Detection of interstellar methyl-diacetylene

Journal Article · Thu Nov 01 00:00:00 EST 1984 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/184377· OSTI ID:6094922

Loren, R B; Mundy, L G; Wootien, A

Four transitions of the molecule methyl-diacetylene (CH/sub 3/C/sub 4/H) have been detected toward the cold molecular cloud TMC-1. The presence of this molecule shows that long carbon chain molecules in the interstellar medium can be built with the methyl end group. The column density of CH/sub 3/C/sub 4/H toward TMC-1 is 2.8 x 10/sup 13/ cm/sup -2/ at T/sub k/ = 15 K or 2.0 x 10/sup 13/ cm/sup -2/ at T/sub k/ = 10 K, a factor of 4 larger than that of the isoelectronic species CH/sub 3/ C/sub 3/N (5 x 10/sup 12/ cm/sup -2/) which has recently been detected in this same cloud by Broton and colleagues. Within the methyl-acetyl-sequence the abundance decreases slowly with increasing complexity; the (CH/sub 3/C/sub 2/H)/(CH/sub 3/C/sub 4/H) abundance ratio is 4, similar to the abundance ratio for the cyanopolyynes (HC/sub 3/N)/(HC/sub 5/N). The molecules of comparable complexity in the methy-acetyl-sequence are somewhat more abundant than those in the methyl-cyano-sequence but somewhat less abundant than those in the cyanopolyyne sequence.

• Research Organization: Millimeter Wave Observatory, Electrical Engineering Research Laboratory, and Department of Astronomy, The University of Texas at Austin
• OSTI ID: 6094922
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Vol. 286:1
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
HYDROCARBONS
ABUNDANCE
INTERSTELLAR GRAINS
ENERGY SPECTRA
ENERGY-LEVEL TRANSITIONS
METHYL RADICALS
SPECTRAL DENSITY
ALKYL RADICALS
FUNCTIONS
ORGANIC COMPOUNDS
PARTICLES
RADICALS
SPECTRA
SPECTRAL FUNCTIONS
640105* - Astrophysics & Cosmology- Galaxies