EDP Sciences
Free access
Issue
A&A
Volume 425, Number 1, October I 2004
Page(s) 249 - 253
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20041009


A&A 425, 249-253 (2004)
DOI: 10.1051/0004-6361:20041009

A low-mass stellar companion of the planet host star HD 75289

M. Mugrauer1, R. Neuhäuser1, T. Mazeh2, J. Alves3 and E. Guenther4

1  Astrophysikalisches Institut, Universität Jena, Schillergäßchen 2-3, 07745 Jena, Germany
    e-mail: markus@astro.uni-jena.de
2  Tel Aviv University, Tel Aviv 69978, Israel
3  European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
4  Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany

(Received 2 April 2004 / Accepted 3 June 2004)

Abstract
We report on the detection of a new low-mass stellar companion of HD 75289, a G0V star that harbors one known radial-velocity planet (Udry et al. 2000, A&A, 356, 590). Comparing an image from 2MASS with an image we obtained with SofI at the ESO 3.58 m NTT three years later, we detected a co-moving companion located $21.465\pm0.023$ arcsec ( $621\pm10$ AU at 29 pc) east of HD 75289. A second SofI image taken 10 months later confirmed the common proper motion of HD 75289 B with its host star. The infrared spectrum and colors of the companion are consistent with an M 2 to M 5 main-sequence star at the distance of HD 75289. No further (sub)stellar companion down to H=19 mag could be detected. With the SofI detection limit we can rule out additional stellar companions beyond 140 AU and substellar companions with masses $m\ge0.050~M_{\odot}$ from 400 AU up to 2000 AU.


Key words: stars: low-mass, brown dwarfs -- stars: planetary systems

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© ESO 2004