Binary coding is one of simplest ways to characterize spectral features. One commonly used method is a binary coding-based image software system, called Spectral Analysis Manager (SPAM) for remotely sensed imagery developed by Mazer et al. For a given spectral signature, the SPAM calculates its spectral mean and inter-band spectral difference and uses them as thresholds to generate a binary code word for this particular spectral signature. Such coding scheme is generally effective and also very simple to implement. This paper revisits the SPAM and further develops three new SPAM-based binary coding methods, called equal probability partition (EPP) binary coding, halfway partition (HP) binary coding and median partition (MP) binary coding. These three binary coding methods along with the SPAM well be evaluated for spectral discrimination and identification. In doing so, a new criterion, called a posteriori discrimination probability (APDP) is also introduced for performance measure.

  12. Eclipsing Binary Update, No. 2.

    NASA Astrophysics Data System (ADS)

    Williams, D. B.

    1996-01-01

    Contents: 1. Wrong again! The elusive period of DHK 41. 2. Stars observed and not observed. 3. Eclipsing binary chart information. 4. Eclipsing binary news and notes. 5. A note on SS Arietis. 6. Featured star: TX Ursae Majoris.

  13. Separation in Binary Alloys

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Facemire, B. R.; Kaukler, W. F.; Witherow, W. K.; Fanning, U.

    1986-01-01

    Studies of monotectic alloys and alloy analogs reviewed. Report surveys research on liquid/liquid and solid/liquid separation in binary monotectic alloys. Emphasizes separation processes in low gravity, such as in outer space or in free fall in drop towers. Advances in methods of controlling separation in experiments highlighted.

  14. Orbits For Sixteen Binaries

    NASA Astrophysics Data System (ADS)

    Cvetkovic, Z.; Novakovic, B.

    2006-12-01

    In this paper orbits for 13 binaries are recalculated and presented. The reason is that recent observations show higher residuals than the corresponding ephemerides calculated by using the orbital elements given in the Sixth Catalog of Orbits of Visual Binary Stars. The binaries studied were: WDS 00182+7257 = A 803, WDS 00335+4006 = HO 3, WDS 00583+2124 = BU 302, WDS 01011+6022 = A 926, WDS 01014+1155 = BU 867, WDS 01112+4113 = A 655, WDS 01361-2954 + HJ 3447, WDS 02333+5219 = STT 42 AB, WDS 04362+0814 = A 1840 AB, WDS 08017-0836 = A 1580, WDS 08277-0425 = A 550, WDS 17471+1742 = STF 2215 and WDS 18025+4414 = BU 1127 Aa-B. In addition, for three binaries - WDS 01532+1526 = BU 260, WDS 02563+7253 =STF 312 AB and WDS 05003+3924 = STT 92 AB - the orbital elements are calculated for the first time. In this paper the authors present not only the orbital elements, but the masses, dynamical parallaxes, absolute magnitudes and ephemerides for the next five years, as well.

  15. Planetary systems in binaries

    NASA Astrophysics Data System (ADS)

    Takeda, Genya

    In this thesis we investigate the orbital evolution of planets in binaries. Unlike our own Solar System, at least one out of five planetary systems known to date is associated with additional stellar companions. Despite their large distances from the planetary systems, these stellar companions play an important role in significantly altering the planetary architecture over very long timescales. Most of the planets in binaries are found in hierarchical configurations in which a planet orbits around a component of a wide stellar binary. The evolution of such hierarchical triples has been analytically understood through the framework of the Kozai mechanism, in which the orbital eccentricity of a planet secularly grows through angular momentum exchange with the stellar companion. The aim of our first study is to investigate the global effect of stellar companions in exciting planetary eccentricities through the Kozai mechanism, using synthetic eccentricity distributions computed numerically from various initial assumptions motivated by observational studies. As inferred from observations and theoretical planet formation simulations, newly formed planetary systems are more likely to be oligarchic, containing multiple giant planets. However, the long-term evolution of gravitationally coupled planets perturbed by a stellar companion has been little understood in the previous studies. From a large ensemble of numerical integrations of double-planet systems in binaries, we have found that there are various evolutionary classes of multiple planets in binaries compared to simple hierarchical triple systems containing only one planet. Using the Kozai mechanism and the Laplace-Lagrange secular theory, we also provide analytic criteria that can readily predict the secular evolutionary behavior of a pair of planetary orbits in binaries. In the last part of this thesis we discuss an alternative channel of planetary migration induced by a combined effect of dissipative tidal forces

  16. Correlated binary regression with covariates specific to each binary observation.

    PubMed

    Prentice, R L

    1988-12-01

    Regression methods are considered for the analysis of correlated binary data when each binary observation may have its own covariates. It is argued that binary response models that condition on some or all binary responses in a given "block" are useful for studying certain types of dependencies, but not for the estimation of marginal response probabilities or pairwise correlations. Fully parametric approaches to these latter problems appear to be unduly complicated except in such special cases as the analysis of paired binary data. Hence, a generalized estimating equation approach is advocated for inference on response probabilities and correlations. Illustrations involving both small and large block sizes are provided.

  17. Astrometric Binaries: White Dwarfs?

    NASA Astrophysics Data System (ADS)

    Oliversen, Nancy A.

    We propose to observe a selection of astrometric or spectroscopicastrometric binaries nearer than about 20 pc with unseen low mass companions. Systems of this type are important for determining the luminosity function of low mass stars (white dwarfs and very late main sequence M stars), and their contribution to the total mass of the galaxy. Systems of this type are also important because the low mass, invisible companions are potential candidates in the search for planets. Our target list is selected primarily from the list of 31 astrometric binaries near the sun by Lippincott (1978, Space Sci. Rev., 22, 153), with additional candidates from recent observations by Kamper. The elimination of stars with previous IUE observations, red companions resolved by infrared speckle interferometry, or primaries later than M1 (because if white dwarf companions are present they should have been detected in the visible region) reduces the list to 5 targets which need further information. IUE SWP low dispersion observations of these targets will show clearly whether the remaining unseen companions are white dwarfs, thus eliminating very cool main sequence stars or planets. This is also important in providing complete statistical information about the nearest stars. The discovery of a white dwarf in such a nearby system would provide important additional information about the masses of white dwarfs. Recent results by Greenstein (1986, A. J., 92, 859) from binary systems containing white dwarfs imply that 80% of such systems are as yet undetected. The preference of binaries for companions of approximately equal mass makes the Lippincott-Kamper list of A through K primaries with unseen companions a good one to use to search for white dwarfs. The mass and light dominance of the current primary over the white dwarf in the visible makes ultraviolet observations essential to obtain an accurate census of white dwarf binaries.

  18. Learning to assign binary weights to binary descriptor

    NASA Astrophysics Data System (ADS)

    Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

    2016-10-01

    Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

  19. Tidal Evolution of Solar System Binaries

    NASA Astrophysics Data System (ADS)

    Taylor, Patrick A.; Margot, J. L.

    2007-10-01

    We approximate tidal evolution timescales for small (radius < 200 km), rocky bodies [1, 2] following a fission event, interpreted here as any process resulting in the placement of mass into orbit above the synchronous height, and explicitly calculate timescales for well-characterized systems. Binaries with nearly equal mass components orbit within 6 primary radii and have likely fully despun rapidly while smaller secondaries despin more slowly and end their tidal evolution at wider separations. The final separation of the components is limited by the conversion of spin to orbital angular momentum. Binary systems with separations beyond this limit require a different formation mechanism such as n-body capture. The product μQ, where μ is the rigidity and Q is the tidal dissipation factor, combines the idealized elastic properties of the asteroid that affect the tidal strength. Since binaries in the Main Belt must evolve to their current configuration within the age of the Solar System, a binary near this limit would place an upper bound on μQ for the system. Precise orbit, density, and component size information are required because ten percent errors in primary radius and density can cause approximately 20 and 25 percent changes in μQ, respectively. Assuming μQ of 1011 N/m2, many near-Earth binaries, if produced through fission, have tidally evolved for longer than their typical dynamical lifetime of 10 My [3]. This implies that either these binaries were formed prior to injection into the near-Earth region or μQ is at least an order of magnitude smaller than assumed, which might occur for highly fractured or rubble pile bodies. The effect of a non-spherical primary is also analyzed. [1] A. W. Harris and W. R. Ward, AREPS, 10, 1982. [2] S. J. Weidenschilling et al., in Asteroids II, 1989. [3] B. J. Gladman et al., Science, 277, 1997.

  20. NEA rotations and binaries

    NASA Astrophysics Data System (ADS)

    Pravec, Petr; Harris, A. W.; Warner, B. D.

    2007-05-01

    Of nearly 3900 near-Earth asteroids known in June 2006, 325 have got estimated rotation periods. NEAs with sizes down to 10 meters have been sampled. Observed spin distribution shows a major changing point around D=200 m. Larger NEAs show a barrier against spin rates >11 d-1 (period P~2.2 h) that shifts to slower rates with increasing equatorial elongation. The spin barrier is interpreted as a critical spin rate for bodies held together by self-gravitation only, suggesting that NEAs larger than 200 m are mostly strenghtless bodies (i.e., with zero tensile strength), so called `rubble piles'. The barrier disappears at D<200 m where most objects rotate too fast to be held together by self-gravitation only, so a non-zero cohesion is implied in the smaller NEAs. The distribution of NEA spin rates in the `rubble pile' range (D>0.2 km) is non-Maxwellian, suggesting that other mechanisms than just collisions worked there. There is a pile up in front of the barrier (P of 2-3 h). It may be related to a spin up mechanism crowding asteroids to the barrier. An excess of slow rotators is seen at P>30 h. The spin-down mechanism has no clear lower limit on spin rate; periods as long as tens of days occur. Most NEAs appear to be in basic spin states with rotation around the principal axis. Excited rotations are present among and actually dominate in slow rotators with damping timescales >4.5 byr. A few tumblers observed among fast rotating coherent objects consistently appear to be more rigid or younger than the larger, rubble-pile tumblers. An abundant population of binary systems among NEAs has been found. The fraction of binaries among NEAs larger than 0.3 km has been estimated to be 15 +/-4%. Primaries of the binary systems concentrate at fast spin rates (periods 2-3 h) and low amplitudes, i.e., they lie just below the spin barrier. The total angular momentum content in the binary systems suggests that they formed at the critical spin rate, and that little or no angular

  1. Microfluidic binary phase flow

    NASA Astrophysics Data System (ADS)

    Angelescu, Dan; Menetrier, Laure; Wong, Joyce; Tabeling, Patrick; Salamitou, Philippe

    2004-03-01

    We present a novel binary phase flow regime where the two phases differ substantially in both their wetting and viscous properties. Optical tracking particles are used in order to investigate the details of such multiphase flow inside capillary channels. We also describe microfluidic filters we have developed, capable of separating the two phases based on capillary pressure. The performance of the filters in separating oil-water emulsions is discussed. Binary phase flow has been previously used in microchannels in applications such as emulsion generation, enhancement of mixing and assembly of custom colloidal paticles. Such microfluidic systems are increasingly used in a number of applications spanning a diverse range of industries, such as biotech, pharmaceuticals and more recently the oil industry.

  2. Binary Love relations

    NASA Astrophysics Data System (ADS)

    Yagi, Kent; Yunes, Nicolás

    2016-07-01

    When in a tight binary, the mutual tidal deformations of neutron stars get imprinted onto observables, encoding information about their internal structure at supranuclear densities and gravity in the extreme-gravity regime. Gravitational wave (GW) observations of their late binary inspiral may serve as a tool to extract the individual tidal deformabilities, but this is made difficult by degeneracies between them in the GW model. We here resolve this problem by discovering approximately equation-of-state (EoS)-insensitive relations between dimensionless combinations of the individual tidal deformabilities. We show that these relations break degeneracies in the GW model, allowing for the accurate extraction of both deformabilities. Such measurements can be used to better differentiate between EoS models, and improve tests of general relativity and cosmology.

  3. Parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.; Crockett, Thomas W.; Nicol, David M.

    1993-01-01

    Binary dissection is widely used to partition non-uniform domains over parallel computers. This algorithm does not consider the perimeter, surface area, or aspect ratio of the regions being generated and can yield decompositions that have poor communication to computation ratio. Parametric Binary Dissection (PBD) is a new algorithm in which each cut is chosen to minimize load + lambda x(shape). In a 2 (or 3) dimensional problem, load is the amount of computation to be performed in a subregion and shape could refer to the perimeter (respectively surface) of that subregion. Shape is a measure of communication overhead and the parameter permits us to trade off load imbalance against communication overhead. When A is zero, the algorithm reduces to plain binary dissection. This algorithm can be used to partition graphs embedded in 2 or 3-d. Load is the number of nodes in a subregion, shape the number of edges that leave that subregion, and lambda the ratio of time to communicate over an edge to the time to compute at a node. An algorithm is presented that finds the depth d parametric dissection of an embedded graph with n vertices and e edges in O(max(n log n, de)) time, which is an improvement over the O(dn log n) time of plain binary dissection. Parallel versions of this algorithm are also presented; the best of these requires O((n/p) log(sup 3)p) time on a p processor hypercube, assuming graphs of bounded degree. How PBD is applied to 3-d unstructured meshes and yields partitions that are better than those obtained by plain dissection is described. Its application to the color image quantization problem is also discussed, in which samples in a high-resolution color space are mapped onto a lower resolution space in a way that minimizes the color error.

  4. Binary Optics Toolkit

    SciTech Connect

    Neal, Daniel

    1996-04-02

    This software is a set of tools for the design and analysis of binary optics. It consists of a series of stand-alone programs written in C and some scripts written in an application-specific language interpreted by a CAD program called DW2000. This software can be used to optimize the design and placement of a complex lens array from input to output and produce contours, mask designs, and data exported for diffractive optic analysis.

  5. Processing Of Binary Images

    NASA Astrophysics Data System (ADS)

    Hou, H. S.

    1985-07-01

    An overview of the recent progress in the area of digital processing of binary images in the context of document processing is presented here. The topics covered include input scan, adaptive thresholding, halftoning, scaling and resolution conversion, data compression, character recognition, electronic mail, digital typography, and output scan. Emphasis has been placed on illustrating the basic principles rather than descriptions of a particular system. Recent technology advances and research in this field are also mentioned.

  6. Double Eclipsing Binary Fitting

    NASA Astrophysics Data System (ADS)

    Cagas, P.; Pejcha, O.

    2012-06-01

    The parameters of the mutual orbit of eclipsing binaries that are physically connected can be obtained by precision timing of minima over time through light travel time effect, apsidal motion or orbital precession. This, however, requires joint analysis of data from different sources obtained through various techniques and with insufficiently quantified uncertainties. In particular, photometric uncertainties are often underestimated, which yields too small uncertainties in minima timings if determined through analysis of a χ2 surface. The task is even more difficult for double eclipsing binaries, especially those with periods close to a resonance such as CzeV344, where minima get often blended with each other. This code solves the double binary parameters simultaneously and then uses these parameters to determine minima timings (or more specifically O-C values) for individual datasets. In both cases, the uncertainties (or more precisely confidence intervals) are determined through bootstrap resampling of the original data. This procedure to a large extent alleviates the common problem with underestimated photometric uncertainties and provides a check on possible degeneracies in the parameters and the stability of the results. While there are shortcomings to this method as well when compared to Markov Chain Monte Carlo methods, the ease of the implementation of bootstrapping is a significant advantage.

  7. Binary-Signal Recovery

    NASA Technical Reports Server (NTRS)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  8. Visual binary stars: data to investigate formation of binaries

    NASA Astrophysics Data System (ADS)

    Kovaleva,, D.; Malkov,, O.; Yungelson, L.; Chulkov, D.

    Statistics of orbital parameters of binary stars as well as statistics of their physical characteristics bear traces of star formation history. However, statistical investigations of binaries are complicated by incomplete or missing observational data and by a number of observational selection effects. Visual binaries are the most common type of observed binary stars, with the number of pairs exceeding 130 000. The most complete list of presently known visual binary stars was compiled by cross-matching objects and combining data of the three largest catalogues of visual binaries. This list was supplemented by the data on parallaxes, multicolor photometry, and spectral characteristics taken from other catalogues. This allowed us to compensate partly for the lack of observational data for these objects. The combined data allowed us to check the validity of observational values and to investigate statistics of the orbital and physical parameters of visual binaries. Corrections for incompleteness of observational data are discussed. The datasets obtained, together with modern distributions of binary parameters, will be used to reconstruct the initial distributions and parameters of the function of star formation for binary systems.

  9. Binary optics: Trends and limitations

    NASA Astrophysics Data System (ADS)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-08-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  10. Binary optics: Trends and limitations

    NASA Technical Reports Server (NTRS)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-01-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  11. The Search for Trojan Binaries

    NASA Astrophysics Data System (ADS)

    Merline, William J.; Tamblyn, P. M.; Dumas, C.; Close, L. M.; Chapman, C. R.; Durda, D. D.; Levison, H. F.; Hamilton, D. P.; Nesvorny, D.; Storrs, A.; Enke, B.; Menard, F.

    2007-10-01

    We report on observations of Jupiter Trojan asteroids in search of binaries. We made observations using HST/ACS of 35 small (V = 17.5-19.5) objects in Cycle 14, without detecting any binaires. We have also observed a few dozen Trojans in our ground-based study of larger Trojans, discovering only one binary. The result is that the frequency of moderately-separated binaries among the Trojans seem rather low, likely less than 5%. Although we have only statistics of small numbers, it appears that the binary frequencies are more akin to the larger Main-Belt asteroids, than to the frequency in the TNO region, which probably exceeds 10%. The low frequency is inconsistent with the projections based on Trojan contact binaries by Mann et al. (2006, BAAS 38, 6509), although our work cannot detect very close or contact binaries. We discovered and characterized the orbit and density of the first Trojan binary, (617) Patroclus using the Gemini AO system (Merline et al. 2001 IAUC 7741). A second binary, (624) Hecktor, has now been reported by Marchis et al. (2006, IAUC 8732). In a broad survey of Main Belt asteroids, we found that, among the larger objects, the binary fraction is about 2%, while we are finding that the fraction is significantly higher among smaller asteroids (and this is even more apparent from lightcurve discoveries). Further, characteristics of these smaller systems indicate a distinctly different formation mechanism the the larger MB binaries. Because the Trojans have compositions that are more like the KBOs, while they live in a collisional environment much more like the Main Belt than the KBOs, these objects should hold vital clues to binary formation mechanics. And because there seems to be a distinct difference in larger and smaller main-belt binaries, we sought to detect such differences among the Trojans as well.

  12. 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.

  13. Particle acceleration in binaries

    NASA Astrophysics Data System (ADS)

    Sinitsyna, V. G.; Sinitsyna, V. Y.

    2017-06-01

    Cygnus X-3 massive binary system is one of the powerful sources of radio and X-ray emission consisting of an accreting compact object, probably a black hole, with a Wolf-Rayet star companion. Based on the detections of ultra high energy gamma-rays by Kiel and Havera Park, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of long-term observations of the Cyg X-3 binary at energies 800 GeV-85 TeV detected by SHALON in 1995 are presented with images, integral spectra and spectral energy distribution. The identification of source with Cygnus X-3 detected by SHALON was secured by the detection of its 4.8 hour orbital period in TeV gamma-rays. During the whole observation period of Cyg X-3 with SHALON significant flux increases were detected at energies above 0.8 TeV. These TeV flux increases are correlated with flaring activity at a lower energy range of X-ray and/or at observations of Fermi LAT as well as with radio emission from the relativistic jets of Cygnus X-3. The variability of very high-energy gamma-radiation and correlation of radiation activity in the wide energy range can provide essential information on particle mechanism production up to very high energies. Whereas, modulation of very high energy emission connected to the orbital motion of the binary system, provides an understanding of the emission processes, nature and location of particle acceleration.

  14. Very Wide Binaries

    NASA Astrophysics Data System (ADS)

    Olling, Robert; Shaya, E.

    2011-01-01

    We develop Bayesian statistical methods for discovering and assigning probabilities to physical stellar companions. The probabilities depend on similarities in "corrected" proper motion, parallax, and the phase-space density of field stars. Very wide binaries with separations over 10,000 AU have recently been predicted to form during the dissolution process of low-mass star clusters. In this case, these wide systems would still carry information about the density and size of the star cluster in which they formed. Alternatively, Galactic tides and weak interactions with passing stars peel off stars from such very wide binaries in less than 1/2 of a Hubble time. In the past, these systems have been used to rule in/out MACHOs or less compact dark (matter) objects. Ours is the first all-sky survey to locate escaped companions that are still drifting along with each other, long after their binary bond has been broken. We test stars for companionship up to an apparent separation of 8 parsec: 10 to 100 times wider than previous searches. Among Hipparcos stars within 100 pc, we find about 260 systems with separations between 0.01 and 1 pc, and another 190 with separation from 1 to 8 parsec. We find a number of previously unnoticed naked-eye companions, among which: Capella & 50 Per; Alioth, Megrez & Alcor; gamma & tau Cen; phi Eri & eta Hor; 62 & 63 Cnc; gamma & tau Per; zeta & delta Hya; beta01, beta02 & beta03 Tuc; 44 & 58 Oph and pi & rho Cep. At least 15 of our candidates are exoplanet host stars.

  15. Evolution of Close Binary Systems

    SciTech Connect

    Yakut, K; Eggleton, P

    2005-01-24

    We collected data on the masses, radii, etc. of three classes of close binary stars: low-temperature contact binaries (LTCBs), near-contact binaries (NCBs), and detached close binaries (DCBs). They restrict themselves to systems where (1) both components are, at least arguably, near the Main Sequence, (2) the periods are less than a day, and (3) there is both spectroscopic and photometric analysis leading to reasonably reliable data. They discuss the possible evolutionary connections between these three classes, emphasizing the roles played by mass loss and angular momentum loss in rapidly-rotating cool stars.

  16. 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.

  17. Low autocorrelation binary sequences

    NASA Astrophysics Data System (ADS)

    Packebusch, Tom; Mertens, Stephan

    2016-04-01

    Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time O(N {1.73}N). We computed all optimal sequences for N≤slant 66 and all optimal skewsymmetric sequences for N≤slant 119.

  18. BINARY STORAGE ELEMENT

    DOEpatents

    Chu, J.C.

    1958-06-10

    A binary storage device is described comprising a toggle provided with associsted improved driver circuits adapted to produce reliable action of the toggle during clearing of the toggle to one of its two states. or transferring information into and out of the toggle. The invention resides in the development of a self-regulating driver circuit to minimize the fluctuation of the driving voltages for the toggle. The disclosed driver circuit produces two pulses in response to an input pulse: a first or ''clear'' pulse beginning nt substantially the same time but endlrg slightly sooner than the second or ''transfer'' output pulse.

  19. Observational Types of Binaries in the Binary Star Database

    NASA Astrophysics Data System (ADS)

    Malkov, O.; Kovaleva, D.; Kaygorodov, P.

    2017-06-01

    In the present paper we describe observational types of binaries, included in BDB, the Binary star database, which presently contains data on physical and positional parameters for about 260 000 components of 120 000 stellar systems of multiplicity 2 to more than 20, taken from a large variety of published catalogues and databases.

  20. Cepheid Binary Companions

    NASA Astrophysics Data System (ADS)

    Remage Evans, Nancy

    Blue main sequence companions of binary Cepheids can be used to determine Clio luminosity of the Cepheids. By matching the composite spectrum of the companion and the Cepheid with those of standard stars, the spectral type of the companion and the magnitude difference between the two stars can be determined. The main sequence absolute magnitude calibration of the companion then leads to the absolute magnitude of the Cepheid. The aim of this project is to obtain low dispersion SWP spectra of three Cepheids (T Vul, Y Lac, and RS Ori) for which the LWP spectra show excess flux at 2500 from the companion. In addition, we request LWP low dispersion spectra of five Cepheids to complete the survey of all Cepheids brighter than 8" magnitude to look for companions. Archival IUE spectra are non-existant or inadequate (no LWP or overexposed). The purpose of this survey is to accurately determine the percentage of Cepheids which are binaries, to compare with evolutionary predictions. This IUE survey will identify definitively Cepheids with blue companions, about which there is come confusion from groundbased photometric techniques, and hence prevent distortions to such parameters as luminosity, color and reddening. In addition, the distribution of mass ratios (from the spectral type of the main sequence mass and the evolutionary mass of the Cepheid (Evans and Bolton, 1989)), is basic information about star formation.

  1. Relativistic Binaries in Globular Clusters.

    PubMed

    Benacquista, Matthew J; Downing, Jonathan M B

    2013-01-01

    Galactic globular clusters are old, dense star systems typically containing 10(4)-10(6) stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  2. Multilevel Models for Binary Data

    ERIC Educational Resources Information Center

    Powers, Daniel A.

    2012-01-01

    The methods and models for categorical data analysis cover considerable ground, ranging from regression-type models for binary and binomial data, count data, to ordered and unordered polytomous variables, as well as regression models that mix qualitative and continuous data. This article focuses on methods for binary or binomial data, which are…

  3. Multilevel Models for Binary Data

    ERIC Educational Resources Information Center

    Powers, Daniel A.

    2012-01-01

    The methods and models for categorical data analysis cover considerable ground, ranging from regression-type models for binary and binomial data, count data, to ordered and unordered polytomous variables, as well as regression models that mix qualitative and continuous data. This article focuses on methods for binary or binomial data, which are…

  4. Signature Visualization of Software Binaries

    SciTech Connect

    Panas, T

    2008-07-01

    In this paper we present work on the visualization of software binaries. In particular, we utilize ROSE, an open source compiler infrastructure, to pre-process software binaries, and we apply a landscape metaphor to visualize the signature of each binary (malware). We define the signature of a binary as a metric-based layout of the functions contained in the binary. In our initial experiment, we visualize the signatures of a series of computer worms that all originate from the same line. These visualizations are useful for a number of reasons. First, the images reveal how the archetype has evolved over a series of versions of one worm. Second, one can see the distinct changes between version. This allows the viewer to form conclusions about the development cycle of a particular worm.

  5. Magnetic activity of interacting binaries

    NASA Astrophysics Data System (ADS)

    Hill, Colin A.

    2017-10-01

    Interacting binaries provide unique parameter regimes, both rapid rotation and tidal distortion, in which to test stellar dynamo theories and study the resulting magnetic activity. Close binaries such as cataclysmic variables (CVs) have been found to differentially rotate, and so can provide testbeds for tidal dissipation efficiency in stellar convective envelopes, with implications for both CV and planet-star evolution. Furthermore, CVs show evidence of preferential emergence of magnetic flux tubes towards the companion star, as well as large, long-lived prominences that form preferentially within the binary geometry. Moreover, RS CVn binaries also show clear magnetic interactions between the two components in the form of coronal X-ray emission. Here, we review several examples of magnetic interactions in different types of close binaries.

  6. How do binary clusters form?

    NASA Astrophysics Data System (ADS)

    Arnold, Becky; Goodwin, Simon P.; Griffiths, D. W.; Parker, Richard. J.

    2017-10-01

    Approximately 10 per cent of star clusters are found in pairs, known as binary clusters. We propose a mechanism for binary cluster formation; we use N-body simulations to show that velocity substructure in a single (even fairly smooth) region can cause binary clusters to form. This process is highly stochastic and it is not obvious from a region's initial conditions whether a binary will form and, if it does, which stars will end up in which cluster. We find the probability that a region will divide is mainly determined by its virial ratio, and a virial ratio above 'equilibrium' is generally necessary for binary formation. We also find that the mass ratio of the two clusters is strongly influenced by the initial degree of spatial substructure in the region.

  7. BINARY ASTROMETRIC MICROLENSING WITH GAIA

    SciTech Connect

    Sajadian, Sedighe

    2015-04-15

    We investigate whether or not Gaia can specify the binary fractions of massive stellar populations in the Galactic disk through astrometric microlensing. Furthermore, we study whether or not some information about their mass distributions can be inferred via this method. In this regard, we simulate the binary astrometric microlensing events due to massive stellar populations according to the Gaia observing strategy by considering (i) stellar-mass black holes, (ii) neutron stars, (iii) white dwarfs, and (iv) main-sequence stars as microlenses. The Gaia efficiency for detecting the binary signatures in binary astrometric microlensing events is ∼10%–20%. By calculating the optical depth due to the mentioned stellar populations, the numbers of the binary astrometric microlensing events being observed with Gaia with detectable binary signatures, for the binary fraction of about 0.1, are estimated to be 6, 11, 77, and 1316, respectively. Consequently, Gaia can potentially specify the binary fractions of these massive stellar populations. However, the binary fraction of black holes measured with this method has a large uncertainty owing to a low number of the estimated events. Knowing the binary fractions in massive stellar populations helps with studying the gravitational waves. Moreover, we investigate the number of massive microlenses for which Gaia specifies masses through astrometric microlensing of single lenses toward the Galactic bulge. The resulting efficiencies of measuring the mass of mentioned populations are 9.8%, 2.9%, 1.2%, and 0.8%, respectively. The numbers of their astrometric microlensing events being observed in the Gaia era in which the lens mass can be inferred with the relative error less than 0.5 toward the Galactic bulge are estimated as 45, 34, 76, and 786, respectively. Hence, Gaia potentially gives us some information about the mass distribution of these massive stellar populations.

  8. 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.

  9. Binaries and Multiple Stellar Systems

    NASA Astrophysics Data System (ADS)

    Horch, Elliott

    Binary and multiple stellar systems have importance in three main areas of astronomy and astrophysics. First, because of the relatively simple gravitational interaction at work in the case of binary stars, these systems provide a basic check on stellar structure and evolution theory since the masses may be determined through observation. When these masses can be linked to other properties of the two stars, such as luminosity, color, and radius, they can provide very stringent constraints on stellar models. Second, the statistics of binary and multiple star systems provide clues to star formation mechanisms and environmental effects in the galactic gravitational potential and in clusters. Although a number of good results have been obtained in nearby star clusters and associations, knowledge of the field population has been somewhat limited until recently by a lack of large, complete samples of binaries. However, there appears to be a great deal of promise in this area for the coming decade in part due to astrometric satellites such as Hipparcos and Gaia. Third, the binary scenario is invoked to explain several important types of astrophysical phenomena such as Type Ia supernovae, cataclysmic variables, and stellar x-ray sources. Since the first of these mentioned is a standard candle for the extragalactic distance scale, it may even be said binary stars play a minor role in field of cosmology. However, in this chapter, the focus will mainly be on normal stars in binary and multiple-stellar systems. The basic physics of binaries will be reviewed, and the observational methods in use today will be discussed together with their limitations and prospects for the future. Finally, an overview of the current science in the three main areas mentioned where binaries have a significant impact will be given.

  10. Modified evolution of stellar binaries from supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Wang, Yi-Han; Yuan, Ye-Fei

    2017-04-01

    The evolution of main-sequence binaries resided in the galactic centre is influenced a lot by the central supermassive black hole (SMBH). Due to this perturbation, the stars in a dense environment are likely to experience mergers or collisions through secular or non-secular interactions. In this work, we study the dynamics of the stellar binaries at galactic centre, perturbed by another distant SMBH. Geometrically, such a four-body system is supposed to be decomposed into the inner triple (SMBH-star-star) and the outer triple (SMBH-stellar binary-SMBH). We survey the parameter space and determine the criteria analytically for the stellar mergers and the tidal disruption events (TDEs). For a relative distant and equal masses SMBH binary, the stars have more opportunities to merge as a result from the Lidov-Kozai (LK) oscillations in the inner triple. With a sample of tight stellar binaries, our numerical experiments reveal that a significant fraction of the binaries, ˜70 per cent, experience merger eventually. Whereas the majority of the stellar TDEs are likely to occur at a close periapses to the SMBH, induced by the outer Kozai effect. The tidal disruptions are found numerically as many as ˜10 per cent for a close SMBH binary that is enhanced significantly than the one without the external SMBH. These effects require the outer perturber to have an inclined orbit (≥40°) relatively to the inner orbital plane and may lead to a burst of the extremely astronomical events associated with the detection of the SMBH binary.

  11. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1997-01-01

    Electrophoresis has long been recognized as an effective analytic technique for the separation of proteins and other charged species, however attempts at scaling up to accommodate commercial volumes have met with limited success. In this report we describe a novel electrophoretic separation technique - Binary Oscillatory Crossflow Electrophoresis (BOCE). Numerical simulations indicate that the technique has the potential for preparative scale throughputs with high resolution, while simultaneously avoiding many problems common to conventional electrophoresis. The technique utilizes the interaction of an oscillatory electric field and a transverse oscillatory shear flow to create an active binary filter for the separation of charged protein species. An oscillatory electric field is applied across the narrow gap of a rectangular channel inducing a periodic motion of charged protein species. The amplitude of this motion depends on the dimensionless electrophoretic mobility, alpha = E(sub o)mu/(omega)d, where E(sub o) is the amplitude of the electric field oscillations, mu is the dimensional mobility, omega is the angular frequency of oscillation and d is the channel gap width. An oscillatory shear flow is induced along the length of the channel resulting in the separation of species with different mobilities. We present a model that predicts the oscillatory behavior of charged species and allows estimation of both the magnitude of the induced convective velocity and the effective diffusivity as a function of a in infinitely long channels. Numerical results indicate that in addition to the mobility dependence, the steady state behavior of solute species may be strongly affected by oscillating fluid into and out of the active electric field region at the ends of the cell. The effect is most pronounced using time dependent shear flows of the same frequency (cos((omega)t)) flow mode) as the electric field oscillations. Under such conditions, experiments indicate that

  12. Stability of binaries. Part II: Rubble-pile binaries

    NASA Astrophysics Data System (ADS)

    Sharma, Ishan

    2016-10-01

    We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

  13. Binary star database: binaries discovered in non-optical bands

    NASA Astrophysics Data System (ADS)

    Malkov, Oleg Yu.; Tessema, Solomon B.; Kniazev, Alexei Yu.

    The Binary star Database (BDB) is the world's principal database of binary and multiple systems of all observational types. In particular, it should contain data on binaries discovered in non-optical bands, X-ray binaries (XRBs) and radio pulsars in binaries. The goal of the present study was to compile complete lists of such objects. Due to the lack of a unified identification system for XRBs, we had to select them from five principal catalogues of X-ray sources. After cross-identification and positional cross-matching, a general catalogue of 373 XRBs was constructed for the first time. It contains coordinates, indication of photometric and spectroscopic binarity, and extensive cross-identification. In the preparation of the catalogue, a number of XRB classification disagreements were resolved, some catalogued identifiers and coordinates were corrected, and duplicated entries in the original catalogues were found. We have also compiled a general list of 239 radio pulsars in binary systems. The list is supplied with indication of photometric, spectroscopic or X-ray binarity, and with cross-identification data.

  14. Binary black hole spectroscopy

    NASA Astrophysics Data System (ADS)

    Van Den Broeck, Chris; Sengupta, Anand S.

    2007-03-01

    We study parameter estimation with post-Newtonian (PN) gravitational waveforms for the quasi-circular, adiabatic inspiral of spinning binary compact objects. In particular, the performance of amplitude-corrected waveforms is compared with that of the more commonly used restricted waveforms, in Advanced LIGO and EGO. With restricted waveforms, the properties of the source can only be extracted from the phasing. In the case of amplitude-corrected waveforms, the spectrum encodes a wealth of additional information, which leads to dramatic improvements in parameter estimation. At distances of ~100 Mpc, the full PN waveforms allow for high-accuracy parameter extraction for total mass up to several hundred solar masses, while with the restricted ones the errors are steep functions of mass, and accurate parameter estimation is only possible for relatively light stellar mass binaries. At the low-mass end, the inclusion of amplitude corrections reduces the error on the time of coalescence by an order of magnitude in Advanced LIGO and a factor of 5 in EGO compared to the restricted waveforms; at higher masses these differences are much larger. The individual component masses, which are very poorly determined with restricted waveforms, become measurable with high accuracy if amplitude-corrected waveforms are used, with errors as low as a few per cent in Advanced LIGO and a few tenths of a per cent in EGO. The usual spin orbit parameter β is also poorly determined with restricted waveforms (except for low-mass systems in EGO), but the full waveforms give errors that are small compared to the largest possible value consistent with the Kerr bound. This suggests a way of finding out if one or both of the component objects violate this bound. On the other hand, we find that the spin spin parameter σ remains poorly determined even when the full waveform is used. Generally, all errors have but a weak dependence on the magnitudes and orientations of the spins. We also briefly

  15. Mesoscopic model for binary fluids

    NASA Astrophysics Data System (ADS)

    Echeverria, C.; Tucci, K.; Alvarez-Llamoza, O.; Orozco-Guillén, E. E.; Morales, M.; Cosenza, M. G.

    2017-10-01

    We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.

  16. An adaptable binary entropy coder

    NASA Technical Reports Server (NTRS)

    Kiely, A.; Klimesh, M.

    2001-01-01

    We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

  17. Cryptography with DNA binary strands.

    PubMed

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'.

  18. CHAOTIC ZONES AROUND GRAVITATING BINARIES

    SciTech Connect

    Shevchenko, Ivan I.

    2015-01-20

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.

  19. Binary stars in moving groups

    NASA Astrophysics Data System (ADS)

    Azulay, R.; Guirado, J. C.; Marcaide, J. M.; Martí-Vidal, I.; Ros, E.

    Precise determination of dynamical masses of pre-main-sequence (PMS) stars is necessary to calibrate PMS stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 M_sun. Binary stars in young, nearby loose associations are particularly good candidates, since all members share a common age. We present phase-reference EVN observations of the binary system HD 160934 A/c, that belongs to the AB Doradus moving group, from which we have measured both the relative and absolute orbital motion. Accordingly, we obtained precise estimates of the mass of the components of this binary. Also we report on other PMS binary systems as EK Dra and AB Dor B.

  20. Separation in 5 Msun Binaries

    NASA Astrophysics Data System (ADS)

    Evans, Nancy R.; Bond, H. E.; Schaefer, G.; Mason, B. D.; Karovska, M.; Tingle, E.

    2013-01-01

    Cepheids (5 Msun stars) provide an excellent sample for determining the binary properties of fairly massive stars. International Ultraviolet Explorer (IUE) observations of Cepheids brighter than 8th magnitude resulted in a list of ALL companions more massive than 2.0 Msun uniformly sensitive to all separations. Hubble Space Telescope Wide Field Camera 3 (WFC3) has resolved three of these binaries (Eta Aql, S Nor, and V659 Cen). Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations for a sample of 18 Cepheids, and also a distribution of mass ratios. The distribution of orbital periods shows that the 5 Msun binaries prefer shorter periods than 1 Msun stars, reflecting differences in star formation processes.

  1. Radio emission from binary stars

    NASA Technical Reports Server (NTRS)

    Dulk, George A.

    1986-01-01

    Radio emission from binary star systems; characteristics of the binary systems inferred from the radio observations; and the reasons for the activity are reviewed. Binary stars with two main sequence stars, with one normal star and a white dwarf, and those containing a neutron star or a black hole are described. Energy may be directly available as matter falls into the potential well of a compact object. Electromagnetic induction effects may occur due to relative motions of magnetic fields and matter. By enforcing rapid rotation, binaries can induce strong dynamo action and hence generate free energy in the form of intense, complex, evolving magnetic fields. Whatever the source of energy, the observations at radio and X-ray wavelengths demonstrate that electrons are accelerated to high energies (mildly relativistic and, ultrarelativistic). Observed or inferred radio brightness temperatures range up to 10 to the 15th power K or more, implying coherent emission for sources brighter than 10 billion K.

  2. On Binary-State Phyllosilicate Automata

    NASA Astrophysics Data System (ADS)

    Adamatzky, Andrew

    Phyllosilicate is a sheet of silicate tetrahedra bound by basal oxygens. A phyllosilicate automaton is a regular network of finite state machines, which mimics the structure of phyllosilicate. A node of a binary state phyllosilicate automaton takes states 0 and 1. A node updates its state in discrete time depending on a sum of states of its three (silicon nodes) or six (oxygen nodes) closest neighbors. We phenomenologically select the main types of patterns generated by phyllosilicate automata based on their shape: convex and concave hulls, almost circularly growing patterns, octagonal patterns, and those with dendritic growth; and, the patterns' interior: disordered, solid, labyrinthine. We also present the rules exhibiting traveling localizations.

  3. Quick matching of binary images

    NASA Astrophysics Data System (ADS)

    Mustafa, Adnan A. Y.

    2015-09-01

    Matching images is a fundamental problem in image processing. The most common technique used to compare binary images is to calculate the correlation between two images or simply to subtract them. Both of these methods -as well as other matching methods- require some type of similarity operation to be applied to the whole image, and hence they are image size dependent. This implies that as image size increases, more processing time is required. However, with image sizes already exceeding 20 mega-pixels and standard image sizes doubling approximately every five years, the need to find a size invariant image matching method is becoming crucial. In this paper, we present a quick way to compare and match binary images based on the Probabilistic Matching Model (PMM). We present two simple image size invariant methods based on PMM: one for fast detection of dissimilar binary images and another for matching binary images. For detecting dissimilar binary images we introduce the Dissimilar Detection via Mapping method (DDM). We compare DDM to other popular matching methods used in the image processing arena and show that DDM is magnitudes faster than any other method. For binary image matching, we use DDM as a preprocessor for other popular methods to speed up their matching speed. In particular, we use DDM with cross correlation to speed it up. Test results are presented for real images varying in size from 16 kilo-pixel images to 10 mega-pixel images to show the method's size invariance.

  4. 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.

  5. Commission 42: Close Binary Stars

    NASA Astrophysics Data System (ADS)

    Ribas, Ignasi; Richards, Mercedes T.; Rucinski, Slavek; Bradstreet, David H.; Harmanec, Petr; Kaluzny, Janusz; Mikolajewska, Joanna; Munari, Ulisse; Niarchos, Panagiotis; Olah, Katalin; Pribulla, Theodor; Scarfe, Colin D.; Torres, Guillermo

    2012-04-01

    The present report covers the main developments in the field of close binaries during the triennium 2009-2012. In addition to scientific publications, there have been several opportunities for direct interaction of researchers working on close binaries. A number of meetings focused on more or less specific topics have taken place during this past years but the highlight for Commission 42 is arguably IAU Symposium 282 held in 2011 in Slovakia. The meeting exploited a strong connection in the methodology and tools used by close binary studies and the rapidly advancing field of exoplanet research. After all, exoplanetary systems are mostly discovered and studied using techniques employed by analyses of close binaries for decades. Modelling of exoplanet radial velocity curves and transiting planet light curves are just particular cases of single-lined and eclipsing binary systems, respectively, with very unequal component properties. As shown by IAU Symposium 282, the synergies between the two fields are strong and potentially very useful. Found below is a summary of the main scientific topics and conclusions from this very successful Symposium.

  6. Black Hole Binaries in Quiescence

    NASA Astrophysics Data System (ADS)

    Bailyn, Charles D.

    I discuss some of what is known and unknown about the behavior of black hole binary systems in the quiescent accretion state. Quiescence is important for several reasons: 1) the dominance of the companion star in optical and IR wavelengths allows the binary parameters to be robustly determined - as an example, we argue that the longer proposed distance to the X-ray source GRO J1655-40 is correct; 2) quiescence represents the limiting case of an extremely low accretion rate, in which both accretion and jets can be observed; 3) understanding the evolution and duration of the quiescent state is a key factor in determining the overall demographics of X-ray binaries, which has taken on a new importance in the era of gravitational wave astronomy.

  7. Experience with parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.

    1993-01-01

    Parametric Binary Dissection (PBD) is a new algorithm that can be used for partitioning graphs embedded in 2- or 3-dimensional space. It partitions explicitly on the basis of nodes + (lambda)x(edges cut), where lambda is the ratio of time to communicate over an edge to the time to compute at a node. The new algorithm is faster than the original binary dissection algorithm and attempts to obtain better partitions than the older algorithm, which only takes nodes into account. The performance of parametric dissection with plain binary dissection on 3 large unstructured 3-d meshes obtained from computational fluid dynamics and on 2 random graphs were compared. It was showm that the new algorithm can usually yield partitions that are substantially superior, but that its performance is heavily dependent on the input data.

  8. Statistical study of visual binaries

    NASA Astrophysics Data System (ADS)

    Abdel-Rahman, H. I.; Nouh, M. I.; Elsanhoury, W. H.

    2017-04-01

    In this paper, some statistical distributions of wide pairs included in Double Star Catalogue are investigated. Frequency distributions and testing hypothesis are derived for some basic parameters of visual binaries. The results reached indicate that, it was found that the magnitude difference is distributed exponentially, which means that the majority of the component of the selected systems is of the same spectral type. The distribution of the mass ratios is concentrated about 0.7 which agree with Salpeter mass function. The distribution of the linear separation appears to be exponentially, which contradict with previous studies for close binaries.

  9. Protocols for quantum binary voting

    NASA Astrophysics Data System (ADS)

    Thapliyal, Kishore; Sharma, Rishi Dutt; Pathak, Anirban

    Two new protocols for quantum binary voting are proposed. One of the proposed protocols is designed using a standard scheme for controlled deterministic secure quantum communication (CDSQC), and the other one is designed using the idea of quantum cryptographic switch, which uses a technique known as permutation of particles. A few possible alternative approaches to accomplish the same task (quantum binary voting) have also been discussed. Security of the proposed protocols is analyzed. Further, the efficiencies of the proposed protocols are computed, and are compared with that of the existing protocols. The comparison has established that the proposed protocols are more efficient than the existing protocols.

  10. Mental Effort in Binary Categorization Aided by Binary Cues

    ERIC Educational Resources Information Center

    Botzer, Assaf; Meyer, Joachim; Parmet, Yisrael

    2013-01-01

    Binary cueing systems assist in many tasks, often alerting people about potential hazards (such as alarms and alerts). We investigate whether cues, besides possibly improving decision accuracy, also affect the effort users invest in tasks and whether the required effort in tasks affects the responses to cues. We developed a novel experimental tool…

  11. The Fate of Neutron Star Binary Mergers

    NASA Astrophysics Data System (ADS)

    Piro, Anthony L.; Giacomazzo, Bruno; Perna, Rosalba

    2017-08-01

    Following merger, a neutron star (NS) binary can produce roughly one of three different outcomes: (1) a stable NS, (2) a black hole (BH), or (3) a supramassive, rotationally supported NS, which then collapses to a BH following angular momentum losses. Which of these fates occur and in what proportion has important implications for the electromagnetic transient associated with the mergers and the expected gravitational wave (GW) signatures, which in turn depend on the high density equation of state (EOS). Here we combine relativistic calculations of NS masses using realistic EOSs with Monte Carlo population synthesis based on the mass distribution of NS binaries in our Galaxy to predict the distribution of fates expected. For many EOSs, a significant fraction of the remnants are NSs or supramassive NSs. This lends support to scenarios in which a quickly spinning, highly magnetized NS may be powering an electromagnetic transient. This also indicates that it will be important for future GW observatories to focus on high frequencies to study the post-merger GW emission. Even in cases where individual GW events are too low in signal to noise to study the post merger signature in detail, the statistics of how many mergers produce NSs versus BHs can be compared with our work to constrain the EOS. To match short gamma-ray-burst (SGRB) X-ray afterglow statistics, we find that the stiffest EOSs are ruled out. Furthermore, many popular EOSs require a significant fraction of ˜60%-70% of SGRBs to be from NS-BH mergers rather than just binary NSs.

  12. Binary YORP Effect and Evolution of Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Steinberg, Elad; Sari, Re'em

    2011-02-01

    The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over ~104-105 years for a Dp = 2 km primary with a Ds = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORP effect on asteroids and the BYORP effect on binaries including J 2 effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.

  13. BINARY YORP EFFECT AND EVOLUTION OF BINARY ASTEROIDS

    SciTech Connect

    Steinberg, Elad; Sari, Re'em

    2011-02-15

    The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over {approx}10{sup 4}-10{sup 5} years for a D{sub p} = 2 km primary with a D{sub s} = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORP effect on asteroids and the BYORP effect on binaries including J{sub 2} effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.

  14. KEPLER ECLIPSING BINARIES WITH STELLAR COMPANIONS

    SciTech Connect

    Gies, D. R.; Matson, R. A.; Guo, Z.; Lester, K. V.; Orosz, J. A.; Peters, G. J. E-mail: rmatson@chara.gsu.edu E-mail: lester@chara.gsu.edu E-mail: gjpeters@mucen.usc.edu

    2015-12-15

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

  15. Generating Constant Weight Binary Codes

    ERIC Educational Resources Information Center

    Knight, D.G.

    2008-01-01

    The determination of bounds for A(n, d, w), the maximum possible number of binary vectors of length n, weight w, and pairwise Hamming distance no less than d, is a classic problem in coding theory. Such sets of vectors have many applications. A description is given of how the problem can be used in a first-year undergraduate computational…

  16. Generating Constant Weight Binary Codes

    ERIC Educational Resources Information Center

    Knight, D.G.

