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Post Info TOPIC: HIP 11952


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HIP 11952

Title: Planetary companions around the metal-poor star HIP 11952
Authors: J. Setiawan, V. Roccatagliata, D. Fedele, Th. Henning, A. Pasquali, M.V. Rodríguez-Ledesma, E. Caffau, U. Seemann, R.J. Klement

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 solar masses, we computed minimum planetary masses of 0.78 Jupiter masses for the inner and 2.93 Jupiter masses 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

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Posts: 131433

 Oldest known planets in Universe found

Astronomers have discovered the oldest known planets from the early days of the Universe, orbiting a star that is almost on our cosmic doorstep.
The ancient solar system is thought to have formed around 12.8 billion years ago, just a few hundred million years after the Big Bang. Two newly detected exoplanets lie just 375 light-years away from the Earth, within our own Milky Way galaxy. But their host star was born when our galaxy was still forming.
European scientists used a giant telescope in Chile to detect two planets orbiting a star labelled HIP 11952 in the constellation of Cetus, the mythological sea monster. One planet, HIP 11952c, is the size of Jupiter while the other, HIP 11952b, is around three times the size of Jupiter

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