1995A&A...295..755T

¹²CO, ¹³CO and C¹⁸O J=1->0 observations of the L1778/L 1780 high latitude (b=36.7deg) dark cloud have been carried out using the Gornergrat 3m and SEST 15m telescopes. The observations revealed a cometary cloud structure: a dense core asymmetrically surrounded by a diffuse outer layer. The mass of the cloud calculated from the CO observations is 21.6M_☉. The compact ¹³CO core has a mass of 8.3M_☉ and is found to be in virial equilibrium. The CO data have been compared to previous optical, HI, and IRAS observations. We suggest that the structure and the morphology of L 1780 have been influenced by two large scale environmental effects: (1) the asymmetric interstellar UV radiation field and (2) a shock front, both caused by the high mass stars of the Sco - Cen OB association.