![Blue-shifted lines of [NeII]12.8µm, [OI]5577 6300, etc. (e.g., Pascucci+09)
line
of
sight
observer
Fang+18
Line High-velocity component： Jet
Low-velocity component Broad component: MHD wind(⁇)
Narrow component: MHD wind and/or photoevaporation⁇
Young
Old⁇
Detection and intensity of each component may correlate with disk evolution (See e.g., Pascucci+2022 review)
Wind = blue-shifted lines](https://image.slidesharecdn.com/cl235122-250415014858-bf7cef8b/85/Modeling-protoplanetary-Disk-CL23_5122-pdf-8-320.jpg)
![Bally and Scoville (1982): simplified EUV RT
Hollenbach+94: 1+1D EUV RT
Yorke&Weltz96, Richling&Yorke97,98,99: FUV/EUV RT + hydro + chem
Gorti & Hollenbach04: FUV/EUV/ RT + chem
Alexander+04: EUV/ RT
Ercolano+08,09: EUV/ RT + chem
Gorti+09: FUV/EUV/ RT + chem
Font04: (EUV table) + hydro
Owen+10: (EUV/ table) + hydro
1980
1990
2000
2010
2020
2030
Nakatani+18a,b: FUV/EUV/ + hydro + chem
Wang & Goodman 2017: FUV/EUV/ + hydro + chem
New studies⁇
Upgrade computational methods for RT and chemistry⁇
w/ non-ideal global MHD (Wang+19; Gressel+20)
• Recent observations suggest (MHD) wind signature
evolves with disk (e.g., [OI] declines with time).
• (Resolved) wind obs by ALMA, JWST, …, will develop.
observational motivation
planet formation
Disk formation Dust to Planets Disk dispersal
top-level question
etc.
Viscous Acc. MHD winds Photoevaporation
altogether + 10Myr-long 3D simulation
Ideal:
-2030(⁇)
Owen+10
Wang+ 17
1Myr Disk age
3Myr 6Myr
Nakatani+18
Nakatani+21
-2020
0
1Myr 3Myr 6Myr
0
New hydro models at different stages w/ appropriate physics
Real: at most ~0.01Myr simulation is feasible](https://image.slidesharecdn.com/cl235122-250415014858-bf7cef8b/85/Modeling-protoplanetary-Disk-CL23_5122-pdf-23-320.jpg)
Modeling protoplanetary Disk CL23_5122.pdf
- 1. Riouhei Nakatani Core2Disk III @ Institut Pascal, Paris-Saclay, France, 10/??/2023 Jet Propulsion Laboratory, California Institute of Technology RIKEN
- 2. Debris disk/planetary system (e.g., Solar System) GMC, Dark Cloud Clumps Jet Protostellar disk Envelope ~1Myr Pre-main-sequence star Protoplanetary disk ~10Myr Itokawa (Credit: NASA/JPL) planets 103 km Planetesimals 1 km Rocks 1 m Dust < 1mm Dust ring Grain growth to planet formation Planetesimal formation Planet formation
- 3. (e.g. Haisch et al. (2001), Meyer et al. (2007), Mamajek (2009)) Typical (IR) disk lifetime (e-folding time): 2-3 Myr Circumstellar dust Currie & Sicilia-aguilar 11 Stellar PPD system’s SED I R - e x c e s s = d u s t i n d i c a t o r decrease w ith cluster ages Disk fraction of a cluster = N★, w/excess / N★, tot Ribas+14 (Hernández+07,08) Similar conclusions obtained for MIR, submm. → Primordial dust dispersal timescale ≲ "# $%&
- 4. (e.g. Zuckerman+95; Calvet+05; Pascucci+06; Fedele+10; Sicilia-Aguilar+10; Dent+13; Rugel+18). Fedele+10 Low-mass stars Herbig Ae/Be Arun+19 e-folding time: ~ 2 Myr Gas signature decays on the same timescale as dust. → Gas lifetimes < 10 Myr
- 5. Hollenbach & Yorke (2000) (massive star context) Viscous accretion (tν) Falling onto the star Stellar winds (tWS) strip strip Photoevaporation (tE, tC) Stellar encounter (tSE) strip wind wind Viscous accretion & Photoevaporation are dominant. Not all !!"#$ (~ 0.01 !#%&~10 !'%(")*+) goes into planets (or the star). disk cross-section (disk cross-section)
