A Photometric and [S II] Survey of the Young Cluster Roslund 4

Optical B- and V-band CCD data have been obtained for the young cluster Roslund 4 in conjunction with a large-scale photometric survey of open clusters. In addition, [S II] and off-line continuum CCD emission-line imaging data have also been obtained, revealing three regions in the cluster field where shock-excited gas is present. Two Herbig-Haro–like emission features are found, while a more extended emission feature, along an apparent cloud boundary, may be a result of stellar winds encountering the edge of a molecular cloud. The emission-line features are located near IRAS sources with properties consistent with star-forming regions. A previously published age for Roslund 4 (~10 Myr) would seemingly suggest that shocked gas features should not be present in the cluster region, but an upper limit on the age (less than 4 Myr) derived from the new photometry is more consistent with their presence. Finally, the distance to Roslund 4 is found to be 1700–2000 pc, considerably closer than the previous published estimate.