| Issue |
A&A
Volume 506, Number 1, October IV 2009
The CoRoT space mission: early results
|
|
|---|---|---|
| Page(s) | 263 - 268 | |
| Section | Stellar atmospheres | |
| DOI | https://doi.org/10.1051/0004-6361/200911895 | |
| Published online | 28 July 2009 | |
On the differential rotation of CoRoT-2a*
1
Astrophysikalisches Institut Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany e-mail: HEFroehlich@aip.de
2
Thüringer Landessternwarte Tautenburg, Karl-Schwarzschild-Observatorium (TLS), Sternwarte 5, 07778 Tautenburg, Germany e-mail: artie@tls-tautenburg.de
Received:
20
February
2009
Accepted:
15
July
2009
We apply a robust spot model to fit the light curve of CoRoT-2a.
The spots are assumed to be long-living and each has its own rotation period.
A model with three circular spots reproduces the basic features of the
longitude-time spot coverage map. One of the spots exhibits a noticeably
lower rotational frequency than the other two.
From the rotational frequencies of the three dark features we infer a differential
rotation of above 0.11 rad/d, in rough agreement with theoretical models.
Mean field models of angular momentum transport by convection and meridional
flow lead to an equatorial rotational frequency that exceeds that of the poles
by 0.09 rad/d. The spot decay corresponds to a turbulent magnetic
diffusivity of 
cm2/s.
Key words: stars: activity / stars: individual: CoRoT-2a / stars: interiors / stars: late-type / stars: rotation / starspots
© ESO, 2009
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