2001A&A...375..122Z -
Astronomy and Astrophysics, volume 375, 122-129 (2001/8-3)
New spectroscopic observations of the B[e]/K binary system MWC623.
ZICKGRAF F.-J.
Abstract (from CDS):
The B[e]/K binary system MWC 623 was reinvestigated using new spectroscopic observations. The absorption lines of the K and the B star do not exhibit any significant radial velocity variations over a time interval of 14 years. The spectral classification using a recent echelle spectrum yielded spectral types of K2II-Ib and B4III. The luminosity class of the K star gives an estimate of the distance towards MWC 623 of 2.4+1.4–0.9kpc. This is consistent with the kinematic distance of 2.0+0.6–0.3kpc. The masses derived from the locations of the binary components in the H-R diagram are 7±1.5M☉ and 7.5±2.5M☉ for the B and K star, respectively, i.e. the mass ratio is close to 1. Both stars are coeval with an age of 50+10–20 Myr as shown by the comparison with isochrones. The high luminosity of the K star excludes a pre-main sequence evolutionary phase as explanation for the strong LiIλ6708 absorption line observed in the late-type component. Rather, the high lithium abundance is a consequence of the young age. Likewise, the B[e] star is a slightly evolved object starting it post-main sequence evolution.
Abstract Copyright:
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Journal keyword(s):
stars: circumstellar matter - stars: early-type - stars: late-type - stars: emission-line - stars: evolution
Simbad objects:
17
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