Widicus Weaver Group Contributes to Ground-Breaking Result on the Chemistry of Planet-forming Discs

This artist’s impression shows the closest known protoplanetary disc, around the star TW Hydrae in the huge constellation of Hydra (The Female Watersnake). The organic molecule methyl alcohol (methanol) has been found by the Atacama Large Millimeter/Submillimeter Array (ALMA) in this disc. This is the first such detection of the compound in a young planet-forming disc. Credit: ESO/M. Kornmesser
This artist’s impression shows the closest known protoplanetary disc, around the star TW Hydrae in the huge constellation of Hydra (The Female Watersnake). The organic molecule methyl alcohol (methanol) has been found by the Atacama Large Millimeter/Submillimeter Array (ALMA) in this disc. This is the first such detection of the compound in a young planet-forming disc.
Credit: ESO/M. Kornmesser

The Widicus Weaver Group contributed to recently released research that confirms the presence of the organic molecule methyl alcohol (methanol) in the protoplanetary disc surrounding the young star TW Hydrae. This is the first such detection of the compound in a young planet-forming disc.

“Methanol is the starting point for all complex organic chemistry in space,” explains Susanna Widicus Weaver. The detection of methanol surrounding TW Hyrdrae, the closest-known protoplanetary disc to Earth, helps astronomers understand the chemical processes that occur during the formation of planetary systems and that ultimately lead to the creation of the ingredients for life.

The finding comes via the Atacama Large Millimeter/Submillimeter Array (ALMA), the most powerful observatory in existence for mapping the chemical composition and the distribution of cold gas in nearby discs. Catherine Walsh, lead author of the study, explains: “Finding methanol in a protoplanetary disc shows the unique capability of ALMA to probe the complex organic ice reservoir in discs and so, for the first time, allows us to look back in time to the origin of chemical complexity in a planet nursery around a young Sun-like star.”

Walsh’s observations relied in part on a chemical network developed by Widicus Weaver and collaborators Eric Herbst and Rob Gerrod at the University of Virginia. “We had originally applied this network to star-forming regions, but not to discs,” explained Widicus Weaver. Their unique chemical perspective on organic molecule formation in star and planet-forming regions helped the study’s lead author, Dr. Catherine Walsh, to develop the observing proposal that allowed her to obtain time using ALMA.

“This is a truly exceptional, ground-breaking result,” says Widicus Weaver. “We have long suspected that the ingredients for more complex organic chemistry like we see on Earth comes from the material in a planet-forming disc around a new star. The result gives us direct evidence that this is indeed the case [ . . . ] The field of astrochemistry has waited a long time for this result to be possible. It is an exciting time to be an astrochemist!”

[Full Press Release]

Further Reading

Garrod R. T., Widicus Weaver S. L., & Herbst E. “Chemistry during the warm-up phase of a hot core: A new grain/gas chemical model.”  Astrophys. J., 682, 283-304, 2008.

Laas J. C., Garrod R. T., Herbst E., & Widicus Weaver S. L., “Contributions from grain surface and gas phase chemistry to the formation of methyl formate and its structural isomers.” Astrophys. J., 728 71 (9pp), 2011.

Walsh, C., Herbst E., Nomura H., Millar T. J., and Widicus Weaver S. L., “Complex organic molecules along the accretion flow in isolated and externally irradiated protoplanetary disks.” Faraday Discuss., 168, 2014.

Walsh, C., Millar T. J., Nomura H., Herbst E., Widicus Weaver S. L., Aikawa Y., Laas J. C., and Vasyunin A. I. “Complex organic molecules in protoplanetary disks.” Astron. & Astrophys., 563, A33, 2013.