The accretion shock in planet formation

Transcription

1 The accretion shock in planet formation Gabriel-Dominique Marleau Ch. Mordasini, N. Turner R. Kuiper, H. Klahr

2 Direct imaging (of gas giants) Quanz et al Courtesy of M. Bonnefoy (Grenoble)

3 Direct imaging (II) Recent technique, fewer planet detections (rare) but growing number Sensitive to M ~ several MJup at au which are young or even forming (embedded) Bowler (2016)

4 Luminosity of young gas giants Measure brightness of planet (L) + age (of host star) Determining planet mass: need to use cooling curves: L = L(age, mass, L init )

5 Luminosity of young gas giants Measure brightness of planet (L) + age (of host star) Determining planet mass: need to use cooling curves: L = L(age, mass, L init ) Problem: post-formation luminosity L init unknown (large) uncertainty in mass! Marley et al. (2017) Marleau & Cumming (2014)

6 Luminosity of young gas giants Measure brightness of planet (L) + age (of host star) Determining planet mass: need to use cooling curves: L = L(age, mass, L init ) Problem: post-formation luminosity L init unknown (large) uncertainty in mass! Up to recently, no prediction of L statistics (dn/dldm) Marley et al. (2017) Marleau & Cumming (2014) key physics which sets L init not simulated

7 Luminosity of young gas giants Measure brightness of planet (L) + age (of host star) Determining planet mass: need to use cooling curves: L = L(age, mass, L init ) Problem: post-formation luminosity L init unknown (large) uncertainty in mass! Up to recently, Marley et al. (2017) Marleau & Cumming (2014) no prediction of L statistics (dn/dldm) key physics which sets L init not simulated This is starting to change! Mordasini, Marleau & Mollière (2017) Marleau et al. (2017) Szulágyi & Mordasini (2017) Berardo, Cumming & Marleau (2017)

8 What sets L init? Gas accreting onto planet: Sets thermal content of planet Processed through disc and shocks

9 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks F. Masset

10 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks F. Masset

11 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks F. Masset Tanigawa et al. (2012) cf. Szulágyi et al. (2016)

12 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks shock onto circumplanetary disc F. Masset Tanigawa et al. (2012) cf. Szulágyi et al. (2016)

13 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks shock onto circumplanetary disc F. Masset Tanigawa et al. (2012) cf. Szulágyi et al. (2016)

14 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks shock onto circumplanetary disc W. Benz Tanigawa et al. (2012) cf. Szulágyi et al. (2016)

15 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks shock onto circumplanetary disc shock at planet surface F. Masset W. Benz Tanigawa et al. (2012) cf. Szulágyi et al. (2016)

16 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks Focus on planetary surface shock No dedicated shock simulations yet Dominant shock (Mach ~ 3 30) Shock sets planet structure directly Berardo, Cumming & Marleau (2017) shock onto circumplanetary disc shock at planet surface Dong et al. (2016) F. Masset W. Benz Tanigawa et al. (2012) cf. Szulágyi et al. (2016)

17 What sets L init? Gas accreting onto planet: Sets thermal content of planet spiral waves steepen to shock Processed through disc and shocks Focus on planetary surface shock No dedicated shock simulations yet Dominant shock (Mach ~ 3 30) Shock sets planet structure directly Berardo, Cumming & Marleau (2017) shock Possibly onto3d accretion geometry, circumplanetary (non-ideal) MHD, disc equation of state, detailed radiation transport shock at planet surface Dong et al. (2016) F. Masset W. Benz Start with 1D simulations Already rich physics Tanigawa et al. (2012) cf. Szulágyi et al. (2016)

18 Simulation set-up

19 Simulation set-up

20 Simulation set-up Bodenheimer et al. (2000) Mignone et al. (2007) Vaidya et al. (2015) Kuiper et al. (2010) R Hill

21 Simulation set-up Bodenheimer et al. (2000) Mignone et al. (2007) Vaidya et al. (2015) Kuiper et al. (2010) R Hill local circumstellar disc

22 Simulation set-up Bodenheimer et al. (2000) Mignone et al. (2007) Vaidya et al. (2015) Kuiper et al. (2010) R Hill local circumstellar disc planet (growing, hydrostatic) M ~ M Jup R ~ 2 5 R Jup dm/dt ~ 10 ² M Earth /yr

23 Simulation set-up Bodenheimer et al. (2000) Mignone et al. (2007) Vaidya et al. (2015) Kuiper et al. (2010) R Hill simulation box (sph. symm.) local circumstellar disc planet (growing, hydrostatic) M ~ M Jup R ~ 2 5 R Jup dm/dt ~ 10 ² M Earth /yr

24 Simulation set-up Simulate top atmosphere layers and out to ~ R Hill in 1D Bodenheimer et al. (2000) Hydrodynamics + non-equilibrium FLD radiation transport Mignone et al. (2007) Vaidya et al. (2015) Kuiper et al. (2010) Snapshots in parameter space: mass, radius, accretion rate (M, R, dm/dt) R Hill simulation box (sph. symm.) local circumstellar disc planet (growing, hydrostatic) M ~ M Jup R ~ 2 5 R Jup dm/dt ~ 10 ² M Earth /yr

25 Quantities of interest Question: What fraction of kinetic energy is converted into radiation?

26 Quantities of interest Question: What fraction of kinetic energy is converted into radiation? Loss efficiency η = Lum. at R Hill lum. below shock Energy input rate L acc ~ GMM' R

