Observations of young cometary nebula NGC 2261 with the IRAM 30-m telescope

The prototype young cometary nebula NGC 2261, around the star R Mon, has been extensively observed with 20'' resolution in the J=1-0 line of CO and 13CO with the IRAM 30-m telescope (located on the Pico Veleta, near Granada, Spain). The molecular line maps are compared with optical observations to obtain detailed information on the nature of this cometary nebula as well as on the kinematic structure of the gas. Our observations suggest that cometary nebula NGC 2261 is actually the brightests fan of a bipolar nebula. Furthermore, it appears that the optical nebula is a hollow cone which has been emptied by the action of winds from R Mon, the star located at the tip of the nebula. High velocity CO flows along the cone walls. Toward the position of the star R Mon a molecular maximum is observed which could be due to residual material originated during the collapse process that led to the formation of the star. (author). 3 figs., 14 refs