Friday, August 01, 2025

Semi-heavy water ice detected around young Sun-like star

JWST image of the protostellar system L1527 IRS. The protostar is, embedded within a cloud of dust, gas and ice (including semi-heavy water ice), which feeds its growth. © NASA/ESA/CSA/STScI




For the first time, a team at Leiden University led by Ewine van Dishoek, an external scientific member of MPE, has robustly detected semi-heavy water ice around a young, sun-like star. These results support the theory that some of the water in our solar system originated before the Sun and its planets formed. The researchers used the James Webb Space Telescope to make their discovery, which they have published in The Astrophysical Journal Letters.

One way astronomers trace the origin of water is by measuring its deuteration ratio. Deuterium is a stable isotope of hydrogen whose nucleus contains a neutron as well as the proton. Water composed of one deuterium atom and one hydrogen atom – HDO rather than H₂O – is also known as semi-heavy water. A high fraction of semi-heavy water indicates that the water formed in a very cold place, such as the primitive dark clouds of dust, ice, and gas from which stars are born.

In our oceans, comets, and icy moons, up to one in a couple of thousand water molecules consists of semi-heavy water. This is about ten times higher than expected based on the composition of the Sun. Therefore, astronomers hypothesise that some of the water pin our solar system originated as ice in dark clouds hundreds of thousands of years before the birth of the Sun. To confirm this, they must measure the deuteration ratio of water ice in star-forming regions.

An international team of astronomers has now detected a high ratio of semi-heavy water ice in a protostellar envelope. This is the cloud of material surrounding a star in its embryonic stages.

The astronomers used the James Webb Space Telescope. Prior to its launch, the water deuteration ratio in star-forming regions could only be reliably measured in the gas phase, where chemical alteration occurs."Now, with the unprecedented sensitivity of Webb, we observe a beautifully clear semi-heavy water ice signature toward a protostar," says Katie Slavicinska, the Leiden University (Netherlands) PhD student who led the study.

The L1527 water deuteration ratio is very similar to that of some comets, as well as to the protoplanetary disk of a more evolved young star. This suggests that the water found in all of these objects has similar cold and ancient chemical origins.

"This finding adds to the mounting evidence that the bulk of water ice makes its journey largely unchanged from the earliest to the latest stages of star formation," says co-author Ewine van Dishoeck, a professor of astronomy at Leiden University who has spent much of her career tracing the journey of water through space.




Contact:

Ewine van Dishoeck
external scientific member
tel:
+49 89 30000-3592
fax: +49 89 30000-3569
ewine@mpe.mpg.de



Original publication

K. Slavicinska, Ł. Tychoniec, M. G. Navarro, E. F. van Dishoeck, et al.
HDO ice detected toward an isolated low-mass protostar with JWST 2025 ApJL L19


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More Information

Detection of semi-heavy water ice around young sunlike star


OJ 287: New image reveals sharply curved plasma jet at heart of mysterious galaxy

A new image of galaxy OJ 287 reveals for the first time the sharply curved, ribbon-like structure of the plasma jet emitted from its center. Credit: Dr Efthalia Traianou, Heidelberg University, IWR


For more than 150 years, the OJ 287 galaxy and its brightness variations five billion light years away has both puzzled and fascinated astronomers, because they suspect two supermassive black holes are merging in the core.

An international research team led by Dr. Efthalia Traianou of Heidelberg University recently succeeded in taking an image of the heart of the galaxy at a special level of detail. The groundbreaking image, taken with the aid of a space radio telescope, shows a heretofore unknown, heavily curved segment of the plasma jet spinning off the galaxy's center. The image provides new insights into the extreme conditions that prevail around supermassive black holes.

The research is published in the journal Astronomy & Astrophysics.

The core of the OJ 287 galaxy belongs to the class of blazars that exhibit high activity and striking luminosity. The driving forces behind these active galactic cores are black holes. They absorb matter from their surroundings and can fling it off in the form of giant plasma jets comprised of cosmic radiation, heat, heavy atoms, and magnetic fields.

"We have never before observed a structure in the OJ 287 galaxy at the level of detail seen in the new image," emphasizes Dr. Traianou, a postdoctoral researcher in the team of Dr. Roman Gold at the Interdisciplinary Center for Scientific Computing of Heidelberg University.

The image, which penetrates deep into the galaxy's center, reveals the sharply curved, ribbon-like structure of the jet; it also points to new insights into the composition and the behavior of the plasma jet. Some regions exceed temperatures of ten trillion degrees Kelvin—evidence of extreme energy and movement being released in close proximity to a black hole.

The researchers also observed the formation, spread, and collision of a new shock wave along the jet and attribute it to an energy in the trillion-electron volt range from an unusual gamma ray measurement taken in 2017.

The image in the radio range was taken with a ground-space radio interferometer consisting of a radio telescope in Earth's orbit—a ten-meter-long antenna of the RadioAstron mission on board the Spektr-R satellite—and a network of 27 ground observatories distributed across Earth.

In this way, the researchers were able to create a virtual space telescope with a diameter five times greater than the diameter of Earth; its high resolution stems from the distance of the individual radio observatories to one another. The image is based on a method of measurement that takes advantage of the wave nature of light and the associated overlapping waves.

The interferometric image underpins the assumption that a binary supermassive black hole is located inside galaxy OJ 287. It also provides important information on how the movements of such black holes influence the form and orientation of the plasma jets emitted.

"Its special properties make the galaxy an ideal candidate for further research into merging black holes and the associated gravitational waves," states Efthalia Traianou.

Institutions from Germany, Italy, Russia, Spain, South Korea, and the US all contributed to the research.

Source:  Phys.org/News



More information: E. Traianou et al, Revealing a ribbon-like jet in OJ 287 with RadioAstron, Astronomy & Astrophysics (2025). DOI: 10.1051/0004-6361/202554929

Journal information: Astronomy & Astrophysics



.Provided by Heidelberg University

by Marietta Fuhrmann-Koch, Heidelberg University

edited by Gaby Clark, reviewed by Robert Egan