Hubble telescope spots Jupiter-like planet forming in a strange way

5 Apr 2022

Artist's impression of the newly formed planet, AB Aurigae b. Image: NASA, ESA, Joseph Olmsted

NASA said the discovery supports a long-debated theory for how planets like Jupiter form, through a process called ‘disc instability’.

The Hubble Space Telescope has taken images of a new Jupiter-like protoplanet that is being formed through an “intense and violent process”, according to researchers.

The new planet – known as AB Aurigae b – is embedded in a disc of dust and gas with a distinct spiral structure, surrounding a young star that’s estimated to be only around 2m years old.

The protoplanet is estimated to be around nine times larger than Jupiter and orbits its host star at a distance of 8.6bn miles, which is two times farther than Pluto is from our sun. Researchers said it would take a very long time for a Jupiter-sized planet to form through usual methods at this distance.

“Nature is clever; it can produce planets in a range of different ways,” said Thayne Currie, lead researcher of a study into this discovery published in the journal Nature Astronomy.

How are Jupiter-like planets formed?

All planets are made from material that has come from a circumstellar disc, which is an accumulation of matter such as gas and dust in orbit around a star.

The dominant theory for how planets like Jupiter and Saturn form is through a process called ‘core accretion’. This is a bottom-up approach where planets embedded in the disc grow from small objects that collide.

Another theory, called ‘disc instability’, is a top-down model. This theory posits that as a massive disc around a star cools, gravity causes the disc to rapidly break up into one or more planet-mass fragments.

Researchers believe that disc instability has enabled the planet AB Aurigae b to form at such a great distance from its host star, in contrast to the widely accepted core accretion model for gas giants.

“This new discovery is strong evidence that some gas giant planets can form by the disc instability mechanism,” Carnegie Institution for Science observational astronomer Alan Boss said.

“In the end, gravity is all that counts, as the leftovers of the star-formation process will end up being pulled together by gravity to form planets, one way or the other.”

Currie said the NASA and European Space Agency Hubble Space Telescope played an important role in the project, as it was able to provide “a clean image to better separate the light from the disc and any planet”. The team compared Hubble’s data to imaging provided by Japan’s Subaru Telescope located in Hawaii for its analysis.

The team believes that understanding the early days of the formation of Jupiter-like planets can help astronomers find out more about our own solar system’s history.

This research also paves the way for future studies into the chemical make-up of protoplanetary discs like AB Aurigae with the help of Hubble’s successor, the James Webb Space Telescope.

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Leigh Mc Gowran is a journalist with Silicon Republic