- AB Aurigae b is a newly forming planet projected to be nine times the size of Jupiter.
- Images of the exoplanet were captured by the Hubble Space and Subaru telescopes.
- New research supports the “disk instability” theory for the formation of gas giants.
Scientists have observed the early stages of the formation of an enormous, Jupiter-like exoplanet. And the images released Monday “provide the key to understanding” how gas giants are born.
According to NASA, AB Aurigae b is a newly forming planet (or protoplanet) that is projected to be nine times the size of Jupiter and orbiting its host star at a distance of 8.6 billion miles. The protoplanet’s star is estimated to be a relatively young 2 million years old, the same age at which our now 4.6 billion-year-old solar system saw planet formation.
Images of the exoplanet, captured by NASA’s orbiting Hubble Space Telescope and the Subaru Telescope in Hawaii, were published in a peer-reviewed study from Nature Astronomy on Monday.
“There’s not very many planets embedded in… their birth disc that they were formed from that have been imaged before,” University of Oklahoma, Norman’s Kellen Lawson, a co-author of the study, told USA TODAY. “[AB Aurigae] is arguably only the second case of this ever happening – the other one being PDS 70, which is a much more evolved system… So this gives us a chance to study this very, very early stage of planet formation directly.”
AB Auriage lies about 500 light-years away from Earth. And it wasn’t an easy task to identify the planet within its system.
“Distinguishing between infant planets and complex disk features unrelated to planets is very difficult,” added Lawson, noting that one way to distinguish a planet is to observe the system at different light wavelengths and uncover the planet’s brightness, which is initially buried between the strong light of his parent star.
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The researchers’ findings also support a debated theory for how jovian planets form, called “disk instability.”
Olivier Guyon, a co-author from the University of Arizona, Tucson and Subaru Telescope, Hawaii, explains that there are “two main models” for forming a gas giant. The current dominant theory is called the “core accretion” model, which “starts with little pebbles of rock sticking to each other and gradually getting bigger… when these rocks become massive enough, there is enough gravity to start attracting gas.”
In contrast, the intense process of disk instability consists of “a cold area of gas that has enough mass that gravity suddenly takes over and the gas collapses in itself – [forming] a giant planet, but much quicker,” Guyon continues.
According to NASA, researchers believe AB Aurigae b is forming through disk instability because of its enormous distance from the host star (8.6 billion miles is more than two times farther than Pluto is from our sun). As a result, the conditions would take too long for core accretion, if possible at all.
“Nature is clever; it can produce planets in a range of different ways,” Thayne Currie of the Subaru Telescope and Eureka Scientific, lead researcher on the study, stated in a NASA news release.
The scientists also underlined the power of the collaboration between Hubble and Subaru resources, as well as opportunities for future research.
“This discovery and all the work that went into it is a very nice example of how much we can get done by combining space and ground telescopes observation, and that was critical,” said Guyon.
“It took a long time for us to be able to come to a decision about the tests that we needed to do to convince ourselves that this was, in fact, an embedded planet,” added Lawson. “Hopefully, this foundation that we’ve built up here will help other groups, or us in the future, to find other objects like this more confidently.”
George is Digismak’s reported cum editor with 13 years of experience in Journalism