    2008-01-01

    The determination of bounds for A(n, d, w), the maximum possible number of binary vectors of length n, weight w, and pairwise Hamming distance no less than d, is a classic problem in coding theory. Such sets of vectors have many applications. A description is given of how the problem can be used in a first-year undergraduate computational…

  17. Clostridium difficile binary toxin CDT

    PubMed Central

    Gerding, Dale N; Johnson, Stuart; Rupnik, Maja; Aktories, Klaus

    2014-01-01

    Binary toxin (CDT) is frequently observed in Clostridium difficile strains associated with increased severity of C. difficile infection (CDI). CDT belongs to the family of binary ADP-ribosylating toxins consisting of two separate toxin components: CDTa, the enzymatic ADP-ribosyltransferase which modifies actin, and CDTb which binds to host cells and translocates CDTa into the cytosol. CDTb is activated by serine proteases and binds to lipolysis stimulated lipoprotein receptor. ADP-ribosylation induces depolymerization of the actin cytoskeleton. Toxin-induced actin depolymerization also produces microtubule-based membrane protrusions which form a network on epithelial cells and increase bacterial adherence. Multiple clinical studies indicate an association between binary toxin genes in C. difficile and increased 30-d CDI mortality independent of PCR ribotype. Further studies including measures of binary toxin in stool, analyses of CDI mortality caused by CDT-producing strains, and examination of the relationship of CDT expression to TcdA and TcdB toxin variants and PCR ribotypes are needed. PMID:24253566

  18. A Galactic Binary Detection Pipeline

    NASA Technical Reports Server (NTRS)

    Littenberg, Tyson B.

    2011-01-01

    The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

  19. Eclipsing binaries - selection of targets

    NASA Astrophysics Data System (ADS)

    Zasche, P.

    2017-04-01

    Are the ground-based observations still needed in the era of robotic all-sky surveys? There were highlighted several fields in the eclipsing binary research, where also the amateur photometry would be very fruitful with also a few suitable systems where the monitoring is needed also using the smaller telescopes.

  20. Binary logic is rich enough

    SciTech Connect

    Zapatrin, R.R.

    1992-02-01

    Given a finite ortholattice L, the *-semigroup is explicitly built whose annihilator ortholattice is isomorphic to L. Thus, it is shown that any finite quantum logic is the additive part of a binary logic. Some areas of possible applications are outlined. 7 refs.

  1. Coevolution of binaries and circumbinary gaseous discs

    NASA Astrophysics Data System (ADS)

    Fleming, David P.; Quinn, Thomas R.

    2017-01-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc which drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for 104 binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentric binaries which strongly couple to the disc develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance which corresponds to an alignment of gas particle longitude of periastrons. All systems display binary semimajor axis decay due to dissipation from the viscous disc.

  2. Learning Rotation-Invariant Local Binary Descriptor.

    PubMed

    Duan, Yueqi; Lu, Jiwen; Feng, Jianjiang; Zhou, Jie

    2017-08-01

    In this paper, we propose a rotation-invariant local binary descriptor (RI-LBD) learning method for visual recognition. Compared with hand-crafted local binary descriptors, such as local binary pattern and its variants, which require strong prior knowledge, local binary feature learning methods are more efficient and data-adaptive. Unlike existing learning-based local binary descriptors, such as compact binary face descriptor and simultaneous local binary feature learning and encoding, which are susceptible to rotations, our RI-LBD first categorizes each local patch into a rotational binary pattern (RBP), and then jointly learns the orientation for each pattern and the projection matrix to obtain RI-LBDs. As all the rotation variants of a patch belong to the same RBP, they are rotated into the same orientation and projected into the same binary descriptor. Then, we construct a codebook by a clustering method on the learned binary codes, and obtain a histogram feature for each image as the final representation. In order to exploit higher order statistical information, we extend our RI-LBD to the triple rotation-invariant co-occurrence local binary descriptor (TRICo-LBD) learning method, which learns a triple co-occurrence binary code for each local patch. Extensive experimental results on four different visual recognition tasks, including image patch matching, texture classification, face recognition, and scene classification, show that our RI-LBD and TRICo-LBD outperform most existing local descriptors.

  3. Binary nucleation at low temperatures

    NASA Technical Reports Server (NTRS)

    Zahoransky, R. A.; Peters, F.

    1985-01-01

    The onset of homogeneous condensation of binary vapors in the supersaturated state is studied in ethanol/n-propanol and water/ethanol via their unsteady expansion in a shock tube at temperatures below 273 K. Ethanol/n-propanol forms a nearly ideal solution, whereas water/ethanol is an example of a strongly nonideal mixture. Vapor mixtures of various compositions are diluted in dry air at small mole fractions and expanded in the driver section from room temperature. The onset of homogeneous condensation is detected optically and the corresponding thermodynamic state is evaluated. The experimental results are compared with the binary nucleation theory, and the particular problems of theoretical evaluation at low temperatures are discussed.

  4. Mass transfer between binary stars

    NASA Technical Reports Server (NTRS)

    Modisette, J. L.; Kondo, Y.

    1980-01-01

    The transfer of mass from one component of a binary system to another by mass ejection is analyzed through a stellar wind mechanism, using a model which integrates the equations of motion, including the energy equation, with an initial static atmosphere and various temperature fluctuations imposed at the base of the star's corona. The model is applied to several situations and the energy flow is calculated along the line of centers between the two binary components, in the rotating frame of the system, thereby incorporating the centrifugal force. It is shown that relatively small disturbances in the lower chromosphere or photosphere can produce mass loss through a stellar wind mechanism, due to the amplification of the disturbance propagating into the thinner atmosphere. Since there are many possible sources of the disturbance, the model can be used to explain many mass ejection phenomena.

  5. Binary Stars in SBS Survey

    NASA Astrophysics Data System (ADS)

    Erastova, L. K.

    2016-06-01

    Thirty spectroscopic binary stars were found in the Second Byurakan Survey (SBS). They show composite spectra - WD(DA)+dM or dC (for example Liebert et al. 1994). They may have red color, if the radiation of the red star dominates, and blue one, if the blue star is brighter and have peculiar spectrum in our survey plate. We obtained slit spectra for most of such objects. But we often see the spectrum of one component, because our slit spectra did not cover all optical range. We examine by eye the slit spectra of all SBS stellar objects (˜700) in SDSS DR7, DR8 or DR9 independent on our observations. We confirmed or discovered the duplicity of 30 stars. Usually they are spectroscopic binaries, where one component is WD (DA) and the second one is a red star with or without emission. There also are other components combinations. Sometimes there are emission lines, probably, indicating variable ones.

  6. Binary Inspiral in Quadratic Gravity

    NASA Astrophysics Data System (ADS)

    Yagi, Kent

    2015-01-01

    Quadratic gravity is a general class of quantum-gravity-inspired theories, where the Einstein-Hilbert action is extended through the addition of all terms quadratic in the curvature tensor coupled to a scalar field. In this article, we focus on the scalar Gauss- Bonnet (sGB) theory and consider the black hole binary inspiral in this theory. By applying the post-Newtonian (PN) formalism, we found that there is a scalar dipole radiation which leads to -1PN correction in the energy flux relative to gravitational radiation in general relativity. From the orbital decay rate of a low-mass X-ray binary A0600-20, we obtain the bound that is six orders of magnitude stronger than the current solar system bound. Furthermore, we show that the excess in the orbital decay rate of XTE J1118+480 can be explained by the scalar radiation in sGB theory.

  7. Close supermassive binary black holes.

    PubMed

    Gaskell, C Martin

    2010-01-07

    It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive black-hole binary (SMBB). The AGN J1536+0441 ( = SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that J1536+0441 is an example of line emission from a disk. If this is correct, the lack of clear optical spectral evidence for close SMBBs is significant, and argues either that the merging of close SMBBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.

  8. Information graphs for binary predictors.

    PubMed

    Hughes, G; McRoberts, N; Burnett, F J

    2015-01-01

    Binary predictors are used in a wide range of crop protection decision-making applications. Such predictors provide a simple analytical apparatus for the formulation of evidence related to risk factors, for use in the process of Bayesian updating of probabilities of crop disease. For diagrammatic interpretation of diagnostic probabilities, the receiver operating characteristic is available. Here, we view binary predictors from the perspective of diagnostic information. After a brief introduction to the basic information theoretic concepts of entropy and expected mutual information, we use an example data set to provide diagrammatic interpretations of expected mutual information, relative entropy, information inaccuracy, information updating, and specific information. Our information graphs also illustrate correspondences between diagnostic information and diagnostic probabilities.

  9. Close Binaries, Triples, and Eclipses

    NASA Astrophysics Data System (ADS)

    Sanborn, Jason; Zavala, R. T.

    2013-01-01

    Observations of the variable radio source b Per (HR1324) are part of an ongoing survey of close binary systems using the Navy Precision Optical Interferometer. Historical observations of b Per include sparse photometric and spectroscopic observations dating back to 1923, clearly showing this object to be a non-eclipsing, single-lined ellipsoidal variable. This is where the story for b Per stopped until recent inclusion of optical interferometric data which led to the detection of a third, long-period component. As the interferometric observations continue to build up so to is the understanding of this binary system, with the modeled orbital parameters pointing to an edge-on orientation that may allow for the detection of an eclipse by the long-period component. These types of eclipse events are quite rare for long-period binaries due to the nearly edge-on orientation required for their detection, leaving open the opportunity for more traditional methods of observation to add to the body of knowledge concerning this understudied system. Here we present the latest observational data of the b Per system along with an introduction to the best fit orbital parameters governing the eclipsing nature of this complex triple-system.

  10. Binary stars in loose associations

    NASA Astrophysics Data System (ADS)

    Azulay, R.; Guirado, J. C.; Marcaide, J. M.; Martí-Vidal, I.

    2013-05-01

    Precise determinations of dynamical masses of pre-main-sequence (PMS) stars are necessary to calibrate PMS stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 M_{⊙}. Binary stars in young, nearby loose associations (moving groups) are particularly good candidates, primarily because all members share a common age. Belonging to the AB Doradus moving group, we have observed the binary AB Dor Ba/Bb, 0.06" separation, with the Australian Long Baseline Array at 8.4 GHz. We have detected the two components Ba/Bb, which facilitates (i) a measurement of the relative orbital motion through subsequent radio maps, and (ii) an estimate of the orbital parameters, once combined the radio information with infrared relative astrometry. Our preliminary analysis shows that best-fit orbit corresponds to that with a period of 1.1 yr and semi major axis of 0.068". The sum of the masses AB Dor Ba/Bb is 0.3±0.1 M_{⊙}. The study of this binary, along with other stars of the same association, will constitute a benchmark for testing PMS models of low-mass stars.

  11. Marangoni convection in binary mixtures.

    PubMed

    Zhang, Jie; Behringer, Robert P; Oron, Alexander

    2007-07-01

    Marangoni instabilities in binary mixtures in the presence of the Soret effect and evaporation are different from those in pure liquids. In contrast to a large amount of experimental work on Marangoni convection in pure liquids, such experiments in binary mixtures are not available in the literature, to our knowledge. Using binary mixtures of NaCl/water in an open system, evaporation of water molecules at the liquid-vapor interface is inevitable. We have systematically investigated the pattern formation for a set of substrate temperatures and solute concentrations in an open system. The flow patterns evolve with time, driven by surface-tension fluctuations due to evaporation and the Soret effect, while the air-liquid interface does not deform. A shadow-graph method is used to follow the pattern formation in time. The patterns are mainly composed of polygons and rolls. The mean pattern size first decreases slightly, and then gradually increases during the evolution. Evaporation affects the pattern formation mainly at the early stages and the local evaporation rate tends to become spatially uniform at the film surface. The Soret effect becomes important at the later stages and affects the mixture for a large mean solute concentration where the Soret number is significantly above zero. The strength of convection increases with the initial solute concentration and the substrate temperature. Our findings differ from the theoretical predictions in which evaporation is neglected.

  12. Pulsed Accretion onto Eccentric and Circular Binaries

    NASA Astrophysics Data System (ADS)

    Muñoz, Diego J.; Lai, Dong

    2016-08-01

    We present numerical simulations of circumbinary accretion onto eccentric and circular binaries using the moving-mesh code AREPO. This is the first set of simulations to tackle the problem of binary accretion using a finite-volume scheme on a freely moving mesh, which allows for accurate measurements of accretion onto individual stars for arbitrary binary eccentricity. While accretion onto a circular binary shows bursts with period of ˜ 5 times the binary period P b, accretion onto an eccentric binary is predominantly modulated at the period ˜ 1{P}{{b}}. For an equal-mass circular binary, the accretion rates onto individual stars are quite similar to each other, following the same variable pattern in time. By contrast, for eccentric binaries, one of the stars can accrete at a rate 10-20 times larger than its companion. This “symmetry breaking” between the stars, however, alternates over timescales of order 200P b and can be attributed to a slowly precessing, eccentric circumbinary disk. Over longer timescales, the net accretion rates onto individual stars are the same, reaching a quasi-steady state with the circumbinary disk. These results have important implications for the accretion behavior of binary T Tauri stars and supermassive binary black holes.

  13. GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

    SciTech Connect

    Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-09-10

    Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.

  14. All Bright Cold Classical KBOs are Binary

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.; Parker, Alex H.; Grundy, William M.

    2014-11-01

    When sorted by absolute magnitude as seen in ground based observations, an extremely high fraction of the brightest Cold Classical (CC) Kuiper Belt objects (KBO) are, in fact resolved as binaries when observed at higher angular resolution. Of the 22 CCs brighter than H=6.1 observed by HST, 16 have been found to be binary yielding a binary fraction of 73±10%. When low inclination interlopers from the hot population and close binaries are considered, this very high fraction is consistent with 100% of bright CCs being binary. At fainter absolute magnitudes, this fraction drops to ~20%. Such a situation is a natural outcome of a broken size distribution with a steep drop-off in the number of CCs with individual component diameters larger than 150 km (for an assumed albedo of 0.15). A sharp cutoff in the size distribution for CCs is consistent with formation models that suggest that most planetesimals form at a preferred modal size of order 100 km.The very high fraction of binaries among the largest CCs also serves to limit the separation distribution of KBO binaries. At most, 27% of the brightest CCs are possible unresolved binaries. The apparent power law distribution of binary separation must cut off near the current observational limits of HST ( 1800 km at 43 AU). It is worth noting, however, that this observation does not constrain how many components of resolved binaries may themselves be unresolved multiples like 47171 1999 TC36. Finally, it is important to point out that, when sorted by the size of the primary rather than absolute magnitude of the unresolved pair, the fraction of binaries is relatively constant with size (Nesvorny et al. 2011, AJ 141, 159) eliminating observational bias as cause of the pile up of binaries among the brightest Cold Classical Kuiper Belt objects.The very high fraction of binaries among the brightest CCs appears to be an effect of the underlying CC size distribution.

  15. Eclipsing Binaries in the 21st Century—Opportunities for Amateur Astronomers

    NASA Astrophysics Data System (ADS)

    Guinan, E. F.; Engle, S. G.; Devinney, E. J.

    2012-06-01

    Eclipsing binaries play major roles in modern astrophysical research. These stars provide fundamental data on the masses, radii, ages, atmospheres, and interiors of stars as well as serving as test beds for stellar structure and evolution models. The study of eclipsing binaries also returns vital information about the formation and evolution of close binaries themselves. Studying the changes in their periods from the observations of eclipse timings provides insights into evolution of close binaries, mass exchange and loss, apsidal motion for eccentric systems, as well as the discovery of the low mass (unseen) third bodies. Moreover eclipsing binaries in clusters and other galaxies can provide accurate distances to the star clusters and galaxies in which they reside. More recently observations of eclipsing exoplanet-star systems (that is, transiting exoplanets) when coupled with spectroscopy are yielding fundamental information about the frequency and the physical properties of planets orbiting other stars. For the reasons discussed above, observations of eclipsing binary systems have been popular for AAVSO observers and many papers have been published (see Williams et al. 2012, JAAVSO, 40, No. 1). A recent example is the highly successful AAVSO’s Citizen Sky Project focused on the enigmatic long-period eclipsing binary ɛ Aur. Building on the success of the AAVSO during the last century, this paper explores the present and future prospects for research in eclipsing binaries. We focus on what can be done by AAVSO members and other amateur astronomers in the study of eclipsing binaries. Several examples of observing strategies and interesting (and scientifically valuable) projects are discussed as well as future prospects. As discussed, there are many opportunities for AAVSO members to contribute to study of eclipsing binary stars and an increasing variety of objects to observe.

  16. New RR Lyrae variables in binary systems

    NASA Astrophysics Data System (ADS)

    Hajdu, G.; Catelan, M.; Jurcsik, J.; Dékány, I.; Drake, A. J.; Marquette, J.-B.

    2015-04-01

    Despite their importance, very few RR Lyrae (RRL) stars have been known to reside in binary systems. We report on a search for binary RRL in the OGLE-III Galactic bulge data. Our approach consists in the search for evidence of the light-travel time effect in so-called observed minus calculated (O-C) diagrams. Analysis of 1952 well-observed fundamental-mode RRL in the OGLE-III data revealed an initial sample of 29 candidates. We used the recently released OGLE-IV data to extend the baselines up to 17 yr, leading to a final sample of 12 firm binary candidates. We provide O-C diagrams and binary parameters for this final sample, and also discuss the properties of eight additional candidate binaries whose parameters cannot be firmly determined at present. We also estimate that ≳ 4 per cent of the RRL reside in binary systems.

  17. Binary Black Holes from Dense Star Clusters

    NASA Astrophysics Data System (ADS)

    Rodriguez, Carl

    2017-01-01

    The recent detections of gravitational waves from merging binary black holes have the potential to revolutionize our understanding of compact object astrophysics. But to fully utilize this new window into the universe, we must compare these observations to detailed models of binary black hole formation throughout cosmic time. In this talk, I will review our current understanding of cluster dynamics, describing how binary black holes can be formed through gravitational interactions in dense stellar environments, such as globular clusters and galactic nuclei. I will review the properties and merger rates of binary black holes from the dynamical formation channel. Finally, I will describe how the spins of a binary black hole are determined by its formation history, and how we can use this to discriminate between dynamically-formed binaries and those formed from isolated evolution in galactic fields.

  18. Measuring Close Binary Stars with Speckle Interferometry

    DTIC Science & Technology

    2014-09-01

    Measuring Close Binary Stars with Speckle Interferometry Keith T. Knox Air Force Research Laboratory ABSTRACT Speckle interferometry...Labeyrie, 1970) is a well-tested and still used method for detecting and measuring binary stars that are closer together than the width of the...orientation of the binary star system (Horch, 1996, Tokovinin, 2010). In this talk, a method for analyzing the fringes in the power spectrum will be

  19. Microlensing Signature of Binary Black Holes

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

    2012-01-01

    We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

  20. Survival of planets around shrinking stellar binaries

    PubMed Central

    Muñoz, Diego J.; Lai, Dong

    2015-01-01

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov–Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like. PMID:26159412

  1. Survival of planets around shrinking stellar binaries

    NASA Astrophysics Data System (ADS)

    Munoz, Diego Jose; Lai, Dong

    2015-12-01

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 days, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. We present new results (PNAS 112, 30, p 9264) on the orbital evolution of planets around binaries undergoing orbital decay by this "LK+tide" mechanism. From secular and N-body calculations, we show how planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Either outcome can explain these planets' elusiveness to detection. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer specific predictions as to what their orbital configurations should be like.

  2. Survival of planets around shrinking stellar binaries.

    PubMed

    Muñoz, Diego J; Lai, Dong

    2015-07-28

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like.

  3. Young and Waltzing Binary Stars

    NASA Astrophysics Data System (ADS)

    2001-10-01

    ADONIS Observes Low-mass Eclipsing System in Orion Summary A series of very detailed images of a binary system of two young stars have been combined into a movie . In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes . A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars . Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy. They are located some 1500 light-years away in the Orion star-forming region and they probably formed just 10 million years ago . This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars . The new result provides an important piece of information for our current understanding of how young stars evolve. The observations were obtained by a team of astronomers from Italy and ESO [1] using the ADaptive Optics Near Infrared System (ADONIS) on the 3.6-m telescope at the ESO La Silla Observatory. PR Photo 29a/01 : The RXJ 0529.4+0041 system before primary eclipse PR Photo 29b/01 : The RXJ 0529.4+0041 system at mid-primary eclipse PR Photo 29c/01 : The RXJ 0529.4+0041 system after primary eclipse PR Photo 29d/01 : The RXJ 0529.4+0041 system before secondary eclipse PR Photo 29e/01 : The RXJ 0529.4+0041 system at mid-secondary eclipse PR Photo 29f/01 : The RXJ 0529.4+0041 system after secondary eclipse PR Video Clip 06/01 : Video of the RXJ 0529.4+0041 system Binary stars and stellar masses Since some time, astronomers have noted that most stars seem to form in binary or multiple systems. This is quite fortunate, as the study of binary stars is the only way in which it is possible to measure directly one of the most fundamental quantities of a star, its mass. The mass of a

  4. Crustal Failure during Binary Inspiral

    NASA Astrophysics Data System (ADS)

    Penner, A. J.; Andersson, N.; Jones, D. I.; Samuelsson, L.; Hawke, I.

    2012-04-01

    We present the first fully relativistic calculations of the crustal strain induced in a neutron star by a binary companion at the late stages of inspiral, employing realistic equations of state for the fluid core and the solid crust. We show that while the deep crust is likely to fail only shortly before coalescence, there is a large variation in elastic strain, with the outermost layers failing relatively early on in the inspiral. We discuss the significance of the results for both electromagnetic and gravitational-wave astronomy.

  5. Spectroscopic Orbits of Three Binaries

    NASA Astrophysics Data System (ADS)

    Scarfe, C. D.

    2017-10-01

    This paper presents new spectroscopic orbits of three binaries with evolved primaries and periods of the order of a few years, two of them very eccentric. All the orbits were determined primarily from observations made with the DAO 1.2-m telescope and coudé spectrograph. Observations were obtained using the radial velocity spectrometer until it was decommissioned in 2004, and since then using a CCD detector, and cross-correlating the spectra with those of standard stars. It will be evident that the latter procedure leads to smaller observational scatter than the former did.

  6. Massive Stars in Interactive Binaries

    NASA Astrophysics Data System (ADS)

    St.-Louis, Nicole; Moffat, Anthony F. J.

    Massive stars start their lives above a mass of ~8 time solar, finally exploding after a few million years as core-collapse or pair-production supernovae. Above ~15 solar masses, they also spend most of their lives driving especially strong, hot winds due to their extreme luminosities. All of these aspects dominate the ecology of the Universe, from element enrichment to stirring up and ionizing the interstellar medium. But when they occur in close pairs or groups separated by less than a parsec, the interaction of massive stars can lead to various exotic phenomena which would not be seen if there were no binaries. These depend on the actual separation, and going from wie to close including colliding winds (with non-thermal radio emission and Wolf-Rayet dust spirals), cluster dynamics, X-ray binaries, Roche-lobe overflow (with inverse mass-ratios and rapid spin up), collisions, merging, rejuventation and massive blue stragglers, black-hole formation, runaways and gamma-ray bursts. Also, one wonders whether the fact that a massive star is in a binary affects its parameters compared to its isolated equivalent. These proceedings deal with all of these phenomena, plus binary statistics and determination of general physical properties of massive stars, that would not be possible with their single cousins. The 77 articles published in these proceedings, all based on oral talks, vary from broad revies to the lates developments in the field. About a third of the time was spent in open discussion of all participants, both for ~5 minutes after each talk and 8 half-hour long general dialogues, all audio-recorded, transcribed and only moderately edited to yield a real flavour of the meeting. The candid information in these discussions is sometimes more revealing than the article(s) that preceded them and also provide entertaining reading. The book is suitable for researchers and graduate students interested in stellar astrophysics and in various physical processes involved when

  7. CRUSTAL FAILURE DURING BINARY INSPIRAL

    SciTech Connect

    Penner, A. J.; Andersson, N.; Jones, D. I.; Hawke, I.; Samuelsson, L.

    2012-04-20

    We present the first fully relativistic calculations of the crustal strain induced in a neutron star by a binary companion at the late stages of inspiral, employing realistic equations of state for the fluid core and the solid crust. We show that while the deep crust is likely to fail only shortly before coalescence, there is a large variation in elastic strain, with the outermost layers failing relatively early on in the inspiral. We discuss the significance of the results for both electromagnetic and gravitational-wave astronomy.

  8. SYSTEMATICALLY MISCLASSIFIED BINARY DEPENDENT VARIABLES

    PubMed Central

    TENNEKOON, VIDHURA; ROSENMAN, ROBERT

    2014-01-01

    When a binary dependent variable is misclassified, that is, recorded in the category other than where it really belongs, probit and logit estimates are biased and inconsistent. In some cases the probability of misclassification may vary systematically with covariates, and thus be endogenous. In this paper we develop an estimation approach that corrects for endogenous misclassification, validate our approach using a simulation study, and apply it to the analysis of a treatment program designed to improve family dynamics. Our results show that endogenous misclassification could lead to potentially incorrect conclusions unless corrected using an appropriate technique. PMID:27293307

  9. The Young Visual Binary Database

    NASA Astrophysics Data System (ADS)

    Prato, Lisa A.; Avilez, Ian; Allen, Thomas; Zoonematkermani, Saeid; Biddle, Lauren; Muzzio, Ryan; Wittal, Matthew; Schaefer, Gail; Simon, Michal

    2017-01-01

    We have obtained adaptive optics imaging and high-resolution H-band and in some cases K-band spectra of each component in close to 100 young multiple systems in the nearby star forming regions of Taurus, Ophiuchus, TW Hya, and Orion. The binary separations for the pairs in our sample range from 30 mas to 3 arcseconds. The imaging and most of our spectra were obtained with instruments behind adaptive optics systems in order to resolve even the closest companions. We are in the process of determining fundamental stellar and circumstellar properties, such as effective temperature, Vsin(i), veiling, and radial velocity, for each component in the entire sample. The beta version of our database includes systems in the Taurus region and provides plots, downloadable ascii spectra, and values of the stellar and circumstellar properties for both stars in each system. This resource is openly available to the community at http://jumar.lowell.edu/BinaryStars/. In this poster we describe initial results from our analysis of the survey data. Support for this research was provided in part by NSF award AST-1313399 and by NASA Keck KPDA funding.

  10. Interacting jets from binary protostars

    NASA Astrophysics Data System (ADS)

    Murphy, G. C.; Lery, T.; O'Sullivan, S.; Spicer, D.; Bacciotti, F.; Rosen, A.

    2008-02-01

    Aims: We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. Methods: We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. Results: We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. Conclusions: While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly parallel, as in most observed cases, we show that the magnetic field can help the collimation and refocusing of both of the two jets.

  11. Close binary neutron star systems

    NASA Astrophysics Data System (ADS)

    Marronetti, Pedro

    1999-12-01

    We present a method to calculate solutions to the initial value problem in (3 + 1) general relativity corresponding to binary neutron-star systems (BNS) in irrotational quasi-equilibrium orbits. The initial value equations are solved using a conformally flat spatial metric tensor. The stellar fluid dynamics corresponds to that of systems with zero vorticity in the inertial reference frame. Irrotational systems like the ones analyzed in the present work are likely to resemble the final stages of the evolution of neutron-star binaries, thus providing insights on the inspiral process. The fluid velocity is derived from the gradient of a scalar potential. A numerical program was developed to solve the elliptic equations for the metric fields and the fluid velocity potential. We discuss the different numerical techniques employed to achieve high resolution across the stellar volume, as well as the methods used to find solutions to the Poisson-like equations with their corresponding boundary conditions. We present sequences of quasi-stable circular orbits which conserve baryonic mass. These sequences mimic the time evolution of the inspiral and are obtained without solving the complex evolution equations. They also provide sets of initial value data for future time evolution codes, which should be valid very close to the final merger. We evaluate the emission of gravitational radiation during the evolution through multipole expansions methods.

  12. Coevality in Young Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Simon, M.; Toraskar, Jayashree

    2017-06-01

    The ages of the components in very short period pre-main-sequence (PMS) binaries are essential to an understanding of their formation. We considered a sample of seven PMS eclipsing binaries (EBs) with ages 1-6.3 MY and component masses 0.2-1.4 {M}⊙ . The very high precision with which their masses and radii have been measured and the capability provided by the Modules for Experiments in Stellar Astrophysics to calculate their evolutionary tracks at exactly the measured masses allows the determination of age differences of the components independent of their luminosities and effective temperatures. We found that the components of five EBs, ASAS J052821+0338.5, Parenago 1802, JW 380, CoRoT 223992193, and UScoCTIO 5, formed within 0.3 MY of each other. The parameters for the components of V1174 Ori imply an implausible large age difference of 2.7 MY and should be reconsidered. The seventh EB in our sample, RX J0529.4+0041 fell outside the applicability of our analysis.

  13. A simulation study for the analysis of uncertain binary responses: Application to first insemination success in beef cattle

    PubMed Central

    Sapp, Robyn L; Spangler, Matthew L; Rekaya, Romdhane; Bertrand, J Keith

    2005-01-01

    A simulation was carried out to investigate the methods of analyzing uncertain binary responses for success or failure at first insemination. A linear mixed model that included, herd, year, and month of mating as fixed effects; and unrelated service sire, sire and residual as random effects was used to generate binary data. Binary responses were assigned using the difference between days to calving and average gestation length. Females deviating from average gestation length lead to uncertain binary responses. Thus, the methods investigated were the following: (1) a threshold model fitted to certain (no uncertainty) binary data (M1); (2) a threshold model fitted to uncertain binary data ignoring uncertainty (M2); and (3) analysis of uncertain binary data, accounting for uncertainty from day 16 to 26 (M3) or from day 14 to 28 (M4) after introduction of the bull, using a threshold model with fuzzy logic classification. There was virtually no difference between point estimates obtained from M1, M3, and M4 with true values. When uncertain binary data were analyzed ignoring uncertainty (M2), sire variance and heritability were underestimated by 22 and 24%, respectively. Thus, for noisy binary data, a threshold model contemplating uncertainty is needed to avoid bias when estimating genetic parameters. PMID:16277971

  14. Method of all-optical frequency encoded decimal to binary and binary coded decimal, binary to gray, and gray to binary data conversion using semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Garai, Sisir Kumar

    2011-07-01

    Conversion of optical data from decimal to binary format is very important in optical computing and optical signal processing. There are many binary code systems to represent decimal numbers, the most common being the binary coded decimal (BCD) and gray code system. There are a wide choice of BCD codes, one of which is a natural BCD having a weighted code of 8421, by means of which it is possible to represent a decimal number from 0 to 9 with a combination of 4bit binary digits. The reflected binary code, also known as the Gray code, is a binary numeral system where two successive values differ in only 1bit. The Gray code is very important in digital optical communication as it is used to prevent spurious output from optical switches as well as to facilitate error correction in digital communications in an optical domain. Here in this communication, the author proposes an all-optical frequency encoded method of ``:decimal to binary, BCD,'' ``binary to gray,'' and ``gray to binary'' data conversion using the high-speed switching actions of semiconductor optical amplifiers. To convert decimal numbers to a binary form, a frequency encoding technique is adopted to represent two binary bits, 0 and 1. The frequency encoding technique offers advantages over conventional encoding techniques in terms of less probability of bit errors and greater reliability. Here the author has exploited the polarization switch made of a semiconductor optical amplifier (SOA) and a property of nonlinear rotation of the state of polarization of the probe beam in SOA for frequency conversion to develop the method of frequency encoded data conversion.

  15. Fabricating binary optics: An overview of binary optics process technology

    NASA Technical Reports Server (NTRS)

    Stern, Margaret B.

    1993-01-01

    A review of binary optics processing technology is presented. Pattern replication techniques have been optimized to generate high-quality efficient microoptics in visible and infrared materials. High resolution optical photolithography and precision alignment is used to fabricate maximally efficient fused silica diffractive microlenses at lambda = 633 nm. The degradation in optical efficiency of four-phase-level fused silica microlenses resulting from an intentional 0.35 micron translational error has been systematically measured as a function of lens speed (F/2 - F/60). Novel processes necessary for high sag refractive IR microoptics arrays, including deep anisotropic Si-etching, planarization of deep topography and multilayer resist techniques, are described. Initial results are presented for monolithic integration of photonic and microoptic systems.

  16. Fill-in binary loop pulse-torque quantizer

    NASA Technical Reports Server (NTRS)

    Lory, C. B.

    1975-01-01

    Fill-in binary (FIB) loop provides constant heating of torque generator, an advantage of binary current switching. At the same time, it avoids mode-related dead zone and data delay of binary, an advantage of ternary quantization.

  17. A candidate sub-parsec supermassive binary black hole system.

    PubMed

    Boroson, Todd A; Lauer, Tod R

    2009-03-05

    The role of mergers in producing galaxies, together with the finding that most large galaxies harbour black holes in their nuclei, implies that binary supermassive black hole systems should be common. Here we report that the quasar SDSS J153636.22+044127.0 is a plausible example of such a system. This quasar shows two broad-line emission systems, separated in velocity by 3,500 km s(-1). A third system of unresolved absorption lines has an intermediate velocity. These characteristics are unique among known quasars. We interpret this object as a binary system of two black holes, having masses of 10(7.3) and 10(8.9) solar masses separated by approximately 0.1 parsec with an orbital period of approximately 100 years.

  18. The Evolution of Compact Binary Star Systems.

    PubMed

    Postnov, Konstantin A; Yungelson, Lev R

    2006-01-01

    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars - compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.

  19. Gravitational radiation, inspiraling binaries, and cosmology

    NASA Technical Reports Server (NTRS)

    Chernoff, David F.; Finn, Lee S.

    1993-01-01

    We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.

  20. An Acidity Scale for Binary Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1987-01-01

    Discusses the classification of binary oxides as acidic, basic, or amphoteric. Demonstrates how a numerical scale for acidity/basicity of binary oxides can be constructed using thermochemical data for oxoacid salts. Presents the calculations derived from the data that provide the numeric scale values. (TW)

  1. The Evolution of Compact Binary Star Systems.

    PubMed

    Postnov, Konstantin A; Yungelson, Lev R

    2014-01-01

    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  2. Gravitational radiation, inspiraling binaries, and cosmology

    NASA Technical Reports Server (NTRS)

    Chernoff, David F.; Finn, Lee S.

    1993-01-01

    We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.

  3. ECCENTRIC EVOLUTION OF SUPERMASSIVE BLACK HOLE BINARIES

    SciTech Connect

    Iwasawa, Masaki; An, Sangyong; Matsubayashi, Tatsushi; Funato, Yoko; Makino, Junichiro

    2011-04-10

    In recent numerical simulations, it has been found that the eccentricity of supermassive black hole (SMBH)-intermediate black hole (IMBH) binaries grows toward unity through interactions with the stellar background. This increase of eccentricity reduces the merging timescale of the binary through the gravitational radiation to a value well below the Hubble time. It also gives a theoretical explanation of the existence of eccentric binaries such as that in OJ287. In self-consistent N-body simulations, this increase of eccentricity is always observed. On the other hand, the result of the scattering experiment between SMBH binaries and field stars indicated that the eccentricity dose not change significantly. This discrepancy leaves the high eccentricity of the SMBH binaries in N-body simulations unexplained. Here, we present a stellar-dynamical mechanism that drives the increase of the eccentricity of an SMBH binary with a large mass ratio. There are two key processes involved. The first one is the Kozai mechanism under a non-axisymmetric potential, which effectively randomizes the angular momenta of surrounding stars. The other is the selective ejection of stars with prograde orbits. Through these two mechanisms, field stars extract the orbital angular momentum of the SMBH binary. Our proposed mechanism causes the increase in the eccentricity of most of SMBH binaries, resulting in the rapid merger through gravitational wave radiation. Our result has given a definite solution to the 'last-parsec problem'.

  4. An Acidity Scale for Binary Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1987-01-01

    Discusses the classification of binary oxides as acidic, basic, or amphoteric. Demonstrates how a numerical scale for acidity/basicity of binary oxides can be constructed using thermochemical data for oxoacid salts. Presents the calculations derived from the data that provide the numeric scale values. (TW)

  5. Binary optics in the '90s

    NASA Astrophysics Data System (ADS)

    Gallagher, Neal C., Jr.

    1991-03-01

    The term binary optics was first employed to the best of my knowledge by Wilfred Veldkamp of MIT Lincoln Laboratory; although, these devices have been in existence prior to this of this term. Generally the term refers to optical components whose transmittance or reflectance occurs in binary steps. Usually fabricated by use of one or more binary masks. Other than simple diffraction gratings the earliest examples of binary optics would be computer generated holograms. Computer generated holograms, or more generally digital holograms, have been used since the middle 1960's, and like holography in general, digital holograms have found a few, but very few, useful applications. It has not been until thinking began to focus on more general diffractive optical concepts, and less on the principles of holography, that new applications began to materialize in the area of binary optics. Two exampies would be compact disc technology and the correction for chromatic aberation in refractive lenses.

  6. The Fraction of KBO Contact Binaries

    NASA Astrophysics Data System (ADS)

    Lacerda, Pedro

    2007-05-01

    We use Roche binary models to improve previous estimates of the contact binariy fraction within the Kuiper Belt object (KBO) population (Sheppard & Jewitt 2004). Our simulations can be used to determine the lightcurve range of Roche binaries at arbitrary observing geometries, and for different surface types. This allows us to better correct the apparent fraction for observing geometry effects. We find that at least 9% of KBOs are contact binaries. Such high incidence of KBOs contact binaries has important implications to binary formation and collisional evolution scenarios. PL is grateful to the Portuguese Fundacao para a Ciencia e a Tecnologia (BPD/SPFH/18828/2004) for financial support. This work was supported, in part, by a grant from the NSF to David C. Jewitt.

  7. Asteroid Systems: Binaries, Triples, and Pairs

    NASA Astrophysics Data System (ADS)

    Margot, J.-L.; Pravec, P.; Taylor, P.; Carry, B.; Jacobson, S.

    In the past decade, the number of known binary near-Earth asteroids has more than quadrupled and the number of known large main-belt asteroids with satellites has doubled. Half a dozen triple asteroids have been discovered, and the previously unrecognized populations of asteroid pairs and small main-belt binaries have been identified. The current observational evidence confirms that small (≲20 km) binaries form by rotational fission and establishes that the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect powers the spin-up process. A unifying paradigm based on rotational fission and post-fission dynamics can explain the formation of small binaries, triples, and pairs. Large (>~20 km) binaries with small satellites are most likely created during large collisions.

  8. Terrestrial Planet Formation in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Quintana, Elisa V.; Lissauer, Jack J.

    More than half of all main sequence stars, and an even larger fraction of pre-main sequence stars, reside in binary or multiple systems (Duquennoy and Mayor 1991; Mathieu et al. 2000). The presence of planet-forming material has been indirectly observed around one or both components of some young binaries, and (Mathieu et al. 2000) numerical simulations of the formation of binary stars suggest that disks form within these systems, as well (Bodenheimer et al. 2000). Terrestrial planets and the cores of giant planets are thought to form by an accretion process within a disk of dust and gas (Safronov 1969; Lissauer 1993), and therefore may be common in binary star systems. In this chapter, we present the results from numerical simulations of the final stages of terrestrial planet formation around one or both stars of a binary.

  9. Neutron Star Mass Distribution in Binaries

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hwan; Kim, Young-Min

    2016-05-01

    Massive neutron stars with ∼ 2Mʘ have been observed in neutron star-white dwarf binaries. On the other hand, well-measured neutron star masses in double-neutron-star binaries are still consistent with the limit of 1.5Mʘ. These observations raised questions on the neutron star equations of state and the neutron star binary evolution processes. In this presentation, a hypothesis of super-Eddington accretion and its implications are discussed. We argue that a 2Mʘ neutron star is an outcome of the super-Eddington accretion during the evolution of neutron star-white dwarf binary progenitors. We also suggest the possibility of the existence of new type of neutron star binary which consists of a typical neutron star and a massive compact companion (high-mass neutron star or black hole) with M ≥ 2Mʘ.

  10. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  11. Constraining Accreting Binary Populations in Normal Galaxies

    NASA Astrophysics Data System (ADS)

    Lehmer, Bret; Hornschemeier, A.; Basu-Zych, A.; Fragos, T.; Jenkins, L.; Kalogera, V.; Ptak, A.; Tzanavaris, P.; Zezas, A.

    2011-01-01

    X-ray emission from accreting binary systems (X-ray binaries) uniquely probe the binary phase of stellar evolution and the formation of compact objects such as neutron stars and black holes. A detailed understanding of X-ray binary systems is needed to provide physical insight into the formation and evolution of the stars involved, as well as the demographics of interesting binary remnants, such as millisecond pulsars and gravitational wave sources. Our program makes wide use of Chandra observations and complementary multiwavelength data sets (through, e.g., the Spitzer Infrared Nearby Galaxies Survey [SINGS] and the Great Observatories Origins Deep Survey [GOODS]), as well as super-computing facilities, to provide: (1) improved calibrations for correlations between X-ray binary emission and physical properties (e.g., star-formation rate and stellar mass) for galaxies in the local Universe; (2) new physical constraints on accreting binary processes (e.g., common-envelope phase and mass transfer) through the fitting of X-ray binary synthesis models to observed local galaxy X-ray binary luminosity functions; (3) observational and model constraints on the X-ray evolution of normal galaxies over the last 90% of cosmic history (since z 4) from the Chandra Deep Field surveys and accreting binary synthesis models; and (4) predictions for deeper observations from forthcoming generations of X-ray telesopes (e.g., IXO, WFXT, and Gen-X) to provide a science driver for these missions. In this talk, we highlight the details of our program and discuss recent results.

  12. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  13. White Dwarfs in Astrometric Binaries?

    NASA Astrophysics Data System (ADS)

    Oliversen, N. A.; Evans, N. R.; Feibelman, W. A.; Kamper, K. W.

    1993-12-01

    Lippincott (1978, Space Sci Rev, 22, 153) compiled a list of astrometric binaries with unseen companions typically within 20 pc of the sun. Red companions have been observed in a number of these systems (e.g. McCarthy, D. W. 1983, IAU Coll. # 76, p. 107). Unseen, low mass companions could also be white dwarfs. We have obtained IUE observations of stars on the list which have primaries with spectral types M1 or earlier (white dwarf companions of cooler primaries could be detected from the ground), and are brighter than 10 mag, which do not have known red companions. Preliminary reductions (comparison with standard stars of appropriate spectral types) indicate that there are no white dwarfs in the sample. Further processing is being done to determine limits on possible white dwarf temperatures.

  14. Record-Breaking Eclipsing Binary

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    A new record holder exists for the longest-period eclipsing binary star system: TYC-2505-672-1. This intriguing system contains a primary star that is eclipsed by its companion once every 69 years with each eclipse lasting several years!120 Years of ObservationsIn a recent study, a team of scientists led by Joseph Rodriguez (Vanderbilt University) characterizes the components of TYC-2505-672-1. This binary star system consists of an M-type red giant star that undergoes a ~3.45-year-long, near-total eclipse with a period of ~69.1 years. This period is more than double that of the previous longest-period eclipsing binary!Rodriguez and collaborators combined photometric observations of TYC-2505-672-1 by the Kilodegree Extremely Little Telescope (KELT) with a variety of archival data, including observations by the American Association of Variable Star Observers (AAVSO) network and historical data from the Digital Access to a Sky Century @ Harvard (DASCH) program.In the 120 years spanned by these observations, two eclipses are detected: one in 1942-1945 and one in 2011-2015. The authors use the observations to analyze the components of the system and attempt to better understand what causes its unusual light curve.Characterizing an Unusual SystemObservations of TYC-2505-672-1 plotted from 1890 to 2015 reveal two eclipses. (The blue KELT observations during the eclipse show upper limits only.) [Rodriguez et al. 2016]By modeling the systems emission, Rodriguez and collaborators establish that TYC-2505-672-1 consists of a 3600-K primary star thats the M giant orbited by a small, hot, dim companion thats a toasty 8000 K. But if the companion is small, why does the eclipse last several years?The authors argue that the best model of TYC-2505-672-1 is one in which the small companion star is surrounded by a large, opaque circumstellar disk. Rodriguez and collaborators suggest that the companion could be a former red giant whose atmosphere was stripped from it, leaving behind

  15. Morphological Moments of Binary Images

    NASA Astrophysics Data System (ADS)

    Lomov, N.; Sidyakin, S.

    2017-05-01

    The concept of morphological moments of binary images is introduced. Morphological moments can be used as a shape descriptor combining an integral width description of an object with a description of its spatial distribution. The relationship between the proposed descriptor and the disc cover of the figure is discussed and an exact analytical method for descriptor calculation is proposed within the continuous morphology framework. The approach is based on the approximation of the shape by a polygonal figure and the extraction of its medial representation in the form of the continuous skeleton and the radial function. The proposed method for calculation of morphological moments achieves high accuracy and it is computationally efficient. Experimentations have been conducted. Obtained results indicate that the morphological moments are a more informative and rich shape descriptor than the area of the disc cover. Application of morphological moments to the font recognition task improves the recognition quality.

  16. Interdiffusion in binary ionic mixtures

    SciTech Connect

    Boercker, D.B.; Pollock, E.L.

    1987-08-15

    In this paper we present molecular-dynamics and kinetic-theory calculations of the interdiffusion coefficients in dense binary ionic mixtures for conditions appropriate to both astrophysical and inertial-confinement fusion (ICF) plasmas. The diffusion coefficient is the product of a Green-Kubo integral and a thermodynamic prefactor. The molecular-dynamics and kinetic-theory estimates of the Green-Kubo portion agree very well, and it is found that this integral may also be well represented by the usual concentration-weighted sum of self-diffusion coefficients. In addition, the low-density limit of the thermodynamic prefactor is shown to represent an enhancement of the diffusion by the ''ambipolar'' electric field.

  17. Stability of multiplanet systems in binaries

    NASA Astrophysics Data System (ADS)

    Marzari, F.; Gallina, G.

    2016-10-01

    Context. When exploring the stability of multiplanet systems in binaries, two parameters are normally exploited: the critical semimajor axis ac computed by Holman & Wiegert (1999, AJ, 117, 621) within which planets are stable against the binary perturbations, and the Hill stability limit Δ determining the minimum separation beyond which two planets will avoid mutual close encounters. Both these parameters are derived in different contexts, i.e. Δ is usually adopted for computing the stability limit of two planets around a single star while ac is computed for a single planet in a binary system. Aims: Our aim is to test whether these two parameters can be safely applied in multiplanet systems in binaries or if their predictions fail for particular binary orbital configurations. Methods: We have used the frequency map analysis (FMA) to measure the diffusion of orbits in the phase space as an indicator of chaotic behaviour. Results: First we revisited the reliability of the empirical formula computing ac in the case of single planets in binaries and we find that, in some cases, it underestimates by 10-20% the real outer limit of stability and it does not account for planets trapped in resonance with the companion star well beyond ac. For two-planet systems, the value of Δ is close to that computed for planets around single stars, but the level of chaoticity close to it substantially increases for smaller semimajor axes and higher eccentricities of the binary orbit. In these configurations ac also begins to be unreliable and non-linear secular resonances with the stellar companion lead to chaotic behaviour well within ac, even for single planet systems. For two planet systems, the superposition of mean motion resonances, either mutual or with the binary companion, and non-linear secular resonances may lead to chaotic behaviour in all cases. We have developed a parametric semi-empirical formula determining the minimum value of the binary semimajor axis, for a given

  18. Application of SKIPSM to binary correlation

    NASA Astrophysics Data System (ADS)

    Waltz, Frederick M.

    1995-10-01

    Binary correlation is often used for finding specified patterns in complex binary images, especially in industrial inspection tasks such as locating the corners and/or edges of parts. As such, it is an important tool for higher-level 'intelligent' vision systems. Binary correlation is a form of binary template matching which provides a numerical value corresponding to 'degree of fit' rather than an 'all or nothing' answer. Commercially available high-speed image processing systems can readily perform this operation using linear convolvers, but such convolvers are very expensive except for very small kernels. Furthermore, linear convolvers constitute a gross 'overkill' for the relatively simple operation of binary correlation. Specialized binary convolvers have been built, but are not part of standard commercial systems. This paper describes a new pipelined implementation of binary correlation which fits into the standard SKIPSM (separated-kernel image processing using finite state machines) architecture and which can be built using standard ICs costing less than $500 total. The same approach can also be implemented in software, providing an order-of-magnitude increase in speed at no extra cost. Furthermore, this same SKIPSM architecture is highly versatile and programmable, allowing it to be software-reconfigured to perform hundreds of other pipelined image processing operations.

  19. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Quintana, Elisa V.; Chambers, John; Duncan, Martin J.; Adams, Fred

    2003-01-01

    Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets within binary star systems, using a new, ultrafast, symplectic integrator that we have developed for this purpose. We show that the late stages of terrestrial planet formation can indeed take place in a wide variety of binary systems and we have begun to delineate the range of parameter space for which this statement is true. Results of our initial simulations of planetary growth around each star in the alpha Centauri system and other 'wide' binary systems, as well as around both stars in very close binary systems, will be presented.

