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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