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arXiv · 1011.6376

A Giant Planet Around a Metal-poor Star of Extragalactic Origin

Johny Setiawan·Rainer J. Klement·Thomas Henning·Hans-Walter Rix·Boyke Rochau·Jens Rodmann·Tim Schulze-Hartung·MPIA Heidelberg·ESTEC Noordwijk
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Abstract

Stars in their late stage of evolution, such as Horizontal Branch stars, are still largely unexplored for planets. We report the detection of a planetary companion around HIP 13044, a very metal-poor star on the red Horizontal Branch, based on radial velocity observations with a high-resolution spectrograph at the 2.2-m MPG/ESO telescope. The star's periodic radial velocity variation of P=16.2 days caused by the planet can be distinguished from the periods of the stellar activity indicators. The minimum mass of the planet is 1.25 Jupiter masses and its orbital semi-major axis 0.116 AU. Because HIP 13044 belongs to a group of stars that have been accreted from a disrupted satellite galaxy of the Milky Way, the planet most likely has an extragalactic origin.

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Johny Setiawan, Rainer J. Klement, Thomas Henning, Hans-Walter Rix, Boyke Rochau, Jens Rodmann, Tim Schulze-Hartung, MPIA Heidelberg, ESTEC Noordwijk. 2010-11-29. A Giant Planet Around a Metal-poor Star of Extragalactic Origin. https://doi.org/10.1126/science.1193342

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