[vsnet-j 2078] BG Gem

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

BG Gem

　変な星かも知れない可能性はまだ否定できないという情報です。主星は重いよう
　ですが見えていないようです。

Paper: astro-ph/0205157
From: Scott J Kenyon <kenyon@cfa.harvard.edu>
Date: Fri, 10 May 2002 19:59:11 GMT   (90kb,P)

Title: The Eclipsing Binary BG Geminorum: Improved Constraints on the Orbit and
  the Structure of the Accretion Disk
Authors: Scott J. Kenyon, Paul J. Groot, and Priscilla Benson
Comments: 9 pages of text, 3 tables, and 4 figures; to appear in AJ, August
  2002
\\
  We describe new optical photometric and spectroscopic observations of the
semi-detached eclipsing binary BG Geminorum. A large change in the amount of Mg
I absorption at secondary maximum indicates the presence of cool material in
the outer edge of the disk surrounding the unseen primary star. Detection of
weak He I emission implies a hot radiation source at the inner edge of the
disk. If the velocity variations in the Hbeta emission line track the orbital
motion of the primary star, the primary star has an orbital semiamplitude of K1
= K(Hbeta) = 16.0 +- 4.6 km/sec. This result yields a mass ratio, q = 0.22 +-
0.07, consistent with the q = 0.1 derived from the large ellipsoidal variation.
Despite this progress, the nature of the primary star - B-type star or black
hole - remains uncertain.
\\ ( http://arXiv.org/abs/astro-ph/0205157 ,  104kb)

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