The HARPS search for southern extra-solar planets XXX. Planetary systems around stars with solar-like magnetic cycles and short-term activity variation

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Dumusque, X (Author) Other; Lovis, C (Author) Other; Segransan, D (Author) Other; Mayor, M (Author) Other; Udry, S (Author) Other; Benz, W (Author) Other; Bouchy, F (Author) Other; Lo Curto, G (Author) Other; Mordasini, C (Author) Other; Pepe, F (Author) Other; Queloz, D (Author) Other; N.C. Santos (Author) FCUP; Naef, D (Author) Other

Journal

Title: Astronomy and Astrophysics

Vol. 535

Final page: A55

ISSN: 0004-6361

Publisher: EDP Sciences

Indexing

ISI Web of Knowledge - 83 Citations

Scopus - 88 Citations

Other information

Authenticus ID: P-002-JTD

DOI: 10.1051/0004-6361/201117148

Abstract (EN): We present the discovery of four new long-period planets within the HARPS high-precision sample: HD 137388b (Msin i = 0.22 M-J), HD 204941b (Msin i = 0.27 M-J), HD 7199b (M sin i = 0.29 M-J), HD 7449b (Msin i = 1.04 M-J). A long-period companion, probably a second planet, is also found orbiting HD 7449. Planets around HD 137388, HD 204941, and HD 7199 have rather low eccentricities (less than 0.4) relative to the 0.82 eccentricity of HD 7449b. All these planets were discovered even though their hosting stars have clear signs of activity. Solar-like magnetic cycles, characterized by long-term activity variations, can be seen for HD 137388, HD 204941 and HD 7199, whereas the measurements of HD 7449 reveal a short-term activity variation, most probably induced by magnetic features on the stellar surface. We confirm that magnetic cycles induce a long-term radial velocity variation and propose a method to reduce considerably the associated noise. The procedure consists of fitting the activity index and applying the same solution to the radial velocities because a linear correlation between the activity index and the radial velocity is found. Tested on HD 137388, HD 204941, and HD 7199, this correction reduces considerably the stellar noise induced by magnetic cycles and allows us to derive precisely the orbital parameters of planetary companions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11