Observations of the extinction and excitation of the molecular hydrogen emission in Orion

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160583· OSTI ID:6302437

Beckwith, S; Evans, II, N J; Gatley, I; Gull, G; Russell, R W

We present the first observations of two quadrupole rotational transitions of molecular hydrogen, the J = 7..-->..5 and 9..-->..7 transitions, along with several previously observed vibration-rotation H/sub 2/ lines in the Orion molecular cloud. The line ratios indicate a 2.1 ..mu..m extinction of approximately 2 mag. This extinction is intermediate between the earliest estimates of 4 mag and the more recent estimate of 1.2--2.0 mag. A comparison of the populations of three vibrational levels indicates a distribution of excitation temperatures between 1000 and 3000 K for the levels included; 1500 K best represents the temperature of the gas responsible for the v = 1..-->..0 line emission. These results imply the total luminosity of the molecular hydrogen emission is 200 +- 80L/sub sun/, and the mass of the emitting gas is of order 0.05 M/sub sun/. The uncertainties in the structure of the extinction and the geometry of the emission region may make it impossible to determine the luminosity and mass of the hot H/sub 2/ any more accurately. The mass and cooling time of the hot H/sub 2/ indicates at least 10 M/sub sun/ of material has been heated over the lifetime of the outflow.

• Research Organization: Department of Astronomy, Cornell University
• OSTI ID: 6302437
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 264:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELEMENTS
EMISSION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
HYDROGEN
INFRARED SPECTRA
INTERSTELLAR GRAINS
LUMINOSITY
MOLECULES
NEBULAE
NONMETALS
OPTICAL PROPERTIES
PARTICLES
PHYSICAL PROPERTIES
ROTATIONAL STATES
SPECTRA