  20. PERIODIC SIGNALS IN BINARY MICROLENSING EVENTS

    SciTech Connect

    Guo, Xinyi; Stefano, Rosanne Di; Esin, Ann; Taylor, Jeffrey

    2015-08-20

    Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binary lenses have already been found through microlensing surveys and a few of these systems show strong evidence of orbital motion on the timescale of the lensing event. We expect that more binary lenses of this kind will be detected in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such light curves is the presence of quasi-periodic features, which are produced as the source traverses the same regions in the rotating lens plane. These repeating features contain information about the orbital period of the lens. If this period can be extracted, then much can be learned about the lensing system even without performing time-consuming, detailed light-curve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification of the standard Lomb–Scargle periodogram analysis. We test our method for four representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods.

  1. Formation of wide binaries by turbulent fragmentation

    NASA Astrophysics Data System (ADS)

    Lee, Jeong-Eun; Lee, Seokho; Dunham, Michael M.; Tatematsu, Ken'ichi; Choi, Minho; Bergin, Edwin A.; Evans, Neal J.

    2017-08-01

    Understanding the formation of wide-binary systems of very low-mass stars (M ≤ 0.1 solar masses, M⊙) is challenging 1,2,3 . The most obvious route is through widely separated low-mass collapsing fragments produced by turbulent fragmentation of a molecular core4,5. However, close binaries or multiples from disk fragmentation can also evolve to wide binaries over a few initial crossing times of the stellar cluster through tidal evolution6. Finding an isolated low-mass wide-binary system in the earliest stage of formation, before tidal evolution could occur, would prove that turbulent fragmentation is a viable mechanism for (very) low-mass wide binaries. Here we report high-resolution ALMA observations of a known wide-separation protostellar binary, showing that each component has a circumstellar disk. The system is too young7 to have evolved from a close binary, and the disk axes are misaligned, providing strong support for the turbulent fragmentation model. Masses of both stars are derived from the Keplerian rotation of the disks; both are very low-mass stars.

  2. Planet Formation in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Martin, Rebecca

    About half of observed exoplanets are estimated to be in binary systems. Understanding planet formation and evolution in binaries is therefore essential for explaining observed exoplanet properties. Recently, we discovered that a highly misaligned circumstellar disk in a binary system can undergo global Kozai-Lidov (KL) oscillations of the disk inclination and eccentricity. These oscillations likely have a significant impact on the formation and orbital evolution of planets in binary star systems. Planet formation by core accretion cannot operate during KL oscillations of the disk. First, we propose to consider the process of disk mass transfer between the binary members. Secondly, we will investigate the possibility of planet formation by disk fragmentation. Disk self gravity can weaken or suppress the oscillations during the early disk evolution when the disk mass is relatively high for a narrow range of parameters. Thirdly, we will investigate the evolution of a planet whose orbit is initially aligned with respect to the disk, but misaligned with respect to the orbit of the binary. We will study how these processes relate to observations of star-spin and planet orbit misalignment and to observations of planets that appear to be undergoing KL oscillations. Finally, we will analyze the evolution of misaligned multi-planet systems. This theoretical work will involve a combination of analytic and numerical techniques. The aim of this research is to shed some light on the formation of planets in binary star systems and to contribute to NASA's goal of understanding of the origins of exoplanetary systems.

  3. Interrupted Binary Mass Transfer in Star Clusters

    NASA Astrophysics Data System (ADS)

    Leigh, Nathan W. C.; Geller, Aaron M.; Toonen, Silvia

    2016-02-01

    Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲ {10}4 {M}⊙ ), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect \\ll 1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ˜2.

  4. Embedded binaries and their dense cores

    NASA Astrophysics Data System (ADS)

    Sadavoy, Sarah I.; Stahler, Steven W.

    2017-08-01

    We explore the relationship between young, embedded binaries and their parent cores, using observations within the Perseus Molecular Cloud. We combine recently published Very Large Array observations of young stars with core properties obtained from Submillimetre Common-User Bolometer Array 2 observations at 850 μm. Most embedded binary systems are found towards the centres of their parent cores, although several systems have components closer to the core edge. Wide binaries, defined as those systems with physical separations greater than 500 au, show a tendency to be aligned with the long axes of their parent cores, whereas tight binaries show no preferred orientation. We test a number of simple, evolutionary models to account for the observed populations of Class 0 and I sources, both single and binary. In the model that best explains the observations, all stars form initially as wide binaries. These binaries either break up into separate stars or else shrink into tighter orbits. Under the assumption that both stars remain embedded following binary break-up, we find a total star formation rate of 168 Myr-1. Alternatively, one star may be ejected from the dense core due to binary break-up. This latter assumption results in a star formation rate of 247 Myr-1. Both production rates are in satisfactory agreement with current estimates from other studies of Perseus. Future observations should be able to distinguish between these two possibilities. If our model continues to provide a good fit to other star-forming regions, then the mass fraction of dense cores that becomes stars is double what is currently believed.

  5. Photometric Survey for Asynchronous Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Pravec, P.

    2005-05-01

    Asynchronous binary asteroids have been found to be abundant among fast- spinning near-Earth asteroids (NEAs) smaller than 2 km in diameter; Pravec et al. (2005, Icarus, submitted) derived that 15 +/- 4 % of NEAs in the size range 0.3 to 2 km are binary with the secondary-to-primary mean diameter ratio >=0.18. The early re-sults from the surveys of the Vesta family and the Hungaria group (Ryan et al., 2004, Planet. Space Sci. 42, 1093; 2004, Bull. Amer. Astron. Society 36, 1181; Warner et al., 2005, IAU Circ. 8511) suggest that the popula-tion extends beyond the region of terrestrial planets, but with characteristics shifted to larger sizes and longer periods; the four known binaries in the Vesta family/Hungaria group are 3 to 6 km large and they have primary rotation periods in a range of 3 to ~4 h, i.e., on the tail of the distribution of primary rotation periods of NEAs. The comparison suggests that formation and evolution mechanisms of asynchronous NEA and main-belt binaries may be similar and are related to their fast spins and rubble-pile structure. None of the current theories of their formation of evolution, however, explains the observed properties of both NEA and main- belt asynchronous bina-ries in full. We have established a collaborative observational program, called "Photometric Survey for Asynchro-nous Binary Asteroids" to discover and describe asynchronous binaries over a range of heliocentric distances from NEAs through Mars-crossers to inner main-belt asteroids. One new binary Amor asteroid, 2005 AB has been found during the first few months of the survey operation (Reddy et al., 2005, IAU Circ. 8483), and we have obtained follow-up data for two other binary systems. I outline the motivations, the technique, and the strategy of the Survey.

  6. Binary image registration using cellular simultaneous recurrent networks

    NASA Astrophysics Data System (ADS)

    Anderson, Keith; Iftekharuddin, Khan; Kim, Paul

    2009-08-01

    Cellular simultaneous recurrent networks (CSRN)s have been traditionally exploited to solve digital control and conventional maze traversing problems. In a previous work [1], we investigate the use of CSRNs for image registration under affine transformations for binary images. In Ref. [1], we attempt to register simulated binary images with in-plane rotations between +/-20° using two different CSRN implementations such as with 1) a general multi-layered perceptron (GMLP) architecture; and (2) a modified MLP architecture with multi-layered feedback. Our results in Ref. 1 show that both architectures achieve moderate local registration, with our modified MLP architecture producing a best result of around 64% for cost function accuracy and 98% for image registration accuracy. In this current work, for the first time in literature, we investigate gray scale image registration using CSRNs. We exploit both types of CSRNs for registration of realistic images and perform complete evaluation of both binary and gray-scale image registration. Simulation results with both CSRN architectures show an average cost function accuracy of 40.5% and an average image accuracy of 33.2%, with a best result of 46.2% and 40.3%, respectively. Image results clearly show that the CSRN shows promise for use in registration of gray-scale images.

  7. Dynamical mass transfer in cataclysmic binaries

    NASA Technical Reports Server (NTRS)

    Melia, Fulvio; Lamb, D. Q.

    1987-01-01

    When a binary comes into contact and mass transfer begins, orbital angular momentum is stored in the accretion disk until the disk couples tidally to the binary system. Taam and McDermott (1987) have suggested that this leads to unstable dynamical mass transfer in many cataclysmic variables in which mass transfer would otherwise be stable, and that it explains the gap between 2 and 3 h in the orbital period distribution of these systems. Here the consequences of this hypothesis for the evolution of cataclysmic binaries are explored. It is found that systems coming into contact longward of the period gap undergo one or more episodes of dynamical mass transfer.

  8. Gravitational waves from neutron star binaries

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hwan

    With H. A. Bethe, G. E. Brown worked on the merger rate of neutron star binaries for the gravitational wave detection. Their prediction has to be modified significantly due to the observations of 2M⊙ neutron stars and the detection of gravitational waves. There still, however, remains a possibility that neutron star-low mass black hole binaries are significant sources of gravitational waves for the ground-based detectors. In this paper, I review the evolution of neutron star binaries with super-Eddington accretion and discuss the future prospect.

  9. Proposed experiment to test fundamentally binary theories

    NASA Astrophysics Data System (ADS)

    Kleinmann, Matthias; Vértesi, Tamás; Cabello, Adán

    2017-09-01

    Fundamentally binary theories are nonsignaling theories in which measurements of many outcomes are constructed by selecting from binary measurements. They constitute a sensible alternative to quantum theory and have never been directly falsified by any experiment. Here we show that fundamentally binary theories are experimentally testable with current technology. For that, we identify a feasible Bell-type experiment on pairs of entangled qutrits. In addition, we prove that, for any n , quantum n -ary correlations are not fundamentally (n -1 ) -ary. For that, we introduce a family of inequalities that hold for fundamentally (n -1 ) -ary theories but are violated by quantum n -ary correlations.

  10. Calibration Binaries Observed at the SOR

    DTIC Science & Technology

    2012-09-01

    Kirtland AFB, NM 87117-5776 ABSTRACT In reviewing observations of binary stars taken with adaptive optics on the 3.5 m Starfire Optical Range telescope ...observations of 62 binaries from these two lists were obtained with Adaptive Optics (AO) on the 3.5 m telescope at the Starfire Optical Range (SOR), where all...adaptive optics on the 3.5 m Starfire Optical Range telescope over the past two years, a quarter of these calibration binaries, taken from two Excel

  11. Variance in binary stellar population synthesis

    NASA Astrophysics Data System (ADS)

    Breivik, Katelyn; Larson, Shane L.

    2016-03-01

    In the years preceding LISA, Milky Way compact binary population simulations can be used to inform the science capabilities of the mission. Galactic population simulation efforts generally focus on high fidelity models that require extensive computational power to produce a single simulated population for each model. Each simulated population represents an incomplete sample of the functions governing compact binary evolution, thus introducing variance from one simulation to another. We present a rapid Monte Carlo population simulation technique that can simulate thousands of populations in less than a week, thus allowing a full exploration of the variance associated with a binary stellar evolution model.

  12. Instabilities in Interacting Binary Stars

    NASA Astrophysics Data System (ADS)

    Andronov, I. L.; Andrych, K. D.; Antoniuk, K. A.; Baklanov, A. V.; Beringer, P.; Breus, V. V.; Burwitz, V.; Chinarova, L. L.; Chochol, D.; Cook, L. M.; Cook, M.; Dubovský, P.; Godlowski, W.; Hegedüs, T.; Hoňková, K.; Hric, L.; Jeon, Y.-B.; Juryšek, J.; Kim, C.-H.; Kim, Y.; Kim, Y.-H.; Kolesnikov, S. V.; Kudashkina, L. S.; Kusakin, A. V.; Marsakova, V. I.; Mason, P. A.; Mašek, M.; Mishevskiy, N.; Nelson, R. H.; Oksanen, A.; Parimucha, S.; Park, J.-W.; Petrík, K.; Quiñones, C.; Reinsch, K.; Robertson, J. W.; Sergey, I. M.; Szpanko, M.; Tkachenko, M. G.; Tkachuk, L. G.; Traulsen, I.; Tremko, J.; Tsehmeystrenko, V. S.; Yoon, J.-N.; Zola, S.; Shakhovskoy, N. M.

    2017-07-01

    The types of instability in the interacting binary stars are briefly reviewed. The project “Inter-Longitude Astronomy” is a series of smaller projects on concrete stars or groups of stars. It has no special funds, and is supported from resources and grants of participating organizations, when informal working groups are created. This “ILA” project is in some kind similar and complementary to other projects like WET, CBA, UkrVO, VSOLJ, BRNO, MEDUZA, AstroStatistics, where many of us collaborate. Totally we studied 1900+ variable stars of different types, including newly discovered variables. The characteristic timescale is from seconds to decades and (extrapolating) even more. The monitoring of the first star of our sample AM Her was initiated by Prof. V.P. Tsesevich (1907-1983). Since more than 358 ADS papers were published. In this short review, we present some highlights of our photometric and photo-polarimetric monitoring and mathematical modeling of interacting binary stars of different types: classical (AM Her, QQ Vul, V808 Aur = CSS 081231:071126+440405, FL Cet), asynchronous (BY Cam, V1432 Aql), intermediate (V405 Aql, BG CMi, MU Cam, V1343 Her, FO Aqr, AO Psc, RXJ 2123, 2133, 0636, 0704) polars and magnetic dwarf novae (DO Dra) with 25 timescales corresponding to different physical mechanisms and their combinations (part “Polar”); negative and positive superhumpers in nova-like (TT Ari, MV Lyr, V603 Aql, V795 Her) and many dwarf novae stars (“Superhumper”); eclipsing “non-magnetic” cataclysmic variables(BH Lyn, DW UMa, EM Cyg; PX And); symbiotic systems (“Symbiosis”); super-soft sources (SSS, QR And); spotted (and not spotted) eclipsing variables with (and without) evidence for a current mass transfer (“Eclipser”) with a special emphasis on systems with a direct impact of the stream into the gainer star's atmosphere, which we propose to call “Impactor” (short from “Extreme Direct Impactor”), or V361 Lyr-type stars. Other

  13. Calibrating binary lumped parameter models

    NASA Astrophysics Data System (ADS)

    Morgenstern, Uwe; Stewart, Mike

    2017-04-01

    Groundwater at its discharge point is a mixture of water from short and long flowlines, and therefore has a distribution of ages rather than a single age. Various transfer functions describe the distribution of ages within the water sample. Lumped parameter models (LPMs), which are mathematical models of water transport based on simplified aquifer geometry and flow configuration can account for such mixing of groundwater of different age, usually representing the age distribution with two parameters, the mean residence time, and the mixing parameter. Simple lumped parameter models can often match well the measured time varying age tracer concentrations, and therefore are a good representation of the groundwater mixing at these sites. Usually a few tracer data (time series and/or multi-tracer) can constrain both parameters. With the building of larger data sets of age tracer data throughout New Zealand, including tritium, SF6, CFCs, and recently Halon-1301, and time series of these tracers, we realised that for a number of wells the groundwater ages using a simple lumped parameter model were inconsistent between the different tracer methods. Contamination or degradation of individual tracers is unlikely because the different tracers show consistent trends over years and decades. This points toward a more complex mixing of groundwaters with different ages for such wells than represented by the simple lumped parameter models. Binary (or compound) mixing models are able to represent a more complex mixing, with mixing of water of two different age distributions. The problem related to these models is that they usually have 5 parameters which makes them data-hungry and therefore difficult to constrain all parameters. Two or more age tracers with different input functions, with multiple measurements over time, can provide the required information to constrain the parameters of the binary mixing model. We obtained excellent results using tritium time series encompassing

  14. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    SciTech Connect

    Haghighipour, Nader; Kaltenegger, Lisa

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  15. Pulsars in binary systems: probing binary stellar evolution and general relativity.

    PubMed

    Stairs, Ingrid H

    2004-04-23

    Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system.

  16. General simulation algorithm for autocorrelated binary processes

    NASA Astrophysics Data System (ADS)

    Serinaldi, Francesco; Lombardo, Federico

    2017-02-01

    The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

  17. Recent Minima of 171 Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Samolyk, G.

    2015-12-01

    This paper continues the publication of times of minima for 171 eclipsing binary stars from observations reported to the AAVSO EB section. Times of minima from observations received by the author from March 2015 thru October 2015 are presented.

  18. High-spin binary black hole mergers

    NASA Astrophysics Data System (ADS)

    Marronetti, Pedro; Tichy, Wolfgang; Brügmann, Bernd; Sperhake, Ulrich; González, José

    2008-04-01

    We study identical mass black hole binaries with spins perpendicular to the binary's orbital plane. These binaries have individual spins ranging from s/m^2=-0.90 to 0.90, (s1= s2 in all cases) which is near the limit possible with standard Bowen-York puncture initial data. The extreme cases correspond to the largest initial spin simulations to date. Our results expand the parameter space covered by Rezzolla et al. and, when combining both data sets, we obtain estimations for the minimum and maximum values for the intrinsic angular momenta of the remnant of binary black hole mergers of J/M^2=0.341(4) and 0.951(4) respectively.

  19. X-ray reprocessing in binaries

    NASA Astrophysics Data System (ADS)

    Paul, Biswajit

    2016-07-01

    We will discuss several aspects of X-ray reprocessing into X-rays or longer wavelength radiation in different kinds of binary systems. In high mass X-ray binaries, reprocessing of hard X-rays into emission lines or lower temperature black body emission is a useful tool to investigate the reprocessing media like the stellar wind, clumpy structures in the wind, accretion disk or accretion stream. In low mass X-ray binaries, reprocessing from the surface of the companion star, the accretion disk, warps and other structures in the accretion disk produce signatures in longer wavelength radiation. X-ray sources with temporal structures like the X-ray pulsars and thermonuclear burst sources are key in such studies. We will discuss results from several new investigations of X-ray reprocessing phenomena in X-ray binaries.

  20. Mass flow in close binary systems

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Mccluskey, G. E.

    1976-01-01

    The manner of mass flow in close binary systems is examined with a special view to the role of the so-called critical Roche (or Jacobian) lobe, taking into consideration relevant physical conditions such as radiation pressure that may affect the restricted three-body problem treatment. The mass does not necessarily flow from component one to component two through the L1 point to form a gaseous ring surrounding the latter. These considerations are applied to X-ray binaries with early-type optical components, such as Cyg X-1 (HDE 226868) and 3U 1700 - 37 (HD 153919). In the two bright close binary systems Beta Lyr and UW CMa, which are believed to be undergoing dynamic mass transfer, recent Copernicus observations show that the gas giving rise to the prominent ultraviolet emission lines surrounds the entire binary system rather than merely component two. Implications of these observations are also discussed.

  1. Classification of close binary systems by Svechnikov

    NASA Astrophysics Data System (ADS)

    Dryomova, G. N.

    The paper presents the historical overview of classification schemes of eclipsing variable stars with the foreground of advantages of the classification scheme by Svechnikov being widely appreciated for Close Binary Systems due to simplicity of classification criteria and brevity.

  2. Trompe L'Oeil 'binary' pulsars

    NASA Astrophysics Data System (ADS)

    Nelson, Robert W.; Finn, Lee S.; Wasserman, Ira

    1990-01-01

    A freely precessing pulsar produces pulse phase residuals which can mimic those of a pulsar in a binary orbit. In particular, discrete sets of phase residuals due to precessional motion of an isolated pulsar are sampled; it is shown that this data is well fit by residuals from a binary pulsar in a sufficiently tight orbit. Analytic and numerical relationships between the projected orbital size, a(p) sin i, and the orbital eccentricity, e, of a misidentified binary pulsar; are found the observations that would distinguish between these models are discussed. Regardless of the mechanism that causes the precession, the maximum amplitude of the phase residual is pi/2: consequently, a(p)sin i is (approximately) bounded by cP(puls)/4. The newly discovered 'binary' millisecond pulsars in the globular cluster 47 Tuc is discussed, and it is shown that the periodic frequency modulation reported cannot be explained by free precession.

  3. TOPICAL REVIEW: Coalescing binary neutron stars

    NASA Astrophysics Data System (ADS)

    Rasio, Frederic A.; Shapiro, Stuart L.

    1999-06-01

    Coalescing compact binaries with neutron star or black hole components provide the most promising sources of gravitational radiation for detection by the LIGO/VIRGO/GEO/TAMA laser interferometers now under construction. This fact has motivated several different theoretical studies of the inspiral and hydrodynamic merging of compact binaries. Analytic analyses of the inspiral waveforms have been performed in the post-Newtonian approximation. Analytic and numerical treatments of the coalescence waveforms from binary neutron stars have been performed using Newtonian hydrodynamics and the quadrupole radiation approximation. Numerical simulations of coalescing black hole and neutron star binaries are also underway in full general relativity. Recent results from each of these approaches will be described and their virtues and limitations summarized.

  4. ROTATIONAL DOPPLER BEAMING IN ECLIPSING BINARIES

    SciTech Connect

    Groot, Paul J.

    2012-01-20

    In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analog of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high-quality photometric light curves and can be used to determine stellar obliquities as well as, e.g., an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.

  5. Composition formulas of binary eutectics

    PubMed Central

    Ma, Y. P.; Dong, D. D.; Dong, C.; Luo, L. J.; Wang, Q.; Qiang, J. B.; Wang, Y. M.

    2015-01-01

    The present paper addresses the long-standing composition puzzle of eutectic points by introducing a new structural tool for the description of short-range-order structural unit, the cluster-plus-glue-atom model. In this model, any structure is dissociated into a 1st-neighbor cluster and a few glue atoms between the clusters, expressed by a cluster formula [cluster]gluex. This model is applied here to establish the structural model for eutectic liquids, assuming that a eutectic liquid consist of two subunits issued from the relevant eutectic phases, each being expressed by the cluster formula for ideal metallic glasses, i.e., [cluster](glue atom)1 or 3. A structural unit is then composed of two clusters from the relevant eutectic phases plus 2, 4, or 6 glue atoms. Such a dual cluster formulism is well validated in all boron-containing (except those located by the extreme phase diagram ends) and in some commonly-encountered binary eutectics, within accuracies below 1 at.%. The dual cluster formulas vary extensively and are rarely identical even for eutectics of close compositions. They are generally formed with two distinctly different cluster types, with special cluster matching rules such as cuboctahedron plus capped trigonal prism and rhombidodecahedron plus octahedral antiprism. PMID:26658618

  6. Composition formulas of binary eutectics.

    PubMed

    Ma, Y P; Dong, D D; Dong, C; Luo, L J; Wang, Q; Qiang, J B; Wang, Y M

    2015-12-14

    The present paper addresses the long-standing composition puzzle of eutectic points by introducing a new structural tool for the description of short-range-order structural unit, the cluster-plus-glue-atom model. In this model, any structure is dissociated into a 1(st)-neighbor cluster and a few glue atoms between the clusters, expressed by a cluster formula [cluster]gluex. This model is applied here to establish the structural model for eutectic liquids, assuming that a eutectic liquid consist of two subunits issued from the relevant eutectic phases, each being expressed by the cluster formula for ideal metallic glasses, i.e., [cluster](glue atom)(1 or 3). A structural unit is then composed of two clusters from the relevant eutectic phases plus 2, 4, or 6 glue atoms. Such a dual cluster formulism is well validated in all boron-containing (except those located by the extreme phase diagram ends) and in some commonly-encountered binary eutectics, within accuracies below 1 at.%. The dual cluster formulas vary extensively and are rarely identical even for eutectics of close compositions. They are generally formed with two distinctly different cluster types, with special cluster matching rules such as cuboctahedron plus capped trigonal prism and rhombidodecahedron plus octahedral antiprism.

  7. Black hole binaries and microquasars

    NASA Astrophysics Data System (ADS)

    Zhang, Shuang-Nan

    2013-12-01

    This is a general review on the observations and physics of black hole X-ray binaries and microquasars, with the emphasize on recent developments in the high energy regime. The focus is put on understanding the accretion flows and measuring the parameters of black holes in them. It includes mainly two parts: i) Brief review of several recent review article on this subject; ii) Further development on several topics, including black hole spin measurements, hot accretion flows, corona formation, state transitions and thermal stability of standard think disk. This is thus not a regular bottom-up approach, which I feel not necessary at this stage. Major effort is made in making and incorporating from many sources useful plots and illustrations, in order to make this article more comprehensible to non-expert readers. In the end I attempt to make a unification scheme on the accretion-outflow (wind/jet) connections of all types of accreting BHs of all accretion rates and all BH mass scales, and finally provide a brief outlook.

  8. Composition formulas of binary eutectics

    NASA Astrophysics Data System (ADS)

    Ma, Y. P.; Dong, D. D.; Dong, C.; Luo, L. J.; Wang, Q.; Qiang, J. B.; Wang, Y. M.

    2015-12-01

    The present paper addresses the long-standing composition puzzle of eutectic points by introducing a new structural tool for the description of short-range-order structural unit, the cluster-plus-glue-atom model. In this model, any structure is dissociated into a 1st-neighbor cluster and a few glue atoms between the clusters, expressed by a cluster formula [cluster]gluex. This model is applied here to establish the structural model for eutectic liquids, assuming that a eutectic liquid consist of two subunits issued from the relevant eutectic phases, each being expressed by the cluster formula for ideal metallic glasses, i.e., [cluster](glue atom)1 or 3. A structural unit is then composed of two clusters from the relevant eutectic phases plus 2, 4, or 6 glue atoms. Such a dual cluster formulism is well validated in all boron-containing (except those located by the extreme phase diagram ends) and in some commonly-encountered binary eutectics, within accuracies below 1 at.%. The dual cluster formulas vary extensively and are rarely identical even for eutectics of close compositions. They are generally formed with two distinctly different cluster types, with special cluster matching rules such as cuboctahedron plus capped trigonal prism and rhombidodecahedron plus octahedral antiprism.

  9. Binary module test. Final report

    SciTech Connect

    Schilling, J.R.; Colley, T.C.; Pundyk, J.

    1980-12-01

    The objective of this project was to design and test a binary loop module representative of and scaleable to commercial size units. The design was based on state-of-the-art heat exchanger technology, and the purpose of the tests was to confirm performance of a supercritical boiling cycle using isobutane and a mixture of isobutane and isopentane as the secondary working fluid. The module was designed as one percent of a 50 MW unit. It was installed at Magma Power's East Mesa geothermal field and tested over a period of approximately 4 months. Most of the test runs were with isobutane but some data were collected for hydrocarbon mixtures. The results of the field tests are reported. In general these results indicate reasonably good heat balances and agreement with overall heat transfer coefficients calculated by current stream analysis methods and available fluid property data; however, measured pressure drops across the heat exchangers were 20 percent higher than estimated. System operation was stable under all conditions tested.

  10. Binary Outputs from Unitary Networks

    PubMed Central

    Crews, David

    2013-01-01

    When considering sex ratios, we have to first define the nature of the question. Are we referring to the gonads, secondary and accessory sex structures, physiology, brain, behavior, or to all of the above elements. If these elements are not concordant, the exceptions can prove illustrative of underlying processes at both the proximate and ultimate levels. At each of these levels, “sex” is the binary outcome resulting from the modulation of conserved networks of genes, proteins, cells, organs, and, in the case of the brain, discrete nuclei. These networks operate at multiple and sequential levels that usually are linear during the lifespan, but in some instances reversals are possible. For example, the gonads arise from a single “anlagen” and, in most instances, ovaries or testes result, although ovotestes are the norm in some species and gonadal reversal a property of other species. Other sexually dimorphic structures differentiate from multiple “anlaga” by reciprocal and sex-specific atrophy/hypertrophy, typically in an exaggerated manner, although the capacity to develop structures characteristic of the opposite gonadal sex remains inherent and intact. A perspective that integrates these different properties are presented here. PMID:23559320

  11. Dixie Valley Bottoming Binary Unit

    SciTech Connect

    McDonald, Dale

    2014-12-21

    This binary plant is the first air cooled, high-output refrigeration based waste heat recovery cycle in the industry. Its working fluid is environmentally friendly and as such, the permits that would be required with a hydrocarbon based cycle are not necessary. The unit is largely modularized, meaning that the unit’s individual skids were assembled in another location and were shipped via truck to the plant site. The Air Cooled Condensers (ACC), equipment piping, and Balance of Plant (BOP) piping were constructed at site. This project further demonstrates the technical feasibility of using low temperature brine for geothermal power utilization. The development of the unit led to the realization of low temperature, high output, and environmentally friendly heat recovery systems through domestic research and engineering. The project generates additional renewable energy, resulting in cleaner air and reduced carbon dioxide emissions. Royalty and tax payments to governmental agencies will increase, resulting in reduced financial pressure on local entities. The major components of the unit were sourced from American companies, resulting in increased economic activity throughout the country.

  12. Binary outputs from unitary networks.

    PubMed

    Crews, David

    2013-12-01

    When considering sex ratios, we have to first define the nature of the question. Are we referring to the gonads, secondary and accessory sex structures, physiology, brain, behavior, or to all of the above elements. If these elements are not concordant, the exceptions can prove illustrative of underlying processes at both the proximate and ultimate levels. At each of these levels, "sex" is the binary outcome resulting from the modulation of conserved networks of genes, proteins, cells, organs, and, in the case of the brain, discrete nuclei. These networks operate at multiple and sequential levels that usually are linear during the lifespan, but in some instances reversals are possible. For example, the gonads arise from a single "anlagen" and, in most instances, ovaries or testes result, although ovotestes are the norm in some species and gonadal reversal a property of other species. Other sexually dimorphic structures differentiate from multiple "anlaga" by reciprocal and sex-specific atrophy/hypertrophy, typically in an exaggerated manner, although the capacity to develop structures characteristic of the opposite gonadal sex remains inherent and intact. A perspective that integrates these different properties are presented here.

  13. The binary fission origin of the moon

    NASA Technical Reports Server (NTRS)

    Binder, Alan B.

    1986-01-01

    The major arguments for and against the binary fission model of lunar origin are reviewed. Unresolved problems include: (1) how the protoearth acquired sufficient angular velocity to fission, and (2) how the earth-moon system lost its excess angular momentum after fission. Despite these uncertainties, the compositional similarities between the earth's mantle and the bulk moon suggest that the fission model is worth considering. The proposed sequence of events in the formation of the moon by binary fission is given.

  14. Statistical pattern classification with binary variables.

    PubMed

    Young, T Y; Liu, P S; Rondon, R J

    1981-02-01

    Binary random variables are regarded as random vectors in a binary-field (modulo-2) linear vector space. A characteristic function is defined and related results derived using this formulation. Minimax estimation of probability distributions using an entropy criterion is investigated, which leads to an A-distribution and bilinear discriminant functions. Nonparametric classification approaches using Hamming distances and their asymptotic properties are discussed. Experimental results are presented.

  15. Icarus: Stellar binary light curve synthesis tool

    NASA Astrophysics Data System (ADS)

    Breton, Rene

    2016-11-01

    Icarus is a stellar binary light curve synthesis tool that generates a star, given some basic binary parameters, by solving the gravitational potential equation, creating a discretized stellar grid, and populating the stellar grid with physical parameters, including temperature and surface gravity. Icarus also evaluates the outcoming flux from the star given an observer's point of view (i.e., orbital phase and orbital orientation).

  16. New White Dwarf-Brown Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Casewell, S. L.; Geier, S.; Lodieu, N.

    2017-03-01

    We present follow-up spectroscopy to 12 candidate white dwarf-brown dwarf binaries. We have confirmed that 8 objects do indeed have a white dwarf primary (7 DA, 1 DB) and two are hot subdwarfs. We have determined the Teff and log g for the white dwarfs and subdwarfs, and when combining these values with a model spectrum and the photometry, we have 3 probable white dwarf-substellar binaries with spectral types between M6 and L6.

  17. Shaping the Outflows of Binary AGB Stars

    NASA Astrophysics Data System (ADS)

    Ramstedt, S.; Vlemmings, W. H. T.; Mohamed, S.

    2015-08-01

    The required conditions for stars to evolve into planetary nebulae (PNe) continue to puzzle. Since PNe are found in a wide variety of shapes, processes that could sculpt circumstellar envelopes (CSEs) are being investigated. A binary companion will have a strong gravitational effect, but known binary AGB stars are rare. We have observed the CO emission from a small sample of known binary AGB stars (R Aqr, Mira, W Aql, and π1 Gru) with ALMA. The stars cover a decisive range in binary separation, necessary to provide essential constraints for 3-D models of the binary interaction. They have previously been observed with Herschel/PACS and VLTI/MIDI allowing the circumstellar morphology to be studied from the very inner CSE out to the very largest scales. The circumstellar gas distribution will strongly depend on how the mass is initially lost from the primary. These observations will therefore not only help us understand the important processes for the binary interaction, but will also provide crucial information needed to understand the mass-loss mechanisms of the primary. The first set of observations has been delivered and preliminary results are presented.

  18. Terrestrial Planet Formation Around Close Binary Stars

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Quintana, Elisa V.

    2003-01-01

    Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets around close binary stars, using a new, ultrafast, symplectic integrator that we have developed for this purpose. The sum of the masses of the two stars is one solar mass, and the initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and in the Alpha Centauri wide binary star system. Giant planets &are included in the simulations, as they are in most simulations of the late stages of terrestrial planet accumulation in our Solar System. When the stars travel on a circular orbit with semimajor axis of up to 0.1 AU about their mutual center of mass, the planetary embryos grow into a system of terrestrial planets that is statistically identical to those formed about single stars, but a larger semimajor axis and/or a significantly eccentric binary orbit can lead to significantly more dynamically hot terrestrial planet systems.

  19. Spectroscopic Orbits for Kepler FOV Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Matson, Rachel A.; Gies, Douglas R.; Williams, Stephen J.; Guo, Zhao

    2013-02-01

    We are currently involved in a four year program of precise eclipsing binary photometry with the NASA Kepler Observatory. Our goal is to search for variations in minimum light timing for intermediate mass eclipsing binaries. Such periodic variations will reveal the reflex motion caused by any distant, low mass object that orbits the close binary. it Kepler's unprecedented accuracy and continuous observations provide a unique opportunity to detect the low mass companions that are predicted to result from the angular momentum of the natal cloud. The goal of this proposal is to obtain blue spectra of short period (0.9-6d) eclipsing binaries, derive radial velocities, and produce a double-lined spectroscopic orbit (as well as estimates of the stellar effective temperatures, gravities, and metallicities). Combined with the it Kepler light curve, we will determine very accurate masses and radii for the members of the close binary, which will yield the mass-inclination product M_3 sin i for any companions detected by light travel time or other effects. An extended sample of eclipsing binaries with longer periods (up to 50d) is now being investigated to test whether the presence of a tertiary companion declines with increasing period. We propose to obtain a single spectrum at quadrature for the brightest 48 stars in this expanded sample to characterize the effective temperatures and total mass contained in these systems.

  20. SPECTROSCOPIC SUBSYSTEMS IN NEARBY WIDE BINARIES

    SciTech Connect

    Tokovinin, Andrei

    2015-12-15

    Radial velocity (RV) monitoring of solar-type visual binaries has been conducted at the CTIO/SMARTS 1.5 m telescope to study short-period systems. The data reduction is described, and mean and individual RVs of 163 observed objects are given. New spectroscopic binaries are discovered or suspected in 17 objects, and for some of them the orbital periods could be determined. Subsystems are efficiently detected even in a single observation by double lines and/or by the RV difference between the components of visual binaries. The potential of this detection technique is quantified by simulation and used for statistical assessment of 96 wide binaries within 67 pc. It is found that 43 binaries contain at least one subsystem, and the occurrence of subsystems is equally probable in either primary or secondary components. The frequency of subsystems and their periods matches the simple prescription proposed by the author. The remaining 53 simple wide binaries with a median projected separation of 1300 AU have an RV difference distribution between their components that is not compatible with the thermal eccentricity distribution f (e) = 2e but rather matches the uniform eccentricity distribution.

  1. Terrestrial Planet Formation Around Close Binary Stars

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Quintana, Elisa V.

    2003-01-01

    Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets around close binary stars, using a new, ultrafast, symplectic integrator that we have developed for this purpose. The sum of the masses of the two stars is one solar mass, and the initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and in the Alpha Centauri wide binary star system. Giant planets &are included in the simulations, as they are in most simulations of the late stages of terrestrial planet accumulation in our Solar System. When the stars travel on a circular orbit with semimajor axis of up to 0.1 AU about their mutual center of mass, the planetary embryos grow into a system of terrestrial planets that is statistically identical to those formed about single stars, but a larger semimajor axis and/or a significantly eccentric binary orbit can lead to significantly more dynamically hot terrestrial planet systems.

  2. Binary IS Typing for Staphylococcus aureus

    PubMed Central

    Budding, Andries E.; Vandenbroucke-Grauls, Christina M. J. E.; Melles, Damian C.; van Duijkeren, Engeline; Kluytmans, Jan A.; Savelkoul, Paul H. M.

    2010-01-01

    Background We present an easily applicable test for rapid binary typing of Staphylococcus aureus: binary interspace (IS) typing. This test is a further development of a previously described molecular typing technique that is based on length polymorphisms of the 16S-23S rDNA interspace region of S. aureus. Methodology/Principal Findings A novel approach of IS-typing was performed in which binary profiles are created. 424 human and animal derived MRSA and MSSA isolates were tested and a subset of these isolates was compared with multi locus sequence typing (MLST) and Amplified Fragment Length Polymorphism (AFLP). Binary IS typing had a high discriminatory potential and a good correlation with MLST and AFLP. Conclusions/Significance Binary IS typing is easy to perform and binary profiles can be generated in a standardized fashion. These two features, combined with the high correlation with MLST clonal complexes, make the technique applicable for large-scale inter-laboratory molecular epidemiological comparisons. PMID:21060683

  3. Texture Classification by Texton: Statistical versus Binary

    PubMed Central

    Guo, Zhenhua; Zhang, Zhongcheng; Li, Xiu; Li, Qin; You, Jane

    2014-01-01

    Using statistical textons for texture classification has shown great success recently. The maximal response 8 (Statistical_MR8), image patch (Statistical_Joint) and locally invariant fractal (Statistical_Fractal) are typical statistical texton algorithms and state-of-the-art texture classification methods. However, there are two limitations when using these methods. First, it needs a training stage to build a texton library, thus the recognition accuracy will be highly depended on the training samples; second, during feature extraction, local feature is assigned to a texton by searching for the nearest texton in the whole library, which is time consuming when the library size is big and the dimension of feature is high. To address the above two issues, in this paper, three binary texton counterpart methods were proposed, Binary_MR8, Binary_Joint, and Binary_Fractal. These methods do not require any training step but encode local feature into binary representation directly. The experimental results on the CUReT, UIUC and KTH-TIPS databases show that binary texton could get sound results with fast feature extraction, especially when the image size is not big and the quality of image is not poor. PMID:24520346

  4. Eclipsing Binary B-Star Mass Determinations

    NASA Astrophysics Data System (ADS)

    Townsend, Amanda; Eikenberry, Stephen S.

    2016-01-01

    B-stars in binary pairs provide a laboratory for key astrophysical measurements of massive stars, including key insights for the formation of compact objects (neutron stars and black holes). In their paper, Martayan et al (2004) find 23 Be binary star pairs in NGC2004 in the Large Magellanic Cloud, five of which are both eclipsing and spectroscopic binaries with archival data from VLT-Giraffe and photometric data from MACHO. By using the Wilson eclipsing binary code (e.g., Wilson, 1971), we can determine preliminary stellar masses of the binary components. We present the first results from this analysis. This study also serves as proof-of-concept for future observations with the Photonic Synthesis Telescope Array (Eikenberry et al., in prep) that we are currently building for low-cost, precision spectroscopic observations. With higher resolution and dedicated time for observations, we can follow-up observations of these Be stars as well as Be/X-ray binaries, for improved mass measurements of neutron stars and black holes and better constraints on their origin/formation.

  5. Accretion Processes in Magnetic Binaries*

    NASA Astrophysics Data System (ADS)

    Ferrario, Lilia; Li, Jianke; Saxton, Curtis; Wu, Kinwah

    1999-12-01

    In this paper, we give a brief summary of the talks on accretion processes in AM Herculis systems which were presented at the ANU Astrophysical Theory Centre workshop on `Magnetic Fields and Accretion'. One of the topics to be discussed was the mechanism that leads to the formation of magnetically funnelled accretion flows in close interacting magnetic binaries. New solutions to the Bernoulli integral indicate that the field lines must be twisted and have a strong toroidal component at the base of the funnel in order for channelled flow to be possible. The magnetic field pressure of these toroidal fields first lifts the material out of the orbital plane allowing it to `levitate' before freely falling along magnetic field lines towards the stellar surface. Results of recent calculations of the thermal structure and radiation properties of accretion funnels were also presented. These new 3D calculations allow for heating by the soft X-rays originating from the accretion shock, and by magnetic heating at the base of the funnel, and determine self-consistently the thermal structure, and the continuum and line emissions, allowing for both transfer of the external radiation field and the trapping of radiation within the funnel. Calculations were also presented of the expected properties of H- and He-like Fe lines originating from the accretion shock itself at the stellar surface. These lines are predicted to be rather strong and can be used as diagnostics of the accretion flow. Finally, the stability of the accretion shock was also addressed. In particular, it was shown that radiative cooling may cause thermal instability and an oscillatory behaviour, with two competing processes coming into play: bremsstrahlung cooling, which promotes instability, and cyclotron cooling, which tends to dampen the oscillations.

  6. Selective dissolution in binary alloys

    NASA Astrophysics Data System (ADS)

    McCall, Carol Rene

    Corrosion is an important issue in the design of engineering alloys. De-alloying is an aspect of alloy corrosion related to the selective dissolution of one or more of the components in an alloy. The work reported herein focuses on the topic of de-alloying specific to single-phase binary noble metal alloy systems. The alloy systems investigated were gold-silver and gold-copper. The onset of a bulk selective dissolution process is typically marked by a critical potential whereby the more reactive component in the alloy begins dissolving from the bulk, leading to the formation of a bi-continuous solid-void morphology. The critical potential was investigated for the entire composition range of gold-silver alloys. The results presented herein include the formulation of an expression for critical potential as a function of both alloy and electrolyte composition. Results of the first investigation of underpotential deposition (UPD) on alloys are also presented herein. These results were implemented as an analytical tool to provide quantitative measurements of the surface evolution of gold during de-alloying. The region below the critical potential was investigated in terms of the compositional evolution of the alloy surface. Below the critical potential, there is a competition between the dissolution of the more reactive alloying constituent (either silver or copper) and surface diffusion of gold that serves to cover dissolution sites and prevent bulk dissolution. By holding the potential at a prescribed value below the critical potential, a time-dependent gold enrichment occurs on the alloy surface leading to passivation. A theoretical model was developed to predict the surface enrichment of gold based on the assumption of layer-by-layer dissolution of the more reactive alloy constituent. The UPD measurements were used to measure the time-dependent surface gold concentration and the results agreed with the predictions of the theoretical model.

  7. Exploring the Birth of Binary Stars

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-08-01

    More than half of all stars are thought to be in binary or multiple star systems. But how do these systems form? The misaligned spins of some binary protostars might provide a clue.Two Formation ModelsIts hard to tell how multiple-star systems form, since these systems are difficult to observe in their early stages. But based on numerical simulations, there are two proposed models for the formation of stellar binaries:Turbulent fragmentationTurbulence within a single core leads to multiple dense clumps. These clumps independently collapse to form stars that orbit each other.Disk fragmentationGravitational instabilities in a massive accretion disk cause the formation of a smaller, secondary disk within the first, resulting in two stars that orbit each other.Log column density for one of the authors simulated binary systems, just after the formation of two protostars. Diamonds indicate the protostar positions. [Adapted from Offner et al. 2016]Outflows as CluesHow can we differentiate between these formation mechanisms? Led by Stella Offner (University of Massachusetts), a team of scientists has suggested that the key isto examine the alignment of the stars protostellar outflows jets that are often emitted from the poles of young, newly forming stars.Naively, wed expect that disk fragmentation would produce binary stars with common angular momentum. As the stars spins would be aligned, they would therefore also launch protostellar jets that were aligned with each other. Turbulent fragmentation, on the other hand, would cause the stars to have independent angular momentum. This would lead to randomly oriented spins, so the protostellar jets would be misaligned.Snapshots from the authors simulations. Left panel of each pair: column density; green arrows giveprotostellar spin directions. Right panel: synthetic observations produced from the simulations; cyan arrows giveprotostellar outflow directions. [Offner et al. 2016]Simulations of FragmentationIn order to better

  8. Birth of Massive Black Hole Binaries

    SciTech Connect

    Colpi, M.; Dotti, M.; Mayer, L.; Kazantzidis, S.; /KIPAC, Menlo Park

    2007-11-19

    If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BHs in gas-rich galaxy mergers that underscore the vital role played by a cool, gaseous component in promoting the rapid formation of the BH binary. The BH binary is found to reside at the center of a massive self-gravitating nuclear disc resulting from the collision of the two gaseous discs present in the mother galaxies. Hardening by gravitational torques against gas in this grand disc is found to continue down to sub-parsec scales. The eccentricity decreases with time to zero and when the binary is circular, accretion sets in around the two BHs. When this occurs, each BH is endowed with it own small-size ({approx}< 0.01 pc) accretion disc comprising a few percent of the BH mass. Double AGN activity is expected to occur on an estimated timescale of {approx}< 1 Myr. The double nuclear point-like sources that may appear have typical separation of {approx}< 10 pc, and are likely to be embedded in the still ongoing starburst. We note that a potential threat of binary stalling, in a gaseous environment, may come from radiation and/or mechanical energy injections by the BHs. Only short-lived or sub-Eddington accretion episodes can guarantee the persistence of a dense cool gas structure around the binary necessary for continuing BH inspiral.

  9. Terrestrial planet formation surrounding close binary stars

    NASA Astrophysics Data System (ADS)

    Quintana, Elisa V.; Lissauer, Jack J.

    2006-11-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around both components of some young close binary star systems. Additionally, it has been shown that if planets form at the right places within such disks, they can remain dynamically stable for very long times. Herein, we numerically simulate the late stages of terrestrial planet growth in circumbinary disks around 'close' binary star systems with stellar separations 0.05 AU⩽a⩽0.4 AU and binary eccentricities 0⩽e⩽0.8. In each simulation, the sum of the masses of the two stars is 1 M, and giant planets are included. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet formation within our Solar System by Chambers [Chambers, J.E., 2001. Icarus 152, 205-224], and around each individual component of the α Centauri AB binary star system by Quintana et al. [Quintana, E.V., Lissauer, J.J., Chambers, J.E., Duncan, M.J., 2002. Astrophys. J. 576, 982-996]. Multiple simulations are performed for each binary star system under study, and our results are statistically compared to a set of planet formation simulations in the Sun-Jupiter-Saturn system that begin with essentially the same initial disk of protoplanets. The planetary systems formed around binaries with apastron distances Q≡a(1+e)≲0.2 AU are very similar to those around single stars, whereas those with larger maximum separations tend to be sparcer, with fewer planets, especially interior to 1 AU. We also provide formulae that can be used to scale results of planetary accretion simulations to various systems with different total stellar mass, disk sizes, and planetesimal masses and densities.

  10. The mass ratio in spectroscopic binaries

    NASA Astrophysics Data System (ADS)

    Ducati, J. R.; Penteado, E. M.; Turcati, R.

    2003-08-01

    The process of formation of binary and multiple stars is not yet fully understood. Possibilities range from simultaneous processes of condensation from the primeval nebula, to isolated star formation and eventual capture to form a double system. Models exist that predict success probabilities for each theoretical process, and comparison with observational data is crucial. Spectroscopic binaries are specially suited to be used as observational data, since several biases that can arise from general catalogues of binary stars can be avoided, including dominance of systems with large separations between components. A very important parameter in these studies is the mass ratio, the quocient of the masses of primary and secundary members. The histogram of mass ratios provides crucial information to models of binary formation, linked to condensation processes and evolutionaty rates.In this case, spectroscopic binaries can be chosen as the observational sample, provided that the spectrum of the primary is from a non-evolved, main-sequence star,whose mass can be derived reliably from its spectral type. Defining an adequate limiting magnitude (6.5), one avoids bias from eclipsing systems with high inclinations, since nearly all systems up to 6.5 mag were detected. In this paper, a critical review is presented of the existing methods for deriving the distribution of the mass ratios from spectroscopic binary orbital data. After showing the incorrectness of some results published in the litterature, the available data (Batten's 8th Catalogue, 1989) is discussed. Simulations for several distributions of mass ratios (constant, quadratic, etc) are performed. It is shown that the existing data permits only to assert that the spectroscopic binaries with small mass ratios (q < 0.4) are more frequent that those with large mass ratios (q = 0.9 to 1.0).

  11. Gravitational wave background from binary systems

    SciTech Connect

    Rosado, Pablo A.

