AAS 195th Meeting, January 2000
Session 50. Stellar Atmospheres
Display, Thursday, January 13, 2000, 9:20am-6:30pm, Grand Hall

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[50.07] A Recalibration of the Wilson-Bappu Effect for Luminous Stars

S.B. Parsons (CSC / STScI)

From a sample of cool + hot binary systems fit to isochrones, we find deviations correlated with spectral class of up to 2 magnitudes between these binarity M_{v} values and the Wilson-Bappu relation. Additional M_{v} values derived from Hipparcos parallaxes are used to explore and quantify the systematics of the deviations from the correlation between Ca II K-line emission width and absolute visual magnitude, not previously well calibrated for stars more luminous than giants. This study supplements the recent work by Wallerstein, Machado-Pelaez, & Gonzalez (1999, PASP, 111, 335) who brought attention to large deviations for luminous G-type stars.

This research is supported by the Computer Sciences Corporation through contract STI-C-01 (P-816) from the STScI, which is operated by AURA under NASA contract NAS 5-26555.

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