Interstellar detection of c-C3D2

Abstract

We report the first interstellar detection of c-C3D2. The doubly deuterated cyclopropenylidene, a carbene, has been detected toward the starless cores TMC- 1C and L1544 using the IRAM 30m telescope. The J(Ka,Kc) = 3(0,3)-2(1,2), 3(1,3)-2(0,2), and 2(2,1)-1(1,0) transitions of this species have been observed at 3 mm in both sources. The expected 1:2 intensity ratio has been found in the 3(0,3)-2(1,2) and 3(1,3)-2(0,2) lines, belonging to the para and ortho species respectively. We also observed lines of the main species, c-C3H2, the singly deuterated c-C3HD, and the species with one 13C off of the principal axis of the molecule, c-H13CC2H. The lines of c-C3D2 have been observed with high signal to noise ratio, better than 7.5 sigma in TMC-1C and 9 sigma in L1544. The abundance of doubly deuterated cyclopropenylidene with respect to the normal species is found to be (0.4 - 0.8)% in TMC-1C and (1.2 - 2.1)% in L1544. The deuteration of this small hydrocarbon ring is analysed with a comprehensive gas-grain model, the first including doubly deuterated species. The observed abundances of c-C3D2 can be explained solely by gas-phase processes, supporting the idea that c-C3H2 is a good indicator of gas-phase deuteration.

Accepted for publication in ApJ Letters

References in corpus (17)

• A computer program for fast non-LTE analysis of interstellar line spectra
• An atomic and molecular database for analysis of submillimetre line observations
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• Molecular ions in L1544. II. The ionization degree
• First detection of triply-deuterated methanol
• Molecular Evolution in Collapsing Prestellar Cores III: Contraction of A Bonnor-Ebert Sphere
• CO Depletion and Deuterium Fractionation in Prestellar Cores
• Dynamics and Depletion in Thermally Supercritical Starless Cores
• Testing grain surface chemistry : a survey of deuterated formaldehyde and methanol in low-mass Class 0 protostars
• From Prestellar to Protostellar Cores II. Time Dependence and Deuterium Fractionation
• Interstellar deuterated ammonia: From NH3 to ND3
• Formaldehyde and methanol deuteration in protostars: fossiles from a past fast high density pre-collapse phase
• Deuterium chemistry in the Orion Bar PDR - "warm" chemistry starring CH2D+
• Interstellar ices as witnesses of star formation: selective deuteration of water and organic molecules unveiled
• Deuterated Ammonia in Galactic Protostellar Cores
• TMC-1C: an accreting starless core
• Modeling the ortho-to-para abundance ratio of cyclic C3H2 in cold dense cores

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