Stellar activity of planetary host star HD 189733
| Autor: | 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. |
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| Rok vydání: | 2008 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361:200810648 |
| Popis: | Extra-solar planet search programs require high-precision velocity measurements. They need to study how to disentangle radial-velocity variations due to Doppler motion from the noise induced by stellar activity. We monitored the active K2V star HD 189733 and its transiting planetary companion that 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 189733 over nearly two months. We refined the HD 189733b orbit parameters and put limits on the eccentricity and on a long-term velocity gradient. After subtracting the orbital motion of the planet, we compared the variability of spectroscopic activity indices to the evolution of the radial-velocity residuals and the shape of spectral lines. The radial velocity, the spectral-line profile and the activity indices measured in HeI (5875.62 \AA), Halpha (6562.81 \AA) and the CaII H&K lines (3968.47 \AA and 3933.66 \AA, respectively) show a periodicity around the stellar rotation period and the correlations between them are consistent with a spotted stellar surface in rotation. We used such correlations to correct for the radial-velocity jitter due to stellar activity. This results in achieving high precision on the orbit parameters, with a semi-amplitude K = 200.56 \pm 0.88 m.s-1 and a derived planet mass of M_{P}=1.13 \pm 0.03 M$_{Jup}$. Comment: 9 pages, 2 tables, 9 figures, accepted for publication in A&A on 20/11/2008 |
| Databáze: | arXiv |
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