Core accretion in MHD simulations of layered protoplanetary discs - PowerPoint PPT Presentation

Context: planet formation theory Results: embedded planet core Core accretion in MHD simulations of layered protoplanetary discs Oliver Gressel ⋆ Niels Bohr International Academy (NBIA), Copenhagen Richard P . Nelson (QMUL, London) Neal J. Turner (JPL-Caltech, Pasadena) Udo Ziegler (AIP , Potsdam) February 10/11, 2014 Star and Planet Formation for All ⋆ oliver.gressel@nbi.dk O. Gressel 2014-02-10 – SnPFfA Lund 1/13

Context: planet formation theory Results: embedded planet core gas giant interiors Image Credit: NASA, Lunar and Planetary Institute O. Gressel 2014-02-10 – SnPFfA Lund 2/13

Context: planet formation theory Results: embedded planet core motivation our goals core accretion picture identify . . . accretion time-scales 1D spherical envelopes role of circumplanetary disc I: quasi-static contraction potential bottle-necks II: runaway growth phase influence of magnetic field O. Gressel 2014-02-10 – SnPFfA Lund 3/13

Context: planet formation theory Results: embedded planet core schematics of protostellar disc Armitage (2011) O. Gressel 2014-02-10 – SnPFfA Lund 4/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD spiral arms and gap isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 5/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD spiral arms and gap isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 5/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD spiral arms and gap isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 5/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD gap opening Saturn-mass planet rapid growth phase Hill-sphere radius ≃ gas scale height Gap opening play via tidal torques and gas accretion onto planet core formation not complete gap contrast of 20–30 O. Gressel 2014-02-10 – SnPFfA Lund 6/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD embedded sub-disc isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 7/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD embedded sub-disc isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 7/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD embedded sub-disc isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 7/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD disc variability O. Gressel 2014-02-10 – SnPFfA Lund 8/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD the circumplanetary disc Disc rotation profile sub-keplerian rotation inner disc hotter → pressure support CPD extends to about half the Hill radius Disc surface density non-isoth. case: flat surface density isothermal case: steeper profile m = 2 spiral arms O. Gressel 2014-02-10 – SnPFfA Lund 9/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD the horseshoe region isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 10/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD the horseshoe region isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 10/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD the horseshoe region isothermal HD non-isoth. HD non-isoth. MHD O. Gressel 2014-02-10 – SnPFfA Lund 10/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD accretion flow properties play O. Gressel 2014-02-10 – SnPFfA Lund 11/13

Context: planet formation theory global properties / PPD Results: embedded planet core local properties / CPD circum-jovian jet � predicted theoretically by Quillen & Trilling (1998) and Fendt (2003) O. Gressel 2014-02-10 – SnPFfA Lund 12/13

summary of results Gap opening process incomplete, but contrasts of 20–30 reached in the MHD model: enlivening of the dead zone Core accretion spin-out circumplanetary disc mainly vertical inflow of low-metallicity gas → efficient cooling of contracting envelope (!?) high accretion rate ( ∼ 8 × 10 − 3 M ⊕ yr − 1 ) → Jupiter size after ∼ 30 , 000 yr Launching of a planetary jet tornado-like flow drags down azimuthal field swirling → helical field → magneto-centrifugal jet disc wind important for CPD accretion (!?) O. Gressel 2014-02-10 – SnPFfA Lund 13/13