- 6. • Accretion (e.g. Shakura & Sunyaev 1973, Lynden-Bell & Pringle 1974) Angular momentum transfer due to viscous friction → Materials fall • Photoevaporation (e.g. Hollenbach et al. 1994, Alexander+14 (review)) Irradiation → Thermally driven winds • MHD winds (e.g. Suzuki & Inutsuka 2009, Bai & Stone 2013, Turner+14 (review)) Magneto-hydrodynamical effects → driving winds & accretion Stripping from the surface Falling onto the star My expertise (These three are currently the developing topics in the field) Don't worry when you find a “bug,” be happy! MHD winds are also found to be important on disk dispersal (late 2000-)
- 7. Kunitomo+20 Early phase (< a few Myr): MHD-winds-dominated epoch (This view is consistent with jet/wind observations) In 2020s, the roles (and interplays) of the dispersal processes are studied. MHD wind Disk Accretion Photoevaporative wind Disk Late phase (> a few Myr): Photoevaporation-dominated epoch • High disk mass = high mass loss • Power-law decline of mass (slow) • Disk mass doesn’t matter • Linear decline (relatively fast)
- 8. Blue-shifted lines of [NeII]12.8µm, [OI]5577 6300, etc. (e.g., Pascucci+09) line of sight observer Fang+18 Line High-velocity component： Jet Low-velocity component Broad component: MHD wind(⁇) Narrow component: MHD wind and/or photoevaporation⁇ Young Old⁇ Detection and intensity of each component may correlate with disk evolution (See e.g., Pascucci+2022 review) Wind = blue-shifted lines
- 9. Ultimate goal: planet formation Disk formation Dust to Planets Disk dispersal top-level question etc. Viscous Acc. MHD winds Photoevaporation “External” photoevaporation massive star-forming region (e.g., Orion) “Internal” photoevaporation low-mass star-forming region (e.g., Taurus)
- 10. e.g., Bally & Scoville (1982); Shu et al. (1993), Hollenbach et al. (1994) Surface gas heating FUV EUV X-rays Photon energy 6 eV ≦ hν ≦ 13.6 eV 13.6 eV ≦ hν ≦ 100 eV 0.1 keV ≦ hν ≦ 10 keV Main absorber Small dust H/He H, He, Metal elements (≧ 0.3 keV) Penetratability High Low High Mass-loss rates High ~10-8 Msun/yr Low ~10-10 Msun/yr High ~10-8 Msun/yr Unbound, hot Photoevaporative flow FUV Submicron grain PAH e Thermalize e EUV Thermalizing electron H H+ X-ray primary electron secondary electron secondary electron H H+ H+ H+ H+ FUV, EUV, X-ray
- 11. Bally and Scoville (1982): simplified EUV RT Hollenbach+94: 1+1D EUV RT Yorke&Weltz96, Richling&Yorke97,98,99: FUV/EUV RT + hydro + chem Gorti & Hollenbach04: FUV/EUV/ RT + chem Alexander+04: EUV/ RT Ercolano+08,09: EUV/ RT + chem Gorti+09: FUV/EUV/ RT + chem Font04: (EUV table) + hydro Owen+10: (EUV/ table) + hydro 1980 1990 2000 2010 1960 Credits: NASA, J. Bally HST −90s: Mainly massive stars Spitzer Kahn 1957: the concept of EUV photoevaporation developed 00’s TT stars/massive stars (detailed chemistry) X-ray dominates mass-loss FUV dominates mass-loss (selected, biased) https://www.nasa.gov/mission_pages/spitzer/infrared/index.html VS
- 12. • small grains are responsible for the bulk of heating. • grain growth, settling, etc. can reduce the abundance of small grains • Observations suggest PAH abundances smaller than that in the ISM (e.g., Geers+07; Oliveira+10) Bakes & Tielens 1994 Photoelectric heating rate rapidly decreases with increasing dust size a ~ 10 nm a ~ 30 nm Ercolano+09 see Nomura+07; Nakatani+18b Hard X-ray (> 1keV) hardly contribute to heating or photoevaporation. (it’s also important to look at the spectrum when comparing models) Photoevaporation rates depend on not only luminosities but star & disk properties.
