1 University of Leicester, 2 The University of Arizona 3 Harvard-Smithsonian Center for Astrophysics

4 University of Colorado, 5 Universidad Diego Portales

The Dispersal of Protoplanetary Disks

R. Alexander1, I. Pascucci2, S. Andrews3, P. Armitage4, L. Cieza5

Monday, July 22, 13

Kraus et al. 2012, ApJ, 745, 19

Typical disk lifetimes are a few Myr

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

P: 2S058 – Ribas, A.

Dis

k fr

actio

n

P: 1K086 – Mamajek, E.

PPVI review talk by R. Jeffries

Monday, July 22, 13

Disk dispersal timescales are ~105 yrs

Alexander et al. PPVI review chapterMonday, July 22, 13

planet formation

stellar encounters

photoevaporation

disk and stellar winds

disk accretion

Disk Dispersal Mechanisms

Monday, July 22, 13

planet formation

stellar encounters

photoevaporation

disk and stellar winds

disk accretion

Disk Dispersal Mechanisms

previous PP reviews by Hollenbach et al. (2000) and Dullemond et al. (2007)

Hollenbach et al. 2000, 401, PPIV, eds. Manning, Boss, Russell, U. of Arizona PressDullemond et al. 2007, 555, PPV, eds. Reipurth, Jewitt, Keil, U. of Arizona Press

Monday, July 22, 13

Viscous accretion

Hartmann et al. 1998, ApJ, 495, 385

see also Lynden-Bell & Pringle 1974, MNRAS, 168, 603

PPVI review talk by G. Lesur

Monday, July 22, 13

Viscous accretion

Hartmann et al. 1998, ApJ, 495, 385

see also Lynden-Bell & Pringle 1974, MNRAS, 168, 603

PPVI review talk by G. Lesur

Monday, July 22, 13

Photoevaporation – thermal wind

Rg

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

Monday, July 22, 13

Photoevaporation – thermal wind

Rg

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

e.g. Dullemond et al. 2007, PPV, eds. Reipurth, Jewitt, Keil, U. of Arizona Press

Monday, July 22, 13

Dual timescale with accretion & photoevaporation

Alexander & Armitage 2007, MNRAS, 375, 500

see also Clarke et al. 2001, MNRAS, 328, 485Monday, July 22, 13

Dual timescale with accretion & photoevaporation

Alexander & Armitage 2007, MNRAS, 375, 500

NOTE: the disk is photoevaporating even before the gap is opened

see also Clarke et al. 2001, MNRAS, 328, 485Monday, July 22, 13

Outline

Monday, July 22, 13

1. Models of photoevaporative winds (new advances)

Outline

Monday, July 22, 13

1. Models of photoevaporative winds (new advances)

Outline

2. Direct and indirect observations of photoevaporation

Monday, July 22, 13

1. Models of photoevaporative winds (new advances)

Outline

2. Direct and indirect observations of photoevaporation

3. Implications for planets

Monday, July 22, 13

1. Models of photoevaporative winds (new advances)

Outline

2. Direct and indirect observations of photoevaporation

3. Implications for planets

4. Schematic picture of disk evolution

Monday, July 22, 13

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

Monday, July 22, 13

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)

Monday, July 22, 13

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)

P: 2S037 – Guarcello M. G.

P: 2S040 – Pfalzner, S.

P: 2S064 – Tamura, T.

Monday, July 22, 13

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)

– 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)

P: 2S037 – Guarcello M. G.

P: 2S040 – Pfalzner, S.

P: 2S064 – Tamura, T.

Monday, July 22, 13

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)

– 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)

P: 2S037 – Guarcello M. G.

P: 2S040 – Pfalzner, S.

P: 2S064 – Tamura, T.

P: 2S049 – Bai, X. P: 2S054 – Simon J.

Monday, July 22, 13

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)

– 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 )

P: 2S037 – Guarcello M. G.

P: 2S040 – Pfalzner, S.

P: 2S064 – Tamura, T.

P: 2S049 – Bai, X. P: 2S054 – Simon J.

Monday, July 22, 13

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)

– 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 )

P: 2S037 – Guarcello M. G.

P: 2S040 – Pfalzner, S.

P: 2S064 – Tamura, T.

P: 2S059 – Daemgen, S.

P: 2K058 – Kraus, A.

P: 2S049 – Bai, X. P: 2S054 – Simon J.

Monday, July 22, 13

Models of photoevaporative winds

Monday, July 22, 13

EUV

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-driven winds

AU

Monday, July 22, 13

Monday, July 22, 13

EUV: 13.6-100eV

~1020 cm-2EUV

Monday, July 22, 13

EUV: 13.6-100eV

~1020 cm-2EUV

X-rays~1022 cm-2

Xrays: 0.1-10keV

Monday, July 22, 13

EUV: 13.6-100eV

~1020 cm-2EUV

X-rays~1022 cm-2

Xrays: 0.1-10keV

FUV> 1021 cm-2

FUV: 6-13.6eV

Monday, July 22, 13

X-rays

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)

X-ray-driven winds

P: 2B002 – Owen, J.

