Johns Hopkins University Applied Physics Laboratory | 2017 Oct 19
APL Scientist Sees Evidence of Planet Formation in Narrow Rings of Other Solar Systems
[img3="Gemini Planet Imager observations reveal a complex pattern ofNarrow dense rings of comets are coming together to form planets on the outskirts of at least three distant solar systems, astronomers have found in data from a pair of NASA telescopes.
variations in brightness and polarization around the HR 4796A disk.
Credit: Marshall Perrin (STScI), Gaspard Duchene (UC Berkeley),
Max Millar-Blanchaer (Univ of Toronto), and the GPI Team"]http://www.jhuapl.edu/newscenter/pressr ... ge1_lg.jpg[/img3][hr][/hr]
Estimating the mass of these rings from the amount of light they reflect shows that each of these developing planets is at least the size of a few Earths, according to Carey Lisse, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland.
Over the past few decades, using powerful NASA observatories such as the Infrared Telescope Facility in Hawaii and the Spitzer Space Telescope, scientists have found a number of young debris disk systems with thin but bright outer rings composed of comet-like bodies at 75 to 200 astronomical units from their parent stars — about two to seven times the distance of Pluto from our own Sun. The composition of the material in these rings varies from ice-rich (seen in the Fomalhaut and HD 32297 systems) to ice-depleted but carbon rich (the HR 4796A system). ...
Lisse traces the extreme red color to the burnt-out rocky organic remains of comets, a result of the system’s ring being close enough to the star that they have all boiled off. The researchers don’t see red ring dust in Fomalhaut or HD 32297, but instead see normal bluish comet dust containing ices — because these systems’ rings are far enough out that their comets are cold and mostly stable. ...
After eliminating other possibilities due to the lack of primordial circumstellar gas seen in these systems, Lisse and his co-authors have attributed the tight structure to multiple coalescing bodies “shepherding” material through the rings. ...
Infrared Spectroscopy of HR 4796A's Bright Outer Cometary Ring + Tenuous Inner Hot Dust Cloud - Carey M. Lisse et al
- Astronomical Journal 154(5):182 (Nov 2017) DOI: 10.3847/1538-3881/aa855e
arXiv.org > astro-ph > arXiv:1708.02834 > 09 Aug 2017
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