Volume 540, April 2012
|Number of page(s)||8|
|Section||Planets and planetary systems|
|Published online||17 April 2012|
Planetary companions around the metal-poor star HIP 11952
1 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
3 Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
4 Astronomisches Rechen-Institut, Zentrum für Astronomie, Mönchhofstrasse, 12-14, 69120 Heidelberg, Germany
5 Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
6 European Southern Observatory, Karl-Schwarzschild Str. 2, 85748 Garching bei München, Germany
7 University of Würzburg, Department of Radiation Oncology, 97080 Würzburg, Germany
Received: 4 August 2011
Accepted: 27 February 2012
Aims. We carried out a radial-velocity survey to search for planets around metal-poor stars. In this paper we report the discovery of two planets around HIP 11952, a metal-poor star with [Fe/H] = −1.9 that belongs to our target sample.
Methods. Radial velocity variations of HIP 11952 were monitored systematically with FEROS at the 2.2 m telescope located at the ESO La Silla observatory from August 2009 until January 2011. We used a cross-correlation technique to measure the stellar radial velocities (RV).
Results. We detected a long-period RV variation of 290 d and a short-period one of 6.95 d. The spectroscopic analysis of the stellar activity reveals a stellar rotation period of 4.8 d. The Hipparcos photometry data shows intra-day variabilities, which give evidence for stellar pulsations. Based on our analysis, the observed RV variations are most likely caused by the presence of unseen planetary companions. Assuming a primary mass of 0.83 M⊙, we computed minimum planetary masses of 0.78 MJup for the inner and 2.93 MJup for the outer planet. The semi-major axes are a1 = 0.07 AU and a2 = 0.81 AU, respectively.
Conclusions. HIP 11952 is one of very few stars with [Fe/H] < −1.0 which have planetary companions. This discovery is important to understand planet formation around metal-poor stars.
Key words: stars: abundances / techniques: spectroscopic / planetary systems / techniques: radial velocities / stars: individual: HIP 11952
© ESO, 2012
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.