Hubble finds a planet that forms in an unusual way

In general, the formation of planets in our universe can be likened to cooking a meal. Just as the “ingredients” for forming a planet can change, so can the “cooking method”. Researchers using the Hubble Space Telescope have captured a planet in motion that could be likened to a “flash fry” – a violent and intense process called disk instability. In this method, instead of having a planet that grows and forms from a small nucleus that accumulates matter and gas, the protoplanetary disk around a star cools and gravity causes it to split into one or more planets of mass. Astronomers have long sought clear evidence of this process as a viable candidate for the formation of large Jupiter-like planets, and Hubble’s analysis and longevity have proven to be a key piece of the missing puzzle. The researchers were able to directly image the newly formed exoplanet AB Aurigae b over a period of 13 years, using the Hubble Space Telescope Imaging Spectroscope (STIS) and the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). Above right, a 2007 Hubble NICMOS image shows AB Aurigae b in a southerly position relative to its host star, which is covered by the instrument’s coronary artery. The image taken in 2021 by STIS shows that the protoplanet has moved counterclockwise over time. Credits: Science: NASA, ESA, Thayne Currie (Subaru Telescope, Eureka Scientific Inc.); Image Editing: Thayne Currie (Subaru Telescope, Eureka Scientific Inc.), Alyssa Pagan (STScI)

Evidence suggests a violent collapse responsible for the formation of a proto-planet resembling Jupiter.

NASA’s Hubble Space Telescope has directly photographed elements of a protoplanet like Jupiter formed by what researchers describe as an “intense and violent process.” This discovery supports a much-discussed theory of how planets like Jupiter form called “disk instability.” The new universe under construction is embedded in a protoplanetary dust and gas disk with a distinct spiral structure orbiting around a young star estimated to be about 2 million years old. This is about the age of our solar system when the formation of the planets was in progress. (The age of the solar system is currently 4.6 billion years.) “Nature is smart. can produce planets in a number of different ways, “said Thayne Currie of the Subaru Telescope and Eureka Scientific, the study’s lead researcher. All planets are made of material from a peristaltic disk. The dominant theory for the formation of Jovian planets is called the “augmentation nucleus”, a bottom-up approach where planets embedded in the disk grow from small objects – ranging in size from dust grains to boulders – colliding and sticking together. orbiting a star. This nucleus then slowly accumulates gas from the disk. In contrast, the disk instability approach is a top-down model, where as a huge disk around a star cools, gravity causes the disk to split rapidly into one or more planetary mass fragments. The newly formed planet, called AB Aurigae b, is probably about nine times more massive than Jupiter and orbits its host star at a vast distance of 8.6 billion miles – more than twice as far as Pluto from our Sun. At this distance it would take a long time, if not never, to form a planet the size of Jupiter with nucleus accumulation. This leads researchers to conclude that disk instability allowed this planet to form at such a great distance. And, it contrasts sharply with the expectations of planet formation from the widely accepted nucleus accretion model. The new analysis combines data from two Hubble instruments: the space telescope imaging spectrograph and the near-infrared camera and the multi-object spectrograph. This data was compared to that of a state-of-the-art planetary imaging instrument called the SCExAO at Japan’s 8.2-meter Subaru Telescope atop Mauna Kea, Hawaii. The richness of data from space and ground-based telescopes has proven crucial, because it is very difficult to distinguish between infant planets and complex disk features unrelated to planets. “Interpreting this system is extremely difficult,” Currie said. “That’s one of the reasons we needed Hubble for this project – a clear picture to better separate the light from the disk and any planet.” Nature itself also provided a helping hand: the huge disk of dust and gas swirling around the star AB Aurigae leans almost face to face with our view of the Earth. Currie stressed that Hubble’s longevity played a special role in helping researchers measure the orbit of the protoplanet. At first he was very skeptical that AB Aurigae b was a planet. Hubble archival data, combined with images from Subaru, turned out to be a turning point. “We have not been able to detect this movement for a year or two,” Currie said. “Hubble provided a timeline, combined with data from 13-year-old Subaru, that was sufficient to detect orbital motion.” “This result utilizes ground and space observations and we can go back in time with Hubble archival observations,” added Olivier Guyon of the University of Arizona in Tucson and the Subaru Telescope in Hawaii. “AB Aurigae b has now been tested at multiple wavelengths and a consistent picture has emerged – a very stable one.” The team’s results are published in the April 4, 2022 issue of Nature Astronomy. “This new discovery is strong evidence that some gas giant planets can be formed by the disk’s instability mechanism,” said Alan Boss of the Carnegie Institute for Science in Washington, DC. “In the end, gravity is the only thing that matters, as the remnants of the star-forming process will end up being pulled together by gravity to form planets, one way or another.” Understanding the early days of the formation of Jupiter-like planets provides astronomers with more insight into the history of our solar system. This discovery paves the way for future studies of the chemical composition of protoplanetary disks such as AB Aurigae, including NASA’s James Webb Space Telescope. Reference: “Images of integrated Jovian planet formation in large separation around AB Aurigae” by Thayne Currie, Kellen Lawson, Glenn Schneider, Wladimir Lyra, John Wisniewski, Carol Grady, Olivier Guyon, Motohide Tamura, Takayuki Kotany, Hajimova, Uyama, Takayuki Muto, Ruobing Dong, Tomoyuki Kudo, Jun Hashimoto, Misato Fukagawa, Kevin Wagner, Julien Lozi, Jeffrey Chilcote, Taylor Tobin, Tyler Groff, Kimberly Ward-Duong, William Januszewski, Pitterke Norris, Barnabit, Michael Vincent Deo, Sebastien Vievard, Nemanja Jovanovic, Frantz Martinache and Nour Skaf, April 4, 2022, Nature Astronomy.DOI: 10.1038 / s41550-022-01634-x The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland operates the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble Science operations. STScI operates for NASA from the Association of Universities for Astronomy Research in Washington, DC