JWST tests the chemistry around a newborn star

A space telescope is examining the chemistry around a newborn star

Top: MIRI MRS spectrum extracted from IRAS 15398–3359 point source, with key solid-state features indicated. The wavelength axis is a logarithmic scale. The dashed line shows the fitted continuity. Upper (inset): details of the 5.5–8 µm region of the same spectrum with safe and potential identification (see Table 1). Bottom: optical depth spectrum derived using the series shown in the top panel. credit: Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/aca289

The James Webb Space Telescope (JWST) is set to transform astronomers’ understanding of the chemistry of newly formed stars, with analysis by RIKEN researchers of preliminary results showing that it can detect complex organic molecules in the clouds of gas and ice surrounding a newborn star.

A protostar is a newly formed star still feeding on an envelope from the infalling material that produced it. host these envelopes chimical interaction that turn simple chemical building blocks into more complex organic moleculeswhich may be precursors of molecules necessary for the emergence of life.

Researchers believe that these complex organic molecules are formed in chemical reactions that occur on the surfaces of the ice grains. When the star heats the particles, they leave the ice and mix with the gas around them.

“We want to get definitive evidence of these formation pathways,” says Yao-Lun Yang of the RIKEN Star and Planet Formation Laboratory. “And the JWST provides the best opportunity to do that.”

A space telescope is examining the chemistry around a newborn star

False-color image obtained by the James Webb Space Telescope (JWST) of a protostar (orange area at upper left; a different protostar than the one in the current study). JWST uses infrared instruments to study how protostars form the chemistry of icy clouds (the blue tufts). Credit: NASA, European Space Agency, and Canadian Space Agency

JWST was launched in December 2021, and is located 1.5 million km from Earth. Yang, along with RIKEN colleagues Yuki Okoda and Nami Sakai and members of the CORINOS team, used data from the telescope’s mid-infrared instrument (MIRI), obtained in July 2022, to study a very young protostar.

When molecules absorb certain frequencies from infrared lightThey stretch and bend in different ways depending on their structures. Since each type of molecule absorbs infrared light at a distinct range of frequencies, the infrared spectrum detected by MIRI can identify particles around the protostar.

Previous surveys of the protostar have identified complex organic molecules in the gas phase, MIRI provides a much more detailed picture as it can detect organic molecules in the ice, where they are thought to be forming. The results confirm the presence of water ice, Carbon Dioxide and silicates in the dust, along with particles such as ammonia, methane, methanol, formaldehyde, and formic acid. There are also hints of ethanol and acetaldehyde.

Protostars often produce outflows and jets, and this protostar is no exception. MIRI has produced images that reveal the structure of one of the star’s outflows, showing at least four shell-like structures. The outflow contains a mixture of elements including hydrogen, iron, nickel, neon, argon, and sulfur. Some is concentrated in a relatively hot jet moving at about 200 kilometers per second. These ejections are observed when they are perhaps only 170 years old – just a blink of an eye in terms of stellar evolution.

All of these findings bode well for the future. “We’ll start to understand how to do that organic chemistry “We will also reveal the lasting effects on planetary systems similar to our solar system,” says Yang.

The work was published in Astrophysical Journal Letters.

more information:
Yao Lun Yang et al., Corinus. JWST/MIRI spectrum and class 0 imaging Protostar IRAS 15398-3359, Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/aca289

the quote: JWST Chemistry Probes of a Newborn Star (2023, March 17) Retrieved March 17, 2023 from https://phys.org/news/2023-03-jwst-probes-chemistry-newborn-star.html

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