A5102953822- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- High-pressure geophysics and materials
- Nuclear physics research studies
- Advanced Semiconductor Detectors and Materials
- Adaptive optics and wavefront sensing
- Particle accelerators and beam dynamics
- Astrophysics and Cosmic Phenomena
- Historical Astronomy and Related Studies
- Advanced Proteomics Techniques and Applications
- Historical and Architectural Studies
- Genomics and Phylogenetic Studies
- Probiotics and Fermented Foods
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Laser-induced spectroscopy and plasma
- Radiation Detection and Scintillator Technologies
- Public Policy and Administration Research
- Silicone and Siloxane Chemistry
University of Southern California
2013-2023
Space Science Institute
2013
Southern California University for Professional Studies
1994-2011
U.S. National Science Foundation
2000-2008
Kitt Peak National Observatory
2000-2008
Association of Universities For Research In Astronomy
2000-2008
Goddard Space Flight Center
2004
Princeton University
1980
University of California, Los Angeles
1976
Ministry of Agriculture, Fisheries and Food
1967
The B-emission line stars are rapid rotators that were probably spun up by mass and angular momentum accretion through transfer in an interacting binary. Mass will strip the donor star of its envelope to create a small hot subdwarf remnant. Here we report on Hubble Space Telescope/STIS far-ultraviolet spectroscopy sample Be reveals presence sdO companion calculation cross-correlation functions observed model spectra. We clearly detect spectral signature 10 13 sample, signals indicate hot,...
We report on the detection of a hot subdwarf component in Be binary system, 59 Cygni. The spectral signature is found cross-correlation functions photospheric model spectra with far-ultraviolet obtained by International Ultraviolet Explorer Satellite, and we used radial velocities from to determine double-lined spectroscopic orbit. individual components were extracted using Doppler tomography algorithm. flux system dominated rapidly rotating star. However, contributes approximately 4% UV...
Mass transfer during the evolution of intermediate-mass stars in a close binary system can result rejuvenated and spun-up secondary star (which may appear as rapidly rotating Be star) orbiting an unseen, stripped-down, remnant companion. One best candidates for such is long-period (127 days) ϕ Per. Here we present new Hubble Space Telescope Goddard High Resolution Spectrograph spectra Per several UV regions that show clearly first time spectral signature faint We derive double-lined solution...
view Abstract Citations (151) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Uhuru observations of X-ray emission from Seyfert galaxies. Tananbaum, H. ; Peters, G. Forman, W. Giacconi, R. Jones, C. Avni, Y. A point summation technique has been used to analyze systematically the data for 88 galaxies listed by Weedman (1977), plus MCG 8-11-11 reported Ariel 5 group. In addition measuring average intensity 15 sources in 4U and 2A catalogs, three...
We present the first results of a Kepler survey 41 eclipsing binaries that we undertook to search for third star companions. Such tertiaries will periodically alter eclipse timings through light travel time and dynamical effects. discuss prevalence starspots pulsation among these how phenomena influence times. There is no evidence short period companions (P < 700 d) this sample, but do find long term timing variations in 14 targets (34%). argue finding consistent with presence tertiary...
There is growing evidence that some Be stars were spun up through mass transfer in a close binary system, leaving the former donor star as hot, stripped-down object. are five known cases of with hot subdwarf (sdO) companions discovered International Ultraviolet Explorer (IUE) spectroscopy. Here we expand search for Be+sdO candidates using archival FUV spectra from IUE. We collected IUE 264 and formed cross-correlation functions (CCFs) model spectrum subdwarf. Twelve new candidate systems...
Close binary interactions may play a critical role in the formation of rapidly rotating Be stars. Mass transfer can result mass gainer star spun up by accretion and angular momentum, while donor is stripped its envelope to form hot faint helium star. FUV spectroscopy has led detection about 20 such Be+sdO systems. Here we report on three-year program high quality designed determine orbital periods physical properties five These binaries are long period systems with $P =$ 95 237 days small...
The rapid rotation of Be stars may be caused in some cases by past mass and angular momentum accretion an interacting binary which the donor is currently viewed as a small, hot subdwarf stripped its outer envelope. Here we report on spectroscopic detection such system FY Canis Majoris from analysis data acquired IUE spacecraft KPNO Coudé Feed Telescope over course 16 21 yr, respectively. We present double-lined orbit for based radial velocities spectra use orbital solutions with Doppler...