    2011-10-15

    Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter {Omega}(f), commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, {Omega}(f) is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the frequencies of all existing and planned detectors. A semi-analytical formula for {Omega}(f) is derived in the case of stellar binaries (containing white dwarfs, neutron stars or stellar-mass black holes). Besides a realistic expectation of the level of background, upper and lower limits are given, to account for the uncertainties in some astrophysical parameters such as binary coalescence rates. One interesting result concerns all current and planned ground-based detectors (including the Einstein Telescope). In their frequency range, the background of binaries is resolvable and only sporadically present. In other words, there is no stochastic background of binaries for ground-based detectors.

  12. Direct Exoplanet Detection with Binary Differential Imaging

    NASA Astrophysics Data System (ADS)

    Rodigas, Timothy J.; Weinberger, Alycia; Mamajek, Eric E.; Males, Jared R.; Close, Laird M.; Morzinski, Katie; Hinz, Philip M.; Kaib, Nathan

    2015-10-01

    Binaries are typically excluded from direct imaging exoplanet surveys. However, the recent findings of Kepler and radial velocity programs show that planets can and do form in binary systems. Here, we suggest that visual binaries offer unique advantages for direct imaging. We show that Binary Differential Imaging (BDI), whereby two stars are imaged simultaneously at the same wavelength within the isoplanatic patch at a high Strehl ratio, offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star. We demonstrate this by observing a young visual binary separated by 4″ with MagAO/Clio-2 at 3.9 μm, where the Strehl ratio is high, the isoplanatic patch is large, and giant planets are bright. Comparing BDI to angular differential imaging (ADI), we find that BDI’s 5σ contrast is ˜0.5 mag better than ADI’s within ˜1″ for the particular binary we observed. Because planets typically reside close to their host stars, BDI is a promising technique for discovering exoplanets in stellar systems that are often ignored. BDI is also 2-4× more efficient than ADI and classical reference PSF subtraction, since planets can be detected around both the target and PSF reference simultaneously. We are currently exploiting this technique in a new MagAO survey for giant planets in 140 young nearby visual binaries. BDI on a space-based telescope would not be limited by isoplanatism effects and would therefore be an even more powerful tool for imaging and discovering planets. This paper includes data obtained at the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  13. Numerical Relativity Simulations of Black Holes Binaries, Neutron Star Binaries, and Neutron Star Oscillations

    NASA Astrophysics Data System (ADS)

    Rosofsky, Shawn; Gold, Roman; Chirenti, Cecilia; Miller, Cole

    2017-01-01

    We present the results of numerical relativity simulations, using the Einstein Toolkit, of black hole binaries, neutron star binaries, and neutron star oscillations. The black hole binary simulations represent the source of LIGO's first gravitational wave detection, GW150914. We compare the gravitational wave output of this simulation with the LIGO data LIGO on GW150914. The neutron star binaries we simulated have different mass ratios and equations of state. These simulations were compared with each other to illustrate the effect of different mass ratios and equations of state on binary evolution and gravitational wave emission. To perform the neutron star oscillation simulations, we applied pressure and density perturbations to the star using specific eigenmodes. These evolutions of the stars were then compared to the expected oscillation frequencies of those excited eigemodes and contrasted with simulations of unperturbed neutron stars.

  14. Thermal characteristics of oleochemical carbonate binary mixtures for potential latent heat storage

    USDA-ARS?s Scientific Manuscript database

    The present study examines the thermal properties of melting and solidification for binary mixtures between dodecyl carbonate (1a), tetradecyl carbonate (1b), hexadecyl carbonate (1c), and octadecyl carbonate (1d) by differential scanning calorimetry (DSC) in order to gain further understanding of t...

  15. New spectroscopic binary companions of giant stars and updated metallicity distribution for binary systems

    NASA Astrophysics Data System (ADS)

    Bluhm, P.; Jones, M. I.; Vanzi, L.; Soto, M. G.; Vos, J.; Wittenmyer, R. A.; Drass, H.; Jenkins, J. S.; Olivares, F.; Mennickent, R. E.; Vučković, M.; Rojo, P.; Melo, C. H. F.

    2016-10-01

    We report the discovery of 24 spectroscopic binary companions to giant stars. We fully constrain the orbital solution for 6 of these systems. We cannot unambiguously derive the orbital elements for the remaining stars because the phase coverage is incomplete. Of these stars, 6 present radial velocity trends that are compatible with long-period brown dwarf companions. The orbital solutions of the 24 binary systems indicate that these giant binary systems have a wide range in orbital periods, eccentricities, and companion masses. For the binaries with restricted orbital solutions, we find a range of orbital periods of between ~97-1600 days and eccentricities of between ~0.1-0.4. In addition, we studied the metallicity distribution of single and binary giant stars. We computed the metallicity of a total of 395 evolved stars, 59 of wich are in binary systems. We find a flat distribution for these binary stars and therefore conclude that stellar binary systems, and potentially brown dwarfs, have a different formation mechanism than planets. This result is confirmed by recent works showing that extrasolar planets orbiting giants are more frequent around metal-rich stars. Finally, we investigate the eccentricity as a function of the orbital period. We analyzed a total of 130 spectroscopic binaries, including those presented here and systems from the literature. We find that most of the binary stars with periods ≲30 days have circular orbits, while at longer orbital periods we observe a wide spread in their eccentricities. Based on observations collected at La Silla - Paranal Observatory under programs IDs IDs 085.C-0557, 087.C.0476, 089.C-0524, 090.C-0345, 096.A-9020 and through the Chilean Telescope Time under programs IDs CN2012A-73, CN2012B-47, CN2013A-111, CN2013B-51, CN2014A-52 and CN2015A-48.

  16. Serial binary interval ratios improve rhythm reproduction.

    PubMed

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  17. Serial binary interval ratios improve rhythm reproduction

    PubMed Central

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception. PMID:23964258

  18. Satisfiability modulo theory and binary puzzle

    NASA Astrophysics Data System (ADS)

    Utomo, Putranto

    2017-06-01

    The binary puzzle is a sudoku-like puzzle with values in each cell taken from the set {0, 1}. We look at the mathematical theory behind it. A solved binary puzzle is an n × n binary array where n is even that satisfies the following conditions: (1) No three consecutive ones and no three consecutive zeros in each row and each column, (2) Every row and column is balanced, that is the number of ones and zeros must be equal in each row and in each column, (3) Every two rows and every two columns must be distinct. The binary puzzle had been proven to be an NP-complete problem [5]. Research concerning the satisfiability of formulas with respect to some background theory is called satisfiability modulo theory (SMT). An SMT solver is an extension of a satisfiability (SAT) solver. The notion of SMT can be used for solving various problem in mathematics and industries such as formula verification and operation research [1, 7]. In this paper we apply SMT to solve binary puzzles. In addition, we do an experiment in solving different sizes and different number of blanks. We also made comparison with two other approaches, namely by a SAT solver and exhaustive search.

  19. Stacking Analysis of Binary Systems with HAWC

    NASA Astrophysics Data System (ADS)

    Brisbois, Chad; HAWC Collaboration

    2017-01-01

    Detecting binary systems at TeV energies is an important problem because only a handful of such systems are currently known. The nature of such systems is typically thought to be composed of a compact object and a massive star. The TeV emission from these systems does not obviously correspond to emission in GeV or X-ray, where many binary systems have previously been found. This study focuses on a stacking method to detect TeV emission from LS 5039, a known TeV binary, to test its efficacy in HAWC data. Stacking is a widely employed method for increasing signal to noise ratio in optical astronomy, but has never been attempted previously with HAWC. HAWC is an ideal instrument to search for TeV binaries, because of its wide field of view and high uptime. Applying this method to the entire sky may allow HAWC to detect binary sources of very short or very long periods not sensitive to current analyses. NSF, DOE, Los Alamos, Michigan Tech, CONACyt, UNAM, BUAP.

  20. Keck Imaging of Binary L Dwarfs.

    PubMed

    Koerner; Kirkpatrick; McElwain; Bonaventura

    1999-11-20

    We present Keck near-infrared imaging of three binary L dwarf systems, all of which are likely to be substellar. Two are lithium dwarfs, and a third exhibits an L7 spectral type, making it the coolest binary known to date. All have component flux ratios near 1 and projected physical separations between 5 and 10 AU, assuming distances of 18-26 pc from recent measurements of trigonometric parallax. These surprisingly similar binaries represent the sole detections of companions in 10 L dwarf systems that were analyzed in the preliminary phase of a much larger dual-epoch imaging survey. The detection rate prompts us to speculate that binary companions to L dwarfs are common, that similar-mass systems predominate, and that their distribution peaks at radial distances in accord both with M dwarf binaries and with the radial location of Jovian planets in our own solar system. To fully establish these conjectures against doubts raised by biases inherent in this small preliminary survey, however, will require quantitative analysis of a larger volume-limited sample that has been observed with high resolution and dynamic range.

  1. Forming the wide asynchronous binary asteroid population

    NASA Astrophysics Data System (ADS)

    Jacobson, S.; Scheeres, D.; McMahon, J.

    2014-07-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth-asteroid and main-belt-asteroid systems as shown in the attached table. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational-fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide-asynchronous-binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  2. The binary white dwarf LHS 3236

    SciTech Connect

    Harris, Hugh C.; Dahn, Conard C.; Canzian, Blaise; Guetter, Harry H.; Levine, Stephen E.; Luginbuhl, Christian B.; Monet, Alice K. B.; Stone, Ronald C.; Subasavage, John P.; Tilleman, Trudy; Walker, Richard L.; Dupuy, Trent J.; Liu, Michael C.; Hartkopf, William I.; Ireland, Michael J.; Leggett, S. K.

    2013-12-10

    The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 ± 0.25 pc and a tangential velocity of 98 km s{sup –1}, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0 yr period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M {sub ☉}; also possible is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M {sub ☉}. In either case, the cooling ages of the stars are ∼3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66-1.84 M {sub ☉}) is well above the Chandrasekhar limit; however, the timescale for coalescence is long.

  3. The Galactic Distribution of Contact Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Castelaz, Michael W.; Dorn, Leah; Breitfeld, Abby; Mies, Regan; Avery, Tess

    2017-01-01

    The number of eclipsing contact binaries in different galactic latitudes and longitudes show peak distributions in the number per square degree in two latitudinal zones (-30 degrees to -25 degrees and +25 degrees to +30 degrees) and large fluctuations in longitude (Huang and Wade 1966, ApJ, 143, 146). Semi-detached or detached binaries are largely concentrated in the galactic plane as shown by Paczynski et al. (MNRAS, 368, 1311), different from the distribution of contact eclipsing binaries. The differences in distributions of different types of eclipsing binaries may be related to either distances or interstellar reddening. We will present a method to calculate photometric distances of W Urase Majoris systems (W UMa; used as a proxy for contact binaries) from 2MASS J and K magnitudes and interstellar reddening models (Schlafly and Finkbeiner 2011, ApJ. 737, 103). We compare the distances to those calculated from the period-luminosity-color relationship described by Rucinski (2004, NewAR, 48, 703). The W UMa systems are taken from the General Catalog of Variable Stars.

  4. Simulations of binary neutron star mergers

    NASA Astrophysics Data System (ADS)

    Kiuchi, Kenta

    2017-01-01

    The merger of a binary composed of a neutron star and/or a black hole is one of the most promising sources of gravitational waves. If we detected gravitational waves from them, it could tell us a validity of the general relativity in a strong gravitational field and the equation of state of neutron star matter. Furthermore, if gravitational waves from a compact binary merger and a short-hard gamma-ray burst are observed simultaneously, a long-standing puzzle on the central engine of short gamma-ray bursts could be resolved. In addition, compact binary mergers are a theoretical candidate of the rapid process nucleosynthesis site. Motivated by these facts, it is mandatory to build a physically reliable model of compact binary mergers and numerical relativity is a unique approach for this purpose. We are tackling this problem from several directions; the magneto-hydrodynamics, the neutrino radiation transfer, and a comprehensive study with simplified models. I will talk a current status of Kyoto Numerical Relativity group and future prospect on the compact binary mergers.

  5. BIPOLAR JETS PRODUCED BY A SPECTROSCOPIC BINARY

    SciTech Connect

    Mundt, Reinhard; Hamilton, Catrina M.; Herbst, William; Johns-Krull, Christopher M.; Winn, Joshua N.

    2010-01-01

    We present evidence that the spectroscopically identified bipolar jets of the pre-main sequence binary KH 15D (P = 48.4 d, {epsilon}{approx} 0.6, periastron separation {approx}18 R{sub A} , M{sub A} = 0.6 M {sub sun}, M{sub B} = 0.7 M {sub sun}) are a common product of the whole binary system, rather than being launched from either star individually. They may be launched from the innermost part of the circumbinary disk (CBD) or may result from the merging of two outflows driven by the individual stars. This evidence is based on high-resolution H{alpha} and [O I]{lambda}6300 line profiles obtained during eclipse phases of this nearly edge-on system. The occultation of star A (the only currently visible star) by the disk strongly suppresses the stellar H{alpha} and continuum emission and allows one to study the faint redshifted and blueshifted emission components of the bipolar jets. The strongest evidence for jet production by the whole binary system comes from the observed radial velocity symmetry of the two jet components relative to the systemic velocity of the binary in combination with current accretion models from the CBD onto a binary system.

  6. Radiance Data Assimilation for Binary Typhoon Cases

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Snyder, C.; Cha, D. H.

    2015-12-01

    The predictability of track and intensity for binary tropical cyclones (TCs) is relatively low due to the interaction between two TCs. In this study, radiance data were assimilated using the Three Dimensional Variational (3D-Var) data assimilation method to improve track and intensity forecasts of binary TCs. In detail, a total of three binary TC cases over the Northwestern Pacific from 2010 to 2015, which affected the Korean Peninsula, were selected. Infrared and microwave radiance data from multiple instruments and satellites were assimilated with the appropriate treatments of quality control, channel selection, bias correction, and cloud detection. The Weather Research and Forecasting (WRF) model was used as a forecasting model, and the resolution of the innermost domain was high (2 km) to capture the structure and intensity of TCs. Background error covariance was calculated using the National Meteorological Center (NMC) method, where background error statistics were from the differences between 24-h and 12-h forecasts for a month-long period. Overall, track and intensity errors of three binary TCs are reduced through the assimilation of radiance data. Especially, track forecasts are improved significantly because large-scale environments such as the North Pacific High and mid-latitude trough/ridge are simulated well. Analysis increment and its evolution are investigated to reveal the reason for the improvement of each binary TC's forecast, focusing on TC's internal structure and its environment. Additionally, effects of other observational data (e.g. radiosonde, satellite wind) are analyzed through the sensitivity experiments.

  7. Planetary nebula progenitors that swallow binary systems

    NASA Astrophysics Data System (ADS)

    Soker, Noam

    2016-01-01

    I propose that some irregular messy planetary nebulae (PNe) owe their morphologies to triple-stellar evolution where tight binary systems evolve inside and/or on the outskirts of the envelope of asymptotic giant branch (AGB) stars. In some cases, the tight binary system can survive, in others, it is destroyed. The tight binary system might break up with one star leaving the system. In an alternative evolution, one of the stars of the broken-up tight binary system falls towards the AGB envelope with low specific angular momentum, and drowns in the envelope. In a different type of destruction process, the drag inside the AGB envelope causes the tight binary system to merge. This releases gravitational energy within the AGB envelope, leading to a very asymmetrical envelope ejection, with an irregular and messy PN as a descendant. The evolution of the triple-stellar system can be in a full common envelope evolution or in a grazing envelope evolution. Both before and after destruction (if destruction takes place), the system might launch pairs of opposite jets. One pronounced signature of triple-stellar evolution might be a large departure from axisymmetrical morphology of the descendant PN. I estimate that about one in eight non-spherical PNe is shaped by one of these triple-stellar evolutionary routes.

  8. Orbital eccentricities in primordial black hole binaries

    NASA Astrophysics Data System (ADS)

    Cholis, Ilias; Kovetz, Ely D.; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B.; Raccanelli, Alvise

    2016-10-01

    It was recently suggested that the merger of ˜30 M⊙ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly eccentric orbits and can then merge on time scales that in some cases are years or less, retaining some eccentricity in the last seconds before the merger. This is to be contrasted with massive-stellar-binary, globular-cluster, or other astrophysical origins for binary black holes (BBHs) in which the orbits have very effectively circularized by the time the BBH enters the observable LIGO window. Here we discuss the features of the gravitational-wave signals that indicate this eccentricity and forecast the sensitivity of LIGO and the Einstein Telescope to such effects. We show that if PBHs make up the dark matter, then roughly one event should have a detectable eccentricity given LIGO's expected sensitivity and observing time of six years. The Einstein Telescope should see O (10 ) such events after ten years.

  9. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    SciTech Connect

    Fuller, Jim; Lai Dong

    2012-09-01

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10{sup 5}-10{sup 6} years.

  10. The Outflows of Binary AGB Stars

    NASA Astrophysics Data System (ADS)

    Ramstedt, S.; Vlemmings, W. H. T.; Mohamed, S.

    2015-12-01

    The required conditions for stars to evolve into planetary nebulae (PNs) continues to puzzle. Since PNs are found in a wide variety of shapes, processes that could sculpt circumstellar envelopes (CSEs) are being investigated. A binary companion will have a strong gravitational effect, but known binary AGB stars are rare. Using ALMA in Cycle 1 and 2, we have observed a small sample of well-studied, binary AGB stars, covering a decisive range in separation, in order to determine the influence of a companion on the circumstellar morphology of the AGB primary. The first steps toward interpreting and analyzing the data have been taken, and the results will be compared to 3D Smoothed Particle Hydrodynamics (SPH) models of the gravitational interaction.

  11. Rapid Compact Binary Coalescence Parameter Estimation

    NASA Astrophysics Data System (ADS)

    Pankow, Chris; Brady, Patrick; O'Shaughnessy, Richard; Ochsner, Evan; Qi, Hong

    2016-03-01

    The first observation run with second generation gravitational-wave observatories will conclude at the beginning of 2016. Given their unprecedented and growing sensitivity, the benefit of prompt and accurate estimation of the orientation and physical parameters of binary coalescences is obvious in its coupling to electromagnetic astrophysics and observations. Popular Bayesian schemes to measure properties of compact object binaries use Markovian sampling to compute the posterior. While very successful, in some cases, convergence is delayed until well after the electromagnetic fluence has subsided thus diminishing the potential science return. With this in mind, we have developed a scheme which is also Bayesian and simply parallelizable across all available computing resources, drastically decreasing convergence time to a few tens of minutes. In this talk, I will emphasize the complementary use of results from low latency gravitational-wave searches to improve computational efficiency and demonstrate the capabilities of our parameter estimation framework with a simulated set of binary compact object coalescences.

  12. Detecting compact binary coalescences with seedless clustering

    NASA Astrophysics Data System (ADS)

    Coughlin, M.; Thrane, E.; Christensen, N.

    2014-10-01

    Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors. Although matched filtering is the optimal search method for well-modeled systems, alternative detection strategies can be used to guard against theoretical errors (e.g., involving new physics and/or assumptions about spin or eccentricity) while providing a measure of redundancy. In a previous paper, we showed how "seedless clustering" can be used to detect long-lived gravitational-wave transients in both targeted and all-sky searches. In this paper, we apply seedless clustering to the problem of low-mass (Mtotal≤10M⊙) compact binary coalescences for both spinning and eccentric systems. We show that seedless clustering provides a robust and computationally efficient method for detecting low-mass compact binaries.

  13. Tidal evolution in close binary systems.

    NASA Technical Reports Server (NTRS)

    Kopal, Z.

    1972-01-01

    Mathematical outline of the theory of tidal evolution in close binary systems of secularly constant total momentum. Following a general outline of the problem the basic expressions for the energy and momenta of close binaries consisting of components of arbitrary internal structure are established, and the maximum and minimum values of the energy (kinetic and potential) which such systems can attain for a given amount of total momentum are investigated. These results are compared with the actual facts encountered in binaries with components whose internal structure (and, therefore, rotational momenta) are known from evidence furnished by the observed rates of apsidal advance. The results show that all such systems whether of detached or semidetached type - disclose that more than 99% of their total momenta are stored in the orbital momentum. The sum of the rotational momenta of the constituent components amounts to less than 1% of the total -a situation characteristic of a state close to the minimum energy for given total momentum.

  14. Binary Asteroids and Human Exploration Considerations

    NASA Technical Reports Server (NTRS)

    Abell, P. A.

    2013-01-01

    In 2009 the Augustine Commission identified near-Earth asteroids (NEAs) as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. Subsequently, the U.S. presidential administration directed NASA on April 15, 2010 to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010. Current NASA plans to explore NEAs do not include binary systems. However, with a few in situ robotic precursor missions to binary NEAs, and increased confidence in human mission capabilities, the scientific and hazard mitigation benefits, along with the programmatic and operational benefits of a human venture beyond the Earth-Moon system, make a mission to a binary NEA using NASA's proposed exploration systems a compelling endeavor.

  15. Hybrid Black-Hole Binary Initial Data

    NASA Technical Reports Server (NTRS)

    Mundim, Bruno C.; Kelly, Bernard J.; Nakano, Hiroyuki; Zlochower, Yosef; Campanelli, Manuela

    2010-01-01

    "Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class. Quantum Grav. 27:114005 (2010)], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculations was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features."

  16. Compact binary hashing for music retrieval

    NASA Astrophysics Data System (ADS)

    Seo, Jin S.

    2014-03-01

    With the huge volume of music clips available for protection, browsing, and indexing, there is an increased attention to retrieve the information contents of the music archives. Music-similarity computation is an essential building block for browsing, retrieval, and indexing of digital music archives. In practice, as the number of songs available for searching and indexing is increased, so the storage cost in retrieval systems is becoming a serious problem. This paper deals with the storage problem by extending the supervector concept with the binary hashing. We utilize the similarity-preserving binary embedding in generating a hash code from the supervector of each music clip. Especially we compare the performance of the various binary hashing methods for music retrieval tasks on the widely-used genre dataset and the in-house singer dataset. Through the evaluation, we find an effective way of generating hash codes for music similarity estimation which improves the retrieval performance.

  17. High-spin binary black hole mergers

    NASA Astrophysics Data System (ADS)

    Marronetti, Pedro; Tichy, Wolfgang; Brügmann, Bernd; González, Jose; Sperhake, Ulrich

    2008-03-01

    We study identical mass black hole binaries with spins perpendicular to the binary’s orbital plane. These binaries have individual spins ranging from s/m2=-0.90 to 0.90, (s1=s2 in all cases) which is near the limit possible with standard Bowen-York puncture initial data. The extreme cases correspond to the largest initial spin simulations to date. Our results expand the parameter space covered by Rezzolla et al., and when combining both data sets, we obtain estimations for the minimum and maximum values for the intrinsic angular momenta of the remnant of binary black hole mergers of J/M2=0.341±0.004 and 0.951±0.004, respectively. Note, however, that these values are reached through extrapolation to the singular cases |s1|=|s2|=1 and thus remain as estimates until full-fledged numerical simulations provide confirmation.

  18. Binary-phase compression of stretched pulses

    NASA Astrophysics Data System (ADS)

    Lozovoy, Vadim V.; Nairat, Muath; Dantus, Marcos

    2017-10-01

    Pulse stretching and compression are essential for the energy scale-up of ultrafast lasers. Here, we consider a radical approach using spectral binary phases, containing only two values (0 and π) for stretching and compressing laser pulses. We numerically explore different strategies and present results for pulse compression of factors up to a million back to the transform limit and experimentally obtain results for pulse compression of a factor of one hundred, in close agreement with numerical calculations. Imperfections resulting from binary-phase compression are addressed by considering cross-polarized wave generation filtering, and show that this approach leads to compressed pulses with contrast ratios greater than ten orders of magnitude. This new concept of binary-phase stretching and compression, if implemented in a multi-layer optic, could eliminate the need for traditional pulse stretchers and more importantly expensive compressors.

  19. Periodicity of Eclipsing Binary Star GK Cepheus

    NASA Astrophysics Data System (ADS)

    2001-10-01

    Eclipsing Binary stars are stars in which there is some mass exchange taking place between two main bodies. This mass exchange produces a change in the magnitude or “brightness” of the star. The star known as GK Cephius has been listed as an eclipsing binary in number of publications, journal articles, and data tables. If the light curve is examined carefully, it exhibits some behavior that is not typical of simple eclipsing binary stars. A study of this light curve is underway to examine the possibility of another gravitational influence being at work in the region of this star. In this paper we will report on the predictions concerning an additional candidate that may be influencing the light curves of the GK Cephius system.

  20. On binary channels to anomalous Cepheids

    NASA Astrophysics Data System (ADS)

    Gautschy, Alfred; Saio, Hideyuki

    2017-07-01

    Anomalous Cepheids are a rather rare family of pulsating variables preferably found in dwarf galaxies. Attempts to model these variable stars via single-star evolution scenarios still leave space for improvements to better grasp their origin. Focusing on the Large Magellanic Cloud with its rich population of anomalous Cepheids to compare against, we probe the role binary stars might play to understand the nature of anomalous Cepheids. The evolution of donors and accretors undergoing Case-B mass transfer along the first red giant branch as well as merger-like models was calculated. First results show that in binary scenarios, a larger range of star masses and metallicities up to Z ≲ 0.008, higher than deemed possible hitherto, enter and pass through the instability strip. If binary stars play a role in anomalous Cepheid populations, mass donors, mass accretors or even mergers are potential candidates to counteract constraints imposed by the single-star approach.

  1. Gravitational Wave Physics with Binary Love Relations

    NASA Astrophysics Data System (ADS)

    Yagi, Kent; Yunes, Nicolas

    2016-03-01

    Gravitational waves from the late inspiral of neutron star binaries encode rich information about their internal structure at supranuclear densities through their tidal deformabilities. However, extracting the individual tidal deformabilities of the components of a binary is challenging with future ground-based gravitational wave interferometers due to degeneracies between them. We overcome this difficulty by finding new, approximate universal relations between the individual tidal deformabilities that depend on the mass ratio of the two stars and are insensitive to their internal structure. Such relations have applications not only to gravitational wave astrophysics, but also to nuclear physics as they improve the measurement accuracy of tidal parameters. Moreover, the relations improve our ability to test extreme gravity and perform cosmology with gravitational waves emitted from neutron star binaries.

  2. Jets in black-hole binaries

    NASA Astrophysics Data System (ADS)

    Zdziarski, Andrzej

    2016-07-01

    I will review selected aspects of observations and theory of jets in black-hole binaries. The radio and gamma-ray emission of jets differs significantly between the low and high-mass X-ray binaries, which appears to be due jet-wind interaction (in particular, formation of recollimation shocks) in the latter. Also, both radio and X-ray emission of the jets can be significantly absorbed in the stellar wind of the donors in high-mass binaries. I will also review the theory of radiative processes in jets, their contributions to broad-band spectra, estimates of the jet power, the role of black-hole spin in powering jets, and the possibility that the base of the jet is the main source of X-ray emission (the lamppost model).

  3. Cosmological Impact of Population III Binaries

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung; Bromm, Volker; Heger, Alexander; Jeon, Myoungwon; Woosley, Stan

    2015-03-01

    We present the results of the stellar feedback from Population III (Pop III) binaries by employing improved, more realistic Pop III evolutionary stellar models. To facilitate a meaningful comparison, we consider a fixed mass of 60 {{M}⊙ } incorporated in Pop III stars, either contained in a single star, or split up in binary stars of 30 {{M}⊙ } each or an asymmetric case of one 45 and one 15 {{M}⊙ } star. Whereas the sizes of the resulting H ii regions are comparable across all cases, the He iii regions around binary stars are significantly smaller than that of the single star. Consequently, the He+ 1640 \\overset{\\circ}A recombination line is expected to become much weaker. Supernova (SN) feedback exhibits great variety due to the uncertainty in possible explosion pathways. If at least one of the component stars dies as a hypernova about 10 times more energetic than conventional core-collapse SNe, the gas inside the host minihalo is effectively blown out, chemically enriching the intergalactic medium (IGM) to an average metallicity of {{10}-4}-{{10}-3} {{Z}⊙ }, out to ˜ 2 kpc. The single star, however, is more likely to collapse into a black hole, accompanied by at most very weak explosions. The effectiveness of early chemical enrichment would thus be significantly reduced, in contrast to the lower mass binary stars, where at least one component is likely to contribute to heavy element production and dispersal. Important new feedback physics is also introduced if close binaries can form high-mass X-ray binaries, leading to the pre-heating and -ionization of the IGM beyond the extent of the stellar H ii regions.

  4. OSRI: a rotationally invariant binary descriptor.

    PubMed

    Xu, Xianwei; Tian, Lu; Feng, Jianjiang; Zhou, Jie

    2014-07-01

    Binary descriptors are becoming widely used in computer vision field because of their high matching efficiency and low memory requirements. Since conventional approaches, which first compute a floating-point descriptor then binarize it, are computationally expensive, some recent efforts have focused on directly computing binary descriptors from local image patches. Although these binary descriptors enable a significant speedup in processing time, their performances usually drop a lot due to orientation estimation errors and limited description abilities. To address these issues, we propose a novel binary descriptor based on the ordinal and spatial information of regional invariants (OSRIs) over a rotation invariant sampling pattern. Our main contributions are twofold: 1) each bit in OSRI is computed based on difference tests of regional invariants over pairwise sampling-regions instead of difference tests of pixel intensities commonly used in existing binary descriptors, which can significantly enhance the discriminative ability and 2) rotation and illumination changes are handled well by ordering pixels according to their intensities and gradient orientations, meanwhile, which is also more reliable than those methods that resort to a reference orientation for rotation invariance. Besides, a statistical analysis of discriminative abilities of different parts in the descriptor is conducted to design a cascade filter which can reject nonmatching descriptors at early stages by comparing just a small portion of the whole descriptor, further reducing the matching time. Extensive experiments on four challenging data sets (Oxford, 53 Objects, ZuBuD, and Kentucky) show that OSRI significantly outperforms two state-of-the-art binary descriptors (FREAK and ORB). The matching performance of OSRI with only 512 bits is also better than the well-known floating-point descriptor SIFT (4K bits) and is comparable with the state-of-the-art floating-point descriptor MROGH (6K bits

  5. A search for binary candidates among the fundamental mode RR Lyrae stars observed by Kepler

    NASA Astrophysics Data System (ADS)

    Guggenberger, Elisabeth; Steixner, Jakob

    2015-09-01

    Although roughly half of all stars are considered to be part of binary or multiple systems, there are only two confirmed cases of RR Lyrae pulsators with companions. One of them is TU Uma [1] - a classical RR Lyrae star in a very eccentric orbit - and the other is OGLE-BLG-RRLYR-02792 [2]. Considering the wealth of well-studied RR Lyrae stars, this number is astoundingly low. Having more RR Lyrae stars in binary systems at hand would be extremely valuable to get independent measurements of the masses. The data from the Kepler mission with their unprecedented precision and the long time span of about four years offer a unique possibility to systematically search for the signatures of binarity in RR Lyrae stars. Using the pulsation as a clock, we studied the variations in the timing of maximum light to hunt for possible binary systems in the sample.

  6. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    SciTech Connect

    Kaltenegger, Lisa; Haghighipour, Nader

    2013-11-10

    We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

  7. Testing the Binary Black Hole Nature of a Compact Binary Coalescence

    NASA Astrophysics Data System (ADS)

    Krishnendu, N. V.; Arun, K. G.; Mishra, Chandra Kant

    2017-09-01

    We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.

  8. DISTINGUISHING COMPACT BINARY POPULATION SYNTHESIS MODELS USING GRAVITATIONAL WAVE OBSERVATIONS OF COALESCING BINARY BLACK HOLES

    SciTech Connect

    Stevenson, Simon; Ohme, Frank; Fairhurst, Stephen

    2015-09-01

    The coalescence of compact binaries containing neutron stars or black holes is one of the most promising signals for advanced ground-based laser interferometer gravitational-wave (GW) detectors, with the first direct detections expected over the next few years. The rate of binary coalescences and the distribution of component masses is highly uncertain, and population synthesis models predict a wide range of plausible values. Poorly constrained parameters in population synthesis models correspond to poorly understood astrophysics at various stages in the evolution of massive binary stars, the progenitors of binary neutron star and binary black hole systems. These include effects such as supernova kick velocities, parameters governing the energetics of common envelope evolution and the strength of stellar winds. Observing multiple binary black hole systems through GWs will allow us to infer details of the astrophysical mechanisms that lead to their formation. Here we simulate GW observations from a series of population synthesis models including the effects of known selection biases, measurement errors and cosmology. We compare the predictions arising from different models and show that we will be able to distinguish between them with observations (or the lack of them) from the early runs of the advanced LIGO and Virgo detectors. This will allow us to narrow down the large parameter space for binary evolution models.

  9. Testing the Binary Black Hole Nature of a Compact Binary Coalescence.

    PubMed

    Krishnendu, N V; Arun, K G; Mishra, Chandra Kant

    2017-09-01

    We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.

  10. Searching for Binary Supermassive Black Holes via Variable Broad Emission Line Shifts: Low Binary Fraction

    NASA Astrophysics Data System (ADS)

    Wang, Lile; Greene, Jenny E.; Ju, Wenhua; Rafikov, Roman R.; Ruan, John J.; Schneider, Donald P.

    2017-01-01

    Supermassive black hole binaries (SMBHs) are expected to result from galaxy mergers, and thus are natural byproducts (and probes) of hierarchical structure formation in the universe. They are also the primary expected source of low-frequency gravitational wave emission. We search for binary BHs using time-variable velocity shifts in broad Mg ii emission lines of quasars with multi-epoch observations. First, we inspect velocity shifts of the binary SMBH candidates identified in Ju et al., using Sloan Digital Sky Survey spectra with an additional epoch of data that lengthens the typical baseline to ∼10 yr. We find variations in the line of sight velocity shifts over 10 yr that are comparable to the shifts observed over 1–2 yr, ruling out the binary model for the bulk of our candidates. We then analyze 1438 objects with eight-year median time baselines, from which we would expect to see velocity shifts >1000 {km} {{{s}}}-1 from sub-parsec binaries. We find only one object with an outlying velocity of 448 {km} {{{s}}}-1, indicating—based on our modeling—that ≲1% (the value varies with different assumptions) of SMBHs that are active as quasars reside in binaries with ∼0.1 pc separations. Binaries either sweep rapidly through these small separations or stall at larger radii.

  11. ANALYSIS OF THE MOTION OF AN EXTRASOLAR PLANET IN A BINARY SYSTEM

    SciTech Connect

    Plávalová, Eva; Solovaya, Nina A. E-mail: solov@sai.msu.ru

    2013-11-01

    More than 10% of extra-solar planets (EPs) orbit in a binary or multiple stellar system. We investigated the motion of planets revolving in binary systems in the case of the three-body problem. We carried out an analysis of the motion of an EP revolving in a binary system with the following conditions: (1) a planet in a binary system revolves around one of the components (parent star); (2) the distance between the star's components is greater than that between the parent star and the orbiting planet (ratio of the semi-major axes is a small parameter); and (3) the mass of the planet is smaller than the mass of the stars, but is not negligible. The Hamiltonian of the system without short periodic terms was used. We expanded the Hamiltonian in terms of the Legendre polynomial and truncated after the second-order term, depending on only one angular variable. In this case, the solution of the system was obtained and the qualitative analysis of the motion was produced. We have applied this theory to real EPs and compared to the numerical integration. Analyses of the possible regions of motion are presented. It is shown that stable and unstable motions of EPs are possible. We applied our calculations to two binary systems hosting an EP and calculated the possible values for their unknown orbital elements.

  12. Binary Vector Dissimilarity Measures for Handwriting Identification

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Srihari, Sargur N.

    2003-01-01

    Several dissimilarity measures for binary vectors are formulated and examined for their recognition capability in handwriting identification for which the binary micro-features are used to characterize handwritten character shapes. Pertaining to eight dissimilarity measures, i.e., Jaccard-Needham, Dice, Correlation, Yule, Russell-Rao, Sokal-Michener, Rogers-Tanmoto and Kulzinsky, the discriminary power of ten individual characters and their combination is exhaustively studied. Conclusions are made on how to choose a dissimilarity measure and how to combine hybrid features.

  13. Orbital evolution of small binary asteroids

    NASA Astrophysics Data System (ADS)

    Ćuk, Matija; Nesvorný, David

    2010-06-01

    About 15% of both near-Earth and main-belt asteroids with diameters below 10 km are now known to be binary. These small asteroid binaries are relatively uniform and typically contain a fast-spinning, flattened primary and a synchronously rotating, elongated secondary that is 20-40% as large (in diameter) as the primary. The principal formation mechanism for these binaries is now thought to be YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect induced spin-up of the primary followed by mass loss and accretion of the secondary from the released material. It has previously been suggested (Ćuk, M. [2007]. Astrophys. J. 659, L57-L60) that the present population of small binary asteroids is in a steady state between production through YORP and destruction through binary YORP (BYORP), which should increase or decrease secondary's orbit, depending on the satellite's shape. However, BYORP-driven evolution has not been directly modeled until now. Here we construct a simple numerical model of the binary's orbital as well the secondary's rotational dynamics which includes BYORP and selected terms representing main solar perturbations. We find that many secondaries should be vulnerable to chaotic rotation even for relatively low-eccentricity mutual orbits. We also find that the precession of the mutual orbit for typical small binary asteroids might be dominated by the perturbations from the prolate and librating secondary, rather than the oblate primary. When we evolve the mutual orbit by BYORP we find that the indirect effects on the binary's eccentricity (through the coupling between the orbit and the secondary's spin) dominate over direct ones caused by the BYORP acceleration. In particular, outward evolution causes eccentricity to increase and eventually triggers chaotic rotation of the secondary. We conclude that the most likely outcome will be reestablishing of the synchronous lock with a "flipped" secondary which would then evolve back in. For inward evolution we find

  14. Binary Classification and the Subtractive Approach.

    DTIC Science & Technology

    1983-09-01

    AR[l 1,t AFAMRL-TR-83-050 BINARY CLASSIFICATION AND THE SUBTRACTIVE APPROACH Gregory M. Corso Georgia Institute of Technology Suzanne Kelly 9 Danny E...GRANT NUMBER(O) Gregory M. Corso * F49620-82-C-0035 Suzanne Kelly Danny E. Bridges, TSgt, USAF 9 PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM...A NA3 1 BINARY CLASSIFICATION AND THE SABTRACTIVE APPROACH(A) 1/1 EDUCATION INC ST CLOUD FL G M CORSO ET AL. SEP 83 UNCLASSIFIED AFAMRL-T 83 050

  15. Apsidal motion in eclipsing binary GG Orionis

    NASA Astrophysics Data System (ADS)

    Yilan, E.; Bulut, I.

    2016-03-01

    The study of apsidal motion in binary stars with eccentric orbit is well known as an important source of information for the stellar internal structure as well as the possibility of verification of general relativity. In this study, the apsidal motion of the eccentric eclipsing binary GG Ori (P = 6.631 days, e = 0.22) has been analyzed using the times of minimum light taken from the literature and databases and the elements of apsidal motion have been computed. The method described by Giménez and García-Pelayo (1983) has been used for the apsidal motion analysis.

  16. The evolution of ultrashort period binary systems

    NASA Technical Reports Server (NTRS)

    Nelson, L. A.; Rappaport, S. A.; Joss, P. C.

    1986-01-01

    A discussion is presented concerning the results of detailed evolutionary calculations in which a very low mass and hydrogen-depleted semiattached binary star containing a collapsed object can reach an exceptionally short orbital period while sustaining a relatively high mass transfer rate. The observed properties of such systems can be understood under the assumption that they contain moderately to severely hydrogen-defficient secondary stars that are neither fully degenerate nor burning He. It is noted that for extremely hydrogen-depleted stars, the assumption of chemical homogeneity becomes untenable. Attention is given to the binary systems 4U 1626-67, 4U 1916-05, and G61-29.

  17. Spin supplementary conditions for spinning compact binaries

    NASA Astrophysics Data System (ADS)

    Mikóczi, Balázs

    2017-03-01

    We consider different spin supplementary conditions (SSC) for a spinning compact binary with the leading-order spin-orbit (SO) interaction. The Lagrangian of the binary system can be constructed, but it is acceleration-dependent in two cases of SSC. We rewrite the generalized Hamiltonian formalism proposed by Ostrogradsky and compute the conserved quantities and the dissipative part of relative motion during the gravitational radiation of each SSC. We give the orbital elements and observed quantities of the SO dynamics, for instance, the energy and the orbital angular momentum losses and waveforms, and discuss their SSC dependence.

  18. Small geothermal binary plants in Mexico

    SciTech Connect

    Lopez-Diaz, M.

    1996-12-31

    In Mexico, Comision Federal de Electricidad (CFE Federal Commission of Electricity) has identified several low enthalpy sites related with thermal water, at shallow depths. Some of those geothermal prospects are located far from the electrical national grid. In some cases, the population solve their electricity needs by internal combustion engines with very high operating costs. CFE has started a project oriented to use the energy contained in the thermal waters with off-grid binary plants. The two first projects are in the state of Chihuahua at the north of the country: San Antonio El Bravo and Maguarichic. At both places CFE will install a 300 kW, unattended binary power units.

  19. All optical binary delta-sigma modulator

    NASA Astrophysics Data System (ADS)

    Sayeh, Mohammad R.; Siahmakoun, Azad

    2005-09-01

    This paper describes a novel A/D converter called "Binary Delta-Sigma Modulator" (BDSM) which operates only with nonnegative signal with positive feedback and binary threshold. This important modification to the conventional delta-sigma modulator makes the high-speed (>100GHz) all-optical implementation possible. It has also the capability to modify its own sampling frequency as well as its input dynamic range. This adaptive feature helps designers to optimize the system performance under highly noisy environment and also manage the power consumption of the A/D converters.

  20. Binary NS simulations using SpEC

    NASA Astrophysics Data System (ADS)

    Haas, Roland; Szilagyi, Bela; Kaplan, Jeffrey; Ott, Christian; Lippuner, Jonas; Scheel, Mark; Barkett, Kevin; Muhlberger, Curran; Foucart, Francois; Duez, Matthew

    2014-03-01

    NSNS binaries are expected to be one of the major sources of gravitational radiation detectable by Advanced LIGO. Together with neutrinos, gravitational waves are our only means to learn about the processes deep within a merging pair of NS, shedding light on the as yet poorly understood, equation of state governing matter at nuclear densities and beyond. We report on binary neutron star simulations using the Spectral Einstein Code (SpEC) developed by the Caltech-Cornell-CITA-WSU collaboration. We simulate the inspiral through many orbits, follow the post-merger evolution, and compute the full gravitational wave signal.

  1. Survey of Candidate Pulsating Eclipsing Binaries - I

    NASA Astrophysics Data System (ADS)

    Dvorak, S.

    2009-08-01

    Initial results from a photometric survey of stars selected from the list of eclipsing binaries that may contain a pulsating component by Soydugan et al. (2006) are reported. A minimum of two nights of CCD observations with V and/or B filters of each of the 35 stars from this list was collected. Of the 35 stars stud- ied, a pulsating component was detected in three of the systems. Pulsations were also serendiptiously detected in the eclipsing binary RR Leporis, which is not on the candidate list.

  2. Winds from disks in compact binaries

    SciTech Connect

    Mauche, C.W.

    1993-10-27

    We herein present an observational and theoretical review of the winds of compact binaries. After a brief consideration of the accretion disk coronae and winds of X-ray binaries, the review concentrates on the winds of cataclysmic variables (CVs). Specifically, we consider the related problems of the geometry and mass-loss rate of the winds of CVs, their ionization state and variability, and the results from studies of eclipsing CVs. Finally, the properties of bona fide accretion disk wind models are reviewed.

  3. Accretion-powered Compact Binaries

    NASA Astrophysics Data System (ADS)

    Mauche, Christopher W.

    2003-12-01

    Preface; The workshop logo; A short history of the CV workshop F. A. Córdova; Part I. Observations: 1. Low mass x-ray binaries A. P. Cowley, P. C. Schmidtke, D. Crampton, J. B. Hutchings, C. A. Haswell, E. L. Robinson, K. D. Horne, H. M. Johnston, S. R. Kulkarni, S. Kitamoto, X. Han, R. M. Hjellming, R. M. Wagner, S. L. Morris, P. Hertz, A. N. Parmar, L. Stella, P. Giommi, P. J. Callanan, T. Naylor, P. A. Charles, C. D. Bailyn, J. N. Imamura, T. Steiman-Cameron, J. Kristian, J. Middleditch, L. Angelini and J. P. Noris; 2. Nonmagnetic cataclysmic variables R. S. Polidan, C. W. Mauche, R. A. Wade, R. H. Kaitchuck, E. M. Schlegel, P. A. Hantzios, R. C. Smith, J. H. Wood, F. Hessman, A. Fiedler, D. H. P. Jones, J. Casares, P. A. Charles, J. van Paradijs, E. Harlaftis, T. Naylor, G. Sonneborn, B. J. M. Hassall, K. Horne, C. A. la Dous, A. W. Shafter, N. A. Hawkins, D. A. H. Buckley, D. J. Sullivan, F. V. Hessman, V. S. Dhillon, T. R. Marsh, J. Singh, S. Seetha, F. Giovannelli, A. Bianchini, E. M. Sion, D. J. Mullan, H. L. Shipman, G. Machin, P. J. Callanan, S. B. Howell, P. Szkody, E. M. Schlegel and R. F. Webbink; 3. Magnetic cataclysmic variables C. Hellier, K. O. Mason, C. W. Mauche, G. S. Miller, J. C. Raymond, F. K. Lamb, J. Patterson, A. J. Norton, M. G. Watson, A. R. King, I. M. McHardy, H. Lehto, J. P. Osborne, E. L. Robinson, A. W. Shafter, S. Balachandran, S. R. Rosen, J. Krautter, W. Buchholz, D. A. H. Buckley, I. R. Tuoly, D. Crampton, B. Warner, R. M. Prestage, B. N. Ashoka, M. Mouchet, J. M. Bonnet-Bidaud, J. M. Hameury, P. Szkody, P. Garnavich, S. Howell, T. Kii, M. Cropper, K. Mason, J. Bailey, D. T. Wickramasinghe, L. Ferrario, K. Beuermann, A. D. Schwope, H.-C. Thomas, S. Jordan, J. Schachter, A. V. Filippenko, S. M. Kahn, F. B. S. Paerels, K. Mukai, M. L. Edgar, S. Larsson, R. F. Jameson, A. R. King, A. Silber, R. Remillard, H. Bradt, M. Ishida, T. Ohashi and G. D. Schmidt; Part II. Accretion Theory: 4. Nonmagnetic W. Kley, F. Geyer, H. Herold, H

  4. Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae.

    PubMed

    Fryer, Chris L; Oliveira, F G; Rueda, J A; Ruffini, R

    2015-12-04

    Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (E_{iso}≳10^{52}  erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.

  5. Neutron-star–black-hole binaries produced by binary-driven hypernovae

    DOE PAGES

    Fryer, Chris L.; Oliveira, F. G.; Rueda, Jorge A.; ...

    2015-12-04

    Here, binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (Eiso ≳1052 erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed “ultrastripped” binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compactmore » binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.« less

  6. Elucidating the True Binary Fraction of VLM Stars and Brown Dwarfs with Spectral Binaries

    NASA Astrophysics Data System (ADS)

    Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Gelino, Christopher R.; SAHLMANN, JOHANNES; Schmidt, Sarah J.; Gagne, Jonathan; Skrzypek, Nathalie

    2017-01-01

    The very lowest-mass (VLM) stars and brown dwarfs are found in abundance in nearly all Galactic environments, yet their formation mechanism(s) remain an open question. One means of testing current formation theories is to use multiplicity statistics. The majority of VLM binaries have been discovered through direct imaging, and current angular resolution limits (0.05”-0.1") are coincident with the 1-4 AU peak in the projected separation distribution of known systems, suggesting an observational bias. I have developed a separation-independent method to detect T dwarf companions to late-M/early-L dwarfs by identifying methane absorption in their unresolved, low-resolution, near-infrared spectra using spectral indices and template fitting. Over 60 spectral binary candidates have been identified with this and comparable methods. I discuss follow-up observations, including laser-guide star adaptive optics imaging with Keck/NIRC2, which have confirmed 9 systems; and radial velocity and astrometric monitoring observations that have confirmed 7 others. The direct imaging results indicate a resolved binary fraction of 18%, coincident with current estimates of the VLM binary fraction; however, our sample contained 5 previously confirmed binaries, raising its true binary fraction to 47%. To more accurately measure the true VLM binary fraction, I describe the construction of an unbiased, volume-limited, near-infrared spectral sample of M7-L5 dwarfs within 25 pc, of which 4 (1%) are found to be spectral binary candidates. I model the complex selection biases of this method through a population simulation, set constraints on the true binary fraction as traced by these systems, and compare to the predictions of current formation theories. I also describe how this method may be applied to conduct a separation-unbiased search for giant exoplanets orbiting young VLM stars and brown dwarfs.

