TY - JOUR
T1 - Inside-out Planet Formation. IV. Pebble Evolution and Planet Formation Timescales
AU - Hu, Xiao
AU - Tan, Jonathan C.
AU - Zhu, Zhaohuan
AU - Chatterjee, Sourav
AU - Birnstiel, Tilman
AU - Youdin, Andrew N.
AU - Mohanty, Subhanjoy
N1 - Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved..
PY - 2018/4/10
Y1 - 2018/4/10
N2 - Systems 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, ≲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 ∼10-9 M o yr-1 and relatively low viscosity conditions in the DZIB region, i.e., a Shakura-Sunyaev parameter of α ∼ 10-4.
AB - Systems 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, ≲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 ∼10-9 M o yr-1 and relatively low viscosity conditions in the DZIB region, i.e., a Shakura-Sunyaev parameter of α ∼ 10-4.
KW - accretion, accretion disks
KW - planet-disk interactions
KW - planetary systems
KW - planets and satellites: formation
KW - protoplanetary disks
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U2 - 10.3847/1538-4357/aaad08
DO - 10.3847/1538-4357/aaad08
M3 - Article
AN - SCOPUS:85045537253
SN - 0004-637X
VL - 857
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 20
ER -