Detection of molecular hydrogen quadrupole emission in the Orion Nebula

Abstract

Seven lines of the 1-0 vibration-rotation quadrupole spectrum of H2 were detected around the Becklin-Neugebauer (BN) object and in a part of the Kleinmann-Low nebula 10" south of BN. The surface brightness of the S(1) line was found to be 3.0+-0.5 x 1e-3 ergs cm-2 s-1 sr-1 for the region around BN. Analysis showed that a thermal excitation model gives a good fit to the observed line intensities with a temperature of approximately 2000K. A column density for H2 of 9.4 +- 1.5 x 1e18 cm-2 was derived with this temperature.