A multiwavelength study of the star forming H II region Sh2-82

Abstract: Based on a multiwavelength study, the interstellar medium and young stellar objects (YSOs) around the HII region Sh2-82 have been analyzed. Two molecular clumps were found from the archival data of the Galactic Ring Survey, and using the Two Micron All-Sky Survey catalog, we found two corresponding young clusters embedded in the molecular clumps. The very good relations between CO emission, infrared shells and YSOs suggest that it is probably a triggered star formation region from the expansion of Sh2-82. We further used the data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire from Spitzer to study the YSOs within the two clumps, confirming star formation in this region. By spectral energy distribution fits to each YSO candidate with infrared excess, we derived the slope of the initial mass function. Finally, comparing the HII region's dynamical age and the fragmentation time of the molecular shell, we discard the "collect and collapse" process as being the triggering mechanism for YSO formation. Sh2-82 can be a mixture of other processes such as radiative-driven implosion and/or collisions with pre-existing clumps.