An amazing discovery reveals the origin of water in our solar system billions of years before the sun

V883 Ori is a brilliant protostar with a temperature high enough to turn the water in its surrounding disk into gas. This gas can be studied by radio astronomers to trace the origins of the water. Recently, ALMA observations have verified that water in our solar system may have the same source as water found in the disks surrounding protostars in other parts of the universe — the interstellar medium. Credit: ALMA (ESO/NAOJ/NRAO), B. Saxton (NRAO/AUI/NSF)

ALMA traces the history of water in planet formation back to the interstellar medium

Observations of water in the disk forming around protostar V883 Ori have revealed clues about the formation of comets and minor planets in our solar system.

Scientists studying a nearby protostar have detected water in its circumferential disk. The new observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) represent the first detection of water heritable in a protoplanetary disk without significant changes in its composition. These findings also indicate that water in our solar system formed billions of years before the sun. The new observations were published March 8 in the journal nature.

Water in the planet-forming disk around V883 Orionis

This artist’s impression shows the planet-forming disk around the star V883 Orionis. The water on the outside of the disk is frozen as ice and is therefore not easily detectable. A blast of energy from the star heats the inner disk to a temperature where water is gaseous, enabling astronomers to detect it.
The inset image shows the two types of water molecules studied in this disk: plain water, with one oxygen atom and two hydrogen atoms, and a heavier version where the hydrogen atom is replaced by deuterium, a heavy isotope of hydrogen.
Credit: ESO/L. Calzada

V883 Orionis is a protostar located about 1,305 light-years from Earth in the constellation of Orion. New observations of this protostar have helped scientists find a possible link between water in the interstellar medium and water in our solar system by confirming that they have a similar composition.

Water ice turned into gas in V883 Ori

V883 Ori is a unique protostar whose temperature is hot enough that the water in its surrounding disk has turned into gas, making it possible for radio astronomers to trace the origins of water. New observations using the Atacama Large Millimeter/submillimeter Array (ALMA) provided the first confirmation that water in our solar system may come from the same place as water in the disks surrounding protostars elsewhere in the universe: the interstellar medium. Credit: ALMA (ESO/NAOJ/NRAO), B. Saxton (NRAO/AUI/NSF)

“We can think of water’s path through the universe as a path. We know what the endpoints look like, which are water on planets and comets, but we wanted to trace that path back to the origins of Water., lead author on the new paper.”Before now, we could associate Earth with comets, and protostars with the interstellar medium, but we couldn’t associate protostars with comets. V883 Ori has changed that, proving that water molecules in this system and in our solar system have a similar proportion of deuterium and hydrogen. “


Use[{” attribute=””>ALMA, astronomers have detected the chemical signature of gaseous water in the planet-forming disc V883 Orionis. This acts as a timestamp for the water’s formation, allowing us to trace its journey. Credit: ESO

Observing water in the circumstellar disks around protostars is difficult because in most systems water is present in the form of ice. When scientists observe protostars they’re looking for the water snow line or ice line, which is the place where water transitions from predominantly ice to gas, which radio astronomy can observe in detail. “If the snow line is located too close to the star, there isn’t enough gaseous water to be easily detectable and the dusty disk may block out a lot of the water emission. But if the snow line is located further from the star, there is sufficient gaseous water to be detectable, and that’s the case with V883 Ori,” said Tobin, who added that the unique state of the protostar is what made this project possible.

V883 Ori’s disk is quite massive and is just hot enough that the water in it has turned from ice to gas. That makes this protostar an ideal target for studying the growth and evolution of solar systems at radio wavelengths.


