On the formation of planetary systems in photoevaporating transition discs

Journal article

In protoplanetary discs, planetary cores must be at least 0.1 M⊕ at 1 au for migration to be significant; this mass rises to 1 M⊕ at 5 au. Planet formation models indicate that these cores form on million year time-scales. We report here a study of the evolution of 0.1 and 1 M⊕ cores, migrating from about 2 and 5 au, respectively, in million year old photoevaporating discs. In such a disc, a gap opens up at around 2 au after a few million years. The inner region subsequently accrete on to the star on a smaller time-scale. We find that, typically, the smallest cores form systems of non-resonant planets beyond 0.5 au with masses up to about 1.5 M⊕. In low-mass discs, the same cores may evolve in situ. More massive cores form systems of a few Earth-mass planets. They migrate within the inner edge of the disc gap only in the most massive discs. Delivery of material to the inner parts of the disc ceases with opening of the gap. Interestingly, when the heavy cores do not migrate significantly, the type of systems that are produced resembles our Solar system. This study suggests that low-mm flux transition discs may not form systems of planets on short orbits but may instead harbour Earth-mass planets in the habitable zone.

Authors: Terquem, C

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 464
• Issue: 1
• Pages: 924-932
• Publication date: 2016-09-22
• Acceptance date: 2016-09-21
• DOI: 10.1093/mnras/stw2419
• EISSN: 1365-2966
• ISSN: 0035-8711
• Keywords: planet-disc interactions; planetary systems; planets and satellites: formation; accretion; methods:numerical; accretion discs