  7. Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae

    NASA Astrophysics Data System (ADS)

    Fryer, Chris L.; Oliveira, F. G.; Rueda, J. A.; Ruffini, R.

    2015-12-01

    Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (Eiso≳1052 erg ), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.

  8. Neutron-star–black-hole binaries produced by binary-driven hypernovae

    SciTech Connect

    Fryer, Chris L.; Oliveira, F. G.; Rueda, Jorge A.; Ruffini, Remo

    2015-12-04

    Here, binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (Eiso ≳1052 erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed “ultrastripped” binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.

  9. Type 1a Supernova Animation

    NASA Image and Video Library

    Animation showing a binary star system in which a white dwarf accretes matter from a normal companion star. Matter streaming from the red star accumulates on the white dwarf until the dwarf explode...

  10. The Tarantula Massive Binary Monitoring. I. Observational campaign and OB-type spectroscopic binaries

    NASA Astrophysics Data System (ADS)

    Almeida, L. A.; Sana, H.; Taylor, W.; Barbá, R.; Bonanos, A. Z.; Crowther, P.; Damineli, A.; de Koter, A.; de Mink, S. E.; Evans, C. J.; Gieles, M.; Grin, N. J.; Hénault-Brunet, V.; Langer, N.; Lennon, D.; Lockwood, S.; Maíz Apellániz, J.; Moffat, A. F. J.; Neijssel, C.; Norman, C.; Ramírez-Agudelo, O. H.; Richardson, N. D.; Schootemeijer, A.; Shenar, T.; Soszyński, I.; Tramper, F.; Vink, J. S.

    2017-02-01

    Context. Massive binaries play a crucial role in the Universe. Knowing the distributions of their orbital parameters is important for a wide range of topics from stellar feedback to binary evolution channels and from the distribution of supernova types to gravitational wave progenitors, yet no direct measurements exist outside the Milky Way. Aims: The Tarantula Massive Binary Monitoring project was designed to help fill this gap by obtaining multi-epoch radial velocity (RV) monitoring of 102 massive binaries in the 30 Doradus region. Methods: In this paper we analyze 32 FLAMES/GIRAFFE observations of 93 O- and 7 B-type binaries. We performed a Fourier analysis and obtained orbital solutions for 82 systems: 51 single-lined (SB1) and 31 double-lined (SB2) spectroscopic binaries. Results: Overall, the binary fraction and orbital properties across the 30 Doradus region are found to be similar to existing Galactic samples. This indicates that within these domains environmental effects are of second order in shaping the properties of massive binary systems. A small difference is found in the distribution of orbital periods, which is slightly flatter (in log space) in 30 Doradus than in the Galaxy, although this may be compatible within error estimates and differences in the fitting methodology. Also, orbital periods in 30 Doradus can be as short as 1.1 d, somewhat shorter than seen in Galactic samples. Equal mass binaries (q> 0.95) in 30 Doradus are all found outside NGC 2070, the central association that surrounds R136a, the very young and massive cluster at 30 Doradus's core. Most of the differences, albeit small, are compatible with expectations from binary evolution. One outstanding exception, however, is the fact that earlier spectral types (O2-O7) tend to have shorter orbital periods than later spectral types (O9.2-O9.7). Conclusions: Our results point to a relative universality of the incidence rate of massive binaries and their orbital properties in the

  11. Brown Dwarf Binaries from Disintegrating Triple Systems

    NASA Astrophysics Data System (ADS)

    Reipurth, Bo; Mikkola, Seppo

    2015-04-01

    Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi-Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

  12. BROWN DWARF BINARIES FROM DISINTEGRATING TRIPLE SYSTEMS

    SciTech Connect

    Reipurth, Bo; Mikkola, Seppo E-mail: Seppo.Mikkola@utu.fi

    2015-04-15

    Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi–Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

  13. BINARY ASTEROID ENCOUNTERS WITH TERRESTRIAL PLANETS: TIMESCALES AND EFFECTS

    SciTech Connect

    Fang, Julia; Margot, Jean-Luc

    2012-01-15

    Many asteroids that make close encounters with terrestrial planets are in a binary configuration. Here, we calculate the relevant encounter timescales and investigate the effects of encounters on a binary's mutual orbit. We use a combination of analytical and numerical approaches with a wide range of initial conditions. Our test cases include generic binaries with close, moderate, and wide separations, as well as seven well-characterized near-Earth binaries. We find that close approaches (<10 Earth radii) occur for almost all binaries on 1-10 million year timescales. At such distances, our results suggest substantial modifications to a binary's semimajor axis, eccentricity, and inclination, which we quantify. Encounters within 30 Earth radii typically occur on sub-million year timescales and significantly affect the wider binaries. Important processes in the lives of near-Earth binaries, such as tidal and radiative evolution, can be altered or stopped by planetary encounters.

  14. On the dynamical evolution and end states of binary centaurs

    NASA Astrophysics Data System (ADS)

    Brunini, A.

    2014-01-01

    In this paper, we perform a numerical integration of 666 fictitious binary Centaurs coming from the trans Neptunian space. Our population is restricted to tight binaries whose components have sizes between 30 and 100 km. We included the dynamical perturbations from the giant planets, Kozai Cycles induced by the Sun and tidal friction on the orbits of the binaries. We found that most binaries are disrupted during one of the close planetary encounters, making the mean lifetime of binary Centaurs much shorter than the one of single Centaurs. Nearly 10 per cent of the binaries reach a very tight circular orbit, arguing in favour of the existence of a non-negligible population of contact Centaurs. Another 10 per cent survive as a binary during their lifetime as Centaur. Our simulations favour the existence of a small population of very tight binary Centaurs.

  15. Model-independent inference on compact-binary observations

    NASA Astrophysics Data System (ADS)

    Mandel, Ilya; Farr, Will M.; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2017-03-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multidimensional parameter space of observations that are subject to significant measurement errors. We apply this procedure to a mock data set of population-synthesis predictions for the masses of merging compact binaries convolved with realistic measurement uncertainties, and demonstrate that we can accurately distinguish subpopulations of binary neutron stars, binary black holes, and mixed neutron star-black hole binaries with tens of observations.

  16. Binaries among AP and AM stars

    NASA Astrophysics Data System (ADS)

    North, P.; Ginestet, N.; Carquillat, J.-M.; Carrier, F.; Udry, S.

    1998-04-01

    The results of long-term surveys of radial velocities of cool Ap and Am stars are presented. There are two samples, one of about 100 Ap stars and the other of 86 Am stars. Both have been observed with the CORAVEL scanner from Observatoire de Haute-Provence (CNRS), France. The conspicuous lack of short-period binaries among cool Ap stars seems confirmed, although this may be the result of an observational bias; one system has a period as short as 1.6 days. A dozen new orbits could be determined, including that of one SB2 system. Considering the mass functions of 68 binaries from the literature and from our work, we conclude that the distribution of the mass ratios is the same for the Bp-Ap stars than for normal G dwarfs. Among the Am stars, we found 52 binaries, i.e. 60%; an orbit could be computed for 29 of them. Among these 29, there are 7 SB2 systems, one triple and one quadruple system. The 21 stars with an apparently constant radial velocity may show up later as long-period binaries with a high eccentricity. The mass functions of the SB1 systems are compatible with cool main-sequence companions, also suggested by ongoing spectral observations.

  17. Last orbits of binary strange quark stars

    SciTech Connect

    Limousin, Francois; Gourgoulhon, Eric; Gondek-Rosinska, Dorota

    2005-03-15

    We present the first relativistic calculations of the final phase of inspiral of a binary system consisting of two stars built predominantly of strange quark matter (strange quark stars). We study the precoalescing stage within the Isenberg-Wilson-Mathews approximation of general relativity using a multidomain spectral method. A hydrodynamical treatment is performed under the assumption that the flow is either rigidly rotating or irrotational, taking into account the finite density at the stellar surface--a distinctive feature with respect to the neutron star case. The gravitational-radiation driven evolution of the binary system is approximated by a sequence of quasiequilibrium configurations at fixed baryon number and decreasing separation. We find that the innermost stable circular orbit (ISCO) is given by an orbital instability both for synchronized and irrotational systems. This contrasts with neutron stars for which the ISCO is given by the mass-shedding limit in the irrotational case. The gravitational wave frequency at the ISCO, which marks the end of the inspiral phase, is found to be {approx}1400 Hz for two irrotational 1.35 M{sub {center_dot}} strange stars and for the MIT bag model of strange matter with massless quarks and a bag constant B=60 MeV fm{sup -3}. Detailed comparisons with binary neutrons star models, as well as with third order post-Newtonian point-mass binaries are given.

  18. Fission: A Mechanism for Forming Binary Stars

    NASA Astrophysics Data System (ADS)

    Tohline, J. E.; Cazes, J. E.

    2000-05-01

    We demonstrate that it is possible for short period binary star systems to form from a single, rapidly rotating, equilibrium protostellar gas cloud via a natural fission process. This is analogous to the process by which rapidly spinning drops of fluid have been observed to break in two during drop dynamics experiments onboard the space shuttle. In order to demonstrate that fission works in the context of binary star formation, we have used a three-dimensional, computational fluid dynamics technique to, first, construct a rapidly rotating, self-gravitating, equilibrium barlike structure that, by all accounts, appears to be a compressible analog of an incompressible Riemann ellipsoid. Then by slowly cooling this configuration and following its cooling evolution in a fully self-consistent fashion, we have demonstrated that the system contracts along an ellipsoid-dumbbell-binary sequence. Although the hypothesis that binary stars may form via a process of fission has been around for more than 100 years, it has been a difficult hypothesis to test because of the nonlinear dynamical processes involved. This is the first demonstration that fission works in the context of realistic protostellar gas clouds. This work has been supported by the U.S. National Science Foundation through grant AST-9528424, by NASA through grant NAG5-8497, and by a grant of high-performance-computing time through NPACI on machines at the San Diego Supercomputing Center.

  19. Hierarchical cooperative binary ionic porphyrin nanocomposites.

    PubMed

    Tian, Yongming; Busani, Tito; Uyeda, Gregory H; Martin, Kathleen E; van Swol, Frank; Medforth, Craig J; Montaño, Gabriel A; Shelnutt, John A

    2012-05-18

    Cooperative binary ionic (CBI) solids comprise a versatile new class of opto-electronic and catalytic materials consisting of ionically self-assembled pairs of organic anions and cations. Herein, we report CBI nanocomposites formed by growing nanoparticles of one type of porphyrin CBI solid onto a second porphyrin CBI substructure with complementary functionality.

  20. Polarizing binary diffraction grating beam splitter.

    PubMed

    Davis, Jeffrey A; Evans, Garrett H

    2004-07-01

    We report a polarizing beam splitter that uses binary phase gratings written onto a liquid-crystal spatial light modulator. These gratings produce several linearly polarized diffracted orders and a zeroth-order beam whose polarization state can be completely controlled. Experimental results are shown.

  1. Speckle Interferometry of Binary Star HIP 4849

    NASA Astrophysics Data System (ADS)

    Kehrli, Matthew; David, Heather; Drake, Evan; Gonzalez, Corina; Zuchegno, Joe; Genet, Russell

    2017-01-01

    Binary star HIP 4849 was observed on October 18, 2013 UT, using an EMCCD camera on the 2.1-Meter telescope at Kitt Peak National Observatory. HIP 4849 had a separation, rho, of 0.725" and a position angle, theta, of 79.32°. This observation did not deviate significantly from the predicted orbit.

  2. The Binary Pulsar: Gravity Waves Exist.

    ERIC Educational Resources Information Center

    Will, Clifford

    1987-01-01

    Reviews the history of pulsars generally and the 1974 discovery of the binary pulsar by Joe Taylor and Russell Hulse specifically. Details the data collection and analysis used by Taylor and Hulse. Uses this discussion as support for Albert Einstein's theory of gravitational waves. (CW)

  3. Orthogonal Patterns In A Binary Neural Network

    NASA Technical Reports Server (NTRS)

    Baram, Yoram

    1991-01-01

    Report presents some recent developments in theory of binary neural networks. Subject matter relevant to associate (content-addressable) memories and to recognition of patterns - both of considerable importance in advancement of robotics and artificial intelligence. When probed by any pattern, network converges to one of stored patterns.

  4. MODELING FLOWS AROUND MERGING BLACK HOLE BINARIES

    SciTech Connect

    Van Meter, James R.; Centrella, Joan; Baker, John G.; Boggs, William D.; Kelly, Bernard J.; McWilliams, Sean T.; Wise, John H.; Miller, M. Coleman; Reynolds, Christopher S.

    2010-03-10

    Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne Laser Interferometer Space Antenna. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step toward solving this problem by mapping the flow of pressureless matter in the dynamic, three-dimensional general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm these differences, it may allow assessment of the properties of the binaries as well as yielding an identifiable electromagnetic counterpart to the attendant gravitational wave signal.

  5. The Binary Pulsar: Gravity Waves Exist.

    ERIC Educational Resources Information Center

    Will, Clifford

    1987-01-01

    Reviews the history of pulsars generally and the 1974 discovery of the binary pulsar by Joe Taylor and Russell Hulse specifically. Details the data collection and analysis used by Taylor and Hulse. Uses this discussion as support for Albert Einstein's theory of gravitational waves. (CW)

  6. A binary main-belt comet.

    PubMed

    Agarwal, Jessica; Jewitt, David; Mutchler, Max; Weaver, Harold; Larson, Stephen

    2017-09-20

    Asteroids are primitive Solar System bodies that evolve both collisionally and through disruptions arising from rapid rotation. These processes can lead to the formation of binary asteroids and to the release of dust, both directly and, in some cases, through uncovering frozen volatiles. In a subset of the asteroids called main-belt comets, the sublimation of excavated volatiles causes transient comet-like activity. Torques exerted by sublimation measurably influence the spin rates of active comets and might lead to the splitting of bilobate comet nuclei. The kilometre-sized main-belt asteroid 288P (300163) showed activity for several months around its perihelion 2011 (ref. 11), suspected to be sustained by the sublimation of water ice and supported by rapid rotation, while at least one component rotates slowly with a period of 16 hours (ref. 14). The object 288P is part of a young family of at least 11 asteroids that formed from a precursor about 10 kilometres in diameter during a shattering collision 7.5 million years ago. Here we report that 288P is a binary main-belt comet. It is different from the known asteroid binaries in its combination of wide separation, near-equal component size, high eccentricity and comet-like activity. The observations also provide strong support for sublimation as the driver of activity in 288P and show that sublimation torques may play an important part in binary orbit evolution.

  7. Non-binary or genderqueer genders.

    PubMed

    Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John; Nieder, Timo O; T'Sjoen, Guy

    2016-01-01

    Some people have a gender which is neither male nor female and may identify as both male and female at one time, as different genders at different times, as no gender at all, or dispute the very idea of only two genders. The umbrella terms for such genders are 'genderqueer' or 'non-binary' genders. Such gender identities outside of the binary of female and male are increasingly being recognized in legal, medical and psychological systems and diagnostic classifications in line with the emerging presence and advocacy of these groups of people. Population-based studies show a small percentage--but a sizable proportion in terms of raw numbers--of people who identify as non-binary. While such genders have been extant historically and globally, they remain marginalized, and as such--while not being disorders or pathological in themselves--people with such genders remain at risk of victimization and of minority or marginalization stress as a result of discrimination. This paper therefore reviews the limited literature on this field and considers ways in which (mental) health professionals may assist the people with genderqueer and non-binary gender identities and/or expressions they may see in their practice. Treatment options and associated risks are discussed.

  8. Binary Colloidal Alloy Test-5: Aspheres

    NASA Technical Reports Server (NTRS)

    Chaikin, Paul M.; Hollingsworth, Andrew D.

    2008-01-01

    The Binary Colloidal Alloy Test - 5: Aspheres (BCAT-5-Aspheres) experiment photographs initially randomized colloidal samples (tiny nanoscale spheres suspended in liquid) in microgravity to determine their resulting structure over time. BCAT-5-Aspheres will study the properties of concentrated systems of small particles when they are identical, but not spherical in microgravity..

  9. Image registration using binary boundary maps

    NASA Technical Reports Server (NTRS)

    Andrus, J. F.; Campbell, C. W.; Jayroe, R. R.

    1978-01-01

    Registration technique that matches binary boundary maps extracted from raw data, rather than matching actual data, is considerably faster than other techniques. Boundary maps, which are digital representations of regions where image amplitudes change significantly, typically represent data compression of 60 to 70 percent. Maps allow average products to be computed with addition rather than multiplication, further reducing computation time.

  10. Binary Solid-Liquid Phase Equilibria

    ERIC Educational Resources Information Center

    Ellison, Herbert R.

    1978-01-01

    Indicates some of the information that may be obtained from a binary solid-liquid phase equilibria experiment and a method to write a computer program that will plot an ideal phase diagram to which the experimental results may be compared. (Author/CP)

  11. Structure Map for Embedded Binary Alloy Nanocrystals

    SciTech Connect

    Yuan, C.W.; Shin, S.J.; Liao, C.Y.; Guzman, J.; Stone, P.R.; Watanabe, M.; Ager III, J.W.; Haller, E.E.; Chrzan, D.C.

    2008-09-20

    The equilibrium structure of embedded nanocrystals formed from strongly segregating binary-alloys is considered within a simple thermodynamic model. The model identifies two dimensionlessinterface energies that dictate the structure, and allows prediction of the stable structure for anychoice of these parameters. The resulting structure map includes three distinct nanocrystal mor-phologies: core/shell, lobe/lobe, and completely separated spheres.

  12. Binary power multiplier for electromagnetic energy

    DOEpatents

    Farkas, Zoltan D.

    1988-01-01

    A technique for converting electromagnetic pulses to higher power amplitude and shorter duration, in binary multiples, splits an input pulse into two channels, and subjects the pulses in the two channels to a number of binary pulse compression operations. Each pulse compression operation entails combining the pulses in both input channels and selectively steering the combined power to one output channel during the leading half of the pulses and to the other output channel during the trailing half of the pulses, and then delaying the pulse in the first output channel by an amount equal to half the initial pulse duration. Apparatus for carrying out each of the binary multiplication operation preferably includes a four-port coupler (such as a 3 dB hybrid), which operates on power inputs at a pair of input ports by directing the combined power to either of a pair of output ports, depending on the relative phase of the inputs. Therefore, by appropriately phase coding the pulses prior to any of the pulse compression stages, the entire pulse compression (with associated binary power multiplication) can be carried out solely with passive elements.

  13. Biomedical Relation Extraction: From Binary to Complex

    PubMed Central

    Zhong, Dayou

    2014-01-01

    Biomedical relation extraction aims to uncover high-quality relations from life science literature with high accuracy and efficiency. Early biomedical relation extraction tasks focused on capturing binary relations, such as protein-protein interactions, which are crucial for virtually every process in a living cell. Information about these interactions provides the foundations for new therapeutic approaches. In recent years, more interests have been shifted to the extraction of complex relations such as biomolecular events. While complex relations go beyond binary relations and involve more than two arguments, they might also take another relation as an argument. In the paper, we conduct a thorough survey on the research in biomedical relation extraction. We first present a general framework for biomedical relation extraction and then discuss the approaches proposed for binary and complex relation extraction with focus on the latter since it is a much more difficult task compared to binary relation extraction. Finally, we discuss challenges that we are facing with complex relation extraction and outline possible solutions and future directions. PMID:25214883

  14. New Eclipsing Contact Binary System in Auriga

    NASA Astrophysics Data System (ADS)

    Austin, S. J.; Robertson, J. W.; Justice, C.; Campbell, R. T.; Hoskins, J.

    2004-05-01

    We present data on a newly discovered eclipsing binary system. The serendipitous discovery of this variable star was made by J.W. Robertson analyzing inhomogeneous ensemble photometry of stars in the field of the cataclysmic variable FS Aurigae from Indiana University RoboScope data. We obtained differential time-series BVR photometry during 2003 of this field variable using an ensemble of telescopes including the university observatories at ATU, UCA and joint ventures with amateur observatories in the state of Arkansas (Whispering Pines Observatory and Nubbin Ridge Observatory). The orbital period of this eclipsing system is 0.2508 days. The B-V light curve indicates colors of 1.2 around quadrature, to nearly 1.4 at primary eclipse. Binary star light curve models that best fit the BVR differential photometry suggest that the system is a contact binary overfilling the inner Roche Lobe by 12%, a primary component with a temperature of 4350K, a secondary component with a temperature of 3500K, a mass ratio of 0.37, and an inclination of 83 degrees. We present BVR light curves, an ephemeris, and best fit model parameters for the physical characteristics of this new eclipsing binary system.

  15. Binary alloys for refractory-metal brazing

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1974-01-01

    Data on binary-metal eutectics and melting-point minimums have been assembled for use in selecting brazing filler compositions for refractory metals. Data are presented in four tables for ready reference. Brief discussion of problems and potentials of metallides is included in appendix.

  16. Supermassive Black Hole Binaries: The Search Continues

    NASA Astrophysics Data System (ADS)

    Bogdanović, Tamara

    Gravitationally bound supermassive black hole binaries (SBHBs) are thought to be a natural product of galactic mergers and growth of the large scale structure in the universe. They however remain observationally elusive, thus raising a question about characteristic observational signatures associated with these systems. In this conference proceeding I discuss current theoretical understanding and latest advances and prospects in observational searches for SBHBs.

  17. What's Next? Judging Sequences of Binary Events

    ERIC Educational Resources Information Center

    Oskarsson, An T.; Van Boven, Leaf; McClelland, Gary H.; Hastie, Reid

    2009-01-01

    The authors review research on judgments of random and nonrandom sequences involving binary events with a focus on studies documenting gambler's fallacy and hot hand beliefs. The domains of judgment include random devices, births, lotteries, sports performances, stock prices, and others. After discussing existing theories of sequence judgments,…

  18. Predicting Social Trust with Binary Logistic Regression

    ERIC Educational Resources Information Center

    Adwere-Boamah, Joseph; Hufstedler, Shirley

    2015-01-01

    This study used binary logistic regression to predict social trust with five demographic variables from a national sample of adult individuals who participated in The General Social Survey (GSS) in 2012. The five predictor variables were respondents' highest degree earned, race, sex, general happiness and the importance of personally assisting…

  19. Narrow band binary phase locked loops

    NASA Technical Reports Server (NTRS)

    Burhans, R. W.

    1976-01-01

    Very high Q digital filtering circuits for audio frequencies in the range of 1Hz to 15 KHz are implemented in simple CMOS hardware using a binary local reference clock frequency. The circuits have application to VLF navigation receivers and other narrow band audio range tracking problems.

  20. Simple circuit performs binary addition and subtraction

    NASA Technical Reports Server (NTRS)

    Cliff, R. A.; Schaefer, D. H.

    1965-01-01

    Ripple adder reduces the number of logic circuits required to preform binary addition and subtraction. The adder uses dual input and delayed output flip-flops in one register. The contents of this register are summed with those of a standard register through conventional AND/gates.

  1. Testing the Binary Trigger Hypothesis in FUors

    NASA Astrophysics Data System (ADS)

    Green, Joel D.; Kraus, Adam L.; Rizzuto, Aaron C.; Ireland, Michael J.; Dupuy, Trent J.; Mann, Andrew W.; Kuruwita, Rajika

    2016-10-01

    We present observations of three FU Orionis objects (hereafter, FUors) with nonredundant aperture-mask interferometry at 1.59 μm and 2.12 μm that probe for binary companions on the scale of the protoplanetary disk that feeds their accretion outbursts. We do not identify any companions to V1515 Cyg or HBC 722, but we do resolve a close binary companion to V1057 Cyg that is at the diffraction limit (ρ =58.3+/- 1.4 mas or 30 ± 5 au) and currently much fainter than the outbursting star ({{Δ }}K\\prime =3.34+/- 0.10 mag). Given the flux excess of the outbursting star, we estimate that the mass of the companion (M˜ 0.25{M}⊙ ) is similar to or slightly below that of the FUor itself, and therefore it resembles a typical T Tauri binary system. Our observations only achieve contrast limits of {{Δ }}K\\prime ˜ 4 mag, and hence we are only sensitive to companions that were near or above the pre-outburst luminosity of the FUors. It remains plausible that FUor outbursts could be tied to the presence of a close binary companion. However, we argue from the system geometry and mass reservoir considerations that these outbursts are not directly tied to the orbital period (i.e., occurring at periastron passage), but instead must only occur infrequently.

  2. DARPA/TTO program IR binary optics

    NASA Astrophysics Data System (ADS)

    Veldkamp, W. B.

    1984-06-01

    Binary grating optics consist of microfine rectangular (high-low) relief patterns on a dielectric or a metallic surface. By controlling the depth, width and periodicity of the binary pattern, the amplitude and the phase of an electromagnetic wave can be controlled to produce a variety of optical transfer functions. The lithographic tools for fabrication of binary optics are the ones developed for VLSI circuit fabrication. From a single lithographic mask, planar replica optics can be made in quantity. This technology has broad applicability for tactical missile systems as well as for space systems. In addition to making optics cheaper than by conventional means, binary optics allows the fabrication of unique devices that cannot be made conventionally. These include high-speed rotary scanners, multiplexers, filters, beam shapers and coherent laser adders. The goal of this program is the development of high quality planar optical components using VLSI circuit fabrication techniques. The main elements of the plan are: (1) the development of large aperture segmented and piezoelectrically active planar optical surfaces, (2) the development of raster scanning laser telescopes and extension to broadband applications, and (3) the application of diffractive optics technology to the coherent addition of beams from modular laser systems. This report covers progress in the setup of a reactive ion-beam etching laboratory, and the feasibility demonstrations of the coherent beam addition concept with gas lasers.

  3. Design of neurocomputer with binary memory array

    SciTech Connect

    Dyabin, M.I.; Karpinskii, N.G.; Kussul`, E.M.

    1995-03-01

    A neurocomputer using standard domestic integrated circuits and based on autoassociative memory with binary synapse weights is under development. A pattern-recognition algorithm is presented that can be implemented in the neurocomputer. The operating principle of the neurocomputer is described. Performance characteristics, including estimates of learning and recognition times, are presented.

  4. The Binary Temperature-Composition Phase Diagram

    ERIC Educational Resources Information Center

    Sanders, Philip C.; Reeves, James H.; Messina, Michael

    2006-01-01

    The equations for the liquid and gas lines in the binary temperature-composition phase diagram are derived by approximating that delta(H)[subscript vap] of the two liquids are equal. It is shown that within this approximation, the resulting equations are not too difficult to present in an undergraduate physical chemistry lecture.

  5. What's Next? Judging Sequences of Binary Events

    ERIC Educational Resources Information Center

    Oskarsson, An T.; Van Boven, Leaf; McClelland, Gary H.; Hastie, Reid

    2009-01-01

    The authors review research on judgments of random and nonrandom sequences involving binary events with a focus on studies documenting gambler's fallacy and hot hand beliefs. The domains of judgment include random devices, births, lotteries, sports performances, stock prices, and others. After discussing existing theories of sequence judgments,…

  6. A Binary Teetering on the Edge

    NASA Astrophysics Data System (ADS)

    Motl, P. M.; D'Souza, M. C. R.; Tohline, J. E.; Frank, J.

    2005-05-01

    We present a fully three-dimensional hydrodynamical simulation of Roche lobe overflow in a binary near the stability boundary. This boundary separates evolutionary branches that correspond to either an accelerating mass transfer rate leading eventually to merger through tidal instability or to a decaying mass transfer rate as the orbit expands. The binary begins with a mass ratio of 0.4 (ratio of donor to accretor mass) and is initially assumed to be rotating synchronously. We treat the stellar components as simple polytropic fluids characterized by a polytropic index, n = 3/2. As the donor overflows its Roche lobe, the mass transfer rate initially accelerates before stabilizing and eventually dropping over a timescale of tens of orbits. We also note that for this particular binary, the accretion stream impacts on the surface of the donor rather than forming an accretion disk. This simulation allows us to measure the efficiency with which the accretion stream spins up the accretor in this "direct impact" scenario and the degree to which angular momentum is transfered back to the binary orbit via the tidal field.

  7. Acceleration by pulsar winds in binary systems

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Gaisser, T. K.

    1990-01-01

    In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation and the spin-down power will drive a wind of relativistic electron-positron pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. The authors investigate the possibility of particle acceleration at such a pulsar wind shock and the production of very high energy (VHE) and ultra high energy (UHE) gamma rays from interactions of accelerated protons in the companion star's wind or atmosphere. They find that in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma rays. The authors discuss the application of the pulsar wind model to binary sources such as Cygnus X-3, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems.

  8. A binary main-belt comet

    NASA Astrophysics Data System (ADS)

    Agarwal, Jessica; Jewitt, David; Mutchler, Max; Weaver, Harold; Larson, Stephen

    2017-09-01

    Asteroids are primitive Solar System bodies that evolve both collisionally and through disruptions arising from rapid rotation. These processes can lead to the formation of binary asteroids and to the release of dust, both directly and, in some cases, through uncovering frozen volatiles. In a subset of the asteroids called main-belt comets, the sublimation of excavated volatiles causes transient comet-like activity. Torques exerted by sublimation measurably influence the spin rates of active comets and might lead to the splitting of bilobate comet nuclei. The kilometre-sized main-belt asteroid 288P (300163) showed activity for several months around its perihelion 2011 (ref. 11), suspected to be sustained by the sublimation of water ice and supported by rapid rotation, while at least one component rotates slowly with a period of 16 hours (ref. 14). The object 288P is part of a young family of at least 11 asteroids that formed from a precursor about 10 kilometres in diameter during a shattering collision 7.5 million years ago. Here we report that 288P is a binary main-belt comet. It is different from the known asteroid binaries in its combination of wide separation, near-equal component size, high eccentricity and comet-like activity. The observations also provide strong support for sublimation as the driver of activity in 288P and show that sublimation torques may play an important part in binary orbit evolution.

  9. Flip-flopping binary black holes.

    PubMed

    Lousto, Carlos O; Healy, James

    2015-04-10

    We study binary spinning black holes to display the long term individual spin dynamics. We perform a full numerical simulation starting at an initial proper separation of d≈25M between equal mass holes and evolve them down to merger for nearly 48 orbits, 3 precession cycles, and half of a flip-flop cycle. The simulation lasts for t=20 000M and displays a total change in the orientation of the spin of one of the black holes from an initial alignment with the orbital angular momentum to a complete antialignment after half of a flip-flop cycle. We compare this evolution with an integration of the 3.5 post-Newtonian equations of motion and spin evolution to show that this process continuously flip flops the spin during the lifetime of the binary until merger. We also provide lower order analytic expressions for the maximum flip-flop angle and frequency. We discuss the effects this dynamics may have on spin growth in accreting binaries and on the observational consequences for galactic and supermassive binary black holes.

  10. Binary translation using peephole translation rules

    DOEpatents

    Bansal, Sorav; Aiken, Alex

    2010-05-04

    An efficient binary translator uses peephole translation rules to directly translate executable code from one instruction set to another. In a preferred embodiment, the translation rules are generated using superoptimization techniques that enable the translator to automatically learn translation rules for translating code from the source to target instruction set architecture.

  11. EUV spectroscopy of 3 RSCVn binaries

    NASA Technical Reports Server (NTRS)

    Dupree, A. K.; Brickhouse, Nancy S.; Hanson, G. J.

    1995-01-01

    The extreme ultraviolet (EUV) spectroscopy of several binary stars containing cool components is used to define the high temperature plasma structure of these stars and their stellar atmospheres. Different line emission spectra are reported, along with a spectrum analysis of Capella, a nearby bright multiple star system, using data from the EUVE satellite.

  12. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, Rosanne; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    This grant was for the study of Luminous Supersoft X-Ray Sources (SSSs). During the first year a number of projects were completed and new projects were started. The projects include: 1) Time variability of SSSs 2) SSSs in M31; 3) Binary evolution scenarios; and 4) Acquiring new data.

  13. Photometric binary stars in Praesepe and the search for globular cluster binaries

    NASA Technical Reports Server (NTRS)

    Bolte, Michael

    1991-01-01

    A radial velocity study of the stars which are located on a second sequence above the single-star zero-age main sequence at a given color in the color-magnitude diagram of the open cluster Praesepe, (NGC 2632) shows that 10, and possibly 11, of 17 are binary systems. Of the binary systems, five have full amplitudes for their velocity variations that are greater than 50 km/s. To the extent that they can be applied to globular clusters, these results suggests that (1) observations of 'second-sequence' stars in globular clusters would be an efficient way of finding main-sequence binary systems in globulars, and (2) current instrumentation on large telescopes is sufficient for establishing unambiguously the existence of main-sequence binary systems in nearby globular clusters.

  14. Merging Galaxies Create a Binary Quasar

    NASA Astrophysics Data System (ADS)

    2010-02-01

    Astronomers have found the first clear evidence of a binary quasar within a pair of actively merging galaxies. Quasars are the extremely bright centers of galaxies surrounding super-massive black holes, and binary quasars are pairs of quasars bound together by gravity. Binary quasars, like other quasars, are thought to be the product of galaxy mergers. Until now, however, binary quasars have not been seen in galaxies that are unambiguously in the act of merging. But images of a new binary quasar from the Carnegie Institution's Magellan telescope in Chile show two distinct galaxies with "tails" produced by tidal forces from their mutual gravitational attraction. "This is really the first case in which you see two separate galaxies, both with quasars, that are clearly interacting," says Carnegie astronomer John Mulchaey who made observations crucial to understanding the galaxy merger. Most, if not all, large galaxies, such as our galaxy the Milky Way, host super-massive black holes at their centers. Because galaxies regularly interact and merge, astronomers have assumed that binary super-massive black holes have been common in the Universe, especially during its early history. Black holes can only be detected as quasars when they are actively accreting matter, a process that releases vast amounts of energy. A leading theory is that galaxy mergers trigger accretion, creating quasars in both galaxies. Because most such mergers would have happened in the distant past, binary quasars and their associated galaxies are very far away and therefore difficult for most telescopes to resolve. The binary quasar, labeled SDSS J1254+0846, was initially detected by the Sloan Digital Sky Survey, a large scale astronomical survey of galaxies and over 120,000 quasars. Further observations by Paul Green of the Harvard-Smithsonian Center for Astrophysics and colleagues* using NASA's Chandra's X-ray Observatory and telescopes at Kitt Peak National Observatory in Arizona and Palomar

  15. Parameter estimation of gravitational wave compact binary coalescences

    NASA Astrophysics Data System (ADS)

    Haster, Carl-Johan; LIGO Scientific Collaboration Collaboration

    2017-01-01

    The first detections of gravitational waves from coalescing binary black holes have allowed unprecedented inference on the astrophysical parameters of such binaries. Given recent updates in detector capabilities, gravitational wave model templates and data analysis techniques, in this talk I will describe the prospects of parameter estimation of compact binary coalescences during the second observation run of the LIGO-Virgo collaboration.

  16. Searching for Compact Binary Mergers with Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Nitz, Alexander` Harvey

    2017-06-01

    Several binary black hole mergers were discovered during Advanced LIGOs first observing run, and LIGO is currently well into its second observing run. We will discuss the state of the art in searching for merger signals in LIGO data, and how this will aid in the detection of binary neutron star, neutron-star black hole, and binary black hole mergers.

  17. Beyond the Binary: Dexterous Teaching and Knowing in Mathematics Education

    ERIC Educational Resources Information Center

    Adam, Raoul; Chigeza, Philemon

    2015-01-01

    This paper identifies binary oppositions in the discourse of mathematics education and introduces a binary-epistemic model for (re)conceptualising these oppositions and the epistemic-pedagogic problems they represent. The model is attentive to the contextual relationships between pedagogically relevant binaries (e.g., traditional/progressive,…

  18. Rapid method for interconversion of binary and decimal numbers

    NASA Technical Reports Server (NTRS)

    Lim, R. S.

    1970-01-01

    Decoding tree consisting of 40-bit semiconductor read-only memories interconverts binary and decimal numbers 50 to 100 times faster than current methods. Decimal-to-binary conversion algorithm is based on a divided-by-2 iterative equation, binary-to-decimal conversion algorithm utilizes multiplied-by-2 iterative equation.

  19. The Formation of Contact and Very Close Binaries

    SciTech Connect

    Kisseleva-Eggleton, L; Eggleton, P P

    2007-08-10

    We explore the possibility that all close binaries, i.e. those with periods {approx}< 3 d, including contact (W UMa) binaries, are produced from initially wider binaries (periods of say 10's of days) by the action of a triple companion through the medium of Kozai Cycles with Tidal Friction (KCTF).

  20. Numerical study of N = 4 binary-binary scatterings in a background potential

    NASA Astrophysics Data System (ADS)

    Ryu, Taeho; Leigh, Nathan W. C.; Perna, Rosalba

    2017-06-01

    We perform a large suite of (N = 4) numerical scattering experiments between two identical binaries consisting of identical point particles in a (continuous) background potential. For investigative purposes, we assume a uniform (natal or star-forming) gas medium. We explore a range of constant gas densities, from n = 10 cm-3 to 105 cm-3. These densities are relevant for various astrophysical environments, including star-forming molecular clouds and denser, fragmented cores within these clouds. Our primary goal is to characterize the effects of the background potential on the subsequent stellar dynamics. We consider the outcome probabilities and the properties of any binaries formed during the binary-binary encounters, such as the distributions of binary binding energies and eccentricities. We also present the final velocity distributions of the ejected single stars. The background potential has two important effects on the stellar dynamics: (1) the potential acts to reset the zero-point of the total system energy, which affects the types and properties of the products of the encounter; (2) for higher n and weakly bound systems (i.e. large semimajor axes), the stellar dynamics are significantly affected when stars are trapped in the potential, oscillating around the system centre of mass (CM). This, in turn, increases the number of scattering events between stars (single, binary or triple) near the CM and makes it harder for single stars to escape to infinity. This ultimately leads to the preferential ionization of triples and wide binaries and the survival of compact binaries, with the single stars escaping at very high ejection velocities.

  1. Significance testing for correlated binary outcome data.

    PubMed

    Rosner, B; Milton, R C

    1988-06-01

    Multiple logistic regression is a commonly used multivariate technique for analyzing data with a binary outcome. One assumption needed for this method of analysis is the independence of outcome for all sample points in a data set. In ophthalmologic data and other types of correlated binary data, this assumption is often grossly violated and the validity of the technique becomes an issue. A technique has been developed (Rosner, 1984) that utilizes a polychotomous logistic regression model to allow one to look at multiple exposure variables in the context of a correlated binary data structure. This model is an extension of the beta-binomial model, which has been widely used to model correlated binary data when no covariates are present. In this paper, a relationship is developed between the two techniques, whereby it is shown that use of ordinary logistic regression in the presence of correlated binary data can result in true significance levels that are considerably larger than nominal levels in frequently encountered situations. This relationship is explored in detail in the case of a single dichotomous exposure variable. In this case, the appropriate test statistic can be expressed as an adjusted chi-square statistic based on the 2 X 2 contingency table relating exposure to outcome. The test statistic is easily computed as a function of the ordinary chi-square statistic and the correlation between eyes (or more generally between cluster members) for outcome and exposure, respectively. This generalizes some previous results obtained by Koval and Donner (1987, in Festschrift for V. M. Joshi, I. B. MacNeill (ed.), Vol. V, 199-224.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. The Binary White Dwarf LHS 3236

    NASA Astrophysics Data System (ADS)

    Harris, Hugh C.; Dahn, Conard C.; Dupuy, Trent J.; Canzian, Blaise; Guetter, Harry H.; Hartkopf, William I.; Ireland, Michael J.; Leggett, S. K.; Levine, Stephen E.; Liu, Michael C.; Luginbuhl, Christian B.; Monet, Alice K. B.; Stone, Ronald C.; Subasavage, John P.; Tilleman, Trudy; Walker, Richard L.

    2013-12-01

    The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 ± 0.25 pc and a tangential velocity of 98 km s-1, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0 yr period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M ⊙ also possible is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M ⊙. In either case, the cooling ages of the stars are ~3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66-1.84 M ⊙) is well above the Chandrasekhar limit; however, the timescale for coalescence is long. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  3. THE COEVALITY OF YOUNG BINARY SYSTEMS

    SciTech Connect

    Kraus, Adam L.; Hillenbrand, Lynne A.

    2009-10-10

    Multiple star systems are commonly assumed to form coevally; they thus provide the anchor for most calibrations of stellar evolutionary models. In this paper, we study the binary population of the Taurus-Auriga association, using the component positions in an HR diagram in order to quantify the frequency and degree of coevality in young binary systems. After identifying and rejecting the systems that are known to be affected by systematic errors (due to further multiplicity or obscuration by circumstellar material), we find that the relative binary ages, |DELTAlog tau|, have an overall dispersion sigma{sub |D}ELTA{sub logt}au{sub |}approx 0.40 dex. Random pairs of Taurus members are coeval only to within sigma{sub |D}ELTA{sub logt}au{sub |}approx 0.58 dex, indicating that Taurus binaries are indeed more coeval than the association as a whole. However, the distribution of |DELTAlog tau| suggests two populations, with approx2/3 of the sample appearing coeval to within the errors (sigma{sub |D}ELTA{sub logt}au{sub |}approx 0.16 dex) and the other approx1/3 distributed in an extended tail reaching |DELTAlog tau|approx 0.4-0.9 dex. To explain the finding of a multipeaked distribution, we suggest that the tail of the differential age distribution includes unrecognized hierarchical multiples, stars seen in scattered light, or stars with disk contamination; additional follow-up is required to rule out or correct for these explanations. The relative coevality of binary systems does not depend significantly on the system mass, mass ratio, or separation. Indeed, any pair of Taurus members wider than approx10' (approx0.7 pc) shows the full age spread of the association.

  4. Session 9: Heber Geothermal Binary Demonstration Project

    SciTech Connect

    Allen, Richard F.; Nelson, Tiffany T.

    1983-12-01

    The Heber Binary Project had its beginning in studies performed for the Electric Power Research Institute (EPRI), which identified the need for commercial scale (50 Mw or larger) demonstration of the binary cycle technology. In late 1980, SDG&E and the Department of Energy (DOE) signed a Cooperative Agreement calling for DOE to share in 50 percent of the Project costs. Similarly, SDG&E signed Project participation agreements with EPRI, the Imperial Irrigation District, California Department of Water Resources, and Southern California Edison Company, which provided the remaining 50 percent of the required funding. In 1982, the State of California also joined the Project. The objectives of the Heber Binary Project are to demonstrate the potential of moderate-temperature (below 410 F) geothermal energy to produce economic electric power with binary cycle conversion technology, and to establish schedule, cost and equipment performance, reservoir performance, and the environmental acceptability of such plants. The plant will be the first large-scale power generating facility in the world utilizing the binary conversion process, and it is expected that information resulting from this Project will be applicable to a wide range of moderate-temperature hydrothermal reservoirs, which represent 80 percent of geothermal resources in the United States. To accomplish the plant engineering, design, and equipment procurement, SDG&E has hired Fluor Engineers, Inc., Power Division, of Irvine, California. In early 1982, SDG&E contracted for construction management services with Dravo Constructors, Inc. (DCI) of New York. DCI is responsible for casting the Fluor design into construction packages, letting the construction contracts, and overseeing the construction in the field.

  5. Template bank for gravitational waveforms from coalescing binary black holes: Nonspinning binaries

    SciTech Connect

    Ajith, P.; Hewitson, M.; Babak, S.; Chen, Y.; Krishnan, B.; Whelan, J. T.; Dorband, N.; Pollney, D.; Rezzolla, L.; Sintes, A. M.; Bruegmann, B.; Hannam, M.; Husa, S.; Sperhake, U.; Diener, P.; Gonzalez, J.; Santamaria, L.; Thornburg, J.

    2008-05-15

    Gravitational waveforms from the inspiral and ring-down stages of the binary black-hole coalescences can be modeled accurately by approximation/perturbation techniques in general relativity. Recent progress in numerical relativity has enabled us to model also the nonperturbative merger phase of the binary black-hole coalescence problem. This enables us to coherently search for all three stages of the coalescence of nonspinning binary black holes using a single template bank. Taking our motivation from these results, we propose a family of template waveforms which can model the inspiral, merger, and ring-down stages of the coalescence of nonspinning binary black holes that follow quasicircular inspiral. This two-dimensional template family is explicitly parametrized by the physical parameters of the binary. We show that the template family is not only effectual in detecting the signals from black-hole coalescences, but also faithful in estimating the parameters of the binary. We compare the sensitivity of a search (in the context of different ground-based interferometers) using all three stages of the black-hole coalescence with other template-based searches which look for individual stages separately. We find that the proposed search is significantly more sensitive than other template-based searches for a substantial mass range, potentially bringing about remarkable improvement in the event rate of ground-based interferometers. As part of this work, we also prescribe a general procedure to construct interpolated template banks using nonspinning black-hole waveforms produced by numerical relativity.

  6. Binary-disk interaction. II. Gap-opening criteria for unequal-mass binaries

    SciTech Connect

    Del Valle, Luciano; Escala, Andrés

    2014-01-01

    We study the interaction of an unequal-mass binary with an isothermal circumbinary disk, motivated by the theoretical and observational evidence that after a major merger of gas-rich galaxies, a massive gaseous disk with a supermassive black hole binary will be formed in the nuclear region. We focus on the gravitational torques that the binary exerts on the disk and how these torques can drive the formation of a gap in the disk. This exchange of angular momentum between the binary and the disk is mainly driven by the gravitational interaction between the binary and a strong nonaxisymmetric density perturbation that is produced in the disk, in response to the presence of the binary. Using smoothed particle hydrodynamics numerical simulations, we test two gap-opening criteria, one that assumes the geometry of the density perturbation is an ellipsoid/thick spiral and another that assumes a flat spiral geometry for the density perturbation. We find that the flat spiral gap-opening criterion successfully predicts which simulations will have a gap in the disk and which will not. We also study the limiting cases predicted by the gap-opening criteria. Since the viscosity in our simulations is considerably smaller than the expected value in the nuclear regions of gas-rich merging galaxies, we conclude that in such environments the formation of a circumbinary gap is unlikely.

  7. Planetary Formation and Dynamics in Binary Systems

    NASA Astrophysics Data System (ADS)

    Xie, J. W.

