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The Galactic Evolution of Beryllium and Boron Revisited
King, Jeremy R.
The largest, highest-quality, and most near-homogeneously treated extant available samples of Be, B, Fe, and O abundances are analyzed on four different stellar parameter scales, considering different O abundance indicators and deriving uncertainties in their relation with the required aid of jackknife and bootstrap simulations/resampling. Despite…
The Optical Spectroscopic Evolution of V1974 Cygni (Nova Cygni 1992)
Garnavich, Peter M.; Noriega-Crespo, Alberto; Moro-Martín, Amaya
Optical observations of V1974 Cygni (Nova Cygni 1992) spanning a 4 yr period have been used to study its spectroscopic evolution. The data cover a wavelength range from ~3200-8000 Å and follow the nebular evolutionary phase of the ejecta. We have modeled the integrated fluxes by means of the photoionization code CLOUDY. The models were run at a fi…
Archival HST and IUE Study of the Dwarf Novae AH Herculis and CM Delphini: Exposed White Dwarfs?
Wood, Janet H.; Stys, D.; Sion, E. +2 more
We have analyzed Hubble Space Telescope (HST) archival and IUE NEWSIPS archival SWP spectra of the dwarf novae CM Del and AH Her obtained when AAVSO light-curve data indicated the occurrence of dwarf nova quiescence. We have computed synthetic, high-gravity spectra in LTE with solar composition using TLUSTY195 and SYNSPEC42 and have carried out fi…
Ultraviolet Eclipse Observations and Fundamental Parameters of the Binary HR 2554 (G6 II+A1 V)
Kürster, Martin; Bennett, Philip D.; Brown, Alexander +4 more
HR 2554 is an eclipsing binary system that contains a G6 II primary star and an A dwarf secondary. We have obtained ultraviolet spectra during two eclipses of HR 2554 in 1994 March-April and 1995 May using the HST Goddard High Resolution Spectrograph (GHRS) to study the atmospheric structure of the primary and to better establish the properties of…
The Dust Temperature of the ``Dusty'' Radio Galaxy MG 1019+0535: Evidence for an Outflow
Spinrad, Hyron; Manning, Curtis
Radio galaxies characteristically have strong Lyα emission lines. However, a few have Lyα equivalent widths that are substantially weaker in relation to other emission lines. One in particular, MG 1019+0535 (z=2.765), was studied by Dey, Spinrad, & Dickinson in 1995. We report on our reduction of Infrared Space Observatory (ISO) data in the 16…
Australia Telescope Compact Array Observations of the OH Star Roberts 22: Resolved Images of Hydroxyl Emission
Goss, W. M.; Dyer, K. K.; Kemball, A. J.
We have imaged the unusual OH/IR object G284-0.8 (Roberts 22) in the OH transitions at 1612, 1665, and 1667 MHz using the Australia Telescope Compact Array in Narrabri, NSW, Australia. The angular resolution of the OH images we present here is 6" (12,000 AU at a distance of 2 kpc). We find OH emission of extent 1.5" (2800 AU) located inside the op…
Simultaneous Observations of Variability at All Atmospheric Levels of V824 Arae (HD 155555)
Neff, James E.; Lim, Jeremy; Dempsey, Robert C.
We conducted a multiwavelength campaign observing V824 Ara (HD 155555, G5 IV+K0 IV-V) continuously throughout one complete orbital cycle (~1.7 days) in early May of 1996. At the core of this campaign were observations using the GHRS on the Hubble Space Telescope (HST). In all, about 48,000 spectra, many in rapid readout mode, were obtained with th…
Speckle Observations of Composite Star Candidates
Bord, D. J.; Sowell, J. R.; Hart, D. L. +1 more
Speckle observations are reported for 53 stars with composite spectra selected from the Michigan Spectral Catalogue in an effort to improve the orbits of known binaries and to discover new binaries among this class of objects. The data were obtained using the 1.3 and 2.4 m telescopes at the Michigan-Dartmouth-MIT Observatory and the Georgia Tech R…
Goddard High Resolution Spectrograph Observations of NGC 4151
Savage, B. D.; Ebbets, D. C.; Carpenter, K. G. +15 more
Goddard High Resolution Spectrograph observations of the nucleus of the bright, nearby Seyfert galaxy NGC 4151 are presented andbriefly described.
The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
Dehnen, Walter
Hydrodynamic modeling of the inner Galaxy suggests that the radius of the outer Lindblad resonance (OLR) of the Galactic bar lies in the vicinity of the Sun. How does this resonance affect the distribution function in the outer parts of a barred disk, and can we identify any effect of the resonance in the velocity distribution actually observed in…