摘要：A deep objective-prism survey for Hαemission stars towards the Canis Major star-forming clouds was performed. A total of 398 Hαemitters were detected, 353 of which are new detections. There is a strong concentration of these Hαemitters towards the molecular clouds surrounding the CMa OB1 association, and it is likely that these stars are young stellar objects recently born in the clouds. An additional population of Hαemitters is scattered all across the region, and probably includes unrelated foreground dMe stars and background Be stars. About 90% of the Hαemitters are detected by WISE, of which 75% was detected with usable photometry. When plotted in a WISE colour–colour diagram it appears that the majority are Class II YSOs. Coordinates and finding charts are provided for all the new stars, and coordinates for all the detections. We searched theGaia-DR2 catalogue and from 334 Hαemission stars with useful parallaxes, we selected a subset of 98 stars that have parallax errors of less than 20% and nominal distances in the interval 1050 to 1350 pc that surrounds a strong peak at 1185 pc in the distance distribution. Similarly,Gaiadistances were obtained for 51 OB-stars located towards Canis Major and selected with the same parallax errors as the Hαstars. We find a median distance for the OB stars of 1182 pc, in excellent correspondence with the distance from the Hαstars. Two known runaway stars are confirmed as members of the association. Finally, two new Herbig-Haro objects are identified.
