Methyl acetylene as a temperature probe for dense interstellar clouds

Citations Over TimeTop 16% of 1984 papers

Abstract

Methyl acetylene (propyne) appears to be a convenient and reliable probe of kinetic temperature for dense (few x 10 to the 4th/ cu cm) molecular clouds. A method is presented for fitting a (J + 1) - J K-multiplet to obtain the kinetic temperature from a single observation, facilitating the direct construction of kinetic temperature maps. Observations of Tau MC1, Ori MC1, Sgr B2, DR 21, DR 21 (OH), and S140 are presented to demonstrate the validity of the technique. Determination of methyl acetylene column densities requires, in addition, knowledge of the rotational excitation temperature. The relative abundance of CH3CCH appears to be within a factor of 2 of 2.5 x 10 to the -9th. Because of the large uncertainties in estimates of total gas column density, it is not clear whether there is genuine source-to-source variation in the CH3CCH relative abundance.

Related Papers

• → Cosmic-ray astrochemistry(2013)46 cited
• → Anatomy of Orion Molecular Clouds—The Astrochemistry Perspective/Approach(2021)5 cited
• → Reduced networks governing the fractional ionisation in interstellar molecular clouds(2002)12 cited
• → Astrochemistry: Chemistry in dynamically evolving interstellar clouds(1985)
• → The Density and Temperature of Molecular Clouds in M33(1997)