Calibrating Convective properties of Solar-like Stars in the Kepler Field of View

Дата и время публикации : 2012-07-11T20:00:01Z

Авторы публикации и институты :
Ana Bonaca
Joel D. Tanner
Sarbani Basu
William J. Chaplin
Travis S. Metcalfe
Mário J. P. F. G. Monteiro
Jérôme Ballot
Timothy R. Bedding
Alfio Bonanno
Anne-Marie Broomhall
Hans Bruntt
Tiago L. Campante
Jørgen Christensen-Dalsgaard
Enrico Corsaro
Yvonne Elsworth
Rafael A. García
Saskia Hekker
Christoffer Karoff
Hans Kjeldsen
Savita Mathur
Clara Régulo
Ian Roxburgh
Dennis Stello
Regner Trampedach
Thomas Barclay
Christopher J. Burke
Douglas A. Caldwell

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 16 pages, 4 figures, accepted for publication in ApJL
Первичная категория: astro-ph.SR

Все категории : astro-ph.SR

Краткий обзор статьи: Stellar models generally use simple parametrizations to treat convection. The most widely used parametrization is the so-called "Mixing Length Theory" where the convective eddy sizes are described using a single number, alpha, the mixing-length parameter. This is a free parameter, and the general practice is to calibrate alpha using the known properties of the Sun and apply that to all stars. Using data from NASA’s Kepler mission we show that using the solar-calibrated alpha is not always appropriate, and that in many cases it would lead to estimates of initial helium abundances that are lower than the primordial helium abundance. Kepler data allow us to calibrate alpha for many other stars and we show that for the sample of stars we have studied, the mixing-length parameter is generally lower than the solar value. We studied the correlation between alpha and stellar properties, and we find that alpha increases with metallicity. We therefore conclude that results obtained by fitting stellar models or by using population-synthesis models constructed with solar values of alpha are likely to have large systematic errors. Our results also confirm theoretical expectations that the mixing-length parameter should vary with stellar properties.

Category: Physics