Hot ammonia in Orion

Journal Article · Tue Apr 01 04:00:00 EST 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157837· OSTI ID:5235046

Morris, M; Palmer, P; Zuckerman, B

Ten inversion lines from nonmetastable rotational levels of NH/sub 3/ have been detected in the Kleinmann-Low (KL) nebula in Orion. Six of these lines were previoulsy undetected. The emission arises from levels which have energies up to 1150 K above the ground state, indicating that the NH/sub 3/ is immersed in a hot, dense medium. Three well-defined kinematical components within KL are evident in emission from NH/sub 3/ and other molecules. The emission from hot NH/sub 3/ is dominated by the component having V/sub LSR/=5.2 km s/sup -1/ and ..delta..V =10--12 km s/sup -1/. A non-LTE analysis of NH/sub 3/ emission from this ''hot core'' component reveals that the minimum particle density in this source is approx.5 x 10 cm/sup -3/, and that the kinetic temperature is > or approx. =220 K. The diameter of the hot core source is probably within a factor of 2 to 6'' (5 x 10/sup 16/ cm). The hot core is undoubtedly associated with one of the compact infrared sources in KL, and we suggest on the basis of position and velocity coincidences that it is IRc2. The hot core appears to contain about one Jeans mass at the inferred temperature and density. We therefore suggest that this object is a very young protostar which is still in the throes of its initial collapse.

• Research Organization: Astronomy Department, Columbia University
• OSTI ID: 5235046
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 237:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMMONIA
CHEMICAL COMPOSITION
CHEMISTRY
COSMOCHEMISTRY
ELECTROMAGNETIC RADIATION
EMISSION
ENERGY LEVELS
ENERGY SPECTRA
EXCITED STATES
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED RADIATION
INTERSTELLAR SPACE
LINE WIDTHS
MOLECULES
NEBULAE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OPACITY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
ROTATIONAL STATES
SPACE
SPECTRA