Ambipolar diffusion and core accretion in layered protoplanetary - - PowerPoint PPT Presentation

Context: disc environments Results: embedded planet core

Ambipolar diffusion and core accretion

in layered protoplanetary discs Oliver Gressel ⋆

Niels Bohr International Academy (NBIA), Copenhagen

Richard P . Nelson (QMUL, London) Neal J. Turner (JPL-Caltech, Pasadena) Colin P . McNally (NBIA, Copenhagen) Udo Ziegler (AIP

, Potsdam) 6th - 8th May, 2015 Exoplanets in Lund meeting

⋆ oliver.gressel@nbi.dk

• O. Gressel

2015-05-06 – Lund, Sweden 1/15

Context: disc environments Results: embedded planet core

protoplanetary environments

Image Credit: HST Image Credit: NASA

• O. Gressel

2015-05-06 – Lund, Sweden 2/15

Context: disc environments Results: embedded planet core

determining the disc structure ...

Semenov & Henning (2012)

irradiation (UV, X-Ray, CR) → heating (vertical hydrostat. eq.) / ionisation (→ MHD) dust settling/growth/destruction/transport MRI feedback (turbulence, heating) dust opacities (UV→ IR, optical depths) chemistry (condensation, freeze-out) snow/ice-lines, gap/dead-zone edges → vortices, planet traps

• O. Gressel

2015-05-06 – Lund, Sweden 3/15

Context: disc environments Results: embedded planet core

disc ionisation chemistry

irradiation (FUV, X-Ray, CR), radioactive decay → ionising events recombination with gas-phase ions/molecules, absorption on sub-micron dust grains non-ideal MHD effects (Ohmic, Hall, AD) all important

Bai & Stone (2013), Bai (2013), Simon et al. (2013), Bai (2014a/b), Kunz & Lesur (2013), Lesur, Kunz & Fromang (2014), Gressel, Turner, Nelson & McNally (2015)

• O. Gressel

2015-05-06 – Lund, Sweden 4/15

Context: disc environments Results: embedded planet core

gas giant interiors

Image Credit: NASA, Lunar and Planetary Institute

• O. Gressel

2015-05-06 – Lund, Sweden 5/15

Context: disc environments Results: embedded planet core

motivation

core accretion picture 1D spherical envelopes

I: quasi-static contraction II: runaway growth phase

• ur goals

identify . . .

accretion time-scales role of circumplanetary disc potential bottle-necks influence of magnetic field

• O. Gressel

2015-05-06 – Lund, Sweden 6/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

global disc simulations

Gressel et al. (2013)

• O. Gressel

2015-05-06 – Lund, Sweden 7/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

global disc simulations

Gressel et al. (2013)

• O. Gressel

2015-05-06 – Lund, Sweden 7/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

embedded sub-disc

isothermal HD non-isoth. HD non-isoth. MHD

• O. Gressel

2015-05-06 – Lund, Sweden 8/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

embedded sub-disc

isothermal HD non-isoth. HD non-isoth. MHD

• O. Gressel

2015-05-06 – Lund, Sweden 8/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

embedded sub-disc

isothermal HD non-isoth. HD non-isoth. MHD

• O. Gressel

2015-05-06 – Lund, Sweden 8/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

circumplanetary disc variability

• O. Gressel

2015-05-06 – Lund, Sweden 9/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

circum-jovian jet

predicted theoretically by Quillen & Trilling (1998) and Fendt (2003)

• O. Gressel

2015-05-06 – Lund, Sweden 10/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

adding ambipolar diffusion

magneto-centrifugal wind from PPD with AD

Gressel, Nelson, Turner & McNally (2015)

external ionisation

via X-Rays, CRs, new: FUV layer

Ohmic resistivity,

new: ambipolar diffusion

(no) magnetorotational instability (MRI)

→ (no) turbulent surface layers

magneto-centrifugal (laminar) disc winds effect of reduced gas column in the gap region ionisation state of the CPD effect on jet launching

• O. Gressel

2015-05-06 – Lund, Sweden 11/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

laminar disc winds

quasi-MMSN disc model, NVF with midplane βp 0 = 105, d/g mass ratio 10−3, XR+CR+FUV

• O. Gressel

2015-05-06 – Lund, Sweden 12/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

laminar disc winds

quasi-MMSN disc model, NVF with midplane βp 0 = 105, d/g mass ratio 10−3, XR+CR+FUV

• O. Gressel

2015-05-06 – Lund, Sweden 12/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

laminar disc winds

quasi-MMSN disc model, NVF with midplane βp 0 = 105, d/g mass ratio 10−3, XR+CR+FUV

• O. Gressel

2015-05-06 – Lund, Sweden 12/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

laminar disc winds

quasi-MMSN disc model, NVF with midplane βp 0 = 105, d/g mass ratio 10−3, XR+CR+FUV

• O. Gressel

2015-05-06 – Lund, Sweden 12/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

laminar disc winds

quasi-MMSN disc model, NVF with midplane βp 0 = 105, d/g mass ratio 10−3, XR+CR+FUV

• O. Gressel

2015-05-06 – Lund, Sweden 12/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

reduced dust fraction

quasi-MMSN disc model, midplane βp 0 = 105, d/g mass ratio 10−4, XR+CR+FUV

• O. Gressel

2015-05-06 – Lund, Sweden 13/15

Context: disc environments Results: embedded planet core Ohmic dissipation only new microphysics (AD)

laminar disc with embedded planet

quasi-MMSN disc model, midplane βp 0 = 105, d/g mass ratio 10−3, XR+CR+FUV

• O. Gressel

2015-05-06 – Lund, Sweden 14/15

summary of results

Core accretion spin-out circumplanetary disc mainly vertical inflow of low-metallicity gas → efficient cooling of contracting envelope (!?) high accretion rate (∼ 8 × 10−3M⊕ yr−1) Saturn → Jupiter in ∼ 30, 000 yr Launching of a “circumplanetary” jet tornado-like flow drags down azimuthal field swirling → helical field → magneto-centrifugal jet disc outflow important for CPD evolution (!?) Including additional microphysics magneto-centrifugal disc wind with AD evolution of embedded sub-disc – work in progress

• O. Gressel

2015-05-06 – Lund, Sweden 15/15