The Bulletin of The Korean Astronomical Society (천문학회보)
- Volume 37 Issue 1
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- Pages.58.2-58.2
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- 2012
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- 1226-2692(pISSN)
Wilson-Bappu effect : an indicator of stellar surface gravity
- Park, Sun-Kyung (School of Space Research, Kyung Hee University) ;
- Lee, Jeong-Eun (School of Space Research, Kyung Hee University) ;
- Kang, Won-Seok (School of Space Research, Kyung Hee University) ;
- Lee, Sang-Gak (Astronomy Program, Department of Physics and Astronomy, Seoul National University)
- Published : 2012.04.03
Abstract
Wilson and Bappu (1957), for the first time, and other precedent studies (Lutz & Kelker 1975; Pasquini et al. 1988; Dupree & Smith 1995; Wallerwstein et al. 1999; Pace et al. 2003) found a tight correlation (called Wilson-Bappu relationship - WBR) between stellar absolute visual magnitude and the width of the Ca II K line emission feature for late type stars. Here we re-visit WBR to claim that WBR can be an excellent indicator of stellar surface gravity of late type stars as well as a good indicator of distance. We have analyzed 103 high-resolution spectra of G, K and M type stars obtained by UVES and BOES by following the method by Pace et al. (2003) for measuring the widths of Ca II K lines(W). WBR found in our samples is Mv=33.26-17.79logW and the correlation is very tight. In this study, the stellar gravity(log g) has been derived using Kurucz ALAS9 model grid and MOOG code, which can determine
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