We present a spectroscopic investigation of the Be+sdO binary system HR 2142 that is based upon large sets ultraviolet observations from International Ultraviolet Explorer and ground-based H-alpha observations. measured radial velocities for Be star component these spectra, computed revised orbit. In order to search spectral signature hot subdwarf, we cross-correlated short wavelength end each IUE spectrum with model spectrum, then used predicted Doppler shifts subdwarf shift-and-add all...
V393 Scorpii is a Double Periodic Variable characterized by relatively stable non-orbital photometric cycle of 253 days. Mennickent et al. argue for the presence massive optically thick disc around more B-type component and describe evolutionary stage system. In this paper we analyze behavior main spectroscopic optical lines during long cycle. We study radial velocity donor determining their orbital elements find small but significant eccentricity (e = 0.04). The spectral features are...
Many short-period binary stars have distant orbiting companions that played a role in driving the components into close separation. Indirect detection of tertiary star is possible by measuring apparent changes eclipse times eclipsing binaries as orbits common center mass. Here we present an analysis timings 41 observed throughout NASA Kepler mission long duration and precise photometry. This subset characterized relatively deep frequent eclipses both stellar components. We preliminary...
Abstract We used archival International Ultraviolet Explorer ( IUE) high-dispersion, short wavelength spectra data to search for evidence of the hot subdwarf companions six rapidly rotating Be stars in binary systems. searched signature a companion through an analysis cross-correlation functions (CCFs) observed and model that were separated into primary secondary components using Doppler tomography algorithm adopted spectroscopic orbital solutions. A positive detection flux from was made...
view Abstract Citations (54) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observation of the Onset an Emission Episode in Be Star MU Centauri Peters, G. J. A series recent CCD observations which shows rapid development Hα emission pulsating, transient star μ Cen only 2 days and thus establishes a time scale for physical changes photosphere that lead to outburst, are presented. On 1985 March 25, was pure absorption but by 27 centrally...
Abstract EL CVn is the prototype of a class eclipsing binaries that consist an A- or F-type main-sequence star and hot, low-mass, pre-He white dwarf (pre-He WD), stripped down remains former mass donor. Here we present first direct detection characterization spectrum WD in was made possible through far-UV spectroscopy with Hubble Space Telescope Cosmic Origins Spectrograph. These spectra straddle wavelength range where flux dominance shifts from to A star. Radial velocities both components...
AU Mon is a long-period (11.113 d) Algol-type binary system with persistent accretion disk that apparent as double-peaked H-alpha emission. We present previously unpublished optical spectra of which were obtained over several years dense orbital phase coverage. utilize these data, along archival UV spectra, to model the temperature and structure gas stream. Synthetic spectral profiles for lines including H-alpha, H-beta, Al III Si IV doublets computed Shellspec program. The best match...
An extensive collection of spectroscopic observations the interacting binary CX Dra spanning a 23 year interval have been analyzed. This study includes refinement orbital solution Dra; equivalent width measurements that show short-, medium-, and long-term behavior difference profiles; calculation Balmer decrement; velocity maps based on curves Hα He I emission peaks; trailed spectrograms Hα, Hβ, I, Si II lines; Doppler tomograms at these four wavelengths. The main conclusions are:
The discovery of an unusual, periodic, two-component shell phase short duration in the 'classical' Be star HR2142 (HD41335, MWC133) offered convincing evidence that this object is a mass-transfer binary system. A model based solely on phase-dependent behavior hydrogen lines 80d.860 was developed by Peters and Polidan (1973) (1976). present investigation concerned with refinement to earlier model, taking into account utilization orbital solution obtained from measurements wings broad...
We present an investigation of H-alpha emission line variations observed in the massive Algol binary, RY Per. give new radial velocity data for secondary based upon our optical spectra and primary high dispersion UV spectra. revised orbital elements estimate primary's projected rotational (which indicates that is rotating 7 times faster than synchronous). use a Doppler tomography algorithm to reconstruct individual region H-alpha, we subtract latter from each observations obtain profiles its...