Science & Technology

Direct link revealed between protoplanetary disk structure and giant exoplanet

Protoplanetary disks fall into three main categories: transitions, rings, and expansions. These false color images from the Atakama Large Millimeter / Submillimeter Wave Array (ALMA) show these classifications in stark contrast. Left: The RU Lup ring disc features a narrow gap believed to have been carved by a giant planet with masses ranging from Neptune’s mass to Jupiter’s mass. Center: The J1604.3-2130 transition disc is characterized by a large internal cavity that is believed to have been carved by a planet heavier than Jupiter (also known as the Super-Jupiter planet). Right: The Sz104’s compact disc is believed to contain no giant planets, as there are no obvious gaps or cavities associated with the presence of the giant planets. Credits: ALMA (ESO / NAOJ / NRAO), S. Dagnello (NRAO)

New research reveals that the presence of planetary disk gaps is more common for higher mass stars and the development of large gaseous exoplanets.

Scientists have used data from more than 500 young stars observed at the Atacama Large Millimeter / Submillimeter Array (ALMA) to develop protoplanetary disk structures (the planet-forming disks that surround the stars) and planetary demographics. Clarified the direct connection of. This study suggests that massive stars are likely to be surrounded by “gaps” disks, and these gaps are directly correlated with the high occurrence of giant exoplanets observed around such stars. Prove that you are doing. These results provide scientists with a window back in time, allowing them to predict what exoplanet systems would look like throughout each stage of their formation.

Nienke van der Marel, Banting Fellow, Faculty of Physics and Astronomy, University of Victoria, said: He is the lead author of the study in British Columbia. “Heavy-mass stars have relatively more gaps than low-mass stars, which is consistent with known correlations in exoplanets where high-mass stars often host gas giant exoplanets. These correlations directly indicate that the gaps in the planet-forming discs are most likely caused by giant planets above the mass of Kaio. “

Protoplanetary disk gaps have long been considered as overall evidence of planetary formation. However, there was some skepticism because of the orbital distances observed between exoplanets and those stars. “One of the main reasons scientists were previously skeptical about the link between gaps and planets is that extrasolar planets with dozens of astronomical orbits are rare. Extrasolar planets in small orbits of 10 astronomical units are much more common, “said Gijs Mulders, assistant professor of astronomy at Adolfoybanez University in Santiago, Chile, and co-author of the study. “We believe that the planets that fill the gap will later move inward.”

A new study is the first to show that the number of gapped disks in these regions matches the number of giant exoplanets in the star system. “Previous studies have shown that there are disks with far more gaps than the giant exoplanets detected,” Mulders said. “Our study shows that there are enough exoplanets to explain the observed frequency of gapped disks with different stellar masses.”

This correlation also applies to systems with low-mass stars, where scientists are likely to find giant rocky exoplanets, also known as super-earths. Van der Marel, an assistant professor at Leiden University in the Netherlands since September 2021, said: A more compact, gapless disc leads to the formation of a super earth. “

This link between stellar mass and planetary demography could help scientists identify which stars to target in a search for rocky planets throughout the Milky Way. “This new understanding of star-mass dependencies will help guide us in exploring small, rocky planets like Earth near the Sun,” said a member of the NASA-funded Alien Earth team. One Malders said. “We can use the mass of a star to connect a planet-forming disk around a young star to an exoplanet around a mature star. When an exoplanet is detected, it usually forms a planet. The material is gone. Therefore, the stellar mass is a “tag” that shows what the planetary formation environment of these exoplanets looked like. “

And after all, it’s dust. “A key factor in planet formation is the effect of dust evolution,” said Van der Marel. “Without giant planets, dust always floats inward, creating optimal conditions for forming small rocky planets near the stars.”

The current study was conducted using data from more than 500 objects observed in previous studies using ALMA’s high resolution Band 6 and Band 7 antennas. Currently, ALMA is the only telescope capable of disassembling a dust disc to image the distribution of millimeter dust with high angular resolution sufficient to reveal its substructure or its lack. “In the last five years, ALMA has created many snapshots of nearby star-forming regions, resulting in hundreds of measurements of disk dust mass, size, and morphology,” said van der Marel. I will. “The large number of observed disc properties has made it possible to make statistical comparisons between protoplanetary disks and the thousands of exoplanets discovered. Stellar mass dependence of gapped and compact discs. This is the first time that has been successfully demonstrated using the ALMA telescope. “

“Our new discoveries directly link the beautiful gap structure of the discs observed at ALMA to the properties of thousands of exoplanets detected in the NASA Kepler mission and other exoplanet surveys.” Mulders said. “Exoplanets and their formation help us put the origins of the Earth and our solar system in the context of seeing them happening around other stars.”

See also: “Mass Dependence of Structured Disk Stars: Possible Links to Exoplanet Demographics”, Nienke van der Marel and Gijs D. Mulders, June 23, 2021 Astrophysical Journal..
DOI: 10.3847 / 1538-3881 / ac0255

Direct link revealed between protoplanetary disk structure and giant exoplanet Direct link revealed between protoplanetary disk structure and giant exoplanet

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