The Dispersal of Protoplanetary Disks

The Dispersal of Protoplanetary Disks R. Alexander 1, I. Pascucci 2, S. Andrews 3, P. Armitage 4, L. Cieza 5 1 University of Leicester, 2 The University of Arizona 3 Harvard-Smithsonian Center for Astrophysics 4 University of Colorado, 5 Universidad Diego Portales

Typical disk lifetimes are a few Myr P: 1K086 Mamajek, E. P: 2S058 Ribas, A. Disk fraction Kraus et al. 2012, ApJ, 745, 19 PPVI review talk by R. Jeffries see also reviews by Mamajek 2009, AIPC, 1158, 3; Pascucci & Tachibana 2010, 263, Protoplanetary Dust, eds. Apai & Lauretta, Cambridge University Press; Williams & Cieza 2011, ARA&A, 49,67

Disk dispersal timescales are ~10 5 yrs Alexander et al. PPVI review chapter

planet formation disk and stellar winds stellar encounters Disk Dispersal Mechanisms disk accretion photoevaporation

planet formation disk and stellar winds stellar encounters Disk Dispersal Mechanisms previous PP reviews by Hollenbach et al. (2000) and Dullemond et al. (2007) disk accretion photoevaporation Hollenbach et al. 2000, 401, PPIV, eds. Manning, Boss, Russell, U. of Arizona Press Dullemond et al. 2007, 555, PPV, eds. Reipurth, Jewitt, Keil, U. of Arizona Press

Viscous accretion PPVI review talk by G. Lesur Hartmann et al. 1998, ApJ, 495, 385 see also Lynden-Bell & Pringle 1974, MNRAS, 168, 603

Photoevaporation thermal wind from Hollenbach et al. 2000, 401, PPIV, eds. Manning, Boss, Russell, U. of Arizona Press Rg

Photoevaporation thermal wind from Hollenbach et al. 2000, 401, PPIV, eds. Manning, Boss, Russell, U. of Arizona Press Rg e.g. Dullemond et al. 2007, PPV, eds. Reipurth, Jewitt, Keil, U. of Arizona Press

Dual timescale with accretion & photoevaporation Alexander & Armitage 2007, MNRAS, 375, 500 see also Clarke et al. 2001, MNRAS, 328, 485

Dual timescale with accretion & photoevaporation NOTE: the disk is photoevaporating even before the gap is opened Alexander & Armitage 2007, MNRAS, 375, 500 see also Clarke et al. 2001, MNRAS, 328, 485

Outline

Outline 1. Models of photoevaporative winds (new advances)

Outline 1. Models of photoevaporative winds (new advances) 2. Direct and indirect observations of photoevaporation

Outline 1. Models of photoevaporative winds (new advances) 2. Direct and indirect observations of photoevaporation 3. Implications for planets

Outline 1. Models of photoevaporative winds (new advances) 2. Direct and indirect observations of photoevaporation 3. Implications for planets 4. Schematic picture of disk evolution

In the review chapter (but not covered in this talk):

In the review chapter (but not covered in this talk): Cluster environments: External photoevaporation and tidal stripping (excellent agreement between models of EP and observations, e.g. Mesa-Delgado et al. 2012, MNRAS, 426, 614)

In the review chapter (but not covered in this talk): P: 2S037 Guarcello M. G. P: 2S064 Tamura, T. Cluster environments: External photoevaporation and tidal stripping P: 2S040 Pfalzner, S. (excellent agreement between models of EP and observations, e.g. Mesa-Delgado et al. 2012, MNRAS, 426, 614) P: 2S049 Bai, X. P: 2S054 Simon J. MHD disk winds (e.g. Suzuki & Inutsuka 2009, ApJ, 691, L49; Fromang et al. 2013, A&A, 552, A71; Bai & Stone 2013, ApJ, 767,30 and 769, 76; Simon et al. 2013 arxiv:1307.2240) Stellar-mass-dependent disk evolution and binaries (e.g. Andrews et al. 2013, ApJ, 771, 129; Harris et al. 2012, ApJ, 751, 115; Kraus et al. 2012, Apj, 745, 19; Mohanty et al. 2013, ApJ, in press )

Models of photoevaporative winds

EUV-driven winds EUV AU REFs: e.g. Hollenbach et al. 1994, ApJ, 428, 654; Clarke et al. 2001, MNRAS, 328, 485; Alexander et al. 2006, MNRAS, 369, 216 and 369, 229

EUV: 13.6-100eV EUV ~10 20 cm -2

Xrays: 0.1-10keV EUV: 13.6-100eV EUV X-rays ~10 20 cm -2 ~10 22 cm -2

Xrays: 0.1-10keV EUV: 13.6-100eV FUV: 6-13.6eV EUV X-rays FUV ~10 20 cm -2 ~10 22 cm -2 > 10 21 cm -2

