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Direct Detection of the Close Companion of Polaris with the Hubble Space Telescope
Schaefer, Gail H.; Bond, Howard E.; Evans, Nancy Remage +5 more
Polaris, the nearest and brightest classical Cepheid, is a single-lined spectroscopic binary with an orbital period of 30 yr. Using the High Resolution Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope (HST) at a wavelength of ~2255 Å, we have directly detected the faint companion at a separation of 0farcs17. A second …
HD 148937: A Multiwavelength Study of the Third Galactic Member of the Of?p Class
Walborn, Nolan R.; Bond, Howard E.; Nazé, Yaël +3 more
Three Galactic O-type stars belong to the rare class of Of?p objects: HD 108, HD 191612, and HD 148937. The first two stars show a wealth of phenomena, including strong X-ray emission, light variability, and dramatic periodic spectral variability. We present here the first detailed optical and X-ray study of the third Galactic Of?p star, HD 148937…
A Model for the Chromosphere/Wind of 31 Cygni and Its Implications for Single Stars
Eaton, Joel A.
I develop a detailed empirical model for the chromosphere and wind of 31 Cyg based on a previously published analysis of International Ultraviolet Explorer spectra from the 1993 eclipse and on the thermodynamics of how the wind must be driven. I then use this model to interpret observations of single supergiant stars and to assess the evidence tha…