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The Ongoing Outburst of the Eclipsing Symbiotic Nova AS 296: The First 1200 days
Munari, Ulisse; Whitelock, Patricia A.; Gilmore, Alan C. +3 more
Ultraviolet, optical, and infrared photometry is reported for the symbiotic star AS 296, spanning the first 1200 d of its outburst which began in June 1988. The effects of the outburst were restricted to the wavelength interval 2200-7500 A. The progress of the event was followed through two maxima and two eclipses of the hot source by the M5 III c…
CCD observations of additional interstellar lines in stars associated with the VELA remnant and ETA Carinae nebulosity.
Wallerstein, George; Gilroy, Kalpana K.
Nine stars from the Vela Remnant and seven stars in the Eta Carinae complex are examined with CCD spectrograms with high signal-to-noise ratios for data regarding the optical interstellar lines. These data are supplemented by observations of objects with known high-velocity components and substantial interstellar Ti II lines. The CCD spectrograms …
Binary Star Observations With the Hubble Space Telescope Fine Guidance Sensors. II. Bright Hyades
Franz, O. G.; Nelan, E.; Lattanzi, M. G. +3 more
The paper reports on astrometric measurements performed with the Hubble Space Telescope fine guidance sensors in the transfer scan mode on selected bright member stars of the Hyades cluster. The purpose of these measurements was to quickly validate this mode of operation of the fine guidance sensors - in the presence of many optical anomalies - an…
Rotation and Transition Layer Emission in Cool Giants
Boehm-Vitense, Erika
Gray (1981, 1982) found that field giants with T(eff) less than about 5500 K experience a steep decrease in rotational velocities coupled with a decrease in transition layer emission. This decrease may be attributable to fast magnetic braking or to redistribution of angular momentum for rapidly increasing depths of the convection zones if these ro…
The Binary Cepheid BP Cir: A Test of Evolutionary Tracks
Arellano Ferro, A.; Evans, Nancy R.; Udalska, Joanna
IUE spectra of the system containing the Cepheid BP Cir are used to derive the magnitude difference between the two stars (Δ V = 1.88 ± 0.3 mag) and the spectral type of the companion (B6.OV). This is the first system yet encountered for which the standard Seaton reddening law is inappropriate. For BP Cir, a stronger 2200 Å bump than the standard …
CN Anomalies in Extremely Metal-Deficient Red Giants
Twarog, Bruce A.; Anthony-Twarog, Barbara J.; Shawl, Stephen J.
New photometric and UV spectroscopic data for the metal-deficient red giants CD -38 deg 245 and BD -18 deg 5550 are presented and discussed in light of recently noted photometric anomalies. From the IUE spectra it is aparent that the UV excess found in BD -18 deg 5550 is not the result of a hot companion. The IUE spectra, in conjunction with other…
The Luminosity of the Classical Cepheid T VUL
Evans, Nancy R.
The classical Cepheid T Vul has been discovered to have a hot companion on International Ultraviolet Explorer satellite spectra. The companion has a spectral type of A0.8 V. The absolute magnitude of the Cepheid determined from the companion is Mv = -3.43 mag. Because the companion is significantly fainter and less massive than the Ceph…
Detection of a White Dwarf in a Visual Binary System
Boehm-Vitense, Erika
The F6 giant HD 160365 was detected to have a white dwarf companion about 8 arcsec south of the star. The UV energy distribution observed with IUE shows that the white dwarf has an effective temperature of 23,000 +/- 2000 K. If log g = 8 the Lya profile indicates an effective temperature around 24,500 K. Using the theoretical models by Wesemael et…
Ultraviolet Emission in the Dark Cloud Toward HD 62524
O'Donnell, James E.; Cardelli, Jason A.; Churchwell, Ed
We have obtained low resolution IUE short wavelength spectra at several positions within a ridge of molecular gas within the Gunn Nebula. Optical absorption line measurements toward HD 62542 indicate moderately high densities within the ridge. The physical appearance of the ridge, along with H-alpha and IRAS images of the nebula, suggest that wind…