Physical properties of the Sh2-104 H II region as seen by Herschel

Context. Sh2-104 is a Galactic H II region with a bubble morphology, detected at optical and radio wavelengths. It is considered the first observational confirmation of the collect-and-collapse model of triggered star-formation. Aims. We aim to analyze the dust and gas properties of the Sh2-104 region to better constrain its effect on local future generations of stars. In addition, we investigate the relationship between the dust emissivity index beta and the dust temperature, T-dust. Methods. Using Herschel PACS and SPIRE images at 100, 160, 250, 350 and 500 mu m we determine T-dust and beta throughout Sh2-104, fitting the spectral energy distributions (SEDs) obtained from aperture photometry. With the SPIRE Fourier-transform spectrometer (FTS) we obtained spectra at different positions in the Sh2-104 region. We detect J-ladders of (CO)-C-12 and (CO)-C-13, with which we derive the gas temperature and column density. We also detect proxies of ionizing flux as the [NII] P-3(1)-P-3(0) and [CI] P-3(2)-P-3(1) transitions. Results. We find an average value of beta similar to 1.5 throughout Sh2-104, as well as a T-dust difference between the photodissociation region ( PDR, similar to 25K) and the interior (similar to 40K) of the bubble. We recover the anti-correlation between beta and dust temperature reported numerous times in the literature. The relative isotopologue abundances of CO appear to be enhanced above the standard ISM values, but the obtained value is very preliminary and is still affected by large uncertainties.