Substellar-mass Companions to the K-dwarf BD+14 4559 and the K-giants HD 240210 and BD+20 2457

We present the discovery of substellar-mass companions to three stars by the ongoing Penn State-Torun Planet Search conducted with the 9.2 m Hobby-Eberly Telescope. The K2-dwarf, BD+14 4559, has a 1.5 MJ minimum mass companion with the orbital period of 269 days and shows a non-linear, long-term rad...

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Bibliographic Details
Published in:The Astrophysical journal 2009-12, Vol.707 (1), p.768-777
Main Authors: Niedzielski, A, Nowak, G, Adamów, M, Wolszczan, A
Format: Article
Language:English
Subjects:
Astronomy
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Earth, ocean, space
Exact sciences and technology
INCLINATION
MASS
NONLINEAR PROBLEMS
ORBITS
PLANETS
RADIAL VELOCITY
SIMULATION
STARS
TELESCOPES
VELOCITY
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Summary:We present the discovery of substellar-mass companions to three stars by the ongoing Penn State-Torun Planet Search conducted with the 9.2 m Hobby-Eberly Telescope. The K2-dwarf, BD+14 4559, has a 1.5 MJ minimum mass companion with the orbital period of 269 days and shows a non-linear, long-term radial velocity (RV) trend, which indicates a possible presence of another planet-mass body in the system. The K3-giant, HD 240210, exhibits RV variations that require modeling with multiple orbits, but the available data are not yet sufficient to do it unambiguously. A tentative, one-planet model calls for a 5.2 MJ minimum mass planet in a 502 day orbit around the star. The most massive of the three stars, the K2-giant, BD+20 2457, whose estimated mass is 2.8 +/- 1.5 M, has two companions with the respective minimum masses of 21.4 MJ and 12.5 MJ and orbital periods of 380 and 622 days. Depending on the unknown inclinations of the orbits, the currently very uncertain mass of the star, and the dynamical properties of the system, it may represent the first detection of two brown dwarf-mass companions orbiting a giant. The existence of such objects will have consequences for the interpretation of the so-called brown dwarf desert known to exist in the case of solar-mass stars.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/707/1/768