Monday, July 22, 13

FUV-driven winds

The integrated wind rate depends on the total FUV luminosity.For LFUV=5x1031 erg/s and M=1Msun – Ṁw,FUV =3x10-8 Msun/yr (Gorti & Hollenbach 2009, ApJ, 690,1539)

FUV

Monday, July 22, 13

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)

Monday, July 22, 13

Normalized mass loss profiles

Alexander et al. PPVI review chapterMonday, July 22, 13

Stellar accretion rates and total mass lost

Alexander et al. PPVI review chapter

Monday, July 22, 13

Stellar accretion rates and total mass lost

Alexander et al. PPVI review chapter

Monday, July 22, 13

Stellar accretion rates and total mass lost

P: 2S005 – Herczeg, G.

Alexander et al. PPVI review chapter

Monday, July 22, 13

Main uncertainties in theoretical models

Monday, July 22, 13

Main uncertainties in theoretical models

EUV: what is the stellar EUV flux impinging on the disk?

Monday, July 22, 13

EUV ?

Monday, July 22, 13

EUV ? ≳1042 phot/s, based on DEM measurements of 5 CTTs (Alexander et al. 2005, MNRAS, 358,283)

Monday, July 22, 13

EUV ?

~5x1041 phot/s for TWHya : X-ray and FUV line modeling (Herczeg 2007, vol. 243, 147, IAU Symposium, eds. Bouvier & Appenzeller)

≳1042 phot/s, based on DEM measurements of 5 CTTs (Alexander et al. 2005, MNRAS, 358,283)

Monday, July 22, 13

EUV ?

~5x1041 phot/s for TWHya : X-ray and FUV line modeling (Herczeg 2007, vol. 243, 147, IAU Symposium, eds. Bouvier & Appenzeller)

≳1042 phot/s, based on DEM measurements of 5 CTTs (Alexander et al. 2005, MNRAS, 358,283)

Φeuv ~ 5x1040 s-1 impinging on the TWHya disk

see also Owen et al. 2013, MNRAS, in press (arXiv:1307.2240)

Pascucci et al. 2012, ApJ, 751, L42

excess free-free emission

Monday, July 22, 13

Main uncertainties in theoretical models

EUV: what is the stellar EUV flux impinging on the disk?

Monday, July 22, 13

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

Monday, July 22, 13

Direct observations of photoevaporative winds

Monday, July 22, 13

Direct evidence = flowing gas from the ionized and atomic layers

ionized layer

atomic layers

Monday, July 22, 13

Direct evidence = flowing gas from the ionized and atomic layers

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

ionized layer

atomic layers

Monday, July 22, 13

VLT

i = 90o

theoretical profile

observedprofile

R~30,000

EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

[NeII] at 12.8 micron

Monday, July 22, 13

VLT

i = 60o

theoretical profile

observedprofile

R~30,000

[NeII] at 12.8 micron

EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

Monday, July 22, 13

VLT

i = 30o

theoretical profile

observedprofile

R~30,000

[NeII] at 12.8 micron

EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

Monday, July 22, 13

[NeII] at 12.8 micron

EUV wind: simulations from Alexander 2008, MNRAS, 391, L64 & Pascucci et al. 2011, ApJ, 736, 13

VLT

i = 0o

observedprofile

R~30,000

theoretical profile

Monday, July 22, 13

An observed photoevaporative wind

Pascucci & Sterzik 2009, ApJ, 702, 724

model by Alexander 2008, MNRAS, 392, L64

TWHya almost face-on disk

Monday, July 22, 13

An observed photoevaporative wind

Pascucci & Sterzik 2009, ApJ, 702, 724

model by Alexander 2008, MNRAS, 392, L64

TWHya almost face-on disk

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)

Monday, July 22, 13

more wind sources...

Monday, July 22, 13

Sacco et al. 2012, ApJ 747, 142

more wind sources...

Monday, July 22, 13

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, 724van Boekel et al. 2009, A&A, 497, 137Baldovin-Saavedra et al. 2012, A&A, 543A, 30

more wind sources...

Monday, July 22, 13

A fully or partially ionized layer?

REFs: Hollenbach & Gorti 2009, ApJ 703, 1203; Ercolano & Owen 2010, MNRAS, 406, 1553; Pascucci et al. 2011, ApJ, 736, 13

Alexander et al. PPVI review chapter

Monday, July 22, 13

A fully or partially ionized layer?

REFs: Hollenbach & Gorti 2009, ApJ 703, 1203; Ercolano & Owen 2010, MNRAS, 406, 1553; Pascucci et al. 2011, ApJ, 736, 13

EUV wind@10-10Msun/yr

Alexander et al. PPVI review chapter

Monday, July 22, 13

A fully or partially ionized layer?

