Bibcode
Huber, K. F.; Wolter, U.; Czesla, S.; Schmitt, J. H. M. M.; Esposito, M.; Ilyin, I.; González-Pérez, J. N.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 501, Issue 2, 2009, pp.715-728
Fecha de publicación:
7
2009
Revista
Número de citas
20
Número de citas referidas
16
Descripción
Context: The young active G-dwarf star V889 Herculis (HD 171488) shows
pronounced spots in Doppler images as well as large variations in
photometry and radial velocity (RV) measurements. However, the lifetime
and evolution of its active regions are not well known. Aims: We
study the existence and stability of active regions on the star's
surface using complementary data and methods. Furthermore, we analyze
the correlation of spot-induced RV variations and Doppler images. Methods: Photometry and high-resolution spectroscopy are used to
examine stellar activity. A CLEAN-like Doppler imaging (DI) algorithm is
used to derive surface reconstructions. We study high-precision RV
curves to determine their modulation due to stellar activity in analogy
to the Rossiter-McLaughlin effect. To this end we develop a measure for
the shift of a line's center and compare it to RV measurements. Results: We show that large spotted regions are present on V889 Her
for more than one year, remaining similar in their large scale structure
and position. This applies to several time periods of our observations,
which cover more than a decade. We use DI line profile reconstructions
to identify the influence of long-lasting starspots on RV measurements.
In this way we verify the RV curve's agreement with our Doppler images.
Based on long-term RV data we confirm V889 Her's rotation period of
1.3371 ± 0.0002 days.