2004A&A...425..249M

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., 2000A&A...356..590U). Comparing an image from 2MASS with an image we obtained with SofI at the ESO 3.58m NTT three years later, we detected a co-moving companion located 21.465±0.023arcsec (621±10AU at 29pc) east of HD 75289. A second SofI image taken 10 months later confirmed the common proper motion of HD 75289B 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 140AU and substellar companions with masses m≥0.050M_☉ from 400AU up to 2000AU.