    2013-01-01

    As of today, over 500 exoplanets have been detected since the first exoplanet was discovered around a solar-like star in 1995. The planets in binaries could be common as stars are usually born in binary or multiple star systems. Although current observations show that the planet host rate in multiple star systems is around 17%, this fraction should be considered as a lower limit because of noticeable selection effects against binaries in planet searches. Most of the current known planet-bearing binary systems are S-types, meaning the companion star acts as a distant satellite, typically orbiting the inner star-planet system over 100 AU away. Nevertheless, there are four systems with a smaller separation of 20 AU, including the Gamma Cephei, GJ 86, HD 41004, and HD 196885. In addition to the planets in circumprimary (S-type) orbits discussed above, planets in circumbinary (P-type) orbits have been found in only two systems. In this thesis, we mainly study the planet formation in the S-type binary systems. In chapter 1, we first summarize current observational facts of exoplanets both in single-star and binary systems, then review the theoretical models of planet formation, with special attention to the application in binary systems. Perturbative effects from stellar companions render the planet formation process in binary systems even more complex than that in single-star systems. The perturbations from a binary companion can excite planetesimal orbits, and increase their mutual impact velocities to the values that might exceed their escape velocity or even the critical velocity for the onset of eroding collisions. The intermediate stage of the formation process---from planetesimals to planetary embryos---is thus the most problematic. In the following chapters, we investigate whether and how the planet formation goes through such a problematic stage. In chapter 2, we study the effects of gas dissipation on the planetesimals' mutual accretion. We find that in a

  8. How I Learned to Stop Worrying and Love Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Moe, Maxwell Cassady

    Relatively massive B-type stars with closely orbiting stellar companions can evolve to produce Type Ia supernovae, X-ray binaries, millisecond pulsars, mergers of neutron stars, gamma ray bursts, and sources of gravitational waves. However, the formation mechanism, intrinsic frequency, and evolutionary processes of B-type binaries are poorly understood. As of 2012, the binary statistics of massive stars had not been measured at low metallicities, extreme mass ratios, or intermediate orbital periods. This thesis utilizes large data sets of eclipsing binaries to measure the physical properties of B-type binaries in these previously unexplored portions of the parameter space. The updated binary statistics provide invaluable insight into the formation of massive stars and binaries as well as reliable initial conditions for population synthesis studies of binary star evolution. We first compare the properties of B-type eclipsing binaries in our Milky Way Galaxy and the nearby Magellanic Cloud Galaxies. We model the eclipsing binary light curves and perform detailed Monte Carlo simulations to recover the intrinsic properties and distributions of the close binary population. We find the frequency, period distribution, and mass-ratio distribution of close B-type binaries do not significantly depend on metallicity or environment. These results indicate the formation of massive binaries are relatively insensitive to their chemical abundances or immediate surroundings. Second, we search for low-mass eclipsing companions to massive B-type stars in the Large Magellanic Cloud Galaxy. In addition to finding such extreme mass-ratio binaries, we serendipitously discover a new class of eclipsing binaries. Each system comprises a massive B-type star that is fully formed and a nascent low-mass companion that is still contracting toward its normal phase of evolution. The large low-mass secondaries discernibly reflect much of the light they intercept from the hot B-type stars, thereby

  9. Some (Apparently) Very Wide Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Stephens, Robert D.

    2016-10-01

    We present lightcurves for some of the approximately one dozen asteroids that appear to be very widely-separated binaries. Jacobsen et al. (2014, ApJ 780) attribute their formation to a somewhat complex series of events involving BYORP.The lightcurves consist of two components: Period 1 (P1) is very long, P1 = 50-600 h, with amplitudes of A1 = 0.23-1.0 mag. The second period and amplitudes are similar to the primaries of close binary systems, i.e., P2 = 2.2-3.6 h, A2 ~ 0.10 mag. Two candidates have secondary periods in the range of 5-7 hours. The most exceptional example is (19204) Joshuatree, which has values of P1 = 480 h, A1 = 0.25 mag and P2 = 21.25 h, A2 = 0.08 mag. Based on Jacobson et al. (2014, ApJ 780) and Pravec et al. (2016, Icarus 267), we suggest that P1 represents the primary (larger) body of the system and P2 represents the spin rate of the satellite.Supporting this supposition is that the large amplitude (A1) must be from the larger body, otherwise the dilution of amplitude would require the smaller body to be unreasonably elongate. The limiting size ratio for binaries is around 0.6 (see Pravec et al. 2010, Nature 466, Fig. 1), or a magnitude difference of about 1.0. For a secondary 1.0 mag fainter than the primary to produce a combined lightcurve amplitude of ~0.4 mag would require that the secondary undiluted amplitude to be several magnitudes (near-infinite elongation) and also a near equatorial aspect. This is not likely.Given the lack of mutual events, these can be considered to be only possible binaries. Since the orbital period is probably very long, it seems extremely unlikely that mutual events will ever be seen.The changing landscape of binary asteroid discoveries and theories calls for something beyond descriptive terms such as "suspicious", "possible", "likely", and "confirmed" in order to allow more accurate statistical studies. To this end, we are introducing a new "B" rating in the asteroid lightcurve database (Warner et al., 2009

  10. Binary AGB stars observed with Herschel

    NASA Astrophysics Data System (ADS)

    Kornfeld, Klaus

    2012-03-01

    Asymptotic Giant Branch stars are stars at the end of their lifetime with low to intermediate masses. They are important in the Galactic context, since they contribute a lot of dust to the interstellar medium (ISM) and influence the chemical evolution of the Galaxy. Many AGB stars show peculiar outflow morphologies depending on their mass-loss rates. The outflowing wind of these stars collides with the surrounding interstellar medium (ISM). The collisions with the ISM result in the formation of bow shocks or rings, well visible in the latest Herschel Space Observatory images made with the on-board PACS instrument. Kelvin-Helmholtz and Rayleight-Taylor instabilities were found in the bow shock regions. With the help of Herschel and within the framework of the MESS (Mass loss of Evolved StarS) Guaranteed Time Key Program it was tried to distinguish between the different morphologies. The outflow morphologies were categorized in 4 main classes: "fermata", "eye", "ring", and "irregular"; also point sources showing no resolved circumstellar envelopes (CSEs) were found. Some of the AGB stars in the MESS sample are known binary stars and the binary state of some other objects is still in discussion. A new attempt to clarify the binarity of the objects can be made by checking their outflow morphology and to compare the results with known morphological (a-)symmetries in binary systems. This Thesis discusses 14 binary AGB candidates from the MESS sample, the previous findings and the Herschel results. Herschel observes at infrared wavelengths. Light at this wavelengths can be seen through the dust, which is formed in the surrounding environment of these stars. For the unknown cases it is difficult to determine the binary state, because AGB stars can have very strong wind outflows, making the detection of a companion difficult. Photo- and spectroscopy, CO line outflow measurements or composite spectra can be used to identify features caused directly o! r indirectly by the

  11. Rotating and Binary Stars in General Relativit

    NASA Astrophysics Data System (ADS)

    Shapiro, Stuart

    The inspiral and coalescence of compact binary stars is one of the most challenging problems in theoretical astrophysics. Only recently have advances in numerical relativity made it possible to explore this topic in full general relativity (GR). The mergers of compact binaries have important consequences for the detection of gravitational waves. In addition, the coalescence of binary neutron stars (NSNSs) and binary black-hole neutron stars (BHNSs) may hold the key for resolving other astrophysical puzzles, such as the origin of short-hard gamma-ray bursts (GRBs). While simulations of these systems in full GR are now possible, only the most idealized treatments have been performed to date. More detailed physics, including magnetic fields, black hole spin, a realistic hot, nuclear equation of state and neutrino transport must be incorporated. Only then will we be able to identify reliably future sources that may be detected simultaneously in gravitational waves and as GRBs. Likewise, the coalescence of binary black holes (BHBHs) is now a solved problem in GR, but only in vacuum. Simulating the coalescence of BHBHs in the gaseous environments likely to be found in nearby galaxy cores or in merging galaxies is crucial to identifying an electromagnetic signal that might accompany the gravitational waves produced during the merger. The coalescence of a binary white dwarf-neutron star (WDNS) has only recently been treated in GR, but GR is necessary to explore tidal disruption scenarios in which the capture of WD debris by the NS may lead to catastrophic collapse. Alternatively, the NS may survive and the merger might result in the formation of pulsar planets. The stability of rotating neutron stars in these and other systems has not been fully explored in GR, and the final fate of unstable stars has not been determined in many cases, especially in the presence of magnetic fields and differential rotation. These systems will be probed observationally by current NASA

  12. Accreting binary population synthesis and feedback prescriptions

    NASA Astrophysics Data System (ADS)

    Fragos, Tassos

    2016-04-01

    Studies of extagalactic X-ray binary populations have shown that the characteristics of these populations depend strongly on the characteristics of the host galaxy's parent stellar population (e.g. star-formation history and metallicity). These dependencies not only make X-ray binaries promising for aiding in the measurement of galaxy properties themselves, but they also have important astrophysical and cosmological implications. For example, due to the relatively young stellar ages and primordial metallicities in the early Universe (z > 3), it is predicted that X-ray binaries were more luminous than today. The more energetic X-ray photons, because of their long mean-free paths, can escape the galaxies where they are produced, and interact at long distances with the intergalactic medium. This could result in a smoother spatial distribution of ionized regions, and more importantly in an overall warmer intergalactic medium. The energetic X-ray photons emitted from X-ray binaries dominate the X-ray radiation field over active galactic nuclei at z > 6 - 8, and hence Χ-ray binary feedback can be a non-negligible contributor to the heating and reionization of the inter-galactic medium in the early universe. The spectral energy distribution shape of the XRB emission does not change significantly with redshift, suggesting that the same XRB subpopulation, namely black-hole XRBs in the high-soft state, dominates the cumulative emission at all times. On the contrary, the normalization of the spectral energy distribution does evolve with redshift. To zeroth order, this evolution is driven by the cosmic star-formation rate evolution. However, the metallicity evolution of the universe and the mean stellar population age are two important factors that affect the X-ray emission from high-mass and low-mass XRBs, respectively. In this talk, I will review recent studies on the potential feedback from accreting binary populations in galactic and cosmological scales. Furthermore, I

  13. Detectability of Gravitational Waves from High-Redshift Binaries.

    PubMed

    Rosado, Pablo A; Lasky, Paul D; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto

    2016-03-11

    Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳10^{10}M_{⊙} can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.

  14. THE ELM SURVEY. V. MERGING MASSIVE WHITE DWARF BINARIES

    SciTech Connect

    Brown, Warren R.; Kenyon, Scott J.; Kilic, Mukremin; Gianninas, A.; Allende Prieto, Carlos E-mail: skenyon@cfa.harvard.edu E-mail: alexg@nhn.ou.edu

    2013-05-20

    We present the discovery of 17 low-mass white dwarfs (WDs) in short-period (P {<=} 1 day) binaries. Our sample includes four objects with remarkable log g {approx_equal} 5 surface gravities and orbital solutions that require them to be double degenerate binaries. All of the lowest surface gravity WDs have metal lines in their spectra implying long gravitational settling times or ongoing accretion. Notably, six of the WDs in our sample have binary merger times <10 Gyr. Four have {approx}>0.9 M{sub Sun} companions. If the companions are massive WDs, these four binaries will evolve into stable mass transfer AM CVn systems and possibly explode as underluminous supernovae. If the companions are neutron stars, then these may be millisecond pulsar binaries. These discoveries increase the number of detached, double degenerate binaries in the ELM Survey to 54; 31 of these binaries will merge within a Hubble time.

  15. Detectability of Gravitational Waves from High-Redshift Binaries

    NASA Astrophysics Data System (ADS)

    Rosado, Pablo A.; Lasky, Paul D.; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto

    2016-03-01

    Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳1010M⊙ can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.

  16. Einstein observations of selected close binaries and shell stars

    NASA Technical Reports Server (NTRS)

    Guinan, E. F.; Koch, R. H.; Plavec, M. J.

    1984-01-01

    Several evolved close binaries and shell stars were observed with the IPC aboard the HEAO 2 Einstein Observatory. No eclipsing target was detected, and only two of the shell binaries were detected. It is argued that there is no substantial difference in L(X) for eclipsing and non-eclipsing binaries. The close binary and shell star CX Dra was detected as a moderately strong source, and the best interpretation is that the X-ray flux arises primarily from the corona of the cool member of the binary at about the level of Algol-like or RS CVn-type sources. The residual visible-band light curve of this binary has been modeled so as to conform as well as possible with this interpretation. HD 51480 was detected as a weak source. Substantial background information from IUE and ground scanner measurements are given for this binary. The positions and flux values of several accidentally detected sources are given.

  17. Binary interaction dominates the evolution of massive stars.

    PubMed

    Sana, H; de Mink, S E; de Koter, A; Langer, N; Evans, C J; Gieles, M; Gosset, E; Izzard, R G; Le Bouquin, J-B; Schneider, F R N

    2012-07-27

    The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.

  18. Evolution of binaries with compact objects in globular clusters

    NASA Astrophysics Data System (ADS)

    Ivanova, Natalia

    2016-02-01

    Dynamical interactions that take place between objects in dense stellar systems lead to frequent formation of exotic stellar objects, unusual binaries, and systems of higher multiplicity. They are most important for the formation of binaries with neutron stars and black holes, which are usually observationally revealed in mass-transferring binaries. Here we review the current understanding of compact object's retention, of the metallicity dependence on the formation of low-mass X-ray binaries with neutron stars, and how mass-transferring binaries with a black hole and a white dwarf can be formed. We discuss as well one old unsolved puzzle and two new puzzles posed by recent observations: what descendants do ultra-compact X-ray binaries produce, how are very compact triples formed, and how can black hole low-mass X-ray binaries acquire non-degenerate companions?

  19. ABSOLUTE PROPERTIES OF THE ECLIPSING BINARY STAR V335 SERPENTIS

    SciTech Connect

    Lacy, Claud H. Sandberg; Fekel, Francis C.; Claret, Antonio E-mail: fekel@evans.tsuniv.edu

    2012-08-15

    V335 Ser is now known to be an eccentric double-lined A1+A3 binary star with fairly deep (0.5 mag) partial eclipses. Previous studies of the system are improved with 7456 differential photometric observations from the URSA WebScope and 5666 from the NFO WebScope, and 67 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope. From dates of minima, the apsidal period is about 880 years. Accurate (better than 2%) masses and radii are determined from analysis of the two new light curves and the radial velocity curve. Theoretical models match the absolute properties of the stars at an age of about 380 Myr, though the age agreement for the two components is poor. Tidal theory correctly confirms that the orbit should still be eccentric, but we find that standard tidal theory is unable to match the observed asynchronous rotation rates of the components' surface layers.

  20. The state of globular clusters at birth - II. Primordial binaries

    NASA Astrophysics Data System (ADS)

    Leigh, Nathan W. C.; Giersz, Mirek; Marks, Michael; Webb, Jeremy J.; Hypki, Arkadiusz; Heinke, Craig O.; Kroupa, Pavel; Sills, Alison

    2015-01-01

    In this paper, we constrain the properties of primordial binary populations in Galactic globular clusters. Using the MOCCA Monte Carlo code for cluster evolution, our simulations cover three decades in present-day total cluster mass. Our results are compared to the observations of Milone et al. using the photometric binary populations as proxies for the true underlying distributions, in order to test the hypothesis that the data are consistent with a universal initial binary fraction near unity and the binary orbital parameter distributions of Kroupa. With the exception of a few possible outliers, we find that the data are to first-order consistent with the universality hypothesis. Specifically, the present-day binary fractions inside the half-mass radius can be reproduced assuming either high initial binary fractions near unity with a dominant soft binary component as in the Kroupa distribution combined with high initial densities (104-106 M⊙ pc-3), or low initial binary fractions (˜5-10 per cent) with a dominant hard binary component combined with moderate initial densities near their present-day values (102-103 M⊙ pc-3). This apparent degeneracy can potentially be broken using the binary fractions outside the half-mass radius - only high initial binary fractions with a significant soft component combined with high initial densities can reproduce the observed anticorrelation between the binary fractions outside the half-mass radius and the total cluster mass. We further illustrate using the simulated present-day binary orbital parameter distributions and the technique first introduced in Leigh et al. that the relative fractions of hard and soft binaries can be used to further constrain both the initial cluster density and the initial mass-density relation. Our results favour an initial mass-density relation of the form r_h ∝ M_clus^{α } with α < 1/3, corresponding to an initial correlation between cluster mass and density.

  1. Binary population synthesis and SNIa rates

    NASA Astrophysics Data System (ADS)

    Toonen, S.; Nelemans, G.; Bours, M.; Portegies Zwart, S.

    2013-01-01

    Despite the significance of type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. We investigate the potential contribution to the SNeIa rate from the most common progenitor channels using the binary population synthesis (BPS) code SeBa. Using SeBa, we aim constrain binary processes such as the common envelope phase and the efficiency of mass retention of white dwarf accretion. We find that the simulated rates are not sufficient to explain the observed rates. Further, we find that the mass retention efficiency of white dwarf accretion significantly influences the rates, but does not explain all the differences between simulated rates from different BPS codes.

  2. Formation of Binaries from Triple Systems

    PubMed Central

    Szebehely, Victor

    1972-01-01

    The dynamical behavior of three masses moving under their mutual gravitational attraction in a plane is investigated by a systematic series of numerical experiments. It is shown that in 73% of the cases, a triple system disintegrates in less than 150 time units (corresponding to about 150 crossing times), and a binary is formed with the third star that escapes at hyperbolic velocity. The average time for disintegration is of the order of 109 years for triple stellar systems, as well as for triple galaxies. The statistics of the escaping masses show that the escaping mass is usually, but not always, the smallest in the system. A simple equation, giving the balance between the negative energy stored in the binary and the positive energy necessary for escape, explains the results qualitatively. PMID:16591978

  3. Binary function of mRNA.

    PubMed

    Kloc, Malgorzata; Foreman, Victor; Reddy, Sriyutha A

    2011-11-01

    Since the discovery of messenger RNA (mRNA) over half a century ago, the assumption has always been that the only function of mRNA is to make a protein. However, recent studies of prokaryotic and eukaryotic organisms unexpectedly show that some mRNAs may be functionally binary and have additional structural functions that are unrelated to their translation product. These findings imply that some of the phenotypic features of cells and organisms can also be binary, that is, they depend both on the function of a protein and the independent structural function of its mRNA. In this review, we will discuss this concept within the framework of multifunctional RNA molecules and the RNA World Hypothesis. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  4. Binary Minor Planets V9.0

    NASA Astrophysics Data System (ADS)

    Johnston, W. R.

    2016-07-01

    The data set lists orbital and physical properties for well-observed or suspected binary/multiple minor planets including the Pluto system, compiled from the published literature as inspired by Richardson and Walsh (2006) and similar reviews (Merline et al., 2003; Noll, 2006; Pravec et al., 2006; Pravec and Harris, 2007; Descamps and Marchis, 2008; Noll et al., 2008; Walsh, 2009). In total 297 companions in 282 systems are included. Data are presented in three tables: one for orbital and physical properties; one for companion designations, discovery information, and reference codes for data values; and one giving full references for each reference code. This data set is complete for binary/multiple components reported through 31 March 2016.

  5. Sustained magnetic fields in binary millisecond pulsars

    NASA Astrophysics Data System (ADS)

    Chanmugam, G.; Brecher, K.

    1987-10-01

    It is proposed here that the magnetic fields of neutron stars do not decay either in binary millisecond pulsars (BMPs) or in general. This eliminates the severe discrepancy between the hypothesis that neutron stars in BMPs formed from the accretion-induced collapse of white dwarfs with shorter orbital periods and the observation that the fraction of pulsars which are BMPs is too large by a factor of over 100. It is also shown that, if such neutron stars are formed from the accretion-induced magnetic flux and an angular momentum-conserving collapse of white dwarfs, most of them are likely to have been born, and remain, spinning rapidly and to have weak magnetic fields, in agreement with observations of BMPs and low-mass X-ray binaries.

  6. Stellivore extraterrestrials? Binary stars as living systems

    NASA Astrophysics Data System (ADS)

    Vidal, Clément

    2016-11-01

    We lack signs of extraterrestrial intelligence (ETI) despite decades of observation in the whole electromagnetic spectrum. Could evidence be buried in existing data? To recognize ETI, we first propose criteria discerning life from non-life based on thermodynamics and living systems theory. Then we extrapolate civilizational development to both external and internal growth. Taken together, these two trends lead to an argument that some existing binary stars might actually be ETI. Since these hypothetical beings feed actively on stars, we call them "stellivores". I present an independent thermodynamic argument for their existence, with a metabolic interpretation of interacting binary stars. The jury is still out, but the hypothesis is empirically testable with existing astrophysical data.

  7. Very massive binaries in R 136

    NASA Astrophysics Data System (ADS)

    Chené, André-Nicolas; Schnurr, Olivier; Crowther, Paul A.; Fernández-Lajús, Eduardo; Moffat, Anthony F. J.

    2011-07-01

    As recent observations have shown, luminous, hydrogen-rich WN5-7h stars (and their somewhat less extreme cousins, O3f/WN6 stars) are the most massive main-sequence stars known. However, not nearly enough very massive stars have been reliably weighed to yield a clear picture of the upper initial-mass function (IMF). We therefore have carried out repeated high-quality spectroscopy of four new O3f/WN6 and WN5-7h binaries in R136 in the LMC with GMOS at Gemini-South, to derive Keplerian orbits for both components, respectively, and thus to directly determine their masses. We also monitored binary candidates and other, previously unsurveyed stars, to increase the number of very massive stars that can be directly weighed.

  8. Spin-Spin Coupling in Asteroidal Binaries

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin; Morbidelli, Alessandro

    2015-11-01

    Gravitationally bound binaries constitute a substantial fraction of the small body population of the solar system, and characterization of their rotational states is instrumental to understanding their formation and dynamical evolution. Unlike planets, numerous small bodies can maintain a perpetual aspheroidal shape, giving rise to a richer array of non-trivial gravitational dynamics. In this work, we explore the rotational evolution of triaxial satellites that orbit permanently deformed central objects, with specific emphasis on quadrupole-quadrupole interactions. Our analysis shows that in addition to conventional spin-orbit resonances, both prograde and retrograde spin-spin resonances naturally arise for closely orbiting, highly deformed bodies. Application of our results to the illustrative examples of (87) Sylvia and (216) Kleopatra multi-asteroid systems implies capture probabilities slightly below ~10% for leading-order spin-spin resonances. Cumulatively, our results suggest that spin-spin coupling may be consequential for highly elongated, tightly orbiting binary objects.

  9. Low cost paths to binary optics

    NASA Technical Reports Server (NTRS)

    Nelson, Arthur; Domash, Lawrence

    1993-01-01

    Application of binary optics has been limited to a few major laboratories because of the limited availability of fabrication facilities such as e-beam machines and the lack of standardized design software. Foster-Miller has attempted to identify low cost approaches to medium-resolution binary optics using readily available computer and fabrication tools, primarily for the use of students and experimenters in optical computing. An early version of our system, MacBEEP, made use of an optimized laser film recorder from the commercial typesetting industry with 10 micron resolution. This report is an update on our current efforts to design and build a second generation MacBEEP, which aims at 1 micron resolution and multiple phase levels. Trails included a low cost scanning electron microscope in microlithography mode, and alternative laser inscribers or photomask generators. Our current software approach is based on Mathematica and PostScript compatibility.

  10. Massive binaries in R136 using Hubble

    NASA Astrophysics Data System (ADS)

    Caballero-Nieves, Saida; Crowther, Paul; Bostroem, K. Azalee; Maíz Apellániz, Jesus

    2014-09-01

    We have undertaken a complete HST/STIS spectroscopic survey of R136, the young, central dense starburst cluster of the LMC 30 Doradus nebula, which hosts the most massive stars currently known. Our CCD datasets, comprising 17 adjacent 0.2"×52" long slits, were split across Cycles 19 and 20 to allow us to search for spectroscopic binaries. We will present the results of our survey, including a comparison with the massive-star population in the wider 30 Doradus region from the VLT Flames Tarantula survey. We will also describe upcoming HST/FGS observations, which will probe intermediate-separation binaries in R136, and discuss this cluster in the context of unresolved young extragalactic star clusters.

  11. Studies of Long Period Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Ratajczak, M.; Hełminiak, K. G.; Konacki, M.

    2015-07-01

    The survey of long period eclipsing binaries from the All Sky Automated Survey (ASAS) catalog aims at searching for and characterizing subgiants and red giants in double-lined detached binary systems. Absolute physical and orbital parameters are presented based on radial velocities from high-quality optical spectra obtained with the following telescope/instrument combinations: 8.2 m Subaru/HDS, ESO 3.6 m/HARPS, 1.9 m Radcliffe/GIRAFFE, CTIO 1.5 m/CHIRON, and 1.2 m Euler/CORALIE. Photometric data from ASAS, SuperWASP, and the Solaris Project were also used. We discuss the derived uncertainties for the individual masses and radii of the components (better than 3% for several systems), as well as results from the spectral analysis performed for components of systems whose spectra we disentangled.

  12. Automatic Spectral Classification of Unresolved Binary Stars

    NASA Astrophysics Data System (ADS)

    Weaver, W. B.

    2000-12-01

    An artificial neural network (ANN) technique has been developed to perform two-dimensional classification of the components of binary stars of any temperature or luminosity classifications. Using 15 Angstrom-resolution spectra, a single ANN can classify the unresolved components with an average accuracy of 2.5 subclasses in temperature and about 0.45 classes in luminostiy for up to 3 magnitudes difference in luminosity. The use of two ANNs, the first providing coarse classification while the second provides specialist classification, reduces the mean absolute errors to about 0.5 subclasses in temperature and 0.33 classes in luminosity. The system operates with no human intervention except initial wavelength registration and can classify about 20 binaries per second on a Pentium-class computer. This research was supported by the Friends of MIRA.

  13. X-Ray Background from Early Binaries

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    What impact did X-rays from the first binary star systems have on the universe around them? A new study suggests this radiation may have played an important role during the reionization of our universe.Ionizing the UniverseDuring the period of reionization, the universe reverted from being neutral (as it was during recombination, the previous period)to once again being ionized plasma a state it has remained in since then. This transition, which occurred between 150 million and one billion years after the Big Bang (redshift of 6 z 20), was caused by the formation of the first objects energetic enough to reionize the universes neutral hydrogen.ROSAT image of the soft X-ray background throughout the universe. The different colors represent different energy bands: 0.25 keV (red), 0.75 keV (green), 1.5 keV (blue). [NASA/ROSAT Project]Understanding this time period in particular, determining what sources caused the reionization, and what the properties were of the gas strewn throughout the universe during this time is necessary for us to be able to correctly interpret cosmological observations.Conveniently, the universe has provided us with an interesting clue: the large-scale, diffuse X-ray background we observe all around us. What produced these X-rays, and what impact did this radiation have on the intergalactic medium long ago?The First BinariesA team of scientists led by Hao Xu (UC San Diego) has suggested that the very first generation of stars might be an important contributor to these X-rays.This hypothetical first generation, Population III stars, are thought to have formed before and during reionization from large clouds of gas containing virtually no metals. Studies suggest that a large fraction of Pop III stars formed in binaries and when those stars ended their lives as black holes, ensuing accretion from their companions could produceX-ray radiation.The evolution with redshift of the mean X-ray background intensities. Each curve represents a different

  14. Gravity Darkening and Brightening in Binaries

    NASA Astrophysics Data System (ADS)

    White, Helen E.; Baumgarte, Thomas W.; Shapiro, Stuart L.

    2012-06-01

    We apply a von Zeipel gravity darkening model to corotating binaries to obtain a simple, analytical expression for the emergent radiative flux from a tidally distorted primary orbiting a point-mass secondary. We adopt a simple Roche model to determine the envelope structure of the primary, assumed massive and centrally condensed, and use the results to calculate the flux. As for single rotating stars, gravity darkening reduces the flux along the stellar equator of the primary, but, unlike for rotating stars, we find that gravity brightening enhances the flux in a region around the stellar poles. We identify a critical limiting separation beyond which hydrostatic equilibrium no longer is possible, whereby the flux vanishes at the point on the stellar equator of the primary facing the companion. For equal-mass binaries, the total luminosity is reduced by about 13% when this limiting separation is reached.

  15. GRAVITY DARKENING AND BRIGHTENING IN BINARIES

    SciTech Connect

    White, Helen E.; Baumgarte, Thomas W.; Shapiro, Stuart L.

    2012-06-20

    We apply a von Zeipel gravity darkening model to corotating binaries to obtain a simple, analytical expression for the emergent radiative flux from a tidally distorted primary orbiting a point-mass secondary. We adopt a simple Roche model to determine the envelope structure of the primary, assumed massive and centrally condensed, and use the results to calculate the flux. As for single rotating stars, gravity darkening reduces the flux along the stellar equator of the primary, but, unlike for rotating stars, we find that gravity brightening enhances the flux in a region around the stellar poles. We identify a critical limiting separation beyond which hydrostatic equilibrium no longer is possible, whereby the flux vanishes at the point on the stellar equator of the primary facing the companion. For equal-mass binaries, the total luminosity is reduced by about 13% when this limiting separation is reached.

  16. Hysteresis behavior of the binary Ising model

    NASA Astrophysics Data System (ADS)

    Akıncı, Ümit; Karakoyun, Gülşen

    2017-09-01

    Hysteresis behaviors of the binary alloy system represented by the formula AcB1-c have been investigated within the framework of EFT. The system consists of type A atoms (spin-1) with concentration c and type B atoms (spin-1/2) with concentration 1 - c . After giving the phase diagrams, we focused on the different type of hysteresis behaviors in the system. Especially, the mechanisms giving rise to double hysteresis behavior have been explained, which appear at large negative values of the crystal field and low temperatures. It has been observed that binary alloy system could exhibit DH behavior in region 0 < c < 0.557 . Besides, dependence of hysteresis loop area, coercive field and remanent magnetization on the concentration has been investigated.

  17. Multi-Planets in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Pilat-Lohinger, Elke; Haghighipour, Nader; Bazso, Akos

    2017-06-01

    Space missions like Cheops, Tess or Plato will explore the solar neighborhood when searching for other Earth-like worlds. Moreover, observations have shown that many stars build binary or multi-stellar systems which might influence the dynamical behavior of planets moving in such systems where gravitational interactions play an important role. Phenomena like mean motion resonances and secular resonances can be sources of both stability and instability and influence therefore the architecture of a planetary system significantly. In our solar system the two giant planets Jupiter and Saturn also influence the inner part of the planetary system. In this presentation we will show the dynamics of Jupiter-Saturn like configurations in binary stars and we analyse the changes in the dynamical behavior of the planets.

  18. Binary NS simulations using SpEC

    NASA Astrophysics Data System (ADS)

    Haas, Roland; Kaplan, Jeffrey; Ott, Christian; Szilagyi, Bela; Scheel, Mark; Moesta, Philipp; Duez, Matthew; Foucart, Francois

    2012-03-01

    NSNS binaries are expected to be one of the major sources of gravitational radiation detectable by Advanced LIGO. Together with neutrinos, gravitational waves are our only means to learn about the processes deep within a merging pair of NS, shedding light on the as yet poorly understood, equation of state governing matter at nuclear densities and beyond. We report on binary neutron star simulations using the Spectral Einstein Code (SpEC) developed by the Caltech-Cornell-CITA-WSU collaboration. We simulate the inspiral through many orbits, follow the post-merger evolution, and compute the full gravitational wave signal. We provide estimates on the accuracy required for the LIGO scientific goals of constraining EOS parameters.

  19. Binary NS simulations using SpEC

    NASA Astrophysics Data System (ADS)

    Haas, Roland; Kaplan, Jeffrey; Szilagyi, Bela; Muhlberger, Curran; Foucart, Francois; Lippuner, Jonas; Scheel, Mark; Duez, Matthew; Ott, Christian

    2013-04-01

    NSNS binaries are expected to be one of the major sources of gravitational radiation detectable by Advanced LIGO. Together with neutrinos, gravitational waves are our only means to learn about the processes deep within a merging pair of NS, shedding light on the as yet poorly understood, equation of state governing matter at nuclear densities and beyond. We report on binary neutron star simulations using the Spectral Einstein Code (SpEC) developed by the Caltech-Cornell-CITA-WSU collaboration. We simulate the inspiral through many orbits, follow the post-merger evolution, and compute the full gravitational wave signal. We provide estimates on the accuracy required for the LIGO scientific goals of constraining EOS parameters.

  20. Crystals of binary Lennard-Jones solids

    NASA Astrophysics Data System (ADS)

    Middleton, Thomas F.; Hernández-Rojas, Javier; Mortenson, Paul N.; Wales, David J.

    2001-11-01

    We present crystalline structures for 60-, 256-, and 320-atom supercells of binary Lennard-Jones solids. These structures, based on cubic close packing, are much lower in energy than the disordered structures usually considered for this model glass former. We present a disconnectivity graph for a database of minima and transition states for the 320-atom system, which has been simplified using a grouping technique based on the canonical rate constants.

  1. Gas-phase acidities of binary hydrides.

    NASA Technical Reports Server (NTRS)

    Brauman, J. I.; Eyler, J. R.; Blair, L. K.; White, M. J.; Comisarow, M. B.; Smyth, K. C.

    1971-01-01

    The preferred direction of proton transfer in a reaction between a hydride molecule and a hydride ion was studied in order to determine the relative acidities of some binary hydrides. Sufficient data are presented to make clear the periodic trends in acidities and the underlying trends in other fundamental thermochemical quantities which influence acidity. The bond dissociation energies and electron affinities of the hydrides considered are listed in a table.

  2. A Different Look at Cool Contact Binaries

    NASA Astrophysics Data System (ADS)

    Stȩpień, K.

    A brief history of the discovery of W UMa-type eclipsing variables, identified later as cool contact binaries is presented. Further, the main properties of these binaries are discussed and the thermal relaxation oscillation model (TRY) is presented. The model explains two main observational properties of W UMa type stars: the geometry of the binary and the eclipsing light curves. However, the TRO model was developed under the assumptions, some of which turned out to be incorrect. In addition, some of its predictions are not in agreement with observations. In reaction to these problems, a new evolutionary scenario, developed by the present author is presented. It assumes that W UMa-type stars are old objects which have passed the mass transfer episode with the mass ratio reversal. Their structure reminds the Algol-type stars, except that they have smaller angular momenta. The model is in good agreement with observations. The evolutionary model is supplemented by the energy transfer mechanism. It is shown that the lack of hydrostatic equilibrium in a common envelope of the contact binary results in a large-scale flow of matter from the more massive primary to the secondary. The stream matter has a higher entropy than the surface layers of the secondary, hence it flows atop of them. The Coriolis force keeps the flow close to the equator. The stream encircles the secondary and returns to the primary. Because the heat capacity of the stream matter is much larger than the energy, radiated away during the journey around the secondary, the stream temperature hardly decreases. In a stationary situation the stream blocks the core energy of the secondary, flowing beneath, but due to an inconsiderable modification of the convective zone this energy is radiated away by the polar regions, not covered by the stream. The model predicts very similar temperatures of the primary and secondary, in agreement with observations.

  3. Determining Binary Star Orbits Using Kepler's Equation

    NASA Astrophysics Data System (ADS)

    Boule, Cory; Andrews, Kaitlyn; Penfield, Andrew; Puckette, Ian; Goodale, Keith; Harfenist, Steven

    2017-04-01

    Students calculated ephemerides and generated orbits of four well-known binary systems. Using an iterative technique in Microsoft® Excel® to solve Kepler's equation, separation and position angle values were generated as well as plots of the apparent orbits. Current position angle and separation values were measured in the field and compared well to the calculated values for the stars: STF1196AB,C, STF296AB, STF296AB and STF60AB.

  4. Quasiperiodic Oscillations in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    van der Klis, M.; Murdin, P.

    2000-11-01

    The term quasiperiodic oscillation (QPO) is used in high-energy astrophysics for any type of non-periodic variability that is constrained to a relatively narrow range of variability frequencies. X-RAY BINARIES are systems in which a `compact object', either a BLACK HOLE or a NEUTRON STAR, orbits a normal star and captures matter from it. The matter spirals down to the compact object and heats up ...

  5. UV observations of x ray binaries

    NASA Technical Reports Server (NTRS)

    Raymond, John C.

    1990-01-01

    IUE (International Ultraviolet Explorer) has observed both high and low mass x ray binaries throughout its life. The UV spectra of high mass systems reveal the nature of the massive companion star and the effects of the x ray illumination of the stellar wind. In loss mass systems, the x ray illuminated disk or companion star dominates the UV light. System parameters and the characteristics of the accretion disk can be inferred.

  6. THIRTY NEW LOW-MASS SPECTROSCOPIC BINARIES

    SciTech Connect

    Shkolnik, Evgenya L.; Hebb, Leslie; Cameron, Andrew C.; Liu, Michael C.; Neill Reid, I. E-mail: Andrew.Cameron@st-and.ac.u E-mail: mliu@ifa.hawaii.ed

    2010-06-20

    As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity standard stars, we are sensitive to finding multi-lined spectroscopic binaries. We find a low-mass spectroscopic binary fraction of 16% consisting of 27 SB2s, 2 SB3s, and 1 SB4, increasing the number of known low-mass spectroscopic binaries (SBs) by 50% and proving that strong X-ray emission is an extremely efficient way to find M-dwarf SBs. WASP photometry of 23 of these systems revealed two low-mass eclipsing binaries (EBs), bringing the count of known M-dwarf EBs to 15. BD-22 5866, the ESB4, was fully described in 2008 by Shkolnik et al. and CCDM J04404+3127 B consists of two mid-M stars orbiting each other every 2.048 days. WASP also provided rotation periods for 12 systems, and in the cases where the synchronization time scales are short, we used P{sub rot} to determine the true orbital parameters. For those with no P{sub rot}, we used differential radial velocities to set upper limits on orbital periods and semimajor axes. More than half of our sample has near-equal-mass components (q > 0.8). This is expected since our sample is biased toward tight orbits where saturated X-ray emission is due to tidal spin-up rather than stellar youth. Increasing the samples of M-dwarf SBs and EBs is extremely valuable in setting constraints on current theories of stellar multiplicity and evolution scenarios for low-mass multiple systems.

  7. Parallel Analysis with Unidimensional Binary Data

    ERIC Educational Resources Information Center

    Weng, Li-Jen; Cheng, Chung-Ping

    2005-01-01

    The present simulation investigated the performance of parallel analysis for unidimensional binary data. Single-factor models with 8 and 20 indicators were examined, and sample size (50, 100, 200, 500, and 1,000), factor loading (.45, .70, and .90), response ratio on two categories (50/50, 60/40, 70/30, 80/20, and 90/10), and types of correlation…

  8. Automated pupil remapping with binary optics

    DOEpatents

    Neal, D.R.; Mansell, J.

    1999-01-26

    Methods and apparatuses are disclosed for pupil remapping employing non-standard lenslet shapes in arrays; divergence of lenslet focal spots from on-axis arrangements; use of lenslet arrays to resize two-dimensional inputs to the array; and use of lenslet arrays to map an aperture shape to a different detector shape. Applications include wavefront sensing, astronomical applications, optical interconnects, keylocks, and other binary optics and diffractive optics applications. 24 figs.

  9. Automated pupil remapping with binary optics

    DOEpatents

    Neal, Daniel R.; Mansell, Justin

    1999-01-01

    Methods and apparatuses for pupil remapping employing non-standard lenslet shapes in arrays; divergence of lenslet focal spots from on-axis arrangements; use of lenslet arrays to resize two-dimensional inputs to the array; and use of lenslet arrays to map an aperture shape to a different detector shape. Applications include wavefront sensing, astronomical applications, optical interconnects, keylocks, and other binary optics and diffractive optics applications.

  10. White dwarfs in Be star binary systems

    NASA Technical Reports Server (NTRS)

    Apparao, K. M. V.

    1991-01-01

    An evaluation is made of possible reasons for the persistent inability to identify white dwarf stars in the Be binary systems. It is noted that many Be stars exhibiting large optical enhancements may be Be + WD and Be + He systems, and that observations of pulsations in the H-alpha emission, as well as observation of time delays between enhancements of optical line and continuum, can identify such systems.

  11. Mergers of Black Hole -- Neutron Star Binaries

    NASA Astrophysics Data System (ADS)

    Rantsiou, Emmanouela

    Motivated by the scenario that black hole-neutron star (BH-NS) mergers are viable progenitors of observed short Gamma-ray Bursts, we have used a 3D relativistic SPH (smoothed particle hydrodynamics) code to study mergers of such binary systems (with relatively low mass ratios). We have investigated a wide range of parameters for those binaries: mass ratio, Equation of State (EOS) for the NS, compactness of the NS. Most importantly, the BH's spin was varied in our simulations (from non-spinning to maximally spinning BHs), and so was the orbital inclination of the NS. We have found that the outcome of such mergers depends sensitively on both the magnitude of the BH spin and its obliquity (i.e., the inclination of the binary orbit with respect to the equatorial plane of the BH). In particular, only systems with sufficiently high BH spin parameter a and sufficiently low orbital inclinations allow any NS matter to escape or to form a long-lived disk outside the BH horizon after disruption. Mergers of binaries with orbital inclinations above ˜60° lead to complete prompt accretion of the entire NS by the BH, even for the case of an extreme Kerr BH. We find that the formation of a significant disk or torus of NS material around the BH always requires a near-maximal BH spin and a low initial inclination of the NS orbit just prior to merger. Furthermore, we have investigated and we are presenting the gravitational waveforms and gravitational wave energy spectra from some representative cases. Despite using simply the quadrupole formula with post-Newtonian extensions (up to 3.5 terms) for radiation reaction, we were able to clearly see the impact of the BH's spin and NS's orbital inclination on the spectra and waveforms produced in our simulations.

  12. The Kepler Mission and Eclipsing Binaries

    DTIC Science & Technology

    2006-01-01

    Opportunities to Participate, 2005, in A Decade of Extrasolar Planets around Normal Stars (ed. M. Livio), Cambridge: Cambridge University Press, in...smaller planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected and light curves pro- duced...determine the component masses and thereby separate eclipses caused by stellar companions from transits caused by planets . The result will be a rich

  13. Speech Segregation based on Binary Classification

    DTIC Science & Technology

    2016-07-15

    Final performance report 3. DATES COVERED (From - To) 5/2012 - 4/2016 4. TITLE AND SUBTITLE Speech Segregation based on Binary Classification 5a...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) The Ohio State University Research Foundation 1960 Kenny...Road Columbus, OH 43210-1063 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) Dr. Patrick Bradshaw

  14. Alloy softening in binary iron solid solutions

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Witzke, W. R.

    1976-01-01

    An experimental study was conducted to determine whether alloy softening in Fe alloys is dependent on electron concentration and to provide a direct comparison of alloy softening and hardening in several binary Fe alloy systems having the same processing history. Alloy additions to Fe included the elements in the Periods 4-6 and the Groups IV-VIII with the exception of technetium. A total of 19 alloy systems was investigated, and hardness testing was the primary means of evaluation. Testing was carried out at four temperatures over a homologous temperature range of 0.043-0.227 times the absolute melting temperature of unalloyed Fe. Major conclusions are that the atomic radius ratio of solute-to-Fe is the key factor in controlling low-temperature hardness of the binary Fe alloys and that alloy softening rates at 77 K and alloy hardening rates at 411 K are correlated with this atomic radius ratio for 15 of the binary alloy systems. Mechanisms of alloy softening and hardening are proposed.

  15. On the binary expansions of algebraic numbers

    SciTech Connect

    Bailey, David H.; Borwein, Jonathan M.; Crandall, Richard E.; Pomerance, Carl

    2003-07-01

    Employing concepts from additive number theory, together with results on binary evaluations and partial series, we establish bounds on the density of 1's in the binary expansions of real algebraic numbers. A central result is that if a real y has algebraic degree D > 1, then the number {number_sign}(|y|, N) of 1-bits in the expansion of |y| through bit position N satisfies {number_sign}(|y|, N) > CN{sup 1/D} for a positive number C (depending on y) and sufficiently large N. This in itself establishes the transcendency of a class of reals {summation}{sub n{ge}0} 1/2{sup f(n)} where the integer-valued function f grows sufficiently fast; say, faster than any fixed power of n. By these methods we re-establish the transcendency of the Kempner--Mahler number {summation}{sub n{ge}0}1/2{sup 2{sup n}}, yet we can also handle numbers with a substantially denser occurrence of 1's. Though the number z = {summation}{sub n{ge}0}1/2{sup n{sup 2}} has too high a 1's density for application of our central result, we are able to invoke some rather intricate number-theoretical analysis and extended computations to reveal aspects of the binary structure of z{sup 2}.

  16. Circumstellar disks around binary stars in Taurus

    SciTech Connect

    Akeson, R. L.

    2014-03-20

    We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10{sup –4} M {sub ☉}. We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F{sub mm}∝M{sub ∗}{sup 1.5--2.0} to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

  17. Spinodal decomposition of chemically reactive binary mixtures

    NASA Astrophysics Data System (ADS)

    Lamorgese, A.; Mauri, R.

    2016-08-01

    We simulate the influence of a reversible isomerization reaction on the phase segregation process occurring after spinodal decomposition of a deeply quenched regular binary mixture, restricting attention to systems wherein material transport occurs solely by diffusion. Our theoretical approach follows a diffuse-interface model of partially miscible binary mixtures wherein the coupling between reaction and diffusion is addressed within the frame of nonequilibrium thermodynamics, leading to a linear dependence of the reaction rate on the chemical affinity. Ultimately, the rate for an elementary reaction depends on the local part of the chemical potential difference since reaction is an inherently local phenomenon. Based on two-dimensional simulation results, we express the competition between segregation and reaction as a function of the Damköhler number. For a phase-separating mixture with components having different physical properties, a skewed phase diagram leads, at large times, to a system converging to a single-phase equilibrium state, corresponding to the absolute minimum of the Gibbs free energy. This conclusion continues to hold for the critical phase separation of an ideally perfectly symmetric binary mixture, where the choice of final equilibrium state at large times depends on the initial mean concentration being slightly larger or less than the critical concentration.

  18. Stellar and Binary Evolution in Star Clusters

    NASA Technical Reports Server (NTRS)

    McMillan, Stephen L. W.

    2001-01-01

    This paper presents a final report on research activities covered on Stellar and Binary Evolution in Star Clusters. Substantial progress was made in the development and dissemination of the "Starlab" software environment. Significant improvements were made to "kira," an N-body simulation program tailored to the study of dense stellar systems such as star clusters and galactic nuclei. Key advances include (1) the inclusion of stellar and binary evolution in a self-consistent manner, (2) proper treatment of the anisotropic Galactic tidal field, (3) numerous technical enhancements in the treatment of binary dynamics and interactions, and (4) full support for the special-purpose GRAPE-4 hardware, boosting the program's performance by a factor of 10-100 over the accelerated version. The data-reduction and analysis tools in Starlab were also substantially expanded. A Starlab Web site (http://www.sns.ias.edu/-starlab) was created and developed. The site contains detailed information on the structure and function of the various tools that comprise the package, as well as download information, "how to" tips and examples of common operations, demonstration programs, animations, etc. All versions of the software are freely distributed to all interested users, along with detailed installation instructions.

  19. STELLAR BINARY COMPANIONS TO SUPERNOVA PROGENITORS

    SciTech Connect

    Kochanek, Christopher S.

    2009-12-20

    For typical models of binary statistics, 50%-80% of core-collapse supernova (ccSN) progenitors are members of a stellar binary at the time of the explosion. Independent of any consequences of mass transfer, this has observational consequences that can be used to study the binary properties of massive stars. In particular, the secondary companion to the progenitor of a Type Ib/c SN is frequently (approx50%) the more optically luminous star since the high effective temperatures of the stripped progenitors make it relatively easy for a lower luminosity, cooler secondary to emit more optical light. Secondaries to the lower mass progenitors of Type II SN will frequently produce excess blue emission relative to the spectral energy distribution of the red primary. Available data constrain the models weakly. Any detected secondaries also provide an independent lower bound on the progenitor mass and, for historical SN, show that it was not a Type Ia event. Bright ccSN secondaries have an unambiguous, post-explosion observational signature-strong, blueshifted, relatively broad absorption lines created by the developing SN remnant (SNR). These can be used to locate historical SN with bright secondaries, confirm that a source is a secondary, and, potentially, measure abundances of ccSN ejecta. Luminous, hot secondaries will re-ionize the SNR on timescales of 100-1000 yr that are faster than re-ionization by the reverse shock, creating peculiar H II regions due to the high metallicity and velocities of the ejecta.

  20. Phase equilibrium measurements on twelve binary mixtures

    SciTech Connect

    Giles, N.F.; Wilson, H.L.; Wilding, W.V.

    1996-11-01

    Phase equilibrium measurements have been performed on twelve binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following binary systems at two temperatures each: ethanethiol + propylene; nitrobenzene + methanol; pyridine + ethyl acetate; octane + tert-amyl methyl ether; diisopropyl ether + butane; 1,3-dichloro-2-propanol + epichlorohydrin; 2,3-dichloro-1-propanol + epichlorohydrin; 2,3-epoxy-1-propanol + epichlorohydrin; 3-chloro-1,2-propanediol + epichlorohydrin; methanol + hydrogen cyanide. For these systems, equilibrium vapor and liquid phase compositions were derived from the PTx data using the Soave equation of state to represent the vapor phase and the Wilson, NRTL, or Redlich-Kister activity coefficient model to represent the liquid phase. The infinite dilution activity coefficient of methylamine in N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone-rich half of the binary. Liquid-liquid equilibrium studies were made on the triethylene glycol + 1-pentene system at two temperatures by directly analyzing samples taken from each liquid phase.

  1. Modeling Selective Intergranular Oxidation of Binary Alloys

    SciTech Connect

    Xu, Zhijie; Li, Dongsheng; Schreiber, Daniel K.; Rosso, Kevin M.; Bruemmer, Stephen M.

    2015-01-07

    Intergranular attack of alloys under hydrothermal conditions is a complex problem that depends on metal and oxygen transport kinetics via solid-state and channel-like pathways to an advancing oxidation front. Experiments reveal very different rates of intergranular attack and minor element depletion distances ahead of the oxidation front for nickel-based binary alloys depending on the minor element. For example, a significant Cr depletion up to 9 µm ahead of grain boundary crack tips were documented for Ni-5Cr binary alloy, in contrast to relatively moderate Al depletion for Ni-5Al (~100s of nm). We present a mathematical kinetics model that adapts Wagner’s model for thick film growth to intergranular attack of binary alloys. The transport coefficients of elements O, Ni, Cr, and Al in bulk alloys and along grain boundaries were estimated from the literature. For planar surface oxidation, a critical concentration of the minor element can be determined from the model where the oxide of minor element becomes dominant over the major element. This generic model for simple grain boundary oxidation can predict oxidation penetration velocities and minor element depletion distances ahead of the advancing front that are comparable to experimental data. The significant distance of depletion of Cr in Ni-5Cr in contrast to the localized Al depletion in Ni-5Al can be explained by the model due to the combination of the relatively faster diffusion of Cr along the grain boundary and slower diffusion in bulk grains, relative to Al.

  2. High temperature structure in cool binary stars

    NASA Technical Reports Server (NTRS)

    Dupree, A. K.; Brickhouse, Nancy S.; Hanson, G. J.

