Dynamical determination of the quadrupole mass moment of the HD 209458 star

Abstract

Aims. The aim of this paper is the dynamical determination of the quadrupole mass moment J2 of the main-sequence HD 209458 star. Methods. The adopted method is the confrontation between the measured orbital period of its transiting planet Osiris and a model of it. Osiris is assumed to move along an equatorial and circular orbit. Results. Our determination, for given values of the stellar mass M and radius R and by assuming the validity of general relativity, is J2 = (3.5± 0.5)× 10−5. Previous fiducial evaluations based on indirect, spectroscopic measurements yielded, instead, J2 ∼ 10−6: such a value is incompatible with general relativity, given the present-day level of accuracy in measuring the Osiris’ orbital period.

Cite this paper

@inproceedings{Iorio2006DynamicalDO, title={Dynamical determination of the quadrupole mass moment of the HD 209458 star}, author={Lorenzo Iorio}, year={2006} }