TY - JOUR
T1 - On deriving p-mode parameters for inclined solar-like stars
AU - Toutain, Thierry
PY - 2008/8/1
Y1 - 2008/8/1
N2 - Context. Thanks to their high quality, new and upcoming asteroseismic observations, with CoRoT, Kepler, and from the ground, benefit from experience gained with helioseismology.
Aims. We focus, in this paper, on solar- like oscillations, for which the inclination of the rotation axis is unknown. We present a theoretical study of the errors of p-mode parameters determined by means of a maximum-likelihood estimator, and we also analyze correlations and biases.
Methods. We used different, complementary approaches: we performed either semi-analytical computation of the Hessian matrix, fitting of single mean profiles, or Monte Carlo simulations.
Results. First, we give analytical approximations for the errors of frequency, inclination and rotational splitting. The determination of the inclination is very challenging for the common case of slow rotators ( like the Sun), making the determination of a reliable rotational splitting difficult. Moreover, due to the numerous correlations, biases-more or less significant-can appear in the determination of various parameters in the case of bad inclination fittings, especially when a locking at 90 degrees occurs. We also discuss this issue. Nevertheless, the central frequency and some derived parameters, such as the total power of the mode, are free of such biases.
AB - Context. Thanks to their high quality, new and upcoming asteroseismic observations, with CoRoT, Kepler, and from the ground, benefit from experience gained with helioseismology.
Aims. We focus, in this paper, on solar- like oscillations, for which the inclination of the rotation axis is unknown. We present a theoretical study of the errors of p-mode parameters determined by means of a maximum-likelihood estimator, and we also analyze correlations and biases.
Methods. We used different, complementary approaches: we performed either semi-analytical computation of the Hessian matrix, fitting of single mean profiles, or Monte Carlo simulations.
Results. First, we give analytical approximations for the errors of frequency, inclination and rotational splitting. The determination of the inclination is very challenging for the common case of slow rotators ( like the Sun), making the determination of a reliable rotational splitting difficult. Moreover, due to the numerous correlations, biases-more or less significant-can appear in the determination of various parameters in the case of bad inclination fittings, especially when a locking at 90 degrees occurs. We also discuss this issue. Nevertheless, the central frequency and some derived parameters, such as the total power of the mode, are free of such biases.
KW - methods : data analysis
KW - stars : oscillations
KW - methods : statistical
U2 - 10.1051/0004-6361:20079343
DO - 10.1051/0004-6361:20079343
M3 - Article
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
SN - 1432-0756
VL - 486
SP - 867
EP - 875
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
IS - 3
ER -