Millimeter-Wavelength Observations of Circumstellar Disks

1. Millimeter-Wavelength Observations of Circumstellar Disks and what they can tell us about planets David Wilner, Sean Andrews, Charlie Qi, Catherine Espaillat, Jonathan Williams, Nuria Calvet, Paola D’Alessio, Antonio Hales, Simon Casassus, Michael Meyer, John Carpenter, Michiel Hogerheijde A. Meredith Hughes Miller Fellow, UC Berkeley

2. Star and Planet Formation Overview protostar + disk + envelope + outflow MS star + debris disk + planets? PMS star + disk cloud grav. collapse Adapted from Shu et al. 1987

3. Circumstellar Disk Evolution Protoplanetary Pre-MS stars Gas-rich Primordial dust Debris_____ Main sequence No (or very little) gas Dust must be replenished planets? AU Mic, Liu et al. 2004 HH 30, Burrows et al. 1996 Some Questions: What physical processes shape each stage? What physical processes drive dispersal? When and how do planets form? What are the properties of the planets?

4. F star disk  HD 163296, Grady et al. (2000) Circumstellar Disk Structure Why Millimeter Interferometry? • Low star/disk contrast • Optically thin dust emission • Molecular line emission • High spatial resolution Adapted from Dullemond et al. (2007)

5. 1. Disk Dissipation 2. Resolving Debris Disk Structure The Bird’s-Eye View • Constraining physical mechanism(s) driving dissipation • Imaging Inner Holes • Molecular Gas Content • How debris disks can tell us about planets • Finding Uranus/Neptune analogues • Edge-on debris • Masses of directly-imaged planets

6. 0. Protoplanetary Disks as Accretion Disks What I’m NOT going to talk about (But you should ask me about it if you’re interested!) • Observable signatures of viscous transport processes: • Magnetic fields (polarization) • Turbulence (HiRes spectroscopy) • Large-scale structure

7. 1. Disk Dissipation

8. mid-IR deficit Equilibrium temperature: Wien Law: + Identifying Transition Disks: SED Modeling Transitional SED “Normal” star + disk SED star star log F log F dust dust log  log 

9. Why the “?” Boss & Yorke 1996 10x less CO than expected Also true for other transition disks in literature (GM Aur, TW Hya) Modeling Transition Disks in CrA “…we remain skeptical of the existence of such a large central gap devoid of dust” -- Chiang & Goldreich (1999) Inner holes everywhere? ~10% of low- and intermediate-mass stars have transitional SEDs (e.g. Muzerolle, Cieza, Uzpen et al.) Hughes et al. (2010)

10. TW Hya GM Aur Stellar photosphere Calvet et al. (2005) Inner disk Zooming in on the mid-IR… Wall Outer disk Predicted inner hole size: 4 AU Predicted inner hole size: 24 AU Calvet et al. (2002) Weinberger et al. (2002) Schneider et al. (2003) Testing the paradigm:SED deficit = inner hole Calvet et al. (2002) • Spectral type K7 (Rucinski & Krautter 1983) • Age ~10 Myr (Webb et al. 1999) • Distance 51 pc (Mamajek 2005) • Spectral type K5 • Age ~1-5 Myr (Gullbring+ 1998) • Distance 140 pc (Bertout & Genova 2006)

11. TW Hya GM Aur Calvet et al. (2005) Observations Calvet et al. (2002) Hughes et al. (2007) Hughes et al. (2009b)

12. Observations Courtesy J. Williams (PIs Andrews, Brown, Cieza, Hughes, Isella, Mathews, Pietu)

13. Accretion: Taurus median Small amt of hot dust Calvet et al. 2005 Gullbring et al. 1998 Hot CO at 0.5 AU No cold CO Dutrey et al. 2008 Salyk et al. 2007 Origin of the inner hole? Cavity is not empty! Similar for TW Hya

14. Dullemond & Dominik (2005) 1) Grain Growth () e.g. Strom et al. (1989), Dullemond & Dominik (2005) 2) Photoevaporation Alexander, Clarke & Pringle (2006) e.g. Clarke et al. 2001, Alexander & Armitage (2007) Chiang & Murray-Clay (2007) 3) Inside-out MRI Clearing Chiang & Murray-Clay (2007) 4) Binarity e.g. Ireland & Kraus (2008) 5) Planet-Disk Interaction Ireland & Kraus (2008) e.g. Lin & Papaloizou (1986), Bryden et al (1999), Varniere et al. (2006), Lubow & D’Angelo (2006) Bryden et al (1999) Origin of the inner hole? Theory: Consistent Inconsistent -  in disk center - Lack of cold CO - Sharp transition b/w inner/outer disk -  in disk center - Massive outer disk - High accretion rate -  in disk center - m-size grains in • Massive outer disk inner disk • Lack of cold CO - Origin of gap? • High accretion rate •  in disk center - Dynamical mass + photometry • - Keck AO imaging • (<40 Mjup) • - Hot CO, accretion rate • - Accretion rate - Mass/distance? • Small grains in inner disk • Sharp inner/outer disk transition

15. grain growth planets binaries photoevaporation Alexander et al. (2007) The Plane courtesy S. Andrews Najita et al. (2007)

16. “Pre-Transitional” SED Andrews et al. (2010) log F dust star Wolf & D’Angelo (2005) log  What’s next? What will ALMA do? 1. Solve all of science • 2. Sensitivity: • Finding transition disks • Statistics - planet populations • Molecular gas evolution • 3. Resolution: • Measuring accurate cavity sizes • Gaps • 4. Sensitivity + Resolution: • Planetary accretion luminosity • Gas in the cavity

17. 2. Resolving Debris Disk Structure

18. Debris Disks  Pic Fitzgerald et al. (2007) Fomalhaut Kalas et al. (2005) Weinberger et al. (1999) HR 4796A Schneider et al. (1999)

19. If debris disks were primordial, they wouldn’t be there dust ≤10 Myr Debris disks look different at different wavelengths 350 m; Marsh et al. (2006) 850 m; Holland et al. (2006) 70 m; Su et al. (2005) At least 15% of nearby main-sequence stars have debris disks (Habing et al. 2001, Rieke et al. 2005, Trilling et al. 2008, Hillenbrand et al. 2008) Debris Disks

20. How Debris Disks Tell Us about Planets 1. Access to otherwise unobservable Uranus/Neptune analogues Wilner et al. (2002) Courtesy M. Wyatt

21. How Debris Disks Tell Us about Planets 1. Access to otherwise unobservable Uranus/Neptune analogues HD 107146 Corder et al. (2009) CARMA 230 GHz Hughes et al. (in prep)

22. From Thebault et al. (2009) How Debris Disks Tell Us about Planets 2. Vertical structure of edge-on debris disks Wilner et al. (in prep)

23. How Debris Disks Tell Us about Planets 3. Constraints on the masses of directly-imaged planets Chiang et al. (2009) Kalas et al. (2008)

24. Hughes et al. (in prep) How Debris Disks Tell Us about Planets 3. Constraints on the masses of directly-imaged planets

25. What’s next? What will ALMA do? Sensitivity! • (Some) debris disks will be roughly as easy to image as protoplanetary disks are now • Statistics - planet populations • Excellent linear resolution • (Molecular gas?)

26. 1. Disk Dissipation 2. Resolving Debris Disk Structure Calvet et al. (2005) Bryden et al (1999) Summary Access to otherwise unobservable Uranus analogues IR Deficit  mm flux cavity Most transition disks probably cleared by planets Edge-on systems Constraining planet masses Molecular gas?