Any planets forming around the young star SZ Cha had better get a move on
New observations from the James Webb Space Telescope suggest the amount of ionized neon gas present in dusty, planet-forming disks can tell us how quickly planets must form before the disk itself disappears.
Planets are believed to be born in disks of gas and dust that swirl around newborn stars. Astronomers have observed these disks before, but the entire planetary formation process takes hundreds of thousands — and even millions — of years to complete. That means we don’t usually get to see the disks change on small timescales. Rather, the features just appear as snapshots frozen in time.
Now, however, the James Webb Space Telescope has observed one planet-forming disk changing quite substantially.
In 2008, a team led by Catherine Espaillat, who was then at the University of Michigan but is now at Boston University, used NASA’s Spitzer Space Telescope to detect an infrared emission line associated with doubly ionized neon ([Ne III]). The signal was coming from a planet-forming disk ringing the young star SZ Chamaeleontis (SZ Cha). An atom is “ionized” when one of its outer electrons is struck by a high-energy photon and knocked out of position; “doubly ionized” atoms involve the loss of two electrons from the impact of two photons.
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