NASA’s Hubble Space Telescope has directly photographed evidence of a Jupiter-like planet forming through what researchers describe as an “intense and violent process.” The discovery supports a long-debated theory about how planets like Jupiter form, known as “disk instability”.
“It is extremely difficult to interpret this system. This is one of the reasons why we needed Hubble for this project – a clean image to better separate light from the disk and any planets.”
Thayne Currie, research team leader on the study
The new world under construction lies within a protoplanetary disk of dust and gas with a distinct spiral structure around a young star estimated to be about 2 million years old. It’s about the age of our solar system when planet formation was underway. (The age of the solar system is currently 4.6 billion years.)
“Nature is so smart; It can create planets in a variety of ways,” said Thayne Currie of the Subaru Telescope and Eureka Scientific, lead researcher.
All planets are made of matter derived from a stellar disk. The dominant theory of jovian planet formation is known as “core accretion,” a bottom-up approach in which planets lie in disks that grow from small objects – about the size of a grain of dust. to boulders – colliding and sticking together as they orbit a star. The core then slowly accumulates gas from the disk. In contrast, the disk instability approach is a top-down model in which as a massive disk around a star cools, gravity causes the disk to rapidly break apart into one or more pieces. has planetary mass.
The newly formed planet, called AB Aurigae b, could be about nine times more massive than Jupiter and orbit its host star at a giant distance of 8.6 billion miles – more than twice that of the star. Pluto versus our Sun. At that distance, it would take a very long time, if at all, for a planet the size of Jupiter to form by core accretion. This led the researchers to conclude that the disk’s instability allowed the planet to form at a great distance. And, it stands in stark contrast to the widely accepted core accretion model of planet formation.
The new analysis combines data from two Hubble instruments: the Space Telescope Imaging Spectrograph and the Near Infrared Camera and the Multi-Object Spectrograph. These data were compared with data from a modern planetary imaging instrument called SCExAO on the Japanese 8.2-meter Subaru Telescope located at the summit of Mauna Kea, Hawaii. The abundance of data from space and ground-based telescopes proves crucial, because distinguishing between infant planets and complex disc features unrelated to planets is crucial. difficult.
“It is extremely difficult to interpret this system,” says Currie. “This is one of the reasons why we needed Hubble for this project – a clear image to better separate light from the disk and any planets.”
Nature itself helps: the giant disk of dust and gas orbiting the star AB Aurigae is tilted nearly opposite our view from Earth.
Currie emphasizes that Hubble’s longevity plays a special role in helping researchers measure the orbits of protoplanets. At first he strongly suspected AB Aurigae b was a planet. The archival data from Hubble, combined with images from Subaru, proved to be a turning point in his thinking.
“We couldn’t detect this movement on the order of a year or two,” says Currie. “Hubble has provided a time baseline, combined with Subaru data, of 13 years, enough to be able to detect orbital motion.”
“This result advances observations on the ground and in space, and we go back in time with the Hubble archive observations,” added Olivier Guyon from the University of Arizona, Tucson and the Subaru Telescope, Hawaii. “AB Aurigae b has now been considered at multiple wavelengths and a consistent picture has emerged – a very solid picture.”
The team results published in the April 4 issue of Natural Astronomy.
“This new discovery is strong evidence that some gas giants may be formed by disk instability,” said Alan Boss of the Carnegie Institution for Science in Washington, DC. “In the end, gravity is all that counts, as the rest of star formation will be pulled together by gravity to form planets, one way or another.”
Learning about the early days of Jupiter-like planets forms provides astronomers with more context about the history of our solar system. This discovery paves the way for future studies of the chemical makeup of protoplanetary disks such as AB Aurigae, including with NASA’s James Webb Space Telescope.
The Hubble Space Telescope is an international cooperation project between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts science operations on Hubble. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, DC
Illustrator: NASA, ESA, Joseph Olmsted (STScI)
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