SHELIAK litterature and history

Saturday 12 March 2011 by Jean-Noël Terry

Sheliak Bet Lyr; HD 174638; HR 7106

Interacting and eclipsing binary P=12.94 days.

A B6-8 type star is a mass-loosing star, giving matter to a B type star embedded in an accretion disk.

First resolved images by Zhao et al. in 2008 (arXiv:0808.0932)

Always in emission but interesting variations of the profile.

Bet Lyr remains a poorly understood object.

Rapid line-profile variations have been found in Ha and HeI (6678) lines. A period near 4.7 days is proposed (Harmanec et al., A&A, 312, 879, 1996).

Conclusion With a mass transfer rate of $2.10^{-5}M_{\odot}yr^{-1}$ there is no risk of absorption. Various observations are needed to precise periods, the orbital V/R variations are useful to precise the circumstellar shell axis, and observation of the P-Cigny profile coming from the accretionn disk... See also FeII, MgII, CaII, SiII lines.