Sphericallysymmetric model stellar atmospheres and limb darkening. I. Limbdarkening laws, gravitydarkening coefficients and angular diameter corrections for red giant stars
Abstract
Model stellar atmospheres are fundamental tools for understanding stellar observations from interferometry, microlensing, eclipsing binaries and planetary transits. However, the calculations also include assumptions, such as the geometry of the model. We use intensity profiles computed for both planeparallel and spherically symmetric model atmospheres to determine fitting coefficients in the BVRIHK, CoRot and Kepler wavebands for limb darkening using several different fitting laws, for gravitydarkening and for interferometric angular diameter corrections. Comparing predicted variables for each geometry, we find that the spherically symmetric model geometry leads to different predictions for surface gravities log g < 3. In particular, the most commonly used limbdarkening laws produce poor fits to the intensity profiles of spherically symmetric model atmospheres, which indicates the need for more sophisticated laws. Angular diameter corrections for spherically symmetric models range from 0.67 to 1, compared to the much smaller range from 0.95 to 1 for planeparallel models.
Tables 217, and the model intensity profiles are only available at the CDS via anonymous ftp to http://cdsarc.ustrasbg.fr/vizbin/qcat?J/A+A/554/A98
 Publication:

Astronomy and Astrophysics
 Pub Date:
 June 2013
 DOI:
 10.1051/00046361/201321502
 arXiv:
 arXiv:1305.1311
 Bibcode:
 2013A&A...554A..98N
 Keywords:

 stars: atmospheres;
 stars: latetype;
 binaries: eclipsing;
 stars: evolution;
 techniques: interferometric;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 11 pages, 9 figures, accepted for publication in A&