The SOFIA Massive (SOMA) Star Formation Q-band follow-up I. Carbon-chain chemistry of intermediate-mass protostars

Abstract

Evidence for similar chemical characteristics around low- and high-mass protostars has been found: in particular, a variety of carbon-chain species and complex organic molecules (COMs) are formed around them. On the other hand, the chemical compositions around intermediate-mass (IM; $2M_{\odot }<m_{\ast }<8M_{\odot }$) protostars have not been studied with large samples. In particular, it is unclear the extent to which carbon-chain species are formed around them. We aim to obtain the chemical compositions, particularly focusing on carbon-chain species, towards a sample of IM protostars. We have conducted Q-band (31.5-50 GHz) line survey observations towards eleven mainly intermediate-mass protostars with the Yebes 40 m radio telescope. The target protostars were selected from a sub-sample of the source list of the SOFIA Massive (SOMA) Star Formation project. Nine carbon-chain species (HC${}_3$N, HC${}_5$N, C${}_3$H, C${}_4$H, $linear-$H${}_2$CCC, $cyclic-$C${}_3$H${}_2$, CCS, C${}_3$S, and CH${}_3$CCH), three COMs (CH${}_3$OH, CH${}_3$CHO, and CH${}_3$CN), H${}_2$CCO, HNCO, and four simple sulfur (S)-bearing species (${}^{13}$CS, C${}^{34}$S, HCS${}^{+}$, H${}_2$CS) have been detected. The rotational temperatures of HC${}_5$N are derived to be $\sim 20-30$ K in three IM protostars and they are very similar compared to those around low- and high-mass protostars. These results indicate that carbon-chain molecules are formed in lukewarm ($\sim 20-30$ K) gas around the IM protostars by the Warm Carbon-Chain Chemistry (WCCC) process. Carbon-chain formation occurs ubiquitously in the warm gas around protostars across a wide range of stellar masses. Carbon-chain molecules and COMs coexist around most of the target IM protostars, which is similar to the situation in low- and high-mass protostars. The chemical characteristics around protostars are common in the low-, intermediate- and high-mass regimes.

Accepted for publication in the Astronomy and Astrophysics (A&A)

References in corpus (25)

• Astrochemistry During the Formation of Stars
• Formation of complex organic molecules in hot molecular cores through nondiffusive grain-surface and ice-mantle chemistry
• Formation of Complex Organic Molecules in Cold Interstellar Environments through non-diffusive grain-surface and ice-mantle chemistry
• Yebes 40 m radio telescope and the broad band NANOCOSMOS receivers at 7 mm and 3 mm for line surveys
• Modeling the Lukewarm Corino Phase - is L1527 unique?
• L483: Warm Carbon-Chain Chemistry Source Harboring Hot Corino Activity
• The interstellar chemistry of C3H and C3H2 isomers
• SOLIS II. Carbon-chain growth in the Solar-type protocluster OMC2-FIR4
• The observed chemical structure of L1544
• Direct measurements of carbon and sulfur isotope ratios in the Milky Way
• Carbon-Chain Chemistry in the Interstellar Medium
• JOYS: JWST Observations of Young protoStars: Outflows and accretion in the high-mass star-forming region IRAS23385+605
• The Mass Accretion Rate and Stellar Properties in Class I Protostars
• Unveiling the nature and interaction of the intermediate/high-mass YSOs in IRAS 20343+4129
• An unbiased spectral line survey observation toward the low-mass star-forming region L1527
• Survey Observations to Study Chemical Evolution from High-Mass Starless Cores to High-Mass Protostellar Objects II. HC${}_3$N and N${}_2$H${}^{+}$
• IRAS23385+6053: An embedded massive cluster in the making
• The SOFIA Massive (SOMA) Star Formation Survey. IV. Isolated Protostars
• The SOFIA Massive (SOMA) Star Formation Survey. III. From Intermediate- to High-Mass Protostars
• Observations of Cyanopolyynes toward Four High-Mass Star-Forming Regions Containing Hot Cores
• New detections of HC${}_5$N toward hot cores associated with 6.7 GHz methanol masers
• Mass ejection and time variability in protostellar outflows: Cep E. SOLIS XVI
• Chemical Differentiation around Five Massive Protostars Revealed by ALMA -Carbon-Chain Species, Oxygen-/Nitrogen-Bearing Complex Organic Molecules-
• Carbon Chain Chemistry in Hot-Core Regions around Three Massive Young Stellar Objects Associated with 6.7 GHz Methanol Masers
• Investigation of Chemical Differentiation among the NGC2264 Cluster-Forming Clumps

Cited by in corpus (1)

• The evolution of C4H and c-C3H2 in molecular cores