We have carried out a search for co-moving stellar and substellar companions around 18 exoplanet host stars with the infrared camera MAGIC at the 2.2m Calar Alto telescope , by comparing our images with images from the all sky surveys 2MASS , POSS I and II .
Four stars of the sample namely HD 80606 , 55 Cnc , HD 46375 and BD - 10 ^ { \circ } 3166 , are listed as binaries in the Washington Visual Double Star Catalogue ( WDS ) .
The binary nature of HD 80606 , 55 Cnc , and HD 46375 is confirmed with both astrometry as well as photometry , thereby the proper motion of the companion of HD 46375 was determined here for the first time .
We derived the companion masses as well as the longterm stability regions for additional companions in these three binary systems .
We can rule out further stellar companions around all stars in the sample with projected separations between 270 AU and 2500 AU , being sensitive to substellar companions with masses down to \sim 60 { M _ { Jup } } ( S/N = 3 ) .
Furthermore we present evidence that the two components of the WDS binary BD - 10 ^ { \circ } 3166 are unrelated stars , i.e this system is a visual pair .
The spectrophotometric distance of the primary ( a K0 dwarf ) is \sim 67 pc , whereas the presumable secondary BD - 10 ^ { \circ } 3166 B ( a M4 to M5 dwarf ) is located at a distance of 13 pc in the foreground .