Planets form in dusty, gas-rich circumstellar disks around young stars, while at the same time, the planet formation process alters the physical and chemical structure of the disk itself. Embedded planets will locally heat the disk and sublimate volatile-rich ices, or in extreme cases, result in shocks that sputter heavy atoms such as silicon from dust grains. This should cause chemical asymmetries detectable in molecular gas observations. Using archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers detected sulfur monoxide and silicon monosulfide emissions coincident with the position of a giant Jupiter-like protoplanet in the circumstellar disk around the young star HD 169142.
HD 169142 is a young star located 375 light-years away in the constellation of Sagittarius.
The star is of significant interest to astronomers due to the presence of its large, dust- and gas-rich circumstellar disk that is viewed nearly face-on.
Otherwise known as PDS 514 and TIC 51077087, it hosts at least one protoplanet: HD 169142b.
“When we looked at HD 169142 and its disk at submillimeter wavelengths, we identified several compelling chemical signatures of this recently-confirmed gas giant protoplanet,” said Dr. Charles Law, an astronomer at the Harvard & Smithsonian’s Center for Astrophysics.
“We now have confirmation that we can use chemical signatures to figure out what kinds of planets there might be forming in the disks around young stars.”
Dr. Law ad his colleagues focused on the HD 169142 system because they believed that the presence of the giant protoplanet was likely to be accompanied by detectable chemical signatures, and they were right.
They detected carbon monoxide (both 12CO and its isotopologue 13CO) and sulfur monoxide (SO), which had previously been detected and were thought to be associated with protoplanets in other disks.
But for the first time, the astronomers also detected silicon monosulfide (SiS).
This came as a…
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