Details

Autor(en) / Beteiligte

• Boisse, I.
• Moutou, C.
• Vidal-Madjar, A.
• Bouchy, F.
• Pont, F.
• Hébrard, G.
• Bonfils, X.
• Croll, B.
• Delfosse, X.
• Desort, M.
• Forveille, T.
• Lagrange, A.-M.
• Loeillet, B.
• Lovis, C.
• Matthews, J. M.
• Mayor, M.
• Pepe, F.
• Perrier, C.
• Queloz, D.
• Rowe, J. F.
• Santos, N. C.
• Ségransan, D.
• Udry, S.

Titel

Stellar activity of planetary host star HD 189 733

Ist Teil von

• Astronomy and astrophysics (Berlin), 2009-03, Vol.495 (3), p.959-966

Ort / Verlag

Les Ulis: EDP Sciences

Erscheinungsjahr

2009

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Aims. Extra-solar planet search programs require high-precision velocity measurements. They need to determine how to differentiate between radial-velocity variations due to Doppler motion and the noise induced by stellar activity. Methods. We monitored the active K2V star HD 189 733 and its transiting planetary companion, which has a 2.2-day orbital period. We used the high-resolution spectograph SOPHIE mounted on the 1.93-m telescope at the Observatoire de Haute-Provence to obtain 55 spectra of HD 189 733 over nearly two months. We refined the HD 189 733b orbit parameters and placed limits on both the eccentricity and long-term velocity gradient. After subtracting the orbital motion of the planet, we compared the variability in spectroscopic activity indices with the evolution in the radial-velocity residuals and the shape of spectral lines. Results. The radial velocity, the spectral-line profile, and the activity indices measured in He I (5875.62 Å), Hα (6562.81 Å), and both of the Ca II H&K lines (3968.47 Å and 3933.66 Å, respectively) exhibit a periodicity close to the stellar-rotation period and the correlations between them are consistent with a spotted stellar surface in rotation. We used these correlations to correct for the radial-velocity jitter due to stellar activity. This results in achieving high precision in measuring the orbital parameters, with a semi-amplitude K = 200.56 ± 0.88 m s-1 and a derived planet mass of MP = 1.13 ± 0.03 MJup.