1 Introduction

Among the more than 50 extrasolar planetary systems inferred so far from high precision radial velocity surveys (e.g. Marcy et al. 2000) is the signature of a planetary companion with a minimum mass of 4 ${M}_{{\rm Jup}} \sin i$ in a 15.8 days period orbit around the K dwarf Gliese 86 (or Gl 86) (see Queloz et al. 2000).

The radial velocity data measured over the last 20 years do not only show the variation due to the planetary companion, but also exhibit a large, long term, drift of about 0.3 to 0.5 ms^-1day^-1. The combination of these measurements with historical data led to the suspicion that Gl 86 has an additional companion in an orbit with a semi major axis larger than 20 AU. As the distance of Gl 86 is only 10.9 pc towards the sun, direct imaging of such a companion seems worthwhile. As reported in a poster by Sterzik, Marchis & Kürster (unpublished) the ESO adaptive optics system ADONIS was used to search for a companion close to Gl 86 but without success. Their sensitivity estimate in K band excluded any stellar companion earlier than M6 further then $1\hbox{$.^{\prime\prime}$ }0$ from Gl 86.

In this Letter we report on new, high angular resolution, adaptive optics observations of Gl 86 leading to the detection of another substellar companion in this extrasolar planetary system.