Differential rotation in rapidly rotating early-type stars. I. Motivations for combined spectroscopic and interferometric studies.

ZOREC , J.; FRÉMAT , Y.; DOMINICIANO DE SOUZA, A.; DELAA, O.; STEE, P.; MOURARD, D.; CIDALE, L.; MARTAYAN, C.; GEORGY, C.; EKSTROM, S.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Les Ulis - Francia; Año: 2011 vol. 526 p. 1 - 25

0004-6361

Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation. We explore what can be learned from spectroscopic and interferometric observations about the properties of the rotation law in the external layers of these objects. Methods. Using simple relations between the entropy and specific rotational quantities, some of which are found to be eerential rotation in the convective region, we derived analytical solutions that represent possible diferential rotations in the envelope of early-type stars. A surface latitudinal diferential rotation may not only be an external imprint of the inner rotation, but induces changes in the stellar geometry, the gravitational darkening, the aspect of spectral line profiles, and the emitted spectral energy distribution.Using simple relations between the entropy and specific rotational quantities, some of which are found to be efficient at accounting for the solar differential rotation in the convective region, we derived analytical solutions that represent possible diferential rotations in the envelope of early-type stars. A surface latitudinal diferential rotation may not only be an external imprint of the inner rotation, but induces changes in the stellar geometry, the gravitational darkening, the aspect of spectral line profiles, and the emitted spectral energy distribution.