- 13. Taken from Ercolano & Pascucci, RSOS, 4, 4, 2017 Wang+17 RN+18a RN+18b Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes FYI, < Important notes > • There are further differences that significantly affect the results. e.g., input spectra, incorporated heating/cooling, chemical network, codes, etc. • Any of photoevaporation models does not yet incorporate all essential effects. • Models are developing (large parameter space, detailed effects, etc.) Covered in this talk
- 14. Taken from a review (Ercolano & Pascucci 2017) The necessity of coupling RT + hydro + chem has been repeatedly claimed in textbooks & reviews in the 2010s. Hydrodynamics (photo-) Chemistry Radiation Transfer Heating/Cooling Advection, Adiabatic cooling Shields photons Photo-chemistry Absorber production thydro ~ r/cs thydro tcool , theat ← PPVI textbook 2014 Classical estimating technique of photoevaporation rates: 1. Hydrostatic disk + equilibrium thermochemistry + radiative transfer → guessing ρ and v. 2. Hydrodynamics + temperature table (equilibrium thermochemistry) Accurate mass-loss rates were unclear. × × ×
- 15. Length unit: 100au Hollenbach +94 Yorke & Welz 96 Gorti+09 Owen+10 Ercolano & Clarke 10 Wang+17 Hydrodynamic s No Yes No Yes No Yes Yes Radiative transfer Yes Yes Yes No Yes Yes Yes Thermal processes Yes Yes Yes No Yes Yes Yes Chemistry No No Yes No Yes Yes Yes FUV heating No Yes Yes No No Yes Yes EUV heating Yes Yes Yes Yes Yes Yes Yes X-ray heating No No Yes Yes Yes Yes No/Yes Dust temperature No No Yes No Yes No Yes Note that this may be biased; there are many more detailed differences in the methods. In the 2020s, MHD + self-consistent thermochemistry simulations are advancing. (e.g., Wang+19; Gressel+20) Hydrodynamics (photo-) Chemistry Radiation Transfer Heating/Cooling Chemical structures change Shields photons Photo-chemistry Absorber production thydro ~ r/cs thydro tcool , theat ↓ Taken from PPVII Chapter 16
- 16. (Nakatani +18a: no X-ray effects) Color Scales Length unit: 100au Photoevaporating disk II Cold disk ( ~10 - 100 K) + Hot winds (> 102 -103 K) UV-heated region = Wind region Optically thick region = Steady disk region These regions are sharply divided. (Note the 3D view is just for illustration. Our simulations are in 2.5D)
- 17. ! FUV switch off: 1 ! FUV switch off: 2 ! FUV switch off: 3 ! FUV switch off: 4 ! FUV switch off: 5 Visually straightforward movie to show the neutral flows is due to FUV. FUV heating will be switched off at Time = 1. Two flow components 1. EUV-driven H+-dominated (ionized) flow 2. FUV-driven neutral-dominated (neutral) flow After Time = 1, neutral (H, H2) flows cease, and ionized (H+) flows remain. Two flow components 1. ionized flow ← EUV-driven 2. neutral flow ← FUV-driven (Nakatani +18a)
- 18. Mass-loss rates Young disk (ISM grains) Evolved disk (small-grain depleted) Large total dust surface area → Efficient photoelectric heating Mass-loss rates of evolved disks are much smaller than classical values. → Lifetime > 10 Myr 10-8 Msun/yr 10-11 Msun/yr Nakatani+21, to be submitted → Ineffective photoelectric heating → EUV photoevaporation FUV Submicron grain PAH e Thermalize e EUV Thermalizing electron H H+ Small-grain depletion = necessary condition for the primordial-origin scenario to hold. cf.
