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

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 similar to 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 similar to 101 GHz, resolved in this cold dense core.