Astrometric confirmation of a wide low-mass companion to the planet host star HD 89744

In our ongoing deep infrared imaging search for faint wide secondaries of planet-candidate host stars we have confirmed astrometrically the companionship of a low-mass object to be co-moving with HD 89744, a companion-candidate suggested already by Wilson et al. (2000). The derivation of the common proper motion of HD 89744 and its companion, which are separated by 62.996±0. 035 arcsec, is based on about 5 year epoch difference between 2MASS and our own UKIRT/UFTI images. The companion effective temperature is about 2200 K and its mass is in the range between 0.072 and 0.081 M⊙, depending on the evolutionary model. Therefore, HD 89744 B is either a very low mass stellar or a heavy brown dwarf companion.