    1995-01-01

    Strong high temperature emission lines in the EUVE spectra of binary stars containing cool components (Alpha Aur (Capella), 44 iota Boo, Lambda And, and VY Ari) provide the basis to define reliably the differential emission measure of hot plasma. The emission measure distributions for the short-period (P less than or equal to 13 d) binary systems show a high temperature enhancement over a relatively narrow temperature region similar to that originally found in Capella (Dupree et al. 1993). The emission measure distributions of rapidly rotating single stars 31 Com and AB Dor also contain a local enhancement of the emission measure although at different temperatures and width from Capella, suggesting that the enhancement in these objects may be characteristic of rapid rotation of a stellar corona. This feature might be identified with a (polar) active region, although its density and absolute size are unknown; in the binaries Capella and VY Ari, the feature is narrow and it may arise from an interaction region between the components.

  3. Transit Timing Variations In Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Sansone, Eric; Haghighipour, N.

    2012-01-01

    We present the results of a study of the effect of a stellar companion on the transit timing variations (TTV) of a planetary system. The purpose of our study is to determine the ranges of the orbital elements of a secondary star for which the amplitude of a currently existing TTV is enhanced. We chose the system of Kepler 9 as this system represents the first planetary system detected by the transit timing variation method, and studied its TTVs by considering a hypothetical secondary star in this system. By varying the mass, semi-major axis, and eccentricity of the fictitious binary companion, we tested the stability of the known planets Kepler-9c and Kepler-9b and identified the region of the parameter-space for which the binary planetary system would be stable. We calculated TTVs for the two planets of the system for different values of the orbital elements of the secondary star and calculated its difference with the system's already existing TTVs. Results of our study indicate that the effect of the binary companion is significant only when the secondary star is in a highly eccentric orbit and/or the planets of the system are within the range of Super-Earth or terrestrial sizes. This work was funded by the National Science Foundation in the form of a Research Experience for Undergraduates program at the University of Hawaii at Manoa.

  4. Winds of Massive, Main Sequence Close Binaries

    NASA Astrophysics Data System (ADS)

    Koch, R. H.; Pachoulakis, I.; Pfeiffer, R. J.; Stickland, D. J.

    1996-12-01

    We have undertaken a systematic study of the geometry, structure, and interactions of the stellar winds of massive, close binaries as evidenced by the N V, Si IV and C IV UV resonance lines in IUE spectra. Only binaries for which wind-contaminated light curves indicate conspicuous flows are analyzed. This contribution summarizes our results for HD 159176, Y Cyg, and CW Cep that have emerged from a two-step analysis: (a) A modified version of the SEI code is employed to calculate steady-state, composite-wind model line profiles for observed wind lines. The (modeled - observed) wind-line residuals contain evidence for photospheric and wind eclipses and for wind interactions. (b) These residuals are subsequently modeled by a binary wind interaction code for the purposes of disentangling the contributions from the individual interactions and for searching for colliding wind shock fronts. Iteration between these two steps ensures compatibility of the two parameter sets. As a result, the parameters describing the individual winds, density enhancements, and shocks are determined consistently.

  5. The X-ray binary, UW CMa

    NASA Technical Reports Server (NTRS)

    Heap, S. R.

    1982-01-01

    The UW CMa is a close, eclipsing binary composed of an O7f primary with a stron wind and a less luminous O-type companion. It was found that UW CMa a variable X-ray source, whose X-ray variations are in phase with its optical light curve. Since both components of the binary system are O stars, accretion by a compact object is ruled out as a mechanism for generating X-rays. The UW CMa represents a new class of X-ray binaries, in which X-rays result from the collision of a wind from one star with the surface or wind of the other star. It is hypothesised that the impact of a wind against a star generates a shock wave about 0.25 stellar radii above the stellar surface, and material behind the shock front, heated to bout 10 million degrees, radiates the X-ray apparent X-ray variability is due to its location between the two stars, where it undergoes eclipses. The high temperature region maintains an ionization cavity in the wind, as detected with IUE. The ionization cavity is the source of depletion of absorbing ions in the wind between the two stars.

  6. Detecting gravity waves from binary black holes

    NASA Technical Reports Server (NTRS)

    Wahlquist, Hugo D.

    1989-01-01

    One of the most attractive possible sources of strong gravitational waves would be a binary system comprising massive black holes (BH). The gravitational radiation from a binary is an elliptically polarized, periodic wave which could be observed continuously - or at intervals whenever a detector was available. This continuity of the signal is certainly appealing compared to waiting for individual pulses from infrequent random events. It also has the advantage over pulses that continued observation can increase the signal-to-noise ratio almost indefinitely. Furthermore, this system is dynamically simple; the theory of the generation of the radiation is unambiguous; all characteristics of the signal can be precisely related to the dynamical parameters of the source. The current situation is that while there is no observational evidence as yet for the existence of massive binary BH, their formation is theoretically plausible, and within certain coupled constraints of mass and location, their existence cannot be observationally excluded. Detecting gravitational waves from these objects might be the first observational proof of their existence.

  7. Accreting Binary Populations in the Earlier Universe

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann

    2010-01-01

    It is now understood that X-ray binaries dominate the hard X-ray emission from normal star-forming galaxies. Thanks to the deepest (2-4 Ms) Chandra surveys, such galaxies are now being studied in X-rays out to z approximates 4. Interesting X-ray stacking results (based on 30+ galaxies per redshift bin) suggest that the mean rest-frame 2-10 keV luminosity from z=3-4 Lyman break galaxies (LBGs), is comparable to the most powerful starburst galaxies in the local Universe. This result possibly indicates a similar production mechanism for accreting binaries over large cosmological timescales. To understand and constrain better the production of X-ray binaries in high-redshift LBGs, we have utilized XMM-Newton observations of a small sample of z approximates 0.1 GALEX-selected Ultraviolet-Luminous Galaxies (UVLGs); local analogs to high-redshift LBGs. Our observations enable us to study the X-ray emission from LBG-like galaxies on an individual basis, thus allowing us to constrain object-to-object variances in this population. We supplement these results with X-ray stacking constraints using the new 3.2 Ms Chandra Deep Field-South (completed spring 2010) and LBG candidates selected from HST, Swift UVOT, and ground-based data. These measurements provide new X-ray constraints that sample well the entire z=0-4 baseline

  8. Accreting Binary Populations in the Earlier Universe

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann

    2010-01-01

    It is now understood that X-ray binaries dominate the hard X-ray emission from normal star-forming galaxies. Thanks to the deepest (2-4 Ms) Chandra surveys, such galaxies are now being studied in X-rays out to z approximates 4. Interesting X-ray stacking results (based on 30+ galaxies per redshift bin) suggest that the mean rest-frame 2-10 keV luminosity from z=3-4 Lyman break galaxies (LBGs), is comparable to the most powerful starburst galaxies in the local Universe. This result possibly indicates a similar production mechanism for accreting binaries over large cosmological timescales. To understand and constrain better the production of X-ray binaries in high-redshift LBGs, we have utilized XMM-Newton observations of a small sample of z approximates 0.1 GALEX-selected Ultraviolet-Luminous Galaxies (UVLGs); local analogs to high-redshift LBGs. Our observations enable us to study the X-ray emission from LBG-like galaxies on an individual basis, thus allowing us to constrain object-to-object variances in this population. We supplement these results with X-ray stacking constraints using the new 3.2 Ms Chandra Deep Field-South (completed spring 2010) and LBG candidates selected from HST, Swift UVOT, and ground-based data. These measurements provide new X-ray constraints that sample well the entire z=0-4 baseline

  9. Asteroidal binary systems - Detection and formation

    NASA Astrophysics Data System (ADS)

    Zappala, V.; Scaltriti, F.; Farinella, P.; Paolicchi, P.

    1980-04-01

    Recent occultation data and an analysis of some photometric light curves have shown the possible existence of asteroidal binary systems. A simple geometrical model taking into account mutual shadowing effects shows some peculiar features of the light curve which can be recovered in several previously observed objects. On the other hand, while the rotational period distribution of large asteroids (diameter greater than 200 km) is sharply peaked at about 5-8 hours, the surprisingly higher dispersion towards longer periods for intermediate size objects (diameters between 50 and 150 km) could be connected with a larger probability of binary nature within this class. From a theoretical point of view, the collisional fragmentation of asteroids could originate gravitationally bound fragments, with a tidal transfer of rotational into orbital angular momentum, causing a rapid synchronization of the system. This kind of processes could more easily occur for intermediate objects since: (1) for large ones, very massive colliding bodies are needed for fragmentation, that means a very rare event; and (2) for smaller asteroids, solid state interactions are stronger than the gravitational ones, so that breakage probably causes a complete disruption of the gravitational binding. Further collisional events could disintegrate some systems, so that the present frequency of binary asteroids could be lower than that of the objects whose rotational period was increased by such processes.

  10. Kepler as a Binary Star Mission

    NASA Astrophysics Data System (ADS)

    di Stefano, Rosanne

    2010-12-01

    The Kepler observatory was designed to discover transits by Earth-like planets orbiting Sun-like stars. Its first major discoveries, however, are hot objects in close orbits around main-sequence stars. These are likely to be white-dwarf remnants of stars that have transferred mass to the present-day main sequence stars. These particular main-sequence stars are among the Kepler targets because they are bright. The question is: how many of the other Kepler target stars are also orbited by white dwarfs? We have shown that several hundred white dwarfs are likely to transit the Kepler target stars during the mission. In some cases, the signature will be dominated by gravitational lensing, producing distinctive ``antitransits''. Neutron stars and black holes may also be discovered this way. The lensing signature provides a measurement of the gravitational mass of the compact object. Through the discovery of both transits and antitransits caused by white dwarfs, Kepler will discover and study binaries that have already experienced a phase of mass transfer or a common envelope phase. Thus, Kepler will become a premier tool for the study of interacting binaries. During the next phase of interaction, some of the Kepler binaries may become nuclear-burning white dwarfs, and may be candidates for Type Ia supernovae or accretion-induced collapse.

  11. Constraining the Statistics of Population III Binaries

    NASA Technical Reports Server (NTRS)

    Stacy, Athena; Bromm, Volker

    2012-01-01

    We perform a cosmological simulation in order to model the growth and evolution of Population III (Pop III) stellar systems in a range of host minihalo environments. A Pop III multiple system forms in each of the ten minihaloes, and the overall mass function is top-heavy compared to the currently observed initial mass function in the Milky Way. Using a sink particle to represent each growing protostar, we examine the binary characteristics of the multiple systems, resolving orbits on scales as small as 20 AU. We find a binary fraction of approx. 36, with semi-major axes as large as 3000 AU. The distribution of orbital periods is slightly peaked at approx. < 900 yr, while the distribution of mass ratios is relatively flat. Of all sink particles formed within the ten minihaloes, approx. 50 are lost to mergers with larger sinks, and 50 of the remaining sinks are ejected from their star-forming disks. The large binary fraction may have important implications for Pop III evolution and nucleosynthesis, as well as the final fate of the first stars.

  12. The formation of eccentric compact binary inspirals and the role of gravitational wave emission in binary-single stellar encounters

    SciTech Connect

    Samsing, Johan; MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2014-03-20

    The inspiral and merger of eccentric binaries leads to gravitational waveforms distinct from those generated by circularly merging binaries. Dynamical environments can assemble binaries with high eccentricity and peak frequencies within the LIGO band. In this paper, we study binary-single stellar scatterings occurring in dense stellar systems as a source of eccentrically inspiraling binaries. Many interactions between compact binaries and single objects are characterized by chaotic resonances in which the binary-single system undergoes many exchanges before reaching a final state. During these chaotic resonances, a pair of objects has a non-negligible probability of experiencing a very close passage. Significant orbital energy and angular momentum are carried away from the system by gravitational wave (GW) radiation in these close passages, and in some cases this implies an inspiral time shorter than the orbital period of the bound third body. We derive the cross section for such dynamical inspiral outcomes through analytical arguments and through numerical scattering experiments including GW losses. We show that the cross section for dynamical inspirals grows with increasing target binary semi-major axis a and that for equal-mass binaries it scales as a {sup 2/7}. Thus, we expect wide target binaries to predominantly contribute to the production of these relativistic outcomes. We estimate that eccentric inspirals account for approximately 1% of dynamically assembled non-eccentric merging binaries. While these events are rare, we show that binary-single scatterings are a more effective formation channel than single-single captures for the production of eccentrically inspiraling binaries, even given modest binary fractions.

  13. MIL1A

    Atmospheric Science Data Center

    2014-09-03

    ... MISR Level 1A camera charge-coupled device (CCD) Science Data: Reformatted Annotated Level 1A product of the CCD science data. ... :  Data Product Specification Versioning History:  Ellipsoid, Terrain, Browse, CCD, Radiance SCAR-B ...

  14. Binary star formation and the outflows from their discs

    NASA Astrophysics Data System (ADS)

    Kuruwita, Rajika L.; Federrath, Christoph; Ireland, Michael

    2017-09-01

    We carry out magnetohydrodynamical simulations with flash of the formation of a single, a tight binary (a ∼ 2.5 au) and a wide binary star (a ∼ 45 au). We study the outflows and jets from these systems to understand the contributions the circumstellar and circumbinary discs have on the efficiency and morphology of the outflow. In the single star and tight binary case, we obtain a single pair of jets launched from the system, while in the wide binary case, two pairs of jets are observed. This implies that in the tight binary case, the contribution of the circumbinary disc on the outflow is greater than that in the wide binary case. We also find that the single star case is the most efficient at transporting mass, linear and angular momentum from the system, while the wide binary case is less efficient ( ∼ 50 per cent, ∼ 33 per cent, ∼ 42 per cent of the respective quantities in the single star case). The tight binary's efficiency falls between the other two cases ( ∼ 71 per cent, ∼66 per cent, ∼87 per cent of the respective quantities in the single star case). By studying the magnetic field structure, we deduce that the outflows in the single star and tight binary star case are magnetocentrifugally driven, whereas in the wide binary star case, the outflows are driven by a magnetic pressure gradient.

  15. TWIN BINARIES: STUDIES OF STABILITY, MASS TRANSFER, AND COALESCENCE

    SciTech Connect

    Lombardi, J. C.; Holtzman, W.; Gearity, K.; Dooley, K. L.; Kalogera, V.; Rasio, F. A.

    2011-08-20

    Motivated by suggestions that binaries with almost equal-mass components ('twins') play an important role in the formation of double neutron stars and may be rather abundant among binaries, we study the stability of synchronized close and contact binaries with identical components in circular orbits. In particular, we investigate the dependency of the innermost stable circular orbit on the core mass, and we study the coalescence of the binary that occurs at smaller separations. For twin binaries composed of convective main-sequence stars, subgiants, or giants with low-mass cores (M{sub c} {approx}< 0.15M, where M is the mass of a component), a secular instability is reached during the contact phase, accompanied by a dynamical mass transfer instability at the same or at a slightly smaller orbital separation. Binaries that come inside this instability limit transfer mass gradually from one component to the other and then coalesce quickly as mass is lost through the outer Lagrangian points. For twin giant binaries with moderate to massive cores (M{sub c} {approx}> 0.15M), we find that stable contact configurations exist at all separations down to the Roche limit, when mass shedding through the outer Lagrangian points triggers a coalescence of the envelopes and leaves the cores orbiting in a central tight binary. In addition to the formation of binary neutron stars, we also discuss the implications of our results for the production of planetary nebulae with double degenerate central binaries.

  16. The Ruinous Influence of Close Binary Companions on Planetary Systems

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.; Ireland, Michael; Mann, Andrew; Huber, Daniel; Dupuy, Trent J.

    2017-01-01

    The majority of solar-type stars are found in binary systems, and the dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of nearly 500 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. We super-resolve some binary systems to projected separations of under 5 AU, showing that planets might form in these dynamically active environments. However, the full distribution of projected separations for our planet-host sample more broadly reveals a deep paucity of binary companions at solar-system scales. When the binary population is parametrized with a semimajor axis cutoff a cut and a suppression factor inside that cutoff S bin, we find with correlated uncertainties that inside acut = 47 +59/-23 AU, the planet occurrence rate in binary systems is only Sbin = 0.34 +0.14/-0.15 times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion.

  17. The Ruinous Influence of Close Binary Companions on Planetary Systems

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.; Ireland, Michael; Mann, Andrew; Huber, Daniel; Dupuy, Trent J.

    2017-06-01

    The majority of solar-type stars are found in binary systems, and the dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of nearly 500 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. We super-resolve some binary systems to projected separations of under 5 AU, showing that planets might form in these dynamically active environments. However, the full distribution of projected separations for our planet-host sample more broadly reveals a deep paucity of binary companions at solar-system scales. When the binary population is parametrized with a semimajor axis cutoff a cut and a suppression factor inside that cutoff S bin, we find with correlated uncertainties that inside acut = 47 +59/-23 AU, the planet occurrence rate in binary systems is only Sbin = 0.34+0.14/-0.15 times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion.

  18. Massive binaries in the vicinity of Sgr A*

    SciTech Connect

    Pfuhl, O.; Gillessen, S.; Genzel, R.; Eisenhauer, F.; Fritz, T. K.; Ott, T.; Alexander, T.; Martins, F.

    2014-02-20

    A long-term spectroscopic and photometric survey of the most luminous and massive stars in the vicinity of the supermassive black hole Sgr A* revealed two new binaries: a long-period Ofpe/WN9 binary, IRS 16NE, with a modest eccentricity of 0.3 and a period of 224 days, and an eclipsing Wolf-Rayet binary with a period of 2.3 days. Together with the already identified binary IRS 16SW, there are now three confirmed OB/WR binaries in the inner 0.2 pc of the Galactic center. Using radial velocity change upper limits, we were able to constrain the spectroscopic binary fraction in the Galactic center to F{sub SB}=0.30{sub −0.21}{sup +0.34} at a confidence level of 95%, a massive binary fraction close to that observed in dense clusters. The fraction of eclipsing binaries with photometric amplitudes Δm > 0.4 is F{sub EB}{sup GC}=3%±2%, which is consistent with local OB star clusters (F {sub EB} = 1%). Overall, the Galactic center binary fraction seems to be similar to the binary fraction in comparable young clusters.

  19. Learning Compact Binary Face Descriptor for Face Recognition.

    PubMed

    Lu, Jiwen; Liong, Venice Erin; Zhou, Xiuzhuang; Zhou, Jie

    2015-10-01

    Binary feature descriptors such as local binary patterns (LBP) and its variations have been widely used in many face recognition systems due to their excellent robustness and strong discriminative power. However, most existing binary face descriptors are hand-crafted, which require strong prior knowledge to engineer them by hand. In this paper, we propose a compact binary face descriptor (CBFD) feature learning method for face representation and recognition. Given each face image, we first extract pixel difference vectors (PDVs) in local patches by computing the difference between each pixel and its neighboring pixels. Then, we learn a feature mapping to project these pixel difference vectors into low-dimensional binary vectors in an unsupervised manner, where 1) the variance of all binary codes in the training set is maximized, 2) the loss between the original real-valued codes and the learned binary codes is minimized, and 3) binary codes evenly distribute at each learned bin, so that the redundancy information in PDVs is removed and compact binary codes are obtained. Lastly, we cluster and pool these binary codes into a histogram feature as the final representation for each face image. Moreover, we propose a coupled CBFD (C-CBFD) method by reducing the modality gap of heterogeneous faces at the feature level to make our method applicable to heterogeneous face recognition. Extensive experimental results on five widely used face datasets show that our methods outperform state-of-the-art face descriptors.

  20. Binary Cepheids: Separations and Mass Ratios in 5 M ⊙ Binaries

    NASA Astrophysics Data System (ADS)

    Evans, Nancy Evans; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Karovska, Margarita; Tingle, Evan

    2013-10-01

    Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ~5 M ⊙—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ⊙. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ⊙ binaries have systematically shorter periods than do 1 M ⊙ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained by the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  1. BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M {sub ☉} BINARIES

    SciTech Connect

    Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D. E-mail: heb11@psu.edu

    2013-10-01

    Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ∼5 M {sub ☉}—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M {sub ☉}. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M {sub ☉} binaries have systematically shorter periods than do 1 M {sub ☉} stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple.

  2. A precontact binary and a shallow contact binary are in the same field

    NASA Astrophysics Data System (ADS)

    Liu, Liang; Qian, Shengbang; He, Jiajia; Liao, Wenping; Liu, Nianping

    2016-06-01

    The period changes of two close binaries, V1107 Cas and AX Cas, which are in the same field, were investigated. Their periods both show a long-term decrease. After further analysis, we found that the periods have their respective cyclic oscillations (T3 = 6.74 ± 0.24 yr for V1107 Cas and T3 = 13.8 ± 0.3 yr for AX Cas), which are possibly caused by a third body due to the light-time effect. We also obtained the complete VRcIc light curves for V1107 Cas and analyzed them with the 2010 version of the Wilson-Devinney code. The photometric results reveal that V1107 Cas is a W-type shallow contact (15.2%±1.8%) binary, with a mass-ratio of 1.797 ± 0.006. The period variation and photometric solution suggest that V1107 Cas is a newly formed contact binary system. Moreover, we estimated the fundamental parameters for V1107 Cas. They are: M1 = 0.39 ± 0.01 M⊙, M2 = 0.70 ± 0.03 M⊙, R1 = 0.52 ± 0.10 R⊙, R2 = 0.68 ± 0.12 R⊙, L1 = 0.178 ± 0.108 L⊙, and L2 = 0.196 ± 0.116 L⊙. Then, based on the coplane assumption, we deduced the masses of possible third bodies to be M3 = 0.091 ± 0.019 M⊙ for V1107 Cas and M3 = 0.325 ± 0.029 M⊙ for AX Cas. Finally, we inferred the evolutional stage of AX Cas, and believe that it is a precontact binary. Thus, the precontact binary AX Cas and the shallow contact binary V1107 Cas have adjoining evolutional stages.

  3. Rotational properties of the binary and non-binary populations in the trans-Neptunian belt

    NASA Astrophysics Data System (ADS)

    Thirouin, A.; Noll, K. S.; Ortiz, J. L.; Morales, N.

    2014-09-01

    We present results for the short-term variability of binary trans-Neptunian objects (BTNOs). We performed CCD photometric observations using the 3.58 m Telescopio Nazionale Galileo (TNG), the 1.5 m Sierra Nevada Observatory (OSN) telescope, and the 1.23 m Centro Astronómico Hispano Alemán (CAHA) telescope at Calar Alto Observatory. We present results based on five years of observations and report the short-term variability of six BTNOs. Our sample contains three classical objects: (174567) 2003 MW12, or Varda, (120347) 2004 SB60, or Salacia, and 2002 VT130; one detached disk object: (229762) 2007 UK126; and two resonant objects: (341520) 2007 TY430 and (38628) 2000 EB173, or Huya. For each target, possible rotational periods and/or photometric amplitudes are reported. We also derived some physical properties from their light curves, such as density, primary and secondary sizes, and albedo. We compiled and analyzed a vast light curve database for TNOs including centaurs to determine the light-curve amplitude and spin frequency distributions for the binary and non-binary populations. The mean rotational periods, from the Maxwellian fits to the frequency distributions, are 8.63 ± 0.52 h for the entire sample, 8.37 ± 0.58 h for the sample without the binary population, and 10.11 ± 1.19 h for the binary population alone. Because the centaurs are collisionally more evolved, their rotational periods might not be so primordial. We computed a mean rotational period, from the Maxwellian fit, of 8.86 ± 0.58 h for the sample without the centaur population, and of 8.64 ± 0.67 h considering a sample without the binary and the centaur populations. According to this analysis, regular TNOs spin faster than binaries, which is compatible with the tidal interaction of the binaries. Finally, we examined possible formation models for several systems studied in this work and by our team in previous papers. Appendix A is available in electronic form at http

  4. Binary pairs of supermassive black holes - Formation in merging galaxies

    SciTech Connect

    Valtaoja, L.; Valtonen, M.J.; Byrd, G.G.; Alabama Univ., Tuscaloosa )

    1989-08-01

    A process in which supermassive binary blackholes are formed in nuclei of supergiant galaxies due to galaxy mergers is examined. There is growing evidence that mergers of galaxies are common and that supermassive black holes in center of galaxies are also common. Consequently, it is expected that binary black holes should arise in connection with galaxy mergers. The merger process in a galaxy modeled after M87 is considered. The capture probability of a companion is derived as a function of its mass. Assuming a correlation between the galaxy mass and the blackholes mass, the expected mass ratio in binary black holes is calculated. The binary black holes formed in this process are long lived, surviving longer than the Hubble time unless they are perturbed by black holes from successive mergers. The properties of these binaries agree with Gaskell's (1988) observational work on quasars and its interpretation in terms of binary black holes. 39 refs.

  5. Polar Alignment of a Protoplanetary Disk around an Eccentric Binary

    NASA Astrophysics Data System (ADS)

    Martin, Rebecca G.; Lubow, Stephen H.

    2017-02-01

    We use three-dimensional hydrodynamical simulations to show that an initially mildly misaligned circumbinary accretion disk around an eccentric binary can evolve to an orientation that is perpendicular to the orbital plane of the binary (polar alignment). As the disk evolves to the perpendicular state, it undergoes nodal libration oscillations of the tilt angle and the longitude of the ascending node. Dissipation within the disk causes the oscillations to damp. The process operates above a critical initial misalignment angle that depends upon the eccentricity of the binary and the mass of the disk. For binary eccentricity of 0.5, the process operates typically for disk masses smaller than a few percent of the binary mass and initial tilt angle of more than 40°. This evolution has important implications for planet formation around eccentric binary star systems.

  6. Dynamical Formation of Black Hole Binaries in Globular Clusters

    NASA Astrophysics Data System (ADS)

    Rasio, Frederic A.; Chatterjee, Sourav; Kremer, Kyle; Rodriguez, Carl

    2017-08-01

    Theoretical predictions for black holes in field populations of binary stars are extremely sensitive to the assumptions of stellar evolution, leading, for example, to predicted merger rates for binary black holes that span several orders of magnitude. But in dense stellar environments such as globular clusters, binary black holes form by well-understood gravitational interactions. We will present an overview of recent theoretical work on the dynamical formation of black hole binaries based on realistic N-body simulations of globular clusters. By calibrating theoretical models against observed properties of globular clusters, we find that the mergers of dynamically formed binaries could eventually be detected by Advanced LIGO at a rate of at least ~ 100 per year, potentially dominating the overall detection rate of gravitational wave sources. Dynamical processes in globular clusters can also form very naturally the black hole X-ray binaries that have been tentatively identified recently in many Milky Way and extragalactic globular clusters.

  7. Binary pulsar evolution: unveiled links and new species

    NASA Astrophysics Data System (ADS)

    Possenti, Andrea

    2013-03-01

    In the last years a series of blind and/or targeted pulsar searches led to almost triple the number of known binary pulsars in the galactic field with respect to a decade ago. The focus will be on few outliers, which are emerging from the average properties of the enlarged binary pulsar population. Some of them may represent the long sought missing links between two kinds of neutron star binaries, while others could represent the stereotype of new groups of binaries, resulting from an evolutionary path which is more exotic than those considered until recently. In particular, a new class of binaries, which can be dubbed Ultra Low Mass Binary Pulsars (ULMBPs), is emerging from recent data.

  8. An X-Ray Survey of Colliding Wind Binaries

    NASA Astrophysics Data System (ADS)

    Gagné, M.; Fehon, G.; Savoy, M. R.; Cartagena, C. A.; Cohen, D. H.; Owocki, S. P.

    2012-12-01

    We have compiled a list of 35 O + O binaries and 86 Wolf-Rayet (WR) binaries in the Milky Way and Magellanic clouds detected with the Chandra, XMM-Newton, and ROSAT satellites to probe the connection between their X-ray properties and their system characteristics. Of the WR binaries with published model parameters, all have log LX > 32, kT > 1 keV and log LX/Lbol > -7. The most X-ray luminous WR binaries are typically very long period systems. The WR binaries show a nearly four-order of magnitude spread in X-ray luminosity, even among among systems with very similar WR primaries. Among the O + O binaries, short-period systems have soft X-ray spectra and longer period systems show harder X-ray spectra again with a large spread in LX/Lbol.

  9. Learning moment-based fast local binary descriptor

    NASA Astrophysics Data System (ADS)

    Bellarbi, Abdelkader; Zenati, Nadia; Otmane, Samir; Belghit, Hayet

    2017-03-01

    Recently, binary descriptors have attracted significant attention due to their speed and low memory consumption; however, using intensity differences to calculate the binary descriptive vector is not efficient enough. We propose an approach to binary description called POLAR_MOBIL, in which we perform binary tests between geometrical and statistical information using moments in the patch instead of the classical intensity binary test. In addition, we introduce a learning technique used to select an optimized set of binary tests with low correlation and high variance. This approach offers high distinctiveness against affine transformations and appearance changes. An extensive evaluation on well-known benchmark datasets reveals the robustness and the effectiveness of the proposed descriptor, as well as its good performance in terms of low computation complexity when compared with state-of-the-art real-time local descriptors.

  10. The extreme Kuiper Belt binary 2001 QW322.

    PubMed

    Petit, J-M; Kavelaars, J J; Gladman, B J; Margot, J L; Nicholson, P D; Jones, R L; Parker, J Wm; Ashby, M L N; Bagatin, A Campo; Benavidez, P; Coffey, J; Rousselot, P; Mousis, O; Taylor, P A

    2008-10-17

    The study of binary Kuiper Belt objects helps to probe the dynamic conditions present during planet formation in the solar system. We report on the mutual-orbit determination of 2001 QW322, a Kuiper Belt binary with a very large separation whose properties challenge binary-formation and -evolution theories. Six years of tracking indicate that the binary's mutual-orbit period is approximately 25 to 30 years, that the orbit pole is retrograde and inclined 50 degrees to 62 degrees from the ecliptic plane, and, most surprisingly, that the mutual orbital eccentricity is <0.4. The semimajor axis of 105,000 to 135,000 kilometers is 10 times that of other near-equal-mass binaries. Because this weakly bound binary is prone to orbital disruption by interlopers, its lifetime in its present state is probably less than 1 billion years.

  11. Binary Black Hole Mergers from Planet-like Migrations.

    PubMed

    Gould; Rix

    2000-03-20

    If supermassive black holes (BHs) are generically present in galaxy centers, and if galaxies are built up through hierarchical merging, BH binaries are at least temporary features of most galactic bulges. Observations suggest, however, that binary BHs are rare, pointing toward a binary lifetime far shorter than the Hubble time. We show that, almost regardless of the detailed mechanism, all stellar dynamical processes are too slow in reducing the orbital separation once orbital velocities in the binary exceed the virial velocity of the system. We propose that a massive gas disk surrounding a BH binary can effect its merger rapidly, in a scenario analogous to the orbital decay of super-Jovian planets due to a proto-planetary disk. As in the case of planets, gas accretion onto the secondary (here a supermassive BH) is integrally connected with its inward migration. Such accretion would give rise to quasar activity. BH binary mergers could therefore be responsible for many or most quasars.

  12. An Improved Catalog of Halo Wide Binary Candidates

    NASA Astrophysics Data System (ADS)

    Allen, Christine; Monroy-Rodríguez, Miguel A.

    2014-08-01

    We present an improved catalog of halo wide binaries compiled from an extensive literature search. Most of our binaries stem from the common proper motion binary catalogs by Allen et al. and Chanamé & Gould, but we have also included binaries from the lists of Ryan and Zapatero-Osorio & Martín. All binaries were carefully checked and their distances and systemic radial velocities are included when available. Probable membership to the halo population was tested by means of reduced proper motion diagrams for 251 candidate halo binaries. After eliminating obvious disk binaries, we ended up with 211 probable halo binaries, 150 of which have radial velocities available. We compute galactic orbits for these 150 binaries and calculate the time they spend within the galactic disk. Considering the full sample of 251 candidate halo binaries as well as several subsamples, we find that the distribution of angular separations (or expected major semiaxes) follows a power law f(a) ~ a -1 (Oepik's relation) up to different limits. For the 50 most disk-like binaries, those that spend their entire lives within z = ±500 pc, this limit is found to be 19,000 AU (0.09 pc), while for the 50 most halo-like binaries, those that spend on average only 18% of their lives within z = ±500 pc, the limit is 63,000 AU (0.31 pc). In a companion paper, we employ this catalog to establish limits on the masses of the halo massive perturbers (massive compact halo objects).

  13. Efficient algorithms for dilated mappings of binary trees

    NASA Technical Reports Server (NTRS)

    Iqbal, M. Ashraf

    1990-01-01

    The problem is addressed to find a 1-1 mapping of the vertices of a binary tree onto those of a target binary tree such that the son of a node on the first binary tree is mapped onto a descendent of the image of that node in the second binary tree. There are two natural measures of the cost of this mapping, namely the dilation cost, i.e., the maximum distance in the target binary tree between the images of vertices that are adjacent in the original tree. The other measure, expansion cost, is defined as the number of extra nodes/edges to be added to the target binary tree in order to ensure a 1-1 mapping. An efficient algorithm to find a mapping of one binary tree onto another is described. It is shown that it is possible to minimize one cost of mapping at the expense of the other. This problem arises when designing pipelined arithmetic logic units (ALU) for special purpose computers. The pipeline is composed of ALU chips connected in the form of a binary tree. The operands to the pipeline can be supplied to the leaf nodes of the binary tree which then process and pass the results up to their parents. The final result is available at the root. As each new application may require a distinct nesting of operations, it is useful to be able to find a good mapping of a new binary tree over existing ALU tree. Another problem arises if every distinct required binary tree is known beforehand. Here it is useful to hardwire the pipeline in the form of a minimal supertree that contains all required binary trees.

  14. An improved catalog of halo wide binary candidates

    SciTech Connect

    Allen, Christine; Monroy-Rodríguez, Miguel A.

    2014-08-01

    We present an improved catalog of halo wide binaries compiled from an extensive literature search. Most of our binaries stem from the common proper motion binary catalogs by Allen et al. and Chanamé and Gould, but we have also included binaries from the lists of Ryan and Zapatero-Osorio and Martín. All binaries were carefully checked and their distances and systemic radial velocities are included when available. Probable membership to the halo population was tested by means of reduced proper motion diagrams for 251 candidate halo binaries. After eliminating obvious disk binaries, we ended up with 211 probable halo binaries, 150 of which have radial velocities available. We compute galactic orbits for these 150 binaries and calculate the time they spend within the galactic disk. Considering the full sample of 251 candidate halo binaries as well as several subsamples, we find that the distribution of angular separations (or expected major semiaxes) follows a power law f(a) ∼ a {sup –1} (Oepik's relation) up to different limits. For the 50 most disk-like binaries, those that spend their entire lives within z = ±500 pc, this limit is found to be 19,000 AU (0.09 pc), while for the 50 most halo-like binaries, those that spend on average only 18% of their lives within z = ±500 pc, the limit is 63,000 AU (0.31 pc). In a companion paper, we employ this catalog to establish limits on the masses of the halo massive perturbers (massive compact halo objects).

  15. Evolution of binary supermassive black holes via chain regularization.

    PubMed

    Szell, Andras; Merritt, David; Mikkola, Seppo

    2005-06-01

    A chain regularization method is combined with special purpose computer hardware to study the evolution of massive black hole binaries at the centers of galaxies. Preliminary results with up to N = 0.26 x 10(6) particles are presented. The decay rate of the binary is shown to decrease with increasing N, as expected on the basis of theoretical arguments. The eccentricity of the binary remains small.

  16. Constructing binary black hole template banks using numerical relativity waveforms

    NASA Astrophysics Data System (ADS)

    Kumar, Prayush

    2013-04-01

    We present methods for constructing and validating template banks for gravitational waves from high mass binary black holes in advanced gravitational-wave detectors using waveforms from numerical relativity. We construct these template banks using numerical waveforms from the Simulating eXtreme Spacetimes (SXS) collaboration. We show how a template bank can be constructed using numerical waveforms for non-spinning black hole binaries and discuss how this can be extended into the aligned spin black hole binary space.

  17. Asynchonous Binaries, Energy Dissipation and Turbulent Viscosity

    NASA Astrophysics Data System (ADS)

    Koenigsberger, G.; Brott, I.; Moreno, E.

    2015-07-01

    Stars in binary systems are generally modeled under the assumption that they are in an equilibrium configuration and, in particular, that the stellar rotation angular velocity equals the orbital angular velocity. However, asynchronous rotation is more common than generally recognized. All eccentric systems undergo asynchronous rotation and the angular velocity of rotation of many stars in circular orbits differs from that of the orbital angular velocity. Combined with the external gravitational potential, this asynchronous rotation causes shearing motions in the stellar layers and, given that the stellar material is not inviscid, kinetic energy is dissipated into heat. In 1968, Zdeněk Kopal addressed the question of whether the tidal shear energy dissipation rates, Ė, in asynchronous binaries can lead to an internal stellar structure that differs from that in an analogous single star. His calculation, based on the assumption that the viscosity is purely molecular, led him to conclude that Ė is insignificant and therefore has no effect on the internal stellar structure. However, Kopal also pointed out the important caveat that if turbulent viscosity prevailed, then larger values of Ė would obtain. We have revisited the question of the magnitude of Ė using the TIDES code (Moreno 2011) and examined its dependence on viscosity for several layers of a ZAMS 30 M⊙ star with a 20 M⊙ companion in a 6-day eccentric orbit. We find that conditions for turbulent viscosity are favored when the star expands after leaving the main sequence. For example, when the 30 M⊙ star is 5 Myr old and rotating near its corrotation speed, turbulent viscosity might be expected to appear in all layers at distances greater than 60% of the maximum stellar radius. As a consequence, tidal shear energy dissipation may constitute a non-negligible effect in a large number of close binary systems, with possibly interesting consequences for their internal structure and evolution.

  18. Evaporation of binary mixtures in microgravity

    NASA Technical Reports Server (NTRS)

    Girgis, Morris; Matta, Nabil; Kolli, Kiran; Brown, Leon; Chubb, Kevin

    1995-01-01

    The motivation of this research is to obtain a better understanding of phase-change heat transfer within single and binary liquid meniscii, both in 1-g and 0-g environments. During phase 1 and part of phase 2, in a glass test cell with an inclined heated plate, 1-6 experiments on pentane with additions of decane up to 3% were conducted to determine the optimum concentration that will exhibit the maximum heat transfer and stability. During phase 2 emphasis was given to explore fundamental research issues and to ultimately develop a reliable capillary pumped loop (CPL) device for low gravity. In related experimental work, it was found that thermocapillary stresses near the contract line could result in a degraded wettability which ultimately could explain the observed failure of CPL devices in zero-gravity environment. Therefore, the current experimental effort investigates the effect of adding binary constituents in improving the thermocapillary characteristics near the contact line within the loop configuration. Achievements during second phase include: (1) Further enhancement of Central State University's Microgravity Laboratory by adding or improving upon capabilities of photography, video imaging, fluid visualization, and general experimental testing capabilities; (2) Experimental results for the inclined plate cell; (3) Modeling effort with a detailed scaling analysis; (4) Additional testing with a tube loop configuration to extend experimental work by Dickens, et al.; (5) Fabrication of a capillary loop to be tested using binary fluid (pentane/decane). The device that has been recently completed will be set up horizontally so that the effect of gravity on the performance is negligible. Testing will cover a wide range of parameters such as decane/pentane concentration, heat input value, heat input location (below or above meniscus), and loop temperature.

  19. Orbital Parameters for Two Young Spectroscopic Binaries

    NASA Astrophysics Data System (ADS)

    Karnath, Nicole

    I report orbital parameters for two low-mass, pre-main sequence spectroscopic binaries VSB 111 and VSB 126. These systems were originally identified as single-lined on the basis of visible-light spectral observations. High-resolution, infrared spectra were obtained to detect absorption lines of the secondary stars and measure radial velocities of both components in the systems. The combination of the visible and infrared observations of VSB 111 leads to a period of 902.1+/-0.9 days, an eccentricity of 0.788+/-0.008, and a mass ratio of 0.52+/-0.05. VSB 126 has a period of 12.9244+/-0.0002 days, an eccentricity of 0.18+/-0.02, and a mass ratio of 0.29+/-0.02. Visible-light photometry using the 0.8-m telescope at Lowell Observatory provided rotation periods for the primary stars in both systems, 3.74+/-0.02 days for VSB 111 and 5.71+/-0.07 days for VSB 126. Based on the vsini values, the primary rotation periods, and estimates for the primary radii, I find inclinations for the primary-star rotation axes, 42+47 -16° for VSB 111 and 54+36-29° for VSB 126, and compare these to the inclination angle of the binary orbits, iorb = 36+/-4° for VSB 111 and i orb = 45+/-4° for VSB 126, estimated from the orbital solutions. Both binaries are located in the young, star- forming cluster NGC 2264 with a complex and clumpy gas and dust structure at a distance of ~800 pc. The center-of-mass velocities of the two systems are consistent with distinct CO clouds within NGC 2264.

  20. A near-contact binary: CN Andromedae

    NASA Astrophysics Data System (ADS)

    Çiçek, C.; Erdem, A.; Soydugan, F.

    2005-02-01

    New BVR light curves and photometric analysis of the eclipsing binary star CN And are presented. The shape of the light curves are typical of β Lyr type, and there are large asymmetries between maxima. The BVR light curves and the radial velocity curves (from Rucinski et al. 2000) were solved with the Wilson-Devinney method, simultaneously. The results suggest that CN And is a almost contact binary system, in which the component stars are filling ˜99% of their Roche lobes. We discuss the model with a large dark starspot on the more massive star and a bright substellar spot on the companion to account for the light curve asymmetries. The absolute parameters of the system were also derived. The system resembles the near contact binary V1010 Oph according to its Roche configuration and light curve asymmetries. We, also, discuss the evolution of the system: it seems to be in a transition phase to the contact era. All previous times of minimum light were collected and combined with the new ones presented in this work. The variation of the orbital period of the system was then analyzed. The results reveal that the orbital period has a secular decrease of about 1.98±0.04 sec per century, which corresponds to a conservative mass transfer from the more to the less massive component at a rate of (1.52±0.09)×10-7m_⊙/yr or a mass loss from the primary component due to magnetic stellar winds at a rate of (7.83±0.09)×10-8m_⊙/yr.

  1. Evaporation of binary mixtures in microgravity

    NASA Technical Reports Server (NTRS)

    Girgis, Morris; Matta, Nabil; Kolli, Kiran; Brown, Leon; Chubb, Kevin

    1995-01-01

    The motivation of this research is to obtain a better understanding of phase-change heat transfer within single and binary liquid meniscii, both in 1-g and 0-g environments. During phase 1 and part of phase 2, in a glass test cell with an inclined heated plate, 1-6 experiments on pentane with additions of decane up to 3% were conducted to determine the optimum concentration that will exhibit the maximum heat transfer and stability. During phase 2 emphasis was given to explore fundamental research issues and to ultimately develop a reliable capillary pumped loop (CPL) device for low gravity. In related experimental work, it was found that thermocapillary stresses near the contract line could result in a degraded wettability which ultimately could explain the observed failure of CPL devices in zero-gravity environment. Therefore, the current experimental effort investigates the effect of adding binary constituents in improving the thermocapillary characteristics near the contact line within the loop configuration. Achievements during second phase include: (1) Further enhancement of Central State University's Microgravity Laboratory by adding or improving upon capabilities of photography, video imaging, fluid visualization, and general experimental testing capabilities; (2) Experimental results for the inclined plate cell; (3) Modeling effort with a detailed scaling analysis; (4) Additional testing with a tube loop configuration to extend experimental work by Dickens, et al.; (5) Fabrication of a capillary loop to be tested using binary fluid (pentane/decane). The device that has been recently completed will be set up horizontally so that the effect of gravity on the performance is negligible. Testing will cover a wide range of parameters such as decane/pentane concentration, heat input value, heat input location (below or above meniscus), and loop temperature.

  2. Green binary and phase shifting mask

    NASA Astrophysics Data System (ADS)

    Shy, S. L.; Hong, Chao-Sin; Wu, Cheng-San; Chen, S. J.; Wu, Hung-Yu; Ting, Yung-Chiang

    2009-12-01

    SixNy/Ni thin film green mask blanks were developed , and are now going to be used to replace general chromium film used for binary mask as well as to replace molydium silicide embedded material for AttPSM for I-line (365 nm), KrF (248 nm), ArF (193 nm) and Contact/Proximity lithography. A bilayer structure of a 1 nm thick opaque, conductive nickel layer and a SixNy layer is proposed for binary and phase-shifting mask. With the good controlling of plasma CVD of SixNy under silane (50 sccm), ammonia (5 sccm) and nitrogen (100 sccm), the pressure is 250 mTorr. and RF frequency 13.56 MHz and power 50 W. SixNy has enough deposition latitude to meet the requirements as an embedded layer for required phase shift 180 degree, and the T% in 193, 248 and 365 nm can be adjusted between 2% to 20% for binary and phase shifting mask usage. Ni can be deposited by E-gun, its sheet resistance Rs is less than 1.435 kΩ/square. Jeol e-beam system and I-line stepper are used to evaluate these thin film green mask blanks, feature size less than 200 nm half pitch pattern and 0.558 μm pitch contact hole can be printed. Transmission spectrums of various thickness of SixNy film are inspected by using UV spectrometer and FTIR. Optical constants of the SixNy film are measured by n & k meter and surface roughness is inspected by using Atomic Force Microscope (AFM).

  3. Observational signatures of binary supermassive black holes

    SciTech Connect

    Roedig, Constanze; Krolik, Julian H.; Miller, M. Coleman

    2014-04-20

    Observations indicate that most massive galaxies contain a supermassive black hole, and theoretical studies suggest that when such galaxies have a major merger, the central black holes will form a binary and eventually coalesce. Here we discuss two spectral signatures of such binaries that may help distinguish them from ordinary active galactic nuclei. These signatures are expected when the mass ratio between the holes is not extreme and the system is fed by a circumbinary disk. One such signature is a notch in the thermal continuum that has been predicted by other authors; we point out that it should be accompanied by a spectral revival at shorter wavelengths and also discuss its dependence on binary properties such as mass, mass ratio, and separation. In particular, we note that the wavelength λ {sub n} at which the notch occurs depends on these three parameters in such a way as to make the number of systems displaying these notches ∝λ{sub n}{sup 16/3}; longer wavelength searches are therefore strongly favored. A second signature, first discussed here, is hard X-ray emission with a Wien-like spectrum at a characteristic temperature ∼100 keV produced by Compton cooling of the shock generated when streams from the circumbinary disk hit the accretion disks around the individual black holes. We investigate the observability of both signatures. The hard X-ray signal may be particularly valuable as it can provide an indicator of black hole merger a few decades in advance of the event.

  4. CytometryML binary data standards

    NASA Astrophysics Data System (ADS)

    Leif, Robert C.

    2005-03-01

    CytometryML is a proposed new Analytical Cytology (Cytomics) data standard, which is based on a common set of XML schemas for encoding flow cytometry and digital microscopy text based data types (metadata). CytometryML schemas reference both DICOM (Digital Imaging and Communications in Medicine) codes and FCS keywords. Flow Cytometry Standard (FCS) list-mode has been mapped to the DICOM Waveform Information Object. The separation of the large binary data objects (list mode and image data) from the XML description of the metadata permits the metadata to be directly displayed, analyzed, and reported with standard commercial software packages; the direct use of XML languages; and direct interfacing with clinical information systems. The separation of the binary data into its own files simplifies parsing because all extraneous header data has been eliminated. The storage of images as two-dimensional arrays without any extraneous data, such as in the Adobe Photoshop RAW format, facilitates the development by scientists of their own analysis and visualization software. Adobe Photoshop provided the display infrastructure and the translation facility to interconvert between the image data from commercial formats and RAW format. Similarly, the storage and parsing of list mode binary data type with a group of parameters that are specified at compilation time is straight forward. However when the user is permitted at run-time to select a subset of the parameters and/or specify results of mathematical manipulations, the development of special software was required. The use of CytometryML will permit investigators to be able to create their own interoperable data analysis software and to employ commercially available software to disseminate their data.

