Carbon-Chain Chemistry vs. Complex-Organic-Molecule Chemistry in
  Envelopes around Three Low-Mass Young Stellar Objects in the Perseus Region
  We have analyzed ALMA Cycle 5 data in Band 4 toward three low-mass young
stellar objects (YSOs), IRAS 03235+3004 (hereafter IRAS 03235), IRAS 03245+3002
(IRAS 03245), and IRAS 03271+3013 (IRAS 03271), in the Perseus region. The
HC$_{3}$N ($J=16-15$; $E_{\rm {up}}/k = 59.4$ K) line has been detected in all
of the target sources, while four CH$_{3}$OH lines ($E_{\rm {up}}/k =
15.4-36.3$ K) have been detected only in IRAS 03245. Sizes of the HC$_{3}$N
distributions ($\sim 2930-3230$ 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 CH$_{3}$OH emission in IRAS 03245 is $\sim 1760$
au, which is slightly smaller than that of HC$_{3}$N in this source. We compare
the CH$_{3}$OH/HC$_{3}$N 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 HC$_{3}$N formation by the WCCC mechanism. In this temperature
range, CH$_{3}$OH does not thermally desorb from dust grains. Non-thermal
desorption mechanisms or gas-phase formation of CH$_{3}$OH 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 non-thermal desorption mechanisms.
