The HARPS search for southern extra-solar planets*,**
XX. Planets around the active star BD -08°2823
1
Institut d'Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie,
98bis boulevard Arago, 75014 Paris, France e-mail: hebrard@iap.fr
2
Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
3
ESO, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany
4
Observatoire de Paris, GEPI, 5 Place Jules Janssen, 92195 Meudon, France
5
ESO, Alonso de Cordoba 3107, Vitacura Casilla 19001, Santiago, Chile
6
Laboratoire d'Astrophysique de Grenoble,
CNRS (UMR 5571), Université J. Fourier, BP 53, 38041 Grenoble Cedex 9, France
7
Physikalisches Institut Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
8
Observatoire de Haute-Provence, CNRS/OAMP, 04870 Saint-Michel-l'Observatoire, France
9
Laboratoire d'Astrophysique de Marseille, Université de Provence, CNRS (UMR 6110),
BP 8, 13376 Marseille Cedex 12, France
10
Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
Received:
22
October
2009
Accepted:
8
December
2009
We report the detection of a planetary system around BD -08°2823 that includes at least one
Uranus-mass planet and one Saturn-mass planet. This discovery serendipitously originates from
a search for planetary transits in the Hipparcos photometry database. This program preferentially selected
active stars and did not allow the detection of new transiting planets.
It allowed however the identification of the K3V star BD -08°2823 as a target
harboring a multiplanet system, which we secured and
characterized thanks to an intensive monitoring with the HARPS spectrograph at the 3.6-m
ESO telescope in La Silla. The stellar activity level of BD -08°2823 complicates the analysis but does
not prohibit the detection of two planets around this star.
BD -08°2823b has a minimum mass of 14.4±2.1 
and an orbital period of
5.60 days, whereas BD -08°2823c has a minimum mass of 0.33±0.03 MJup and an orbital
period of 237.6 days.
This new system strengthens the observation that low-mass planets are preferentially found in
multiplanetary systems, but not around high-metallicity stars as is the case for
massive planets. It also supports the belief
that active stars should not be neglected in exoplanet searches even when searching
for low-mass planets.
Key words: planetary systems / techniques: radial velocities / stars: individual: BD -08°2823 / techniques: photometric
Based on observations made with HARPS spectrograph on the 3.6-m ESO telescope at La Silla Observatory, Chile, under the programs ID 072.C-0488, 074.C-0364 and 078.C-0044.
The full version of Table 1 (HARPS measurements of BD -08°2823) is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A46
© ESO, 2010