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High Velocity Gas in the Orion Nebula

Published online by Cambridge University Press:  14 August 2015

Nicholas Z. Scoville
Nicholas Z. Scoville*
Affiliation:
Department of Physics and Astronomy University of Massachusetts

Abstract

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Observations at both millimeter and infrared wavelengths reveal energetic activity within the core of the Orion molecular cloud in the vicinity of the KL-BN cluster. New observations of the high velocity CO emission at 2.6-mm with improved angular resolution (HPBW = 44″) show that the source diameter averages 4 × 1017 cm and the center of mass is displaced 10-12″ north of the Kleinmann-Low nebula to a position close to the Becklin-Neugebauer object. The total mass of high velocity gas in the core region is ∼10 M⊙ (assuming 10% of the carbon is in CO); the present kinetic energy is 4 × 1047 ergs. Further evidence that BN may be the ultimate source of this energy is provided by high resolution infrared spectra which show both ionized and high temperature (Tk ≳ 3000 K) neutral gas in this source. CO bandhead emission (v = 2 → 0, 3 → 1, and 4 → 2) seen in BN is thought to arise from collisional excitation at high temperatures in a very dense (nH > 1010 cm−3) region only 1 AU in size. And high spectral resolution profiles of the Br α and γ recombination lines show that the HII region previously detected in BN apparently has motions over 100 km s−1.

Type
Research Article
Information
Symposium - International Astronomical Union , Volume 87: Interstellar Molecules , 1980 , pp. 33 - 38
Copyright
Copyright © Reidel 1980 

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