posted November 20, 2010 09:38 AM         

HIP 13044 b
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HIP 13044 b Extrasolar planet List of extrasolar planets

HIP 13044 b is a Jupiter-like extrasolar planet orbiting the star HIP 13044, about 2000 light years away from the Earth in the constellation Fornax. Its discovery was announced on November 18 2010.[4] HIP 13044 was born in another galaxy, and became part of the Milky Way when the star's parent galaxy was absorbed by our own around 6–9 billion years ago, the remnants of the galaxy forming the Helmi stream.

[edit] Discovery
Rainer Klement of the Max Planck Institute for Astronomy said that the discovery is exciting for astronomers because it is the first time that a planetary system has been discovered in a stellar stream of extragalactic origin.[5] The planet was discovered using the MPG/ESO 2.2-m ground-based telescope at the European Southern Observatory in La Silla, Chile, using the radial velocity method which involves detecting small wobbles in a star caused by a planet as it tugs on it.[5]

The discovery of the planet may also suggest the need for rethinking issues in planet formation and survival, since it is the first planet ever discovered to be circling a star that is both very old and extremely metal-poor.[6] The planet thus challenges the core-accretion model of planet formation, given that it may be unlikely a planetary core of sufficient mass was formed, and may signify it was formed via the competing disk instability model of planet formation.[4][5][6][7][8][9][10]

[edit] Properties
The planet's star, HIP 13044 is rotating somewhat quickly, perhaps because it had swallowed its inner planets during the red giant phase.[4] It is now in the final stages of its life as a horizontal branch star, fusing helium in its core. It is likely that the planet orbited farther away from the star before its red giant phase, and arrived at its current location due to frictional interactions with the star's outer gas envelope. As the star is expected to undergo another phase of expansion before becoming a white dwarf, the planet's ultimate fate is uncertain.[4][5]