SOFIA/FORCAST Observations of Warm Dust in S106: A Fragmented Environment
Hill, T.; Smith, N.; Fazio, G. G.; Gehrz, R. D.; Schneider, N.; Bontemps, S.; Motte, F.; Megeath, S. T.; Hora, J. L.; Simon, R.; Smith, H. A.; Myers, P. C.; Lau, R. M.; Herter, T. L.; Mizuno, D. R.; Staguhn, J. G.; Kraemer, K. E.; Adams, J. D.; Hankins, M.; Allen, L. E.; Gutermuth, R. A.; Keto, E.; Carey, S. J.; Koenig, X. P.; Guzman Fernandez, A.
United States, Germany, France, Chile
Abstract
We present mid-IR (19-37 μm) imaging observations of S106 from SOFIA/FORCAST, complemented with IR observations from Spitzer/IRAC (3.6-8.0 μm), IRTF/MIRLIN (11.3 and 12.5 μm), and Herschel/PACS (70 and 160 μm). We use these observations, observations in the literature, and radiation transfer modeling to study the heating and composition of the warm (∼100 K) dust in the region. The dust is heated radiatively by the source S106 IR, with little contributions from grain-electron collisions and Lyα radiation. The dust luminosity is ≳(9.02 ± 1.01) × 104 L⊙, consistent with heating by a mid- to late-type O star. We find a temperature gradient (∼75-107 K) in the lobes, which is consistent with a dusty equatorial geometry around S106 IR. Furthermore, the SOFIA observations resolve several cool (∼65-70 K) lanes and pockets of warmer (∼75-90 K) dust in the ionization shadow, indicating that the environment is fragmented. We model the dust mass as a composition of amorphous silicates, amorphous carbon, big grains, very small grains, and polycyclic aromatic hydrocarbons. We present the relative abundances of each grain component for several locations in S106.