研究成果藝廊
A Detailed Study of Spitzer-IRAC Emission in Herbig-Haro Objects. II. Interaction between Ejecta and Ambient Gas
top: Distribution of molecular hydrogen emission in the L 1157 jet. Blue, green, and red colors show emissions at 3.6, 4.5, and 8.0μm observed with the Spitzer Space Telescope. The infrared emission originates from shock waves in the jet, the speed of which is ~10-30km s-1. Color variation in the figure results from different temperatures or densities of gas. Bottom: Our new analysis for identifying regions at high temperatures and densities (dark) and low temperatures or densities (bright). We speculate that the protostar may act as a "shot-gun", ejecting the gas bullets (dark spots in the figure) with the trajectory shown with arrows, and entraining the surrounding gas seen as bright
regions. The features with asterisks are due to stars (i.e., not gas in the jet).
The infrared Array Camera (IRAC) on the Spitzer Space Telescope has provided a huge amount of data exceptionally useful for studying star formation in many aspects, including their driving jets and outflows. These show emission from molecular hydrogen, which is the most abundant molecule in space, heated by shock waves in many protostellar outflows. We are exploring a new method to discriminate relatively warm/dense molecular gas from the others. This allows us to investigate how the gas is ejected from the star or accretion disk and interact with the surrounding cold molecular gas. (Michihiro Takami et al. 2011 ApJ 743 193)