Inside-out Planet Formation. IV. Pebble Evolution and Planet Formation Timescales
Tan, Jonathan C.
Youdin, Andrew N.
AffiliationUniv Arizona, Dept Astron, 933 North Cherry Ave, Tucson, AZ 85721 USA
Univ Arizona, Steward Observ, 933 North Cherry Ave, Tucson, AZ 85721 USA
Keywordsaccretion, accretion disks
planets and satellites: formation
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationThe Astrophysical Journal, 857:20 (18pp), 2018 April 10
Rights© 2018. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractSystems with tightly packed inner planets (STIPs) are very common. Chatterjee & Tan proposed Inside-out Planet Formation (IOPF), an in situ formation theory, to explain these planets. IOPF involves sequential planet formation from pebble-rich rings that are fed from the outer disk and trapped at the pressure maximum associated with the dead zone inner boundary (DZIB). Planet masses are set by their ability to open a gap and cause the DZIB to retreat outwards. We present models for the disk density and temperature structures that are relevant to the conditions of IOPF. For a wide range of DZIB conditions, we evaluate the gap-opening masses of planets in these disks that are expected to lead to the truncation of pebble accretion onto the forming planet. We then consider the evolution of dust and pebbles in the disk, estimating that pebbles typically grow to sizes of a few centimeters during their radial drift from several tens of astronomical units to the inner, less than or similar to 1 au scale disk. A large fraction of the accretion flux of solids is expected to be in such pebbles. This allows us to estimate the timescales for individual planet formation and the entire planetary system formation in the IOPF scenario. We find that to produce realistic STIPs within reasonable timescales similar to disk lifetimes requires disk accretion rates of similar to 10(-9) M-circle dot yr(-1) and relatively low viscosity conditions in the DZIB region, i.e., a Shakura-Sunyaev parameter of alpha similar to 10(-4).
VersionFinal published version
SponsorsNASA ATP [NNX15AK20G, NNX17AK40G]; NSF AAG [1616300, 1616929]; Sloan Research Fellowship; European Research Council (ERC) under the European Unions Horizon research and innovation programme ; Royal Society International Exchange grant