2012ApJ...755...20S

The Sh2-294 H II region ionized by a single B0V star features several infrared excess sources, a photodissociation region, and also a group of reddened stars at its border. The star formation scenario in this region seems to be quite complex. In this paper, we present follow-up results of Sh2-294 H II region at 3.6, 4.5, 5.8, and 8.0 µm observed with the Spitzer Space Telescope Infrared Array Camera (IRAC), coupled with H₂(2.12 µm) observation, to characterize the young population of the region and to understand its star formation history. We identified 36 young stellar object (YSO, Class I, Class II, and Class I/II) candidates using IRAC color-color diagrams. It is found that Class I sources are preferentially located at the outskirts of the H II region and associated with enhanced H₂emission; none of them are located near the central cluster. Combining the optical to mid-infrared (MIR) photometry of the YSO candidates and using the spectral energy distribution fitting models, we constrained stellar parameters and the evolutionary status of 33 YSO candidates. Most of them are interpreted by the model as low-mass (<4 M_☉) YSOs; however, we also detected a massive YSO (∼9 M_☉) of Class I nature, embedded in a cloud of visual extinction of ∼24 mag. Present analysis suggests that the Class I sources are indeed a younger population of the region relative to Class II sources (age ∼ 4.5x10⁶ yr). We suggest that the majority of the Class I sources, including the massive YSOs, are second-generation stars of the region whose formation is possibly induced by the expansion of the H II region powered by a ∼4x10⁶ yr B0 main-sequence star.