SWS H_2_ observations in the BD+40 4124 group.
Heras, A. M.; Prusti, T.; van den Ancker, M. E.; Roelfsema, P. R.; Waelkens, C.; Lahuis, F.; Boxhoorn, D. R.; Kester, D. J. M.; Wesselius, P. R.; Young, E. T.; Huygen, E.; Clark, F. O.; Wooden, D. H.
Abstract
We report the detection of pure rotational lines of H_2_observed in the direction of three young stellar objects in the BD+40 4124 group, with the short-wavelength spectrometer (SWS) on board ISO. The rotational population distributions of all three stars are consistent with a thermal distribution. The derived kinetic temperatures are =~500K for BD+40 4124 and LkHα 224 and =~800K for LkHα 225. The amounts of molecular hydrogen detected are 0.01 to 0.04 Msun_. The relative abundances of ortho- and para-hydrogen are consistent with a high temperature equilibrium distribution. We conclude that the molecular hydrogen emission in all three regions appears to lie behind approximately 10-25mag of visual extinction and is probably not directly associated with any of the optical sources.