Detection of interstellar methyl-diacetylene
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), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 286:1; ISSN AJLEA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ALKYL RADICALS
ENERGY SPECTRA
ENERGY-LEVEL TRANSITIONS
FUNCTIONS
HYDROCARBONS
INTERSTELLAR GRAINS
METHYL RADICALS
ORGANIC COMPOUNDS
PARTICLES
RADICALS
SPECTRA
SPECTRAL DENSITY
SPECTRAL FUNCTIONS