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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 607338.0, MPI für Astronomie / Publikationen_mpia
The visitor from an ancient galaxy: A planetary companion around an old, metal-poor red horizontal branch star
Authors:Klement, R. J.; Setiawan, J.; Henning, T.; Rix, H.-W.; Rochau, B.; Rodmann, J.; Schulze-Hartung, T.; Lattanzi, M. G.; Boss, A. P.
Publisher:Cambridge Univ. Press
Date of Publication (YYYY-MM-DD):2011
Title of Proceedings:The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolution
Start Page:121
End Page:125
Volume (in Series):276
Name of Conference/Meeting:The Astrophysics of Planetary Systems: Formation, Structure, and Dynamical Evolution
Audience:Not Specified
Abstract / Description:We report the detection of a planetary companion around HIP 13044, a metal-poor red horizontal branch star belonging to a stellar halo stream that results from the disruption of an ancient Milky Way satellite galaxy. The detection is based on radial velocity observations with FEROS at the 2.2-m MPG/ESO telescope. The periodic radial velocity variation of P = 16.2 days can be distinguished from the periods of the stellar activity indicators. We computed a minimum planetary mass of 1.25 Mjup and an orbital semimajor axis of 0.116 AU for the planet. This discovery is unique in three aspects: First, it is the first planet detection around a star with a metallicity much lower than few percent of the solar value; second, the planet host star resides in a stellar evolutionary stage that is still unexplored in the exoplanet surveys; third, the planetary system HIP 13044 most likely has an extragalactic origin in a disrupted former satellite of the Milky Way.
Free Keywords:galaxy: solar neighborhood; planetary systems: formation; stars: horizontal-branch; stars: individual (HIP 13044); techniques: radial velocities
Comment of the Author/Creator:Date: 2011, November 1, 2011
External Publication Status:published
Document Type:Conference-Paper
Communicated by:N. N.
Affiliations:MPI für Astronomie
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