Molecular gas related to the ring nebula RCW 78 around DH 117688

CAPPA, C.E.; RUBIO, M.; MARTÍN, M.C.; ROMERO, G.A.

San Juan, Argentina

Congreso; Reunión anual 2008 de la Asociación Argentina de Astronomía; 2008

Asoc. Argentina de Astronomía

We investigate the distribution of the interstellar gas related to  RCW\,78 based on $^{12}$CO(1-0) observations  carried out with the SEST telescope and on  data belonging to the NANTEN survey. Complementary H{\sc i} 21cm line data from the SGPS and radio data at 4.85 GHz were also used. We report the detection of molecular gas having velocities in the range [--56,--33] km s$^{-1}$ associated with the western section of RCW\,78.  The CO emission distribution is compatible with the interpretation that  the western section of the nebula originated in the photodissociation and ionization of the molecular gas by the UV photons of the WN7 star HD\,117688, which, along with the action of the stellar winds, carved the molecular cloud.