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

M. Mugrauer*, R. Neuhäuser, T. Mazeh, J. Alves, E. Guenther

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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±0.023 arcsec (621±10 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 ≥ 0.050 M≥ from 400 AU up to 2000 AU.

Original languageEnglish
Pages (from-to)249-253
Number of pages5
JournalAstronomy and Astrophysics
Issue number1
StatePublished - Oct 2004


  • Stars: low-mass, brown dwarfs
  • Stars: planetary systems


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