An analysis of early results by researchers at the RIKEN Star and Planet Formation Laboratory shows that the James Webb telescope is capable of detecting complex organic molecules in clouds of gas and ice surrounding newborn stars.
A protostar is a newly formed star that is still feeding on the shell of matter that gave birth to it. Within these shells, chemical reactions take place that turn simple chemical building blocks into more complex organic molecules that could be precursors to the molecules needed for life to arise.
Researchers suspect that these complex organic molecules are formed as a result of chemical reactions occurring on the surface of ice grains. When the star heats up the molecules, they are released from the ice and mixed with the gas around them.
“We want definitive proof of such formation pathways. And the Webb telescope provides the best opportunity for this,” says Yao-Lun Yang from the RIKEN Star and Planet Formation Laboratory.
Launched in December 2021, the Webb telescope is about 1.5 million kilometers from Earth. Yang and colleagues used Mid-Infrared Instrument (MIRI) data acquired in July 2022 to study a very young protostar.
When molecules absorb certain frequencies of infrared light, they stretch and bend in different ways depending on their structure. Since each type of molecule absorbs infrared light at a characteristic set of frequencies, the infrared spectrum detected by MIRI can determine which molecules are present around the protostar.
Previous studies of the protostar have identified complex organic molecules in the gas phase, MIRI offers a much more detailed picture as this instrument can detect organic molecules in the ice where they are thought to form.
The results confirm the presence of water ice, carbon dioxide and silicates, as well as molecules such as ammonia, methane, methanol, formaldehyde and formic acid in the dust. There are also hints of ethanol and acetaldehyde.
Protostars often have outflows and jets, and this protostar is no exception. MIRI has taken images that show the structure of one of the star’s outflows. The outflow contains a mixture of elements including hydrogen, iron, nickel, neon, argon, and sulfur. Some of them are concentrated in a relatively hot jet moving at a speed of about 200 kilometers per second. These outliers are observed when they are perhaps only 170 years old – a mere blink of an eye in terms of stellar evolution.
“We will begin to understand how organic chemistry comes about,” Yang says. “And we will also find lasting impacts on planetary systems like our solar system.”
Work published in The Astrophysical Journal Letters.
Source: Yao-Lun Yang et al, CORINOS. I. JWST/MIRI Spectroscopy and Imaging of a Class 0 Protostar IRAS 15398–3359, The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/aca289