Discovery of five cyano derivatives of propene with the QUIJOTE line survey

Abstract

We report the discovery of five cyano derivatives of propene towards TMC-1 with the QUIJOTE line survey: trans and cis-crotononitrile (t-CH3CHCHCN, c-CH3CHCHCN), methacrylonitrile (CH2C(CH3)CN), and gauche and cis-allyl cyanide (g-CH2CHCH2CN and c-CH2CHCH2CN). The observed transitions allowed us to derive a common rotational temperature of 7 ± 1 K for all them. The derived column densities are N(t-CH3CHCHCN) = (5 ± 0.5) × 1010 cm−2, N(c-CH3CHCHCN) = (1.3 ± 0.2) × 1011 cm−2, N(CH2C(CH3)CN) = (1.0±0.1) × 1011 cm−2, N(g-CH2CHCH2CN) = (8.0 ± 0.8) × 1010 cm−2, and N(c-CH2CHCH2CN) = (7.0 ± 0.7) × 1010 cm−2, respectively. The abundance of cyano-propene relative to that of propene is thus ∼10−2, which is considerably lower than those of other cyano derivatives of abundant hydrocarbons. Upper limits are obtained for two ethynyl derivatives of propene (E and Z-CH3CHCHCCH).