Search Publications
Rotationally Resolved Spectral Studies of Pluto From 2500 to 4800 Angstroms Obtained With HST
Stern, S. Alan; Trafton, Laurence M.
Ultraviolet spectra of Pluto, excluding Charon, have been acquired at seven rotational phases by using the Faint Object Spectrograph on the Hubble Space Telescope (HST). We present the geometric albedo spectra at each rotational phase over the range 2500-4800 Å, and their average over rotational phase. We compare these results with earlier lUE spe…
Globular Cluster Luminosity Functions and the Hubble Constant From WFPC Imaging: Galaxies in the Coma I Cloud
Forbes, Duncan A.
The membership of some galaxies in the nearby (d ~ 12 Mpc) Coma I cloud is uncertain. Here we present globular cluster luminosity functions (GCLFs) from the Hubble Space Telescope for two bright ellipticals which may belong to this group. After fitting the GCLF, we find a turnover magnitude of m_V_^0^ = 23.23 +/- 0.11 for NGC 4278 and m_V_^0^ = 23…
The Winds of Hot Stars in External Galaxies. III. HST UV Spectroscopy of O and B Supergiants in M31 and M33
Massey, Philip; Hutchings, J. B.; Bianchi, Luciana
HST Faint Object Spectrograph (FOS) UV (1200-3300 A) spectra of nine late-O and early-B supergiants in M31, and one B1.5 supergiant in M33, are presented. The morphologies of the UV line spectra are discussed and compared with those of Galactic and Magellanic Cloud stars of similar optical spectral type. The UV spectral signatures of the M31 and M…
Temperatures of Delta CEP and Nonvariable Supergiants
Evans, Nancy Remage; Teays, Terry J.
This study is a comparison of the energy distributions of nonvariable supergiants and δ Cep with model atmospheres. The data include lUE spectra from 1700 to 3200 A, and broadband B, V, RC, IC, J, H, and K. The model atmosphere comparisons cover a range of temperatures, gravities, and microturbulence. Both the nonvariables an…
Observations of Far-UV Emission From NGC 1275 With the Hopkins Ultraviolet Telescope
Ferguson, Henry C.; Davidsen, Arthur F.; Dixon, W. Van Dyke
The galaxy NGC 1275 was observed with the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 space shuttle mission in 1990 December. NGC 1275 lies at the center of the Perseus cluster cooling flow and is surrounded by a bright emission-line nebula. The galaxy's far-UV spectrum shows a faint continuum and emission from Lyman α λ1216, C Iv λλ154…
Discovery of a White Dwarf Companion (MS0354.6-3650 = EUVE J0356-366) to a G2V Star
Thorstensen, John R.; Vennes, Stephane; Christian, Damian J. +1 more
We present x-ray, ultraviolet, and optical observations of the mysterious EUV/soft x-ray source EUVE J0356-336 (= MS0354.6-3650). Initial Einstein observations identified this source with a cluster of galaxies, but the relatively high source count rate in the Extreme Ultraviolet Explorer (EUVE) 100 Å band and the lack of variability hinted that EU…
IUE and Optical Spectra of AL Comae Berenices During a Rare Superoutburst
Moreno, H.; Szkody, Paula; Howell, Steve B. +4 more
We present optical spectra from 3 to 21 days and lUE spectra at 10 and 19 days following the outburst of the extreme amplitude, very short orbital period cataclysmic variable AL Corn after a 20 yr quiescent interval. The lUE spectra have no evidence of P Cyg profiles and show an early presence of Lyα absorption, which may be indicative of a 25,000…
The Twin Astrographic Catalog (TAC) Version 1.0
Zacharias, N.; Wycoff, G. L.; Zacharias, M. I. +1 more
A first version of the Twin Astrographic Catalog (TAC) of positions for 705,679 stars within -18°≤δ≤90° has been produced. The sky coverage of the TAC is complete to over 90% in that area. The limiting magnitude is about B =12.0. Positions are based on 4912 plates taken with the U.S. Naval Observatory Twin Astrograph (blue, yellow lens) at epochs …
The Eclipse of the Symbiotic Star BF CYG
Pereira, Claudio Bastos; Landaberry, Sayd Jose Codina
Like SY Mus and EG And, BF Cyg is another classical symbiotic system where the effects of Rayleigh scattering can be observed close to eclipse. Here we re-analyzed the ultra-violet observations made by lUE between 1979 and 1989 in order to study the continuum variations due to eclipse effects. We concluded that besides Rayleigh scattering as sourc…
Photospheric Silicon in the DA White Dwarf Wolf 1346
Barstow, M. A.; Bruhweiler, F. C.; Holberg, J. B. +1 more
We present a new coadded lUE echelle spectrum of the moderate temperature (Teff ∼20,000 K) DA white dwarf Wolf 1346. In addition to previously reported stellar and interstellar features, we find a number of new stellar lines due to Si II and Si III. These silicon features have observed Doppler velocities near the +23 km s-1 s…