REFs: Hollenbach & Gorti 2009, ApJ 703, 1203; Ercolano & Owen 2010, MNRAS, 406, 1553; Pascucci et al. 2011, ApJ, 736, 13

EUV wind@10-10Msun/yr

X-ray wind@10-8Msun/yr

Alexander et al. PPVI review chapter

Monday, July 22, 13

Any evidence of an atomic flow?

Monday, July 22, 13

Any evidence of an atomic flow?[OI]6300Å

high-accretion

HVC

Hartigan et al.1995, ApJ, 452, 736

[OI]6300Å

low-accretionLVC

v [km/s]Monday, July 22, 13

– the [OI] 6300Å low velocity component (LVC) is ubiquitous

– typical blueshifts in the LVC ~5km/s

Any evidence of an atomic flow?[OI]6300Å

high-accretion

HVC

Hartigan et al.1995, ApJ, 452, 736

[OI]6300Å

low-accretionLVC

v [km/s]Monday, July 22, 13

P: 2S039 – Rigliaco, E.

Rigliaco et al. 2013, ApJ, 772, 60

Monday, July 22, 13

P: 2S039 – Rigliaco, E.

Rigliaco et al. 2013, ApJ, 772, 60

Monday, July 22, 13

P: 2S039 – Rigliaco, E.

Rigliaco et al. 2013, ApJ, 772, 60

Monday, July 22, 13

P: 2S039 – Rigliaco, E.

Rigliaco et al. 2013, ApJ, 772, 60

velocity (km/s)

Monday, July 22, 13

[OI] likely traces the dissociation of OH molecules by FUV

photons. It has an unbound/wind component → Ṁw > 10-10Msun/yr

P: 2S039 – Rigliaco, E.

Rigliaco et al. 2013, ApJ, 772, 60

velocity (km/s)

Monday, July 22, 13

Indirect observations

Monday, July 22, 13

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)

Monday, July 22, 13

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)

Monday, July 22, 13

Espaillat et al. 2007, ApJ, 670, L135

LkCa 15

Transitional disks

Andrews et al. 2011, ApJ, 742, L5

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

Monday, July 22, 13

Espaillat et al. 2007, ApJ, 670, L135

LkCa 15

Transitional disks

Andrews et al. 2011, ApJ, 742, L5

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

PPVI review talk by J. Muzerolle

Monday, July 22, 13

Non-accreting transitional disks

~10% of the pre-main sequence population (Cieza et al. 2007, ApJ, 667, 308)

Cieza et al. 2012, ApJ, 750, 157

see also:Wahhaj et al. 2010, ApJ, 724, 835Cieza et al. 2013, ApJ, 762, 100

these may be photoevaporating disks

Monday, July 22, 13

Two populations of accreting transition disks?

Owen et al. 2011, MNRAS, 412, 13

see also Morishima 2012, MNRAS, 420, 2851

Monday, July 22, 13

Two populations of accreting transition disks?

Owen et al. 2011, MNRAS, 412, 13

dynamically cleared

see also Morishima 2012, MNRAS, 420, 2851

Monday, July 22, 13

Two populations of accreting transition disks?

Owen et al. 2011, MNRAS, 412, 13

dynamically cleared

photoevaporating

see also Morishima 2012, MNRAS, 420, 2851

Monday, July 22, 13

Two populations of accreting transition disks?

Owen et al. 2011, MNRAS, 412, 13

dynamically cleared

photoevaporating

P: 2S036 – Manara, C. F.

see also Morishima 2012, MNRAS, 420, 2851

Monday, July 22, 13

Impact of photoevaporation on planets

Monday, July 22, 13

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)

Monday, July 22, 13

Migration of giant planets in photoevaporating disks

Monday, July 22, 13

Semi-major axis distribution of exoplanets reproduced

Alexander & Armitage 2009, ApJ, 704, 989

See also Armitage et al. 2002, MNRAS, 334, 248; Mordasini et al. 2012, A&A, 547, A112

PPVI review talk by S. Ida

observations

models

Monday, July 22, 13

Deserts and pile-ups of giant planets at Rc

Alexander & Pascucci 2012, MNRAS, 422, L82

Monday, July 22, 13

Deserts and pile-ups of giant planets at Rc

Alexander & Pascucci 2012, MNRAS, 422, L82

See also Matsuyama et al. 2003, ApJ, 582, 893; Hasegawa & Pudritz 2012, 760, 117; Rosotti et al. 2013, MNRAS, 430, 1392

P: 2S041 – Rosotti, G.

Monday, July 22, 13

Planet scattering in a photoevaporating disk

Moeckel & Armitage 2012, MNRAS, 419, 366

Monday, July 22, 13

Δt =

few

Myr

Δt ~

105

yr

X-rays

UV photons

MHD disk windprimarily neutralphotoevaporative flow

migration

dust disk

photoevaporativegap formation

direct illuminationof outer disk

H

Ne+

Ne+

H HH

volatile loss in partiallyionized wind

0.1 AU 1 AU 10 AU 100 AU

Schematic picture of disk evolution

credit: P. Armitage

Monday, July 22, 13

Key Points

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

• 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

Monday, July 22, 13