Imperial College London
Portrait Picture

DrSubhanjoyMohanty

Faculty of Natural Sciences, Department of Physics

Reader in Astrophysics
 
 
 
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Contact

 

+44 (0)20 7594 7553s.mohanty

 
 
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Location

 

1010 BlackettBlackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Mohanty:2018:1538-4357/aabcd0,
author = {Mohanty, S and Jankovic, MR and Tan, JC and Owen, JE},
doi = {1538-4357/aabcd0},
journal = {Astrophysical Journal},
pages = {1--27},
title = {Inside-out planet formation. V. structure of the inner disk as implied  by the MRI},
url = {http://dx.doi.org/10.3847/1538-4357/aabcd0},
volume = {861},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The large population of Earth to super-Earth sized planets found very closeto their host stars has motivated consideration of $in$ $situ$ formationmodels. In particular, Inside-Out Planet Formation is a scenario in whichplanets coalesce sequentially in the disk, at the local gas pressure maximumnear the inner boundary of the dead zone. The pressure maximum arises from adecline in viscosity, going from the active innermost disk (where thermalionization of alkalis yields high viscosities via the magneto-rotationalinstability (MRI)) to the adjacent dead zone (where the MRI is quenched).Previous studies of the pressure maximum, based on $\alpha$-disk models, haveassumed ad hoc values for the viscosity parameter $\alpha$ in the active zone,ignoring the detailed physics of the MRI. Here we explicitly couple the MRIcriteria to the $\alpha$-disk equations, to find steady-state (constantaccretion rate) solutions for the disk structure. We consider the effects ofboth Ohmic and ambipolar resistivities, and find solutions for a range of diskaccretion rates ($\dot{M}$ = $10^{-10}$ - $10^{-8}$ ${\rm M}_{\odot}$/yr),stellar masses ($M_{\ast}$ = 0.1 - 1 ${\rm M}_{\odot}$), and fiducial values ofthe $non$-MRI $\alpha$-viscosity in the dead zone ($\alpha_{\rm {DZ}} =10^{-5}$ - $10^{-3}$). We find that: (1) A midplane pressure maximum formsradially $outside$ the inner boundary of the dead zone; (2) Hall resistivitydominates near the midplane in the inner disk, which may explain why close-inplanets do $not$ form in $\sim$50% of systems; (3) X-ray ionization can becompetitive with thermal ionization in the inner disk, because of the lowsurface density there in steady-state; and (4) our inner disk solutions areviscously unstable to surface density perturbations.
AU  - Mohanty,S
AU  - Jankovic,MR
AU  - Tan,JC
AU  - Owen,JE
DO  - 1538-4357/aabcd0
EP  - 27
PY  - 2018///
SN  - 0004-637X
SP  - 1
TI  - Inside-out planet formation. V. structure of the inner disk as implied  by the MRI
T2  - Astrophysical Journal
UR  - http://dx.doi.org/10.3847/1538-4357/aabcd0
UR  - http://arxiv.org/abs/1712.07049v2
UR  - https://iopscience.iop.org/article/10.3847/1538-4357/aabcd0
UR  - http://hdl.handle.net/10044/1/55670
VL  - 861
ER  -
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