A critical test of empirical mass loss formulas applied to individual giants and supergiants

¹ Departamento de Astronomía, A. P. 144, Universidad de Guanajuato, 36000 Guanajuato, GTO, Mexico e-mail: kps@astro.ugto.mx
² Zentrum für Astronomie und Astrophysik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany
³ Department of Physics, Science Hall, University of Texas at Arlington, Arlington, TX 76019-0059, USA e-mail: cuntz@uta.edu
⁴ Institut für Theoretische Astrophysik, Universität Heidelberg, Albert Überle Str. 2, 69120 Heidelberg, Germany

Received: 24 October 2006
Accepted: 10 January 2007

Abstract

To test our new, improved Reimers-type mass-loss relation, given by Schröder & Cuntz in 2005 (ApJ, 630, L73), we take a look at the best studied galactic giants and supergiants – particularly those with spatially resolved circumstellar shells and winds, obtained directly or by means of a companion acting as a probing light source. Together with well-known physical parameters, the selected stars provide the most powerful and critical observational venues for assessing the validity of parameterized mass-loss relations for cool winds not driven by molecules or dust. In this study, star by star, we compare our previously published relation with the original Reimers relation (1975, Mem. Roy. Soc. Liège 6. Ser. 8, 369), the Lamers relation (1981, ApJ, 245, 593), and the two relations by de Jager and his group (1988, A&AS, 72, 259; 1990, A&A, 231, 134). The input data, especially the stellar masses, have been constrained using detailed stellar evolution models. We find that only the relationship by Schröder & Cuntz agrees, within the error bars, with the observed mass-loss rates for all giants and supergiants.