27 Quantities of interest Question: What fraction of kinetic energy is converted into radiation? Loss efficiency η = Lum. at R Hill lum. below shock Energy input rate L acc ~ GMM' R Classical assumptions: η = 0 (no loss, hot start) or 100% (full loss, cold start) Differences of in L! Marley et al. (2007)

28 Quantities of interest Question: What fraction of kinetic energy is converted into radiation? Loss efficiency η = Marleau & Cumming (2014) Lum. at R Hill lum. below shock Energy input rate L acc ~ GMM' R Classical assumptions: η = 0 (no loss, hot start) or 100% (full loss, cold start) Differences of in L! Marley et al. (2007)

29 Quantities of interest Question: What fraction of kinetic energy is converted into radiation? Loss efficiency η = Marleau & Cumming (2014) Lum. at R Hill lum. below shock Energy input rate L acc ~ GMM' R Classical assumptions: η = 0 (no loss, hot start) or 100% (full loss, cold start) Differences of in L! Need also post-shock P and T as boundary conditions Use in formation calculations to predict luminosities Marley et al. (2007)

30 Results: Detailed profile H H 2 Marleau et al., in prep. ~ Hill sphere

31 Results: Detailed profile H H 2 Marleau et al., in prep. ~ Hill sphere

32 Results: Detailed profile H H 2 Marleau et al., in prep. ~ Hill sphere

33 Results: Detailed profile H H 2 Marleau et al., in prep. ~ Hill sphere

34 Results: Detailed profile At At shock: temperature» T in in local disc because of of radiative precursor Hot Hot boundary conditions for for planet! H H 2 Marleau et al., in prep.

35 Results: Detailed profile At At shock: temperature» T in in local disc because of of radiative precursor Hot Hot boundary conditions for for planet! H Also obtain L feedback for disc sim's H 2 better than crude estimate Also obtain L feedback for disc sim's e.g. Montesinos et al. (2015) Benítez-Llambay et al. (2015) Marleau et al., in prep.

36 Results: Detailed profile At At shock: temperature» T in in local disc because of of radiative precursor Hot Hot boundary conditions for for planet! H Also obtain L feedback for disc sim's H 2 better than crude estimate Also obtain L feedback for disc sim's e.g. Montesinos et al. (2015) Benítez-Llambay et al. (2015) Typically: ~ K at at Hill Hill sphere heat disc chemistry? Marleau et al., in prep. Cleeves et al. (2015)

37 Loss efficiencies Calculate η for different masses, radii, accretion rates

38 Loss efficiencies Calculate η for different masses, radii, accretion rates Marleau et al. (2017)

39 Loss efficiencies Calculate η for different masses, radii, accretion rates Matches analytical η(mach) but Mach number unknown a priori Marleau et al. (2017)

40 Loss efficiencies Calculate η for different masses, radii, accretion rates Matches analytical η(mach) but Mach number unknown a priori Find: Energy deposition into planet» internal luminosity [(1-η)L acc» L int ] leads to hot starts, disfavour cold accretion! Marleau et al. (2017)

41 Observing accreting planets Part of accretion luminosity escapes Hill sphere If disc optically thin in H α: should be visible Sallum et al. (2015)

42 Observing accreting planets Part of accretion luminosity escapes Hill sphere If disc optically thin in H α: should be visible Estimate L H α up to 10 ³ LSun Mordasini, Marleau & Mollière (2017) Sallum et al. (2015) 3 Myr a=1.5, b=3; Rigliaco et al (2012)

43 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Marleau et al. (2017) Marleau et al., in prep. Key input for early-time luminosity of planets

44 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Marleau et al. (2017) Key input for early-time luminosity of planets Find high shock temperature hot starts Marleau et al., in prep. Cold starts by Marley et al. (2007)

45 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Marleau et al. (2017) Key input for early-time luminosity of planets Find high shock temperature hot starts Marleau et al., in prep. Cold starts by Marley et al. (2007)

46 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Marleau et al. (2017) Key input for early-time luminosity of planets Find high shock temperature hot starts Yields radiative feedback on disc input for global disc simulations Marleau et al., in prep. Cold starts by Marley et al. (2007)

47 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Marleau et al. (2017) Key input for early-time luminosity of planets Find high shock temperature hot starts Yields radiative feedback on disc input for global disc simulations Marleau et al., in prep. Cold starts by Marley et al. (2007) Important: Equation of state (H 2 dissociation)!

48 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Marleau et al. (2017) Key input for early-time luminosity of planets Find high shock temperature hot starts Yields radiative feedback on disc input for global disc simulations Marleau et al., in prep. Cold starts by Marley et al. (2007) Important: Equation of state (H 2 dissociation)! Outlook: Couple to planet structure quantitative L init predictions

49 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Marleau et al. (2017) Key input for early-time luminosity of planets Find high shock temperature hot starts Yields radiative feedback on disc input for global disc simulations Marleau et al., in prep. Cold starts by Marley et al. (2007) Important: Equation of state (H 2 dissociation)! Outlook: Couple to planet structure quantitative L init predictions 1D geometry: Applies to spherical accretion, base of magnetospheric accretion column, or local shock on circumplanetary disc

50 Summary 1-D radiation-hydrodynamics simulations of the planet accretion shock (first ones to do so!) Key input for early-time luminosity of planets Find high shock temperature hot starts Yields radiative feedback on disc input for global disc simulations Marleau et al. (2017) Marleau et al., in prep. Cold starts by Marley et al. (2007) Important: Equation of state (H 2 dissociation)! Outlook: Couple to planet structure quantitative L init predictions Thank you for your attention! 1D geometry: Applies to spherical accretion, base of magnetospheric accretion column, or local shock on circumplanetary disc