Caltech/IPAC Seminar

Chemical composition is a good indicator of the evolution of starless cores and protostellar cores. Classically, unsaturated carbon-chain molecules are known to be abundant in young starless cores, while saturated complex organic molecules (COMs) are abundant in protostellar cores. However, carbon-chain-rich but COM-poor low-mass protostars have been discovered, and this type of source was named Warm Carbon Chain Chemistry (WCCC). This indicates that chemical diversity emerges around low-mass protostars. On the other hand, the chemical complexity around high-mass protostars has not been fully explored. To study it, we have conducted molecular line observations toward six high-mass protostars with ALMA. We found that the carbon-chain chemistry around high-mass protostars is different from WCCC. We named this carbon-chain chemistry Hot Carbon Chain Chemistry (HCCC). One target source, G28.28-0.36, is identified as the first HCCC source, which represents a carbon-chain-rich but COM-poor source. Finally, I also briefly introduce recent findings by radio telescopes and possible future studies combining infrared telescopes, including the JWST.