2021ApJ...910..141T

We have analyzed ALMA Cycle 5 data in Band 4 toward three low-mass young stellar objects, IRAS 03235+3004 (hereafter IRAS 03235), IRAS 03245+3002 (IRAS 03245), and IRAS 03271+3013 (IRAS 03271), in the Perseus region. The HC₃N (J = 16-15; E_up/k = 59.4 K) line has been detected in all of the target sources, while four CH₃OH lines (E_up/k = 15.4-36.3 K) have been detected only in IRAS 03245. Sizes of the HC₃N distributions (∼2930-3230 au) in IRAS 03235 and IRAS 03245 are similar to those of the carbon-chain species in the warm carbon-chain chemistry (WCCC) source L1527. The size of the CH₃OH emission in IRAS 03245 is ∼1760 au, which is slightly smaller than that of HC₃N in this source. We compare the CH₃OH/HC₃N abundance ratios observed in these sources with predictions of chemical models. We confirm that the observed ratio in IRAS 03245 agrees with the modeled values at temperatures around 30-35 K, which supports the HC₃N formation by the WCCC mechanism. In this temperature range, CH₃OH does not thermally desorb from dust grains. Nonthermal desorption mechanisms or gas-phase formation of CH₃OH seem to work efficiently around IRAS 03245. The fact that IRAS 03245 has the highest bolometric luminosity among the target sources seems to support these mechanisms, in particular the nonthermal desorption mechanisms.