- 19. E U V ( H + E U V → H + + e F U V ( d u s t + F U V → d u s t + e ) I o n i z e d f l o w Neutral flow O I c o o l i n g A d ia b a t ic c o o li n g H 2 c o o l i n g Dust Dominant cooling Dominant heating 0 AU 100 AU 100 AU Chemical structure Density distribution Solid lines (nH /cm−3 ) Cyan: 105 Blue: 106 Black: 107 Red: 108 Dashed lines (A V) Magenta: 0.5 Yellow: 1 Black : 2 EUV-driven Ionized flow FUV-driven neutral flow Photoevaporative flows launch at AV ~ 1 (base) (yellow dashed line) Dust-gas collisional cooling (blue region) is dominant at the base Steady disk (Nakatani +18a) dust Dust-gas collisional cooling Tdust Tgas k (Tgas – Tdust) is lost from gas per collision Gas particles Color Scales
- 20. t-ave. <latexit sha1_base64="oHI0ADkyNO+IFLQY9pSZME4tgCk=">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</latexit> @E/@t r · (H~ v) ⇢~ v · r = ⇤ r · (H~ v) ⇢~ v · r r · (H~ v) ⇢~ v · r Time-average over a few orbits gives quasi-steady structure in the flow region. Breakdowns of energy rates (< 200au) HII region Neutral region ← Within 200 au, • HII region: ~10-20% of net heating goes to gravitational energy. • Neutral region: ~60% of net heating goes to gravitational energy. EUV FUV (Nakatani+18a; Nakatani in prep.) ←( ) If completely steady → it should be white everywhere
- 21. high Z Z Disk Disk Disk Ionized flow (EUV-driven)＋ neutral flow (FUV-driven) Only Ionized flow high <---- neutral flow density ----> low FUV penetrates deeper; nH ∝ Z−1 Low temperature (next slide) Dust cooling > FUV heating (Nakatani +18a)
- 22. Density Density Density Temperature Temperature Temperature FUV/EUV/X-ray EUV/X-ray FUV/EUV X-ray doesn’t excite flows (with our numerical configuration.) ・ The temperature is higher in the left ・X-ray amplifies FUV heating (cf. Gorti & Hollenbach 09). E U V -h e a te d re g io n X-ray-heated region E U V -h e a te d re g io n F U V - h e a t e d r e g i o n F U V / X - r a y - h e a t e d r e g i o n (Nakatani +18b)
- 23. Bally and Scoville (1982): simplified EUV RT Hollenbach+94: 1+1D EUV RT Yorke&Weltz96, Richling&Yorke97,98,99: FUV/EUV RT + hydro + chem Gorti & Hollenbach04: FUV/EUV/ RT + chem Alexander+04: EUV/ RT Ercolano+08,09: EUV/ RT + chem Gorti+09: FUV/EUV/ RT + chem Font04: (EUV table) + hydro Owen+10: (EUV/ table) + hydro 1980 1990 2000 2010 2020 2030 Nakatani+18a,b: FUV/EUV/ + hydro + chem Wang & Goodman 2017: FUV/EUV/ + hydro + chem New studies⁇ Upgrade computational methods for RT and chemistry⁇ w/ non-ideal global MHD (Wang+19; Gressel+20) • Recent observations suggest (MHD) wind signature evolves with disk (e.g., [OI] declines with time). • (Resolved) wind obs by ALMA, JWST, …, will develop. observational motivation planet formation Disk formation Dust to Planets Disk dispersal top-level question etc. Viscous Acc. MHD winds Photoevaporation altogether + 10Myr-long 3D simulation Ideal: -2030(⁇) Owen+10 Wang+ 17 1Myr Disk age 3Myr 6Myr Nakatani+18 Nakatani+21 -2020 0 1Myr 3Myr 6Myr 0 New hydro models at different stages w/ appropriate physics Real: at most ~0.01Myr simulation is feasible
- 24. Multi-D simulation to get 1D: Winds Viscous accretion ×104 Multi-dimensional simulation for ~10 Myr Deriving through disk disappearance is necessary! feasible! Kunitomo+20 -2030(⁇) Owen+10 Wang+ 17 1Myr Disk age 3Myr 6Myr Nakatani+18 Nakatani+21 -2020 0 1Myr 3Myr 6Myr 0 New hydro models at different stages w/ appropriate physics Filling the gaps is important in the theoretical context too!