Most of the time, the water in the disks surrounding protostars is in the form of ice, sometimes extending long distances from the star. In the case of V883 Ori, the snow line extends 80 units from the star; This is 80 times the distance between Earth and the Sun, as shown in this animation. But the temperature in V883 Ori is hot enough that much of the ice in its disk has turned into gas, making it possible for radio astronomers to study that water in detail. New observations using the Atacama Large Millimeter/submillimeter Array (ALMA) reveal that water in V883 Ori’s disk has the same basic composition as water on objects in our solar system. This indicates that water in our solar system was formed billions of years before the sun in the interstellar medium. Credit: ALMA (ESO/NAOJ/NRAO), J. Tobin, P. Saxton (NRAO/AUI/NSF)

“This observation highlights the remarkable capabilities of the ALMA instrument in helping astronomers study something so important to life on Earth: water,” said Joe Pesci, National Science Foundation program officer at ALMA. “Understanding the fundamental processes that are important to us on Earth, and which are seen far beyond the galaxy, also informs our knowledge of how nature works in general, and of the processes that must occur for our solar system to evolve into what we know today.”

To connect water in the protoplanetary disk of V883 Ori to that in our solar system, the team measured its composition using ALMA’s highly sensitive Band 5 (1.6 mm) and Band 6 (1.3 mm) receivers and found that it remains relatively unchanged between each stage of solar system formation: Protostar, protoplanetary disk, and comets. This means that the water in our solar system was formed long before the formation of the sun, planets and comets. We already knew that there is a lot of water ice in the interstellar medium. Our results show that this water was incorporated directly into the solar system during its formation, said Merrill van te Hoff, an astronomer at the University of Michigan and one of the authors of the paper. “This is exciting because it indicates that other planetary systems must have received significant amounts of water as well.”

Planet-forming disk around V883 Orionis

While searching for the origins of water in our solar system, scientists have settled on V883 Orionis, a unique protostar located 1,305 light-years from Earth. Unlike other protostars, the circumstellar disk surrounding V883 Ori is hot enough that the water in it has turned from ice to gas, making it possible for scientists to study its composition using radio telescopes such as those on the Atacama Large Millimeter/submillimeter Array (ALMA). Radio observations of the protostar revealed the presence of water (orange), dust streak (green), and molecular gas (blue) indicating that the water on this protostar is very similar to the water on objects in our solar system, and may have the same origins. Credit: ALMA (ESO/NAOJ/NRAO), J. Tobin, B. Saxton (NRAO/AUI/NSF)

Elucidating the role of water in the development of comets and minor planets is critical to building an understanding of how our solar system evolved. Although the Sun is thought to have formed in a dense cluster of stars and V883 Ori is relatively isolated with no stars nearby, the two have one important thing in common: they both formed in giant molecular clouds.

“It is known that the bulk of the water in the interstellar medium forms as ice on the surfaces of tiny dust grains in clouds. When these clouds collapse under their own gravity and form young stars, the water ends up in the disks around them. Eventually, the disks evolve and the icy dust grains coagulate to form a new solar system with planets and comets,” said Margot Lemker, an astronomer at Leiden University and a co-author on the paper. “We have shown that the water that is produced in the clouds follows this path almost unchanged. So, by looking at the water in V883 Ori’s disk, we are looking back in time and seeing what our solar system looked like when it was much younger.”

V883 Orionis star in the constellation of Orion

V883 Orionis is a protostar located about 1,305 light-years from Earth in the constellation of Orion. Credit: ESO/IAU and Sky & Telescope

Tobin added, “So far, the water chain has stalled in the development of our solar system. V883 Ori is the missing link in this case, and we now have an unbroken chain in the water chain from comets and protostars to the interstellar medium.”

For more on this discovery, see Water on Earth is Older Than Our Sun.

Reference: “Deuterium-Enriched Water Binds Planet-forming Disks to Comets and Protostars” by John J. Tobin, Merrill L.R. Van Hove, Margot Lemker, Ewen F. Van Dishoek, Teresa Paneki-Carino, Kenji Furuya, Daniel Harsono, Magnus F. Pearson, Elzidor Cleaves, Patrick D. Sheehan and Lucas Siza, March 8, 2023, Available Here. nature.
DOI: 10.1038/s41586-022-05676-z

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