Search Publications
Ultraviolet Extinction Properties in the Milky Way
Gordon, Karl D.; Clayton, Geoffrey C.; Valencic, Lynne A.
We have assembled a homogeneous database of 417 ultraviolet (UV) extinction curves for reddened sight lines having International Ultraviolet Explorer spectra. We have combined these with optical and Two Micron All Sky Survey photometry, allowing estimates of the ratio of total-to-selective extinction, RV, for the entire sample. Fitzpatr…
Indications of a Large Fraction of Spectroscopic Binaries among Nuclei of Planetary Nebulae
Bond, Howard E.; De Marco, Orsola; Harmer, Dianne +1 more
Previous work indicates that about 10% of planetary-nebula nuclei (PNNi) are photometrically variable short-period binaries with periods of hours to a few days. These systems have most likely descended from common-envelope (CE) interactions in initially much wider binaries. Population-synthesis studies suggest that these very close pairs could be …
Quantitative Studies of the Far-Ultraviolet, Ultraviolet, and Optical Spectra of Late O- and Early B-Type Supergiants in the Magellanic Clouds
Hillier, D. J.; Crowther, P. A.; Evans, C. J. +1 more
We present quantitative studies of eight late O- and early B-type supergiants in the Magellanic Clouds using far-ultraviolet Far Ultraviolet Spectroscopic Explorer, ultraviolet International Ultraviolet Explorer/Hubble Space Telescope, and optical VLT-UVES spectroscopy. Temperatures, mass-loss rates, and CNO abundances are obtained using the non-L…
The Environment of the Optically Brightest Herbig Ae Star, HD 104237
Apai, D.; Stecklum, B.; Wang, Hongchi +16 more
We investigate the environment of the nearest Herbig Ae star, HD 104237, with a multiwavelength combination of optical coronagraphic, near-IR, and mid-IR imaging supported by optical, UV, and far-ultraviolet spectroscopy. We confirm the presence of T Tauri stars associated with the Herbig Ae star HD 104237, noted by Feigelson et al. We find that t…
The N Enrichment and Supernova Ejection of the Runaway Microquasar LS 5039
Kaper, L.; Gies, D. R.; Huang, W. +3 more
We present an investigation of new optical and ultraviolet spectra of the mass donor star in the massive X-ray binary LS 5039. The optical band spectral line strengths indicate that the atmosphere is N-rich and C-poor, and we classify the stellar spectrum as type ON6.5 V((f)). The N-strong and C-weak pattern is also found in the stellar wind P Cyg…
The Ultraviolet Extinction Curve of Intraclump Dust in Taurus (TMC-1): Constraints on the 2175 Å Bump Absorber
Gordon, Karl D.; Whittet, D. C. B.; Clayton, Geoffrey C. +1 more
Ultraviolet extinction curves for three early-type stars that sample dust in the Taurus dark cloud in the vicinity of TMC-1 are analyzed to examine the contribution of internal (intraclump) dust to the total line-of-sight extinction. One of our selected targets samples only dust in the ``diffuse-screen'' component of the cloud, where the dust grai…
The Hot White Dwarf in the Cataclysmic Variable MV Lyrae
Szkody, Paula; Sion, Edward M.; Hoard, D. W. +4 more
We have obtained the first far-ultraviolet spectrum of the nova-like cataclysmic variable MV Lyrae using the Far Ultraviolet Spectroscopic Explorer (FUSE). We also obtained contemporaneous optical light curves and spectra. All data are from a deep faint accretion state of MV Lyr. We constructed a model for the system using the BINSYN software pack…
NGC 3125-1: The Most Extreme Wolf-Rayet Star Cluster Known in the Local Universe
Leitherer, Claus; Chandar, Rupali; Tremonti, Christy A.
We use Space Telescope Imaging Spectrograph long-slit ultraviolet spectroscopy of local starburst galaxies to study the massive star content of a representative sample of super-star clusters, with a primary focus on their Wolf-Rayet (W-R) content as measured from the He II λ1640 emission feature. The goals of this work are threefold. First, we qua…
Terminal Velocities of Luminous, Early-Type Stars in the Small Magellanic Cloud
Lennon, D. J.; Evans, C. J.; Heap, S. R. +2 more
Ultraviolet spectra from the Space Telescope Imaging Spectrograph (STIS) are used to determine terminal velocities for 11 O and B-type giants and supergiants in the Small Magellanic Cloud (SMC) from the Si IV and C IV resonance lines. Using archival data from observations with the Goddard High-Resolution Spectrograph and the International Ultravio…
The Effective Temperatures of Hot Stars. II. The Early-O Types
Bianchi, Luciana; Garcia, Miriam
We derived the stellar parameters of a sample of Galactic early-O type stars by analyzing their UV and far-UV spectra from the Far Ultraviolet Spectroscopic Explorer (905-1187 Å), the International Ultraviolet Explorer, the Hubble Space Telescope STIS, and the Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer (1200-2000 Å). The dat…