  5. An Enterotoxin-like Binary Protein from Pseudomonas protegens with Potent Nematicidal Activity.

    PubMed

    Wei, Jun-Zhi; Siehl, Daniel L; Hou, Zhenglin; Rosen, Barbara; Oral, Jarred; Taylor, Christopher G; Wu, Gusui

    2017-07-21

    Soil microbes are a major food source for free-living soil nematodes. It is known that certain soil bacteria have evolved systems to combat predation. We identified the nematode-antagonistic Pseudomonas protegens strain 15G2 from screening of microbes. Through protein purification we identified a binary protein, designated as Pp-ANP, that is responsible for the nematicidal activity. This binary protein inhibits Caenorhabditis elegans growth and development by arresting larvae at L1 stage and killing older staged worms. The two subunits, Pp-ANP1a and Pp-ANP2a are active when reconstituted from separate expression in Escherichia coli The binary toxin also shows strong nematicidal activity against three other free-living nematodes, Pristionchus pacificus, Panagrellus redivivus, and Acrobeloides sp., but no activity was found for insects and fungi under test conditions, indicating specificity for nematodes. Pp-ANP1a has no significant homology to any known proteins, while Pp-ANP2a shows ∼30% homology to E. coli heat-labile enterotoxin (LT) subunit A and cholera toxin (CT) subunit A. Protein modeling indicates Pp-ANP2a is structurally similar to CT/LT and likely acts as a ADP-ribosyltransferase. Despite the similarity, Pp-ANP shows several characteristics distinct from CT/LT toxins. Our results indicate that Pp-ANP is a new enterotoxin-like binary toxin with potent and specific activity to nematodes. The potency and specificity of Pp-ANP suggests applications in controlling parasitic nematodes and opens an avenue for further research on its mechanism of action and role in bacterium-nematode interaction.IMPORTANCE This study reports the discovery of a new enterotoxin-like binary protein, Pp-ANP from a Pseudomonas protegens strain. Pp-ANP shows strong nematicidal activity against Caenorhabditis elegans larvae and older staged worms. It also shows strong activity on other free-living nematodes, Pristionchus pacificus, Panagrellus redivivus, and Acrobeloides sp. The two

  6. PAGB stars in binary stellar population synthesis model

    NASA Astrophysics Data System (ADS)

    Hernández-Pérez, F. C.; Bruzual, G.; Magris, G.

    2017-07-01

    Post Asymptotic Giant Branch (PAGB) stars are luminous objects (103 - 104L⊙) in final stages of their evolution before reaching the white dwarf cooling sequence. They are an important key to understand galaxy evolution since they are hot enough to contribute to the UV excess in old stellar systems. Binary interactions may change the evolutionary path over the HR diagram and the total number of PAGB stars may also change. In this contribution we remark that rare Yellow PAGB stars are formed through mass transfer in a binary system, however the probability of formation is low. We use a recent implementation of the BC03 stellar population synthesis model that allows a stochastic sampling of the initial mass function to evolve single stars. We select, assemble and evolve binary systems using our binary code. We run ten realizations of simulated clusters for a Z=0.0005, M=106M_⊙, BF=0.9. One evolved stars formed in a binary system appears near the region of observed yellow PAGB stars. To demonstrate that these rare stars may be form through binary interaction, we select binary pairs with period less than critical to ensure mass transfer. The yellow PAGB star is formed by binary interaction. Binary and stochastic effects on the formation of yellow PAGB and the influence on spectral and photometric properties of the stellar systems will be studied in future work.

  7. Improving geothermal power plants with a binary cycle

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Shipkov, A. A.; Sorokina, E. V.

    2015-12-01

    The recent development of binary geothermal technology is analyzed. General trends in the introduction of low-temperature geothermal sources are summarized. The use of single-phase low-temperature geothermal fluids in binary power plants proves possible and expedient. The benefits of power plants with a binary cycle in comparison with traditional systems are shown. The selection of the working fluid is considered, and the influence of the fluid's physicochemical properties on the design of the binary power plant is discussed. The design of binary power plants is based on the chemical composition and energy potential of the geothermal fluids and on the landscape and climatic conditions at the intended location. Experience in developing a prototype 2.5 MW Russian binary power unit at Pauzhetka geothermal power plant (Kamchatka) is outlined. Most binary systems are designed individually for a specific location. Means of improving the technology and equipment at binary geothermal power plants are identified. One option is the development of modular systems based on several binary systems that employ the heat from the working fluid at different temperatures.

  8. Evaporation of companions in VLMXBS and in binary millisecond pulsars.

    NASA Astrophysics Data System (ADS)

    Shaham, J.

    The principles underlying the process of formation of a wind from a stellar atmosphere by external heating are applied to binary companions of neutron stars (NS) which are being heated by radiation from the NS in very-low-mass X-ray binaries (VLMXBs) and in binary millisecond pulsar (BMP) systems. Among others, the possibility of companion evaporation and of self-excited X-ray systems is discussed. The fast changes in the binary period of the "windy" BMP PSR 1957+20 and the nature of the newly discovered "windy" BMP PSR 1744-24A are also discussed.

  9. Modern geothermal power: Binary cycle geothermal power plants

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Shipkov, A. A.

    2017-04-01

    In the second part of the review of modern geothermal power plant technologies and equipment, a role, a usage scale, and features of application of binary cycle plants in the geothermal economy are considered. Data on the use of low-boiling fluids, their impact on thermal parameters and performance of geothermal binary power units are presented. A retrospective of the use of various low-boiling fluids in industrial binary power units in the world since 1965 is shown. It is noted that the current generating capacity of binary power units running on hydrocarbons is equal to approximately 82.7% of the total installed capacity of all the binary power units in the world. At the same time over the past 5 years, the total installed capacity of geothermal binary power units in 25 countries increased by more than 50%, reaching nearly 1800 MW (hereinafter electric power is indicated), by 2015. A vast majority of the existing binary power plants recovers heat of geothermal fluid in the range of 100-200°C. Binary cycle power plants have an average unit capacity of 6.3 MW, 30.4 MW at single-flash power plants, 37.4 MW at double-flash plants, and 45.4 MW at power plants working on superheated steam. The largest binary cycle geothermal power plants (GeoPP) with an installed capacity of over 60 MW are in operation in the United States and the Philippines. In most cases, binary plants are involved in the production process together with a steam cycle. Requirements to the fluid ensuring safety, reliability, and efficiency of binary power plants using heat of geothermal fluid are determined, and differences and features of their technological processes are shown. Application of binary cycle plants in the technological process of combined GeoPPs makes it possible to recover geothermal fluid more efficiently. Features and advantages of binary cycle plants using multiple fluids, including a Kalina Cycle, are analyzed. Technical characteristics of binary cycle plants produced by various

  10. Binary frequency and origin of the OB runaway stars

    SciTech Connect

    Gies, D.R.; Bolton, C.T.

    1986-06-01

    A radial velocity survey of the bright northern OB runaway stars has been undertaken to determine the frequency of binary stars in this high-velocity group. A total of 634 high-dispersion spectrograms of 36 proposed runaway stars were obtained over a two year period. Approximately half of the stars are velocity-variable; these include seven spectroscopic binaries, one possible beta-Cephei variable, and 10 stars with emission lines in their spectra. The latter group contains seven of the eight Be stars observed and three luminous O stars, and it is argued that their variability is caused by nonradial pulsation. Fifteen of the program stars have a peculiar radial velocity greater than 30 km/s; five others are probable runaways on the basis of distance from the galactic plane and proper motion. Only two of the confirmed and probable runaways, HD 3950 and HD 198846 (Y Cyg), are binaries, and both are double-lines systems. New orbital elements are presented for HD 3950 and the five new binary systems found among the low-velocity stars. The statisical methods used to assess velocity variability and periodic signals are described in detail. The higher fractional abundance of runaways among more massive stars, their binary frequency, and the properties of the runaway binaries suggest that they obtained their high velocities through single-binary, binary-binary, or n-body close encounters during the early dynamical evolution of associations. 208 references.

  11. Polarization from Scattering in X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Kallman, T.

    2009-01-01

    A paradox of X-ray binaries is that their strong X-ray flux ionizes much nearby low density gas, making it difficult to observe. Polarization can reveal gas which is fully ionized and can provide new insight into X-ray binary environments. In this talk I will present models for the scattering and polarization in X-ray binaries, adopting gas parameters which are chosen according to current ideas about these systems. These include stellar winds from a massive companion, X-ray induced disk winds, and the photospheres of a disk or binary companion.

  12. DESTRUCTION OF BINARY MINOR PLANETS DURING NEPTUNE SCATTERING

    SciTech Connect

    Parker, Alex H.; Kavelaars, J. J.

    2010-10-20

    The existence of extremely wide binaries in the low-inclination component of the Kuiper Belt provides a unique handle on the dynamical history of this population. Some popular frameworks of the formation of the Kuiper Belt suggest that planetesimals were moved there from lower semimajor axis orbits by scattering encounters with Neptune. We test the effects such events would have on binary systems and find that wide binaries are efficiently destroyed by the kinds of scattering events required to create the Kuiper Belt with this mechanism. This indicates that a binary-bearing component of the cold Kuiper Belt was emplaced through a gentler mechanism or was formed in situ.

  13. Pro-Am Collaborations on Eclipsing Binary Star Problems

    NASA Astrophysics Data System (ADS)

    Terrell, D.

    2004-05-01

    I discuss the fruits of a decade of amateur-professional collaboration on eclipsing binary stars. Our team consists of a mix of visual, photoelectric and CCD observers that use the strengths of each observing approach to study newly discovered and neglected eclipsing binary systems. We have active programs on time of minimum measurements and high-precision photometry that results in detailed analysis of the binaries to find fundamental parameters such as masses and radii. We have also discovered and/or characterized several unusal binaries that have had an influence on stellar evolution theory.

  14. Clouds and Binaries Across the L/T Transition

    NASA Astrophysics Data System (ADS)

    Burgasser, Adam J.

    2014-01-01

    The evolution of clouds plays a primary, if not defining, role in shaping the spectral transition from L to T spectral classes, a transition through which all brown dwarfs must pass. The role of clouds is particularly notable in binary systems which straddle this transition. In this talk, I will briefly review the evidence of cloud evolution across the L/T transition and the observable impacts (the 1 µm brightening, binary excess, flattening of luminosities, spectral feature evolution, spectral binaries). I will then go into detail on the most recently discovered L/T transition binary, Luhman 16AB, and present the first results on spectral variability in this system.

  15. Planetary system disruption by Galactic perturbations to wide binary stars.

    PubMed

    Kaib, Nathan A; Raymond, Sean N; Duncan, Martin

    2013-01-17

    Nearly half the exoplanets found within binary star systems reside in very wide binaries with average stellar separations greater than 1,000 astronomical units (one astronomical unit (AU) being the Earth-Sun distance), yet the influence of such distant binary companions on planetary evolution remains largely unstudied. Unlike their tighter counterparts, the stellar orbits of wide binaries continually change under the influence of the Milky Way's tidal field and impulses from other passing stars. Here we report numerical simulations demonstrating that the variable nature of wide binary star orbits dramatically reshapes the planetary systems they host, typically billions of years after formation. Contrary to previous understanding, wide binary companions may often strongly perturb planetary systems, triggering planetary ejections and increasing the orbital eccentricities of surviving planets. Although hitherto not recognized, orbits of giant exoplanets within wide binaries are statistically more eccentric than those around isolated stars. Both eccentricity distributions are well reproduced when we assume that isolated stars and wide binaries host similar planetary systems whose outermost giant planets are scattered beyond about 10 AU from their parent stars by early internal instabilities. Consequently, our results suggest that although wide binaries eventually remove the most distant planets from many planetary systems, most isolated giant exoplanet systems harbour additional distant, still undetected planets.

  16. Black hole binaries dynamically formed in globular clusters

    NASA Astrophysics Data System (ADS)

    Park, Dawoo; Kim, Chunglee; Lee, Hyung Mok; Bae, Yeong-Bok; Belczynski, Krzysztof

    2017-08-01

    We investigate properties of black hole (BH) binaries formed in globular clusters via dynamical processes, using directN-body simulations. We pay attention to effects of BH mass function on the total mass and mass ratio distributions of BH binaries ejected from clusters. First, we consider BH populations with two different masses in order to learn basic differences from models with single-mass BHs only. Secondly, we consider continuous BH mass functions adapted from recent studies on massive star evolution in a low metallicity environment, where globular clusters are formed. In this work, we consider only binaries that are formed by three-body processes and ignore stellar evolution and primordial binaries for simplicity. Our results imply that most BH binary mergers take place after they get ejected from the cluster. Also, mass ratios of dynamically formed binaries should be close to 1 or likely to be less than 2:1. Since the binary formation efficiency is larger for higher-mass BHs, it is likely that a BH mass function sampled by gravitational-wave observations would be weighed towards higher masses than the mass function of single BHs for a dynamically formed population. Applying conservative assumptions regarding globular cluster populations such as small BH mass fraction and no primordial binaries, the merger rate of BH binaries originated from globular clusters is estimated to be at least 6.5 yr-1 Gpc-3. Actual rate can be up to more than several times of our conservative estimate.

  17. Dark Matter from Binary Tetrahedral Flavor Symmetry

    NASA Astrophysics Data System (ADS)

    Eby, David; Frampton, Paul

    2012-03-01

    Binary Tetrahedral Flavor Symmetry, originally developed as a quark family symmetry and later adapted to leptons, has proved both resilient and versatile over the past decade. In 2008 a minimal T' model was developed to accommodate quark and lepton masses and mixings using a family symmetry of (T'xZ2). We examine an expansion of this earlier model using an additional Z2 group that facilitates predictions of WIMP dark matter, the Cabibbo angle, and deviations from Tribimaximal Mixing, while giving hints at the nature of leptogenesis.

  18. HST observations of Kuiper Belt binaries

    NASA Astrophysics Data System (ADS)

    Margot, J. L.; Brown, M. E.; Trujillo, C. A.; Sari, R.

    2004-11-01

    We report preliminary results from a Hubble Space Telescope (HST) program designed to characterize the orbital and physical properties of six confirmed KBO binaries [Margot et al. 2003]. Our results show that KBOs in our sample have much smaller sizes and larger albedos than expected, possibly requiring continuous collisional resurfacing and implying a Kuiper Belt that is less massive than previously assumed. Table 1 describes a subset of four KBO binaries that can be clearly resolved only with HST (1999 TC36, 1998 SM165, 2001 QC298, 1997 CQ29). The orbital period P and semi-major axis a yield the total mass of the binary M. Uncertainties listed are three times the formal errors of the fit or 1%, whichever is greater. The primary to secondary radius ratio Rp/R_s is based on flux measurements in HST's F606W filter. We used the absolute magnitudes as reported by JPL's Horizons system, assumed that binary components have identical albedos and densities, and derived the densities corresponding to geometric albedos of 5%, 10%, and 20%. Most KBOs in our sample must have albedos in excess of the radiometric average of 8% [Altenhoff et al., 2004] otherwise their density would be implausibly low. For unit density, the primary radii/geometric albedos are (147 km, 23%), (116 km, 15%), (117 km, 7.6%), and (42 km, 41%). Detection of such small KBOs in the IR/mm is challenging. \\begin{tabular}[h]{rrrrrrrr} & P [days] & a [km] & M [1018 kg]& (Rp)/(R_s) & ρ 5 & ρ 10 & ρ 20 TC& 50.38 ± 0.5 & 7640 ± 460 & 13.9 ± 2.5 & 2.7 & 0.1 & 0.3 & 0.8 SM& 130.1 ± 1 & 11310 ± 110 & 6.78 ± 0.24 & 3.0 & 0.2 & 0.5 & 1.5 QC& 19.23 ± 0.2 & 3690 ± 70 & 10.8 ± 0.7 & 1.2 & 0.5 & 1.5 & 4.3 CQ& 309.2 ± 3 & 8320 ± 240 & 0.48 ± 0.04 & 1.2 & - & 0.1 & 0.3 References Margot, Brown, Trujillo, Sari, HST General Observer Prgm 9746, 2003. Altenhoff, Bertoldi, Menten, A&A 415, 2004.

  19. Stretchable Binary Fresnel Lens for Focus Tuning

    PubMed Central

    Li, Xueming; Wei, Lei; Poelma, René H.; Vollebregt, Sten; Wei, Jia; Urbach, Hendrik Paul; Sarro, Pasqualina M.; Zhang, Guo Qi

    2016-01-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material combines the excellent optical absorption properties of the CNT with the transparency and stretchability of the PDMS. By stretching the elastomeric composite in radial direction, the lens focal length is tuned. Good focusing response is demonstrated and a large focus change (≥24%) was achieved by stretching lenses up to 11.4%. PMID:27139747

  20. Analyzing correlated binary data using SAS.

    PubMed

    Lipsitz, S R; Harrington, D P

    1990-06-01

    We discuss methods for analyzing repeated binary measurements on the same individual. In spite of the fact that the repeated measurements on the same individual are correlated, the ordinary logistic regression maximum likelihood estimates (which assume that the repeated measures are independent) are consistent and asymptotically normal (K. Y. Liang and S. L. Zeger, Biometrika 73, 13 (1986]. However, the inverse of the estimated information matrix (assuming independence) can give inconsistent estimates of the asymptotic variance of estimated parameters. We describe how to obtain the logistic regression estimates, as well as a consistent estimate of their covariance matrix, in SAS, with minimal matrix manipulations.

  1. Multiwavelength Studies of gamma-ray Binaries

    NASA Astrophysics Data System (ADS)

    Aragona, Christina

    2011-01-01

    High mass X-ray binaries (HMXBs) consist of an O or B star orbited by either a neutron star or a black hole. Of the 114 known Galactic HMXBs, a handful of these objects, dubbed gamma-ray binaries, have been observed to produce MeV-TeV emission. The very high energy emission can be produced either by accretion from the stellar wind onto a black hole or a collision between the stellar wind and a relativistic pulsar wind. Both these scenarios make gamma-ray binaries valuable nearby systems for studying the physics of shocks and jets. Currently, the nature of the compact object and the high energy production mechanism is unknown or unconfirmed in over half of these systems. My goal for this dissertation is to constrain the parameters describing two of these systems: LS 5039 and HD 259440. LS 5039 exhibits gamma-ray emission modulated with its orbital period. The system consists of an ON6.5V((f)) star and an unidentified compact companion. Using optical spectra from the CTIO 1.5m telescope, we found LS 5039 to have an orbital period of 3.90608 d and an eccentricity of 0.337. Spectra of the Halpha line observed with SOAR indicate a mass loss rate of ˜ 1.9x10 -8 M yr-1. Observations taken with ATCA at 13 cm, 6 cm, and 3 cm indicate radio fluxes between 10--40 mJy. The measurements show variability with time, indicating a source other than thermal emission from the stellar wind. HD 259440 is a B0pe star that was proposed as the optical counterpart to the gamma-ray source HESS J0632+057. Using optical spectra from the KPNO CF, KPNO 2.1m, and OHP telescopes, we find a best fit stellar effective temperature of 27500--30000 K, a log surface gravity of 3.75--4.0, a mass of 13.2--19.0 Msolar, and a radius of 6.0--9.6 Rsolar. By fitting the spectral energy distribution, we find a distance between 1.1--1.7 kpc. We do not detect any significant radial velocity shifts in our data, ruling out orbital periods shorter than one month. If HD 259440 is a binary, it is likely a long

  2. Binary Nucleation of Water and Sodium Chloride

    SciTech Connect

    Nemec, Thomas; Marsik, Frantisek; Palmer, Donald

    2005-01-01

    Nucleation processes in the binary water-sodium chloride system are investigated in the sense of the classical nucleation theory (CNT). The CNT is modified to be able to handle the electrolytic nature of the system and is employed to investigate the acceleration of the nucleation process due to the presence of sodium chloride in the steam. This phenomenon, frequently observed in the Wilson zone of steam turbines, is called early condensation. Therefore, the nucleation rates of the water-sodium chloride mixture are of key importance in the power cycle industry.

  3. Binary stars: Mass transfer and chemical composition

    NASA Technical Reports Server (NTRS)

    Lambert, D. L.

    1982-01-01

    It is noted that mass exchange (and mass loss) within a binary system should produce observable changes in the surface chemical composition of both the mass losing and mass gaining stars as a stellar interior exposed to nucleosyntheses is uncovered. Three topics relating mass exchange and/or mass loss to nucleosynthesis are sketched: the chemical composition of Algol systems; the accretion disk of a cataclysmic variable fed by mass from a dwarf secondary star; and the hypothesis that classical Ba II giants result from mass transfer from a more evolved companion now present as a white dwarf.

  4. Observations of mass accretion in binary stars

    NASA Technical Reports Server (NTRS)

    Polidan, R. S.; Peters, G. J.

    1982-01-01

    Results from high resolution observations of eight close binary stars (TX UMa, U CrB, CX Dra, TT Hya, AU Mon, KX And, HR 2142, and phi Per) are presented. Variable absorption lines, indicative of mass flow, are observed in all systems expect phi Per. Emission lines are seen in KX And and phi Per. Variable high ionization features (NV, SiIV, and CIV) are seen in TX UMa, UCrB, CX Dra, and AU Mon. The observations are modeled using the calculations of Lubow and Shu.

  5. 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.

  6. Modelling Gravitational Radiation from Binary Black Holes

    NASA Technical Reports Server (NTRS)

    Centrella, Joan

    2006-01-01

    The final merger and coalescence of binary black holes is a key source of strong gravitational waves for the LISA mission. Observing these systems will allow us to probe the formation of cosmic structure to high redshifts and test general relativity directly in the strong-field, dynamical regime. Recently, major breakthroughs have been made in modeling black hole mergers using numerical relativity. This talk will survey these exciting developments, focusing on the gravitational waveforms and the recoil kicks produced from non-equal mass mergers.

  7. The Algol binary system KZ Pavonis revisited

    NASA Astrophysics Data System (ADS)

    Sürgit, D.; Erdem, A.; Budding, E.

    2010-09-01

    We present results from analysing new spectroscopic and photometric observations of the KZ Pav (IDS 20490-7048 A-BC) multiple system. High-resolution spectra were taken at the Mt John University Observatory in 2007 and 2008. Radial velocities for the close binary were determined from cross-correlation and spectral disentangling methods. The resulting orbital elements are a1 sin i = 0.0103 +/- 0.0001au, a2 sin i = 0.0158 +/- 0.0001 au, M1 sin3i = 1.598 +/- 0.006 Msolar and M2 sin3i = 1.045 +/- 0.006 Msolar. The close binary components rotated synchronously according to their MgI (5183.6 Å) line profiles. Four photometric data sets (1988-89 BV, 1998 V, Hipparcos and 2006 BVRI) were modelled with modern light-curve synthesis methods. The radial velocity models, including proximity effects, give the close binary mass ratio as 0.641 +/- 0.003. The combination of the photometric light and radial velocity data gives the following absolute parameters: M1 = 1.70 +/- 0.02 Msolar, M2 = 1.09 +/- 0.03 Msolar, R1 = 1.74 +/- 0.01 Rsolar, R2 = 1.94 +/- 0.02 Rsolar, L1 = 5.86 +/- 0.81 Lsolar and L2 = 2.32 +/- 0.40 Lsolar. The distance to KZ Pav is 115 +/- 8 pc from our analysis, taking into account interstellar extinction. The orbital period of the close binary, from times of minimum data covering nearly one century, indicates a quasi-sinusoidal form superimposed on a downward parabola. The secular period decrease was interpreted in terms of the combined effects of mass transfer and loss. The sinusoidal component may reflect a light-time effect from either an unseen component or higher order terms in perturbations from the BC system, or perhaps an internal magnetic field rearrangement (Applegate type) mechanism. The orbits of the A-BC and B-C systems are considered against historic astrometric measurements.

  8. Pycnonuclear reaction rates for binary ionic mixtures

    NASA Technical Reports Server (NTRS)

    Ichimaru, S.; Ogata, S.; Van Horn, H. M.

    1992-01-01

    Through a combination of compositional scaling arguments and examinations of Monte Carlo simulation results for the interparticle separations in binary-ionic mixture (BIM) solids, we have derived parameterized expressions for the BIM pycnonuclear rates as generalizations of those in one-component solids obtained previously by Salpeter and Van Horn and by Ogata et al. We have thereby discovered a catalyzing effect of the heavier elements, which enhances the rates of reactions among the lighter elements when the charge ratio exceeds a critical value of approximately 2.3.

  9. Stretchable Binary Fresnel Lens for Focus Tuning

    NASA Astrophysics Data System (ADS)

    Li, Xueming; Wei, Lei; Poelma, René H.; Vollebregt, Sten; Wei, Jia; Urbach, Hendrik Paul; Sarro, Pasqualina M.; Zhang, Guo Qi

    2016-05-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material combines the excellent optical absorption properties of the CNT with the transparency and stretchability of the PDMS. By stretching the elastomeric composite in radial direction, the lens focal length is tuned. Good focusing response is demonstrated and a large focus change (≥24%) was achieved by stretching lenses up to 11.4%.

  10. Stretchable Binary Fresnel Lens for Focus Tuning.

    PubMed

    Li, Xueming; Wei, Lei; Poelma, René H; Vollebregt, Sten; Wei, Jia; Urbach, Hendrik Paul; Sarro, Pasqualina M; Zhang, Guo Qi

    2016-05-03

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material combines the excellent optical absorption properties of the CNT with the transparency and stretchability of the PDMS. By stretching the elastomeric composite in radial direction, the lens focal length is tuned. Good focusing response is demonstrated and a large focus change (≥24%) was achieved by stretching lenses up to 11.4%.

  11. On some electrodynamic properties of binary pulsars

    NASA Astrophysics Data System (ADS)

    Sironi, Lorenzo

    2006-07-01

    The main purpose of my thesis is to examine some electrodynamic properties of binary pulsars, trying to understand the peculiar physical processes that can happen in their magnetospheres; the ultimate aim is to discuss if such systems can be the source of the observed flux of cosmic rays between the knee and the ankle, since the mechanisms of acceleration for the cosmic rays in this range of energies are still unknown. Attention around binary pulsars has arisen after the recent discovery (December 2003) of the first double neutron star system in which both the stars are visible as pulsars (PSR J0737-3039); the inspection of the physical features of this binary pulsar has led to some intriguing possibilities up to now unexplored. In this thesis I will first of all review what is already known about the main properties of this binary system. I will describe in particular the possibility to go further in the verification of the predictions of general relativity with the so-called post-Keplerian parameters; I will discuss the possibility of studying the optical properties of the magnetospheres, since the inclination angle of the orbit is nearly 90° and some orbital phases show an eclipse of the light from one pulsar due to absorption by the magnetosphere of the companion; I will rapidly summarize how the discovery of that binary pulsar can enlarge our knowledge about the origin and evolution of double neutron star systems; lastly, I will examine the increase in the estimate of the Galactic double neutron star merger rate due to the discovery of PSR J0737-3039. I will then summarize the current knowledge about the magnetosphere of a single pulsar. After describing the Gold-Pacini model for the energy loss of the oblique rotator (in which the magnetic and rotational axes are not parallel), I will discuss the Goldreich-Julian model for the aligned axisymmetric rotator in the force-free approximation in which the inertial and gravitational forces are neglected with

  12. Iterative method for generating correlated binary sequences

    NASA Astrophysics Data System (ADS)

    Usatenko, O. V.; Melnik, S. S.; Apostolov, S. S.; Makarov, N. M.; Krokhin, A. A.

    2014-11-01

    We propose an efficient iterative method for generating random correlated binary sequences with a prescribed correlation function. The method is based on consecutive linear modulations of an initially uncorrelated sequence into a correlated one. Each step of modulation increases the correlations until the desired level has been reached. The robustness and efficiency of the proposed algorithm are tested by generating sequences with inverse power-law correlations. The substantial increase in the strength of correlation in the iterative method with respect to single-step filtering generation is shown for all studied correlation functions. Our results can be used for design of disordered superlattices, waveguides, and surfaces with selective transport properties.

  13. Pycnonuclear reaction rates for binary ionic mixtures

    NASA Technical Reports Server (NTRS)

    Ichimaru, S.; Ogata, S.; Van Horn, H. M.

    1992-01-01

    Through a combination of compositional scaling arguments and examinations of Monte Carlo simulation results for the interparticle separations in binary-ionic mixture (BIM) solids, we have derived parameterized expressions for the BIM pycnonuclear rates as generalizations of those in one-component solids obtained previously by Salpeter and Van Horn and by Ogata et al. We have thereby discovered a catalyzing effect of the heavier elements, which enhances the rates of reactions among the lighter elements when the charge ratio exceeds a critical value of approximately 2.3.

  14. Automatic target detection using binary template matching

    NASA Astrophysics Data System (ADS)

    Jun, Dong-San; Sun, Sun-Gu; Park, HyunWook

    2005-03-01

    This paper presents a new automatic target detection (ATD) algorithm to detect targets such as battle tanks and armored personal carriers in ground-to-ground scenarios. Whereas most ATD algorithms were developed for forward-looking infrared (FLIR) images, we have developed an ATD algorithm for charge-coupled device (CCD) images, which have superior quality to FLIR images in daylight. The proposed algorithm uses fast binary template matching with an adaptive binarization, which is robust to various light conditions in CCD images and saves computation time. Experimental results show that the proposed method has good detection performance.

  15. Is the Coma cluster binary dominated?

    NASA Technical Reports Server (NTRS)

    The, Lih Sin; White, Simon D. M.

    1990-01-01

    It is investigated whether the model of an expanding cluster dominated by a massive binary galaxy, first suggested by Valtonen and Byrd (1979), is consistent with optical data on the surface density and velocity dispersion of the Coma cluster. The evolution of this model is simulated for a wide variety of initial conditions. It is found that galaxy counts in the model can be made to agree with observation, but that the observed velocity dispersion profile cannot be reproduced. A number of other arguments suggest that the central galaxies in Coma cannot be as massive as required by the model. This model is not a viable representation of the Coma cluster.

  16. Binary logic based purely on Fresnel diffraction

    NASA Astrophysics Data System (ADS)

    Hamam, H.; de Bougrenet de La Tocnaye, J. L.

    1995-09-01

    Binary logic operations on two-dimensional data arrays are achieved by use of the self-imaging properties of Fresnel diffraction. The fields diffracted by periodic objects can be considered as the superimposition of weighted and shifted replicas of original objects. We show that a particular spatial organization of the input data can result in logical operations being performed on these data in the considered diffraction planes. Among various advantages, this approach is shown to allow the implementation of dual-track, nondissipative logical operators. Image algebra is presented as an experimental illustration of this principle.

  17. Theory of Periodic-Binary-Sequence Generators

    NASA Technical Reports Server (NTRS)

    Perlman, M.

    1987-01-01

    Algorithms yield feedback shift registers with maximum regularity. Report provides extensive mathematical treatment of new and previous results related to generation of pseudo-noise binary sequences by feedback shift registers. Generator architectures amenable to efficient implementation in very-large-scale integrated (VLSI) circuits. Report includes literature references to applications of such sequences in random-number generation, radar, VLSI testing, data encryption and decryption, algebraic error-detection and error-correction encoding and decoding, and feedback-shift-register synthesis of sequential machines.

  18. Gold strip gratings with binary supercell.

    PubMed

    Magno, Giovanni; Marrocco, Valeria; Grande, Marco; D'Orazio, Antonella

    2013-08-01

    In this Letter, the study of a periodic structure composed of gold strips arranged in double-period unit cells, in a symmetric and asymmetric environment, is reported. The spectral maps show that the formation of the plasmonic bandgap and the extraordinary optical transmission are subjected to the proportion between the strip widths. Moreover, when the asymmetric environment is considered, high-transmittance and high-absorbance states arise. Hence, by controlling the geometrical parameters of the binary-periodic structure, it is possible to tailor the spectral response of the grating enhancing the desired features and exploiting them for different applications.

  19. Physical Structure of Four Symbiotic Binaries

    NASA Technical Reports Server (NTRS)

    Kenyon, Scott J. (Principal Investigator)

    1997-01-01

    Disk accretion powers many astronomical objects, including pre-main sequence stars, interacting binary systems, and active galactic nuclei. Unfortunately, models developed to explain the behavior of disks and their surroundings - boundary layers, jets, and winds - lack much predictive power, because the physical mechanism driving disk evolution - the viscosity - is not understood. Observations of many types of accreting systems are needed to constrain the basic physics of disks and provide input for improved models. Symbiotic stars are an attractive laboratory for studying physical phenomena associated with disk accretion. These long period binaries (P(sub orb) approx. 2-3 yr) contain an evolved red giant star, a hot companion, and an ionized nebula. The secondary star usually is a white dwarf accreting material from the wind of its red giant companion. A good example of this type of symbiotic is BF Cygni: our analysis shows that disk accretion powers the nuclear burning shell of the hot white dwarf and also manages to eject material perpendicular to the orbital plane (Mikolajewska, Kenyon, and Mikolajewski 1989). The hot components in other symbiotic binaries appear powered by tidal overflow from a very evolved red giant companion. We recently completed a study of CI Cygni and demonstrated that the accreting secondary is a solar-type main sequence star, rather than a white dwarf (Kenyon et aL 1991). This project continued our study of symbiotic binary systems. Our general plan was to combine archival ultraviolet and optical spectrophotometry with high quality optical radial velocity observations to determine the variation of line and continuum sources as functions of orbital phase. We were very successful in generating orbital solutions and phasing UV+optical spectra for five systems: AG Dra, V443 Her, RW Hya, AG Peg, and AX Per. Summaries of our main results for these systems appear below. A second goal of our project was to consider general models for the

  20. The orbital evolution of binary galaxies

    NASA Astrophysics Data System (ADS)

    Chan, R.; Junqueira, S.

    2001-02-01

    We present the results of self-consistent numerical simulations performed to study the orbital circularization of binary galaxies. We have generalized a previous model (Junqueira & de Freitas Pacheco 1994) and confirmed partially their results. The orbital evolution of pairs of galaxies is faster when we consider interacting pairs with contacting ``live'' galaxy halos but the circularization time remains larger than the Hubble time. Besides, the time behavior of the orbits has changed in comparison with previous work because of tidal forces and dynamical friction acting on the halos.

  1. Binary Cepheids From High-Angular Resolution

    NASA Astrophysics Data System (ADS)

    Gallenne, A.; Mérand, A.; Kervella, P.

    2015-12-01

    Optical interferometry is the only technique giving access to milli-arcsecond (mas) spatial resolution. This is a powerful and unique tool to detect the close orbiting companions of Cepheids, and offers an unique opportunity to make progress in resolving the Cepheid mass discrepancy. Our goal in studying binary Cepheids is to measure the astrometric position of the high-contrast companion, and then combine them with spectroscopic measurements to derive the orbital elements, distances, and dynamical masses. In the course of this program, we developed a new tool, CANDID, to search for high-contrast companions and set detection limits from interferometric observations

  2. Alloy softening in binary iron solid solutions

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Witzke, W. R.

    1976-01-01

    An investigation was conducted to determine softening and hardening behavior in 19 binary iron-alloy systems. Microhardness tests were conducted at four temperatures in the range 77 to 411 K. Alloy softening was exhibited by 17 of the 19 alloy systems. Alloy softening observed in 15 of the alloy systems was attributed to an intrinsic mechanism, believed to be lowering of the Peierls (lattice friction) stress. Softening and hardening rates could be correlated with the atomic radius ratio of solute to iron. Softening observed in two other systems was attributed to an extrinsic mechanism, believed to be associated with scavenging of interstitial impurities.

  3. Statistics of silicate units in binary glasses.

    PubMed

    Gaddam, Anuraag; Montagne, Lionel; Ferreira, José M F

    2016-09-28

    In this paper, we derive a new model to determine the distribution of silicate units in binary glasses (or liquids). The model is based on statistical mechanics and assumes grand canonical ensemble of silicate units which exchange energy and network modifiers from the reservoir. This model complements experimental techniques, which measure short range order in glasses such as nuclear magnetic resonance (NMR) spectroscopy. The model has potential in calculating the amounts of liquid-liquid phase segregation and crystal nucleation, and it can be easily extended to more complicated compositions. The structural relaxation of the glass as probed by NMR spectroscopy is also reported, where the model could find its usefulness.

  4. Theory of Periodic-Binary-Sequence Generators

    NASA Technical Reports Server (NTRS)

    Perlman, M.

    1987-01-01

    Algorithms yield feedback shift registers with maximum regularity. Report provides extensive mathematical treatment of new and previous results related to generation of pseudo-noise binary sequences by feedback shift registers. Generator architectures amenable to efficient implementation in very-large-scale integrated (VLSI) circuits. Report includes literature references to applications of such sequences in random-number generation, radar, VLSI testing, data encryption and decryption, algebraic error-detection and error-correction encoding and decoding, and feedback-shift-register synthesis of sequential machines.

  5. Unstable Binary Capsulated Transformants in Pneumococcus

    PubMed Central

    Bernheimer, Harriet P.; Wermundsen, Ingbritt E.

    1969-01-01

    Through transformation reactions, binary capsulated SI-III strains of pneumococci have been isolated that are unstable and lose the SI capsular genome at high frequency. The instability is caused by the specific mutation in the SIII capsular genome common to all of the unstable strains. In the family of strains studied, the SI capsular genome was integrated into the recipient chromosome in at least two loci: one apparently adjacent to the resident capsular genome and a second some distance from it. A hypothesis is presented to explain the instability of the strains on the basis of redundancy of genetic information. PMID:4389232

  6. The origin of ultra-compact binaries

    NASA Technical Reports Server (NTRS)

    Hachisu, Izumi; Miyaji, Shigeki; Saio, Hideyuki

    1987-01-01

    The origin of ultra-compact binaries composed of a neutron star and a low-mass (about 0.06 solar mass) white dwarf is considered. Taking account of the systemic losses of mass and angular momentum, it was found that a serious difficulty exists in the scenarios which involve tidal captures of a normal star (a main sequence star or a red giant) by a neutron star. This difficulty can be avoided if a red giant star is captured by a massive white dwarf (M is approx. greater than 1.2 solar masses), which becomes a neutron star through the accretion induced collapse.

  7. Associative memory - An optimum binary neuron representation

    NASA Technical Reports Server (NTRS)

    Awwal, A. A.; Karim, M. A.; Liu, H. K.

    1989-01-01

    Convergence mechanism of vectors in the Hopfield's neural network is studied in terms of both weights (i.e., inner products) and Hamming distance. It is shown that Hamming distance should not always be used in determining the convergence of vectors. Instead, weights (which in turn depend on the neuron representation) are found to play a more dominant role in the convergence mechanism. Consequently, a new binary neuron representation for associative memory is proposed. With the new neuron representation, the associative memory responds unambiguously to the partial input in retrieving the stored information.

  8. Binary Colloidal Alloy Test-5: Phase Separation

    NASA Technical Reports Server (NTRS)

    Lynch, Matthew; Weitz, David A.; Lu, Peter J.

    2008-01-01

    The Binary Colloidal Alloy Test - 5: Phase Separation (BCAT-5-PhaseSep) experiment will photograph initially randomized colloidal samples onboard the ISS to determine their resulting structure over time. This allows the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-PhaseSep studies collapse (phase separation rates that impact product shelf-life); in microgravity the physics of collapse is not masked by being reduced to a simple top and bottom phase as it is on Earth.

  9. Binary Colloidal Alloy Test-5: Compete

    NASA Technical Reports Server (NTRS)

    Frisken, Barbara J.; Bailey, Arthur E.; Weitz, David A.

    2008-01-01

    The Binary Colloidal Alloy Test - 5: Compete (BCAT-5-Compete) investigation will photograph andomized colloidal samples onboard the International Space Station (ISS) to determine their resulting structure over time. The use of EarthKAM software and hardware will allow the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-Compete will utilize samples 6 - 8 in the BCAT-5 hardware to study the competition between phase separation and crystallization, which is important in the manufacture of plastics and other materials.

  10. Neutron star binaries, pulsars and burst sources

    NASA Technical Reports Server (NTRS)

    Lamb, F. K.

    1981-01-01

    Unresolved issues involving neutron star binaries, pulsars, and burst sources are described. Attention is drawn to the types of observations most likely to resolve them. Many of these observations are likely to be carried out during the next decade by one or more missions that have been approved or proposed. Flux measurements with an imaging detector and broad-band spectroscopic studies in the energy range 30-150 keV are discussed. The need for soft X-ray and X-ray observations with an instrument which has arcminute angular resolution and an effective area substantially greater than of ROSAT or EXOSAT is also discussed.

  11. Binary/Analog CCD Correlator Development.

    DTIC Science & Technology

    1981-07-01

    AD-AI04 438 TEXAS INSTRUMENTS INC DALLAS F/ 9 /5 BINARY/ANALOG CCD COPPEL TOR DE VELOPMEN.(U JUL 81 R A HAKEN F19628-78-C-0122 CLASSIFIED TI -08-79...ANALOG CCD CORRELATOR DEVELOPMENT Texas Instruments Inc. R. A. Hakln APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLMITED DTIC S ELECTE SEP 211981i D...transversal filter with split-electrode weighting is well recogniied as a useful tool liInumher of sampled-data filtering applications.’ However, these

  12. Elliptic waveforms for inspiralling compact binaries

    NASA Astrophysics Data System (ADS)

    Mikóczi, Balázs

    2010-03-01

    The inspiral of supermassive black hole binary systems with high orbital eccentricity are the most promising sources for the gravitational wave observatories. The importance of elliptic gravitational waveforms in various physical scenarios has been emphasized by several authors (Wahlquist 1987, Moreno-Garrido, Buitrago and Mediavilla 1994, Martel and Poisson 1999). Taking into account the eccentricity of the orbit in the total waveform improves the parameter estimation for these sources, as it is shown by the construction and analyzation of the Fisher information matrix. In our work we use the Fourier-Bessel analysis of the Kepler motion and the stationary phase approximation of time-depend waveforms.

  13. 6384 Kervin: A Possible Hungaria Binary Asteroid

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Aznar Macia, Amadeo

    2016-04-01

    Analysis of CCD photometric observations in late 2015 of the Hungaria asteroid 6384 Kervin indicates that it may be a binary asteroid with a primary lightcurve of P1 = 3.6194 ± 0.0001 h, A1 = 0.06 ± 0.01 mag. The secondary lightcurve parameters are P2 = 15.94 ± 0.01 h, A2 = 0.03 ± 0.01 mag. No mutual events (occultations or eclipses) were observed. However, other indicators give an estimated diameter ratio on the order of Ds/Dp ~ 0.3, possibly greater.

  14. The origin of ultra-compact binaries

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Miyaji, Shigeki; Saio, Hideyuki

    The origin of ultra-compact binaries composed of a neutron star and a low-mass (about 0.06 solar mass) white dwarf is considered. Taking account of the systemic losses of mass and angular momentum, it was found that a serious difficulty exists in the scenarios which involve tidal captures of a normal star (a main sequence star or a red giant) by a neutron star. This difficulty can be avoided if a red giant star is captured by a massive white dwarf (M is approx. greater than 1.2 solar masses), which becomes a neutron star through the accretion induced collapse.

  15. Alloy softening in binary molybdenum alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Witzke, W. R.

    1972-01-01

    An investigation was conducted to determine the effects of alloy additions of Hf, Ta, W, Re, Os, Ir, and Pt on the hardness of Mo. Special emphasis was placed on alloy softening in these binary Mo alloys. Results showed that alloy softening was produced by those elements having an excess of s+d electrons compared to Mo, while those elements having an equal number or fewer s+d electrons than Mo failed to produce alloy softening. Alloy softening and hardening can be correlated with the difference in number of s+d electrons of the solute element and Mo.

  16. KEPLER ECLIPSING BINARY STARS. II. 2165 ECLIPSING BINARIES IN THE SECOND DATA RELEASE

    SciTech Connect

    Slawson, Robert W.; Doyle, Laurance R.; Prsa, Andrej; Engle, Scott G.; Conroy, Kyle; Coughlin, Jared; Welsh, William F.; Orosz, Jerome A.; Gregg, Trevor A.; Fetherolf, Tara; Short, Donald R.; Windmiller, Gur; Rucker, Michael; Batalha, Natalie; Fabrycky, Daniel C.; Jenkins, Jon M.; Mullally, F.; Seader, Shawn E.

    2011-11-15

    The Kepler Mission provides nearly continuous monitoring of {approx}156,000 objects with unprecedented photometric precision. Coincident with the first data release, we presented a catalog of 1879 eclipsing binary systems identified within the 115 deg{sup 2} Kepler field of view (FOV). Here, we provide an updated catalog augmented with the second Kepler data release which increases the baseline nearly fourfold to 125 days. Three hundred and eighty-six new systems have been added, ephemerides and principal parameters have been recomputed. We have removed 42 previously cataloged systems that are now clearly recognized as short-period pulsating variables and another 58 blended systems where we have determined that the Kepler target object is not itself the eclipsing binary. A number of interesting objects are identified. We present several exemplary cases: four eclipsing binaries that exhibit extra (tertiary) eclipse events; and eight systems that show clear eclipse timing variations indicative of the presence of additional bodies bound in the system. We have updated the period and galactic latitude distribution diagrams. With these changes, the total number of identified eclipsing binary systems in the Kepler FOV has increased to 2165, 1.4% of the Kepler target stars. An online version of this catalog is maintained at http://keplerEBs.villanova.edu.

  17. Binary Star Systems and Extrasolar Planets: The PHASES Search for Planets in Binaries

    NASA Astrophysics Data System (ADS)

    Muterspaugh, M. W.; PTI: Palomar Testbed Interferometer Collaboration; PHASES Team

    2005-12-01

    A new observing method has been developed to perform very high precision differential astrometry on bright binary stars with separations in the range of 0.1-1.0 arcseconds. Typical measurement precisions over an hour of integration are on the order of 10 micro-arcseconds, enabling one to look for perturbations to the Keplerian orbit that would indicate the presence of additional components to the system. This is used as the basis for a new program to find extrasolar planets. The Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) is a search for giant planets orbiting either star in 50 binary systems. The goal of this search is to detect or rule out planets in the systems observed and thus place limits on any enhancements of planet formation in binaries. It is also used to measure fundamental properties of the stars comprising the binary, such as masses and distances, useful for constraining stellar models at the 10-3 level. This work is funded in part by a Michelson Graduate Fellowship, the California Institute of Technology Astronomy Department, and the National Aeronautics and Space Administration under Grant No. NNG05GJ58G issued through the Terrestrial Planet Finder Foundation Science Program.

  18. The luminous red nova M101-OT2015-1: a candidate for common envelope ejection

    NASA Astrophysics Data System (ADS)

    Blagorodnova, Nadejda; Kasliwal, Mansi M.; Kotak, Rubina

    2017-01-01

    Binary interaction is an important phase in the study of stellar evolution. Approximately 50% of O star population live in close binary systems as to allow interaction with the companion. Although massive binary progenitors have been associated with thermonuclear supernovae, stripped core collapse supernovae, cataclysmic variables, X-ray binaries, or the mind blowing massive binary black holes recently detected by LIGO, the exact evolutionary path followed by the system is still under debate. One of the critical phases is the common envelope (CE) phase, required to bring a long period binary into a much shorter orbit. Currently, this phase also represents a challenge for the current stellar evolution models. Given the uncertainty, observational constraints are valuable input to advance in this field. One particular class of transient objects, called Luminous Red Novae (LRNe), has been associated with the termination of the CE phase, when a total or partial ejection of the least bound layers of the primary star are expelled at the expense of decreasing the orbital energy of the system. In my talk I will discuss the results of 16 years of observations of M101-OT2015-1, a LRN in M101 galaxy. I will describe the progenitor star (system) and the main characteristics of the outburst. Finally, I will present the results of the evolution of its remnant in infrared wavelengths. Given the long time span of our observations, this event represents one of the best studied CE ejection candidate at extragalactic distances.

  19. The close binary properties of massive stars in the Milky Way and low-metallicity Magellanic Clouds

    SciTech Connect

    Moe, Maxwell; Di Stefano, Rosanne

    2013-12-01

    In order to understand the rates and properties of Type Ia and Type Ib/c supernovae, X-ray binaries, gravitational wave sources, and gamma-ray bursts as a function of galactic environment and cosmic age, it is imperative that we measure how the close binary properties of O- and B-type stars vary with metallicity. We have studied eclipsing binaries with early B main-sequence primaries in three galaxies with different metallicities: the Large and Small Magellanic Clouds (LMC and SMC, respectively) and the Milky Way (MW). The observed fractions of early B stars that exhibit deep eclipses 0.25 < Δm (mag) < 0.65 and orbital periods 2 < P (days) < 20 in the MW, LMC, and SMC span a narrow range of (0.7-1.0)%, which is a model-independent result. After correcting for geometrical selection effects and incompleteness toward low-mass companions, we find for early B stars in all three environments (1) a close binary fraction of (22 ± 5)% across orbital periods 2 < P (days) < 20 and mass ratios q = M {sub 2}/M {sub 1} > 0.1, (2) an intrinsic orbital period distribution slightly skewed toward shorter periods relative to a distribution that is uniform in log P, (3) a mass-ratio distribution weighted toward low-mass companions, and (4) a small, nearly negligible excess fraction of twins with q > 0.9. Our fitted parameters derived for the MW eclipsing binaries match the properties inferred from nearby, early-type spectroscopic binaries, which further validates our results. There are no statistically significant trends with metallicity, demonstrating that the close binary properties of massive stars do not vary across metallicities –0.7 < log(Z/Z {sub ☉}) < 0.0 beyond the measured uncertainties.

  20. U1A Complex

    SciTech Connect

    2014-10-28

    Some of the most sophisticated experiments in the stockpile stewardship program are conducted in an environmentally safe manner, nearly 1000 feet below the ground at the site. The U1a complex a sprawling underground laboratory and tunnel complex is home to a number of unique capabilities.