Hyperfine structure of the cyanomethyl radical (CH₂CN) in the L1544 prestellar core

¹ Université de Toulouse, UPS-OMP, IRAP, 31028 Toulouse, France
e-mail: charlotte.vastel@irap.omp.eu
² CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France
³ Department of Physics, University of Tokyo, Bunkyo-ku, 113-0033 Tokyo, Japan
⁴ Université de Grenoble Alpes, IPAG, 38000 Grenoble, France
⁵ CNRS, IPAG, 38000 Grenoble, France
⁶ Observatorio Astronómico Nacional (OAN, IGN), Calle Alfonso XII, 3, 28014 Madrid, Spain

Received: 10 August 2015
Accepted: 16 September 2015

Abstract

The L1544 prestellar core has been observed as part of the ASAI IRAM Large Program at 3 mm. These observations led to the detection of many complex molecules. In this Letter we report the detection of the cyanomethyl radical for the first time in a prototypical prestellar core, which is possible through the high sensitivity of the IRAM EMIR receiver. A complex structure in which we suspect the presence of the hyperfine transitions of the ortho and para forms is observed thanks to the high spectral resolution of ~50 kHz. We computed all transition frequencies and line intensities for all transitions including satellite hyperfine components for the ortho and para forms of CH₂CN at the frequencies observed by ASAI. We report the first detection of the fine and hyperfine structure of the ortho and para forms of the cyanomethyl radical at ~101 GHz, resolved in this cold dense core.