X-ray-driven winds X-rays P: 2B002 Owen, J. REFs: e.g. Ercolano et al. 2009, ApJ, 699, 1639; Gorti & Hollenbach 2009, 690, 1539; Owen et al. 2011, MNRAS, 412, 13; Owen et al. 2012, MNRAS, 422, 1880; Morishima 2012, MNRAS, 420, 2851; Bae et al. 2013, ApJ in press (arxiv:1307.2585)

FUV-driven winds FUV The integrated wind rate depends on the total FUV luminosity. For LFUV=5x10 31 erg/s and M=1Msun Ṁw,FUV =3x10-8 Msun/yr (Gorti & Hollenbach 2009, ApJ, 690,1539)

All photoevaporation models predict the same qualitative behavior in disk evolution (inside-out clearing) but the clearing time and the mass lost via photoevaporation are quantitatively different (see also the recent reviews by Armitage 2011, ARA&A, 49, 195 and Clarke 2011, 355 in Physical Processes in Circumstellar Disks around Young Stars, ed. Garcia)

Normalized mass loss profiles Alexander et al. PPVI review chapter

Stellar accretion rates and total mass lost Alexander et al. PPVI review chapter

Stellar accretion rates and total mass lost P: 2S005 Herczeg, G. Alexander et al. PPVI review chapter

Main uncertainties in theoretical models

Main uncertainties in theoretical models EUV: what is the stellar EUV flux impinging on the disk?

EUV?

EUV? 10 42 phot/s, based on DEM measurements of 5 CTTs (Alexander et al. 2005, MNRAS, 358,283)

EUV? 10 42 phot/s, based on DEM measurements of 5 CTTs (Alexander et al. 2005, MNRAS, 358,283) ~5x10 41 phot/s for TWHya : X-ray and FUV line modeling (Herczeg 2007, vol. 243, 147, IAU Symposium, eds. Bouvier & Appenzeller) Φeuv ~ 5x10 40 s -1 impinging on the TWHya disk excess free-free emission see also Owen et al. 2013, MNRAS, in press (arxiv:1307.2240) Pascucci et al. 2012, ApJ, 751, L42

Main uncertainties in theoretical models EUV: what is the stellar EUV flux impinging on the disk?

Main uncertainties in theoretical models EUV: what is the stellar EUV flux impinging on the disk? X-rays: amount and evolution of the soft X-ray component reaching the disk + sensitivity to disk chemistry and dust properties (e.g. settling) FUV: uncertainties in the FUV flux + sensitivity to dust properties (e.g. PAHs) + lack of hydrodynamics

Direct observations of photoevaporative winds

Direct evidence = flowing gas from the ionized and atomic layers atomic layers ionized layer

Direct evidence = flowing gas from the ionized and atomic layers atomic layers ionized layer diagnostics predicted by: Font et al. 2004, ApJ, 607, 890; Alexander 2008, MNRAS, 391, L64; Hollenbach & Gorti 2009, ApJ, 703, 1203; Ercolano & Owen 2010, MNRAS 406, 1553

[NeII] at 12.8 micron i = 90 o VLT R~30,000 theoretical profile observed profile EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

[NeII] at 12.8 micron i = 60 o VLT R~30,000 theoretical profile observed profile EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

[NeII] at 12.8 micron i = 30 o VLT R~30,000 theoretical profile observed profile EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

[NeII] at 12.8 micron i = 0 o VLT R~30,000 theoretical profile observed profile EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

An observed photoevaporative wind TWHya almost face-on disk model by Alexander 2008, MNRAS, 392, L64 Pascucci & Sterzik 2009, ApJ, 702, 724

An observed photoevaporative wind TWHya almost face-on disk model by Alexander 2008, MNRAS, 392, L64 Most of the [NeII] comes from beyond the dust inner cavity and extends out to 10AU in agreement with model predictions (Pascucci et al. 2011, ApJ, 736,13) Pascucci & Sterzik 2009, ApJ, 702, 724

more wind sources...

more wind sources... Sacco et al. 2012, ApJ 747, 142

more wind sources... Sacco et al. 2012, ApJ 747, 142 see also : Herczeg et al. 2007, ApJ, 670, 509; Najita et al. 2009, 679, 957; Pascucci & Sterzik 2009, ApJ, 702, 724 van Boekel et al. 2009, A&A, 497, 137 Baldovin-Saavedra et al. 2012, A&A, 543A, 30

A fully or partially ionized layer? Alexander et al. PPVI review chapter REFs: Hollenbach & Gorti 2009, ApJ 703, 1203; Ercolano & Owen 2010, MNRAS, 406, 1553; Pascucci et al. 2011, ApJ, 736, 13

A fully or partially ionized layer? EUV wind @10-10 Msun/yr Alexander et al. PPVI review chapter REFs: Hollenbach & Gorti 2009, ApJ 703, 1203; Ercolano & Owen 2010, MNRAS, 406, 1553; Pascucci et al. 2011, ApJ, 736, 13

A fully or partially ionized layer? EUV wind @10-10 Msun/yr X-ray wind @10-8 Msun/yr Alexander et al. PPVI review chapter REFs: Hollenbach & Gorti 2009, ApJ 703, 1203; Ercolano & Owen 2010, MNRAS, 406, 1553; Pascucci et al. 2011, ApJ, 736, 13

Any evidence of an atomic flow?

