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The Be Star Gamma Cassiopeiae: X-Ray, Far-UV, and Optical Observations in Early 1989

Murakami, Toshio; Kawai, Nobuyuki; Matsuoka, Masaru +12 more

The state of gamma Cas in early 1989 is presented as the result of joint observations in the X-ray, far-UV, and optical regions. Particular attention has been paid to short- and long-term variations within these spectral ranges. In X-ray observations with the Ginga satellite we have found no specific periodic variabilities in the 64 to 13,000 s ra…

Spectroscopic Determinations of Stellar Parameters and Photospheric Helium Abundances for Alpha Cygni and Beta Orionis

Takeda, Yoichi

A detailed non-LTE analysis of neutral helium lines was carried out for two early A--late B supergiants alpha Cyg and beta Ori in order to obtain information concerning the abundance of helium in their photospheres, the key element for studying evolution-induced mixing in the envelope of such massive stars. To minimize the systematic errors caused…