Large dusty clumps around star provide insight into how giant planets are born

Astronomers observe process of 'gravitational instability' on a planetary level for the first time

Scientists say they may have observed the process of how large plants like Jupiter are formed for the first time.
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The discovery of large dusty clumps close to a star 5,000 light years from Earth may provide an insight into how giant planets like Jupiter are formed.

A team of astronomers used telescopes belonging to the European Southern Observatory, which has headquarters in Munich, Germany, to analyse material surrounding the star V960 Mon in the constellation Monoceros, the unicorn, which was identified in the 17th century by Dutch astronomers.

Researchers said they observed dust clumps coalescing to form much larger bodies, which they believe could eventually be collapsed by gravity to form giant planets.

The scientists believe that this process – known as gravitational instability – may have been witnessed on a planetary scale for the first time in an “incredible discovery”.

Alice Zurlo, a researcher at the Universidad Diego Portales in Chile, said: “This discovery is truly captivating as it marks the very first detection of clumps around a young star that have the potential to give rise to giant planets.”

V960 Mon caught the eye of scientists in 2014, when it suddenly grew brighter.

Observations by the Sphere instruments on ESO’s Very Large Telescope (VLT), located on Cerro Paranal mountain in the Atacama Desert of northern Chile, showed V960's brightness had increased by more than 20 times.

This prompted astronomers to go back and look at data gathered by the Atacama Large Millimetre/Submillimetre Array (Alma), a radio telescope comprising 66 antennas across the desert.

The observations from Alma – which examined the structure of V960 Mon – revealed the stellar material surrounding it was forming spiral arms larger than the Solar System.

“With Alma, it became apparent that the spiral arms are undergoing fragmentation, resulting in the formation of clumps with masses akin to those of planets,” Prof Zurlo said.

Astronomers believe giant planets like Jupiter form either by a process known as core accretion – when dust grains come together – or by a phenomenon known as gravitational instability – when large fragments of the material around a star contract and collapse.

To date, researchers have only found evidence for core accretion.

“No one had ever seen a real observation of gravitational instability happening at planetary scales – until now,” said Philipp Weber, a researcher at the University of Santiago in Chile.

“Our group has been searching for signs of how planets form for more than 10 years and we couldn’t be more thrilled about this incredible discovery,” said Sebastian Perez, also from the University of Santiago.

As part of the next steps, astronomers will use another ESO instrument, the Extremely Large Telescope (ELT), to examine the star system in greater detail.

“The ELT will enable the exploration of the chemical complexity surrounding these clumps, helping us find out more about the composition of the material from which potential planets are forming,” Mr Weber said.

The research is published in the journal Astrophysical Letters.

Updated: July 25, 2023, 2:50 PM