[OI]6300Å Any evidence of an atomic flow? high-accretion HVC [OI]6300Å LVC low-accretion Hartigan et al.1995, ApJ, 452, 736 v [km/s]

[OI]6300Å Any evidence of an atomic flow? high-accretion HVC the [OI] 6300Å low velocity component (LVC) is ubiquitous [OI]6300Å typical blueshifts in the LVC ~5km/s LVC low-accretion Hartigan et al.1995, ApJ, 452, 736 v [km/s]

Rigliaco et al. 2013, ApJ, 772, 60 P: 2S039 Rigliaco, E.

velocity (km/s) Rigliaco et al. 2013, ApJ, 772, 60 P: 2S039 Rigliaco, E.

velocity (km/s) Rigliaco et al. 2013, ApJ, 772, 60 [OI] likely traces the dissociation of OH molecules by FUV photons. It has an unbound/wind component Ṁw > 10-10 Msun/yr P: 2S039 Rigliaco, E.

Indirect observations

Transitional disks deficit of NIR and/or MIR flux with respect to the median SED of CTTs (e.g. Strom et al. 1989, AJ, 97, 1451)

Transitional disks deficit of NIR and/or MIR flux with respect to the median SED of CTTs (e.g. Strom et al. 1989, AJ, 97, 1451) Espaillat et al. 2007, ApJ, 670, L135 LkCa 15

Transitional disks deficit of NIR and/or MIR flux with respect to the median SED of CTTs (e.g. Strom et al. 1989, AJ, 97, 1451) Espaillat et al. 2007, ApJ, 670, L135 Andrews et al. 2011, ApJ, 742, L5 LkCa 15

Non-accreting transitional disks ~10% of the pre-main sequence population (Cieza et al. 2007, ApJ, 667, 308) see also: Wahhaj et al. 2010, ApJ, 724, 835 Cieza et al. 2013, ApJ, 762, 100 Cieza et al. 2012, ApJ, 750, 157 these may be photoevaporating disks

Two populations of accreting transition disks? Owen et al. 2011, MNRAS, 412, 13 see also Morishima 2012, MNRAS, 420, 2851

Two populations of accreting transition disks? dynamically cleared Owen et al. 2011, MNRAS, 412, 13 see also Morishima 2012, MNRAS, 420, 2851

Two populations of accreting transition disks? dynamically cleared photoevaporating Owen et al. 2011, MNRAS, 412, 13 see also Morishima 2012, MNRAS, 420, 2851

Two populations of accreting transition disks? dynamically cleared P: 2S036 Manara, C. F. photoevaporating Owen et al. 2011, MNRAS, 412, 13 see also Morishima 2012, MNRAS, 420, 2851

Impact of photoevaporation on planets

Impact of photoevaporation on planets Increased dust-to-gas ratio and chemical enrichment of the disk discussed in previous PP reviews (Throop & Bally 2005, ApJ, 623, L149; Guillot & Hueso 2006, MNRAS, 367, L47)

Migration of giant planets in photoevaporating disks

Semi-major axis distribution of exoplanets reproduced observations models See also Armitage et al. 2002, MNRAS, 334, 248; Mordasini et al. 2012, A&A, 547, A112 PPVI review talk by S. Ida Alexander & Armitage 2009, ApJ, 704, 989

Deserts and pile-ups of giant planets at Rc Alexander & Pascucci 2012, MNRAS, 422, L82

Deserts and pile-ups of giant planets at Rc Alexander & Pascucci 2012, MNRAS, 422, L82 P: 2S041 Rosotti, G. See also Matsuyama et al. 2003, ApJ, 582, 893; Hasegawa & Pudritz 2012, 760, 117; Rosotti et al. 2013, MNRAS, 430, 1392

Planet scattering in a photoevaporating disk Moeckel & Armitage 2012, MNRAS, 419, 366

Schematic picture of disk evolution MHD disk wind primarily neutral photoevaporative flow UV photons migration X-rays Δt = few Myr dust disk Ne + H H Ne + H H volatile loss in partially ionized wind Δt ~ 10 5 yr photoevaporative gap formation direct illumination of outer disk credit: P. Armitage 0.1 AU 1 AU 10 AU 100 AU

Key Points protoplanetary disk evolution on ~Myr timescales is mainly driven by accretion, but photoevaporative winds may drive significant mass loss disk photoevaporation is now directly detected in several systems photoevaporation can explain the properties of some but not all transition disks disk dispersal affects the architecture of planetary systems We thank A. Dunhill, S. Edwards, B. Ercolano, C. Espaillat, U. Gorti, G. Herczeg, D. Hollenbach, J. Owen, E. Rigliaco, G. Sacco for insightful discussions