A Baby Star in Action: B335 Offers a Natural Laboratory for Astrochemistry

24 December, 2024 / Read time: 4 minutes

Scientists have taken an unprecedented step forward in understanding the chemical processes occurring as new stars form, thanks to observations of the variable protostar B335, a very young forming star 537 light years away. Using the high-resolution capabilities of the Atacama Large Millimeter/submillimeter Array (ALMA), researchers tracked the behavior of complex organic molecules (COMs) during a rare burst of brightness, providing a real-time glimpse into the Universe's building blocks for life.

Stars grow episodically, with periods of slowly increasing mass interrupted by dramatic events when extra-large amounts of matter land on the star. These events increase the star’s brightness, which heats nearby dust and releases previously frozen COMs into the surrounding gas. However, scientists observed a surprising twist: after the burst ended, the COMs did not refreeze onto the dust as quickly as expected.
“This discovery challenges previous assumptions about the freeze-out timescale of these molecules,” says Jeong-Eun Lee, the lead researcher from Seoul National University. “The prolonged presence of gas-phase COMs reveals the dynamic and complex chemical processes around young stars.”

The study marks the first real-time tracking of molecular changes across a burst cycle thanks to ALMA's unparalleled sensitivity. Continuous monitoring of this protostar with ALMA will reveal the timescales for gas cooling, chemical reactions, and interactions between dust grains and gaseous molecules.
Unlike laboratory scientists, astronomers cannot experiment on the cosmos. Remarkably, B335 has performed a “natural experiment” in astrochemistry, showing how the ingredients for life might evolve in stellar nurseries.

“By combining the ALMA results with data from the James Webb Space Telescope (JWST) on the ice component of the COMs in B335, the chemistry of COMs will be fully known,” commented Yao-Lun Yang, another co-author from the RIKEN.

Additional Information

The findings, published in the Astrophysical Journal Letters as “A Natural Laboratory for Astrochemistry, a Variable Protostar B335” by Lee et al., open a new chapter in studying how the building blocks of life form and transform across the cosmos.

The original press release was published by the National Astrónomical Observatory of Japan (NAOJ), an ALMA partner on behalf of East Asia.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan, and by NINS in cooperation with the Academia Sinica(AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). 

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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