1. A New “Radio Era” for Planet Forming Disks K. Teramura UH IfA David J. Wilner Harvard-Smithsonian Center for Astrophysics thanks to S. Andrews, C. Qi, and many collaborators, www.cfa.harvard.edu/disks SMA ALMA HIA, Victoria, March 2013 EVLA

2. Stars Form with Protoplanetary Disks 2 Marois et al. 2010, Keck Observatory McCaughren & O’Dell 1995 Silhouette Disks in Orion Nebula around ~1 Myr-old stars planets orbiting HR 8799 How do disks evolve and form planetary systems?

3. Relevance of Radio Astronomy low dust opacity mass, particle properties many spectral lines gas diagnostics, kinematics access cold material including disk mid-plane contrast with star planet-forming region low T,   low brightness imaging needs sensitivity ALMA EVLA 3

4. 1  m 1mm 1m 1km 1000km <1km Planetesimal formationPlanet formation collisional agglomoration gravity- assisted growth gas capture radial drift fragmentation/ bouncing Debris From Dust to Planets requires growth by 14 orders of magnitudes in size in a few Myr through several physical processes… 4 collisional destruction collective effects???

5. Spectral Signatures of Grain Growth thermal dust emission I  ∝ B  (T) (1 - e -   ) ≈  2 T     I  ∝  2+  index  is observable an diagnostic of the particle size distribution  5 a max = 1  m 1 mm 5 cm 1 m Beckwith & Sargent 1991 Miyake & Nakagawa 1993 Draine 2006 see Draine 2006 ISM grains “pebbles” 2  0 Rodmann et al 2006 Ricci et al. 2010, 2011

6. Disks@EVLA Key Project PI Claire Chandler (NRAO) + 17 co-Is worldwide grain growth and substructure in protoplanetary disks probe last observable link in chain from ISM dust to planets -photometry of 60+ disks at 7/9/13/50 mm -imaging of subsets, some to 50 mas = few AU 6 Birnstiel et al. 2010 95% confidence Isella et al. 2010 RY Tau: CARMA global  : weak model constraints -average level of grain growth only resolved colors,  (r), affected by -turbulence -particle collision model -materials -radial drift efficiency

7. EVLA Taurus Disk Images spectral indices = 9 mm (30.5 and 37.5 GHz) θ ~ 0.7 arcsec = 100 AU Chandler et al, in prep 7

8. UZ Tau Resolved Millimeter Colors radiative transfer:  (r) 8  (r) = d log  (r) / d log a max ~ 10 cm (inner disk) a max ~ 10  m (outer disk) radial drift limited growth? disk resolved at 0.9 -9 mm 100 AU Harris et al. 2013, also Perez et al. 2012

9. Isolating the Effects of Radial Drift thermal pressure: v gas < v Kep – small sizes: entrained by gas – mid sizes: strong headwind – large sizes: drag is weak 9 Weidenschilling 1977 natural size-sorting of solids strong variation of gas:dust as a function of disk radius

10. The TW Hya System HST Weinberger et al. 2002 closest gas-rich disk system (51 pc) – M = 0.6 M , age 3-10 Myr, – southern, isolated, viewed nearly face-on – many studies with SMA – good model of disk physical structure 10 Andrews et al. 2012 Qi et al. 2008

11. Indirect Signature of Radial Drift 1.RT model dust densities 2.assume constant gas:dust 3.non-LTE model gas (CO) 4.compare with data 11 link with work on β (r): constraints on drift rates Rosenfeld et al. 2013 Andrews et al. 2012  gas/dust size discrepancy

12. Signatures of Grain Growth and Drift empirical dependence between dust disk extent and wavelength – emission becomes more compact at longer wavelengths power law index of opacity, , decreases with disk radius – maximum particle size increases with disk radius CO gas disk extent much larger than millimeter dust disk – dust and gas surface density profiles are decoupled 12 observations naturally explained if growth and inward drift of solids concentrates large particles relative to molecular gas reservoir planet-disk interactions also make pressure bumps/particle traps

13. Snow Lines and Planet Formation “snow line” = boundary where volatiles condense out of gas phase enhance planetesimal formation – dramatically increase available solids – increase grain stickiness (icy mantles) – influence bulk composition, e.g. C/O key evaporation temperatures – H 2 O: 170 K (R = a few AU) – CO: 20 K (R = a few 10’s of AU) 13 Hayashi 1981 Ciesla & Cuzzi 2006 Oberg et al. 2011

14. disks are 3D objects: “snow line” = “snow surface” – very difficult to discern in (optically thick) CO emission use chemical selectivity to advantage N 2 H + abundant only where CO highly depleted – CO inhibits N 2 H + formation – CO speeds up N 2 H + destruction – CO freezes out at 20 K – observed in pre-stellar cores CO Snow Line and N 2 H + Chemistry 14 Qi et al. 2012 H3+H3+ HCO + N2H+N2H+ CO N2N2

15. TW Hya SMA Obs  ALMA Prediction 15 SMA N 2 H + data model simulation

16. TW Hya ALMA Cycle 0 N 2 H + Imaging N 2 H + shows a ring 16 2012 November 18  = 0.8 mm (band 7) 26 antennas, 2 hours beam 0.6 x 0.6 arcsec rms = 25 mJy (0.1 km/s) >20x better sensitivity, >20x smaller beam area than SMA N 2 H + obs -rim radius (27 AU) matches prediction for CO snow line -N 2 H + abundant where T drops below 20 K 2011.0.00340.S PI Qi

17. Planetesimal Belts in Debris Disks sister stars in the 12 Myr-old  Pic Moving Group surrounded by dusty disks, cleared of gas, viewed edge-on 17  Pic A6 19.4 pc R disk > 800 AU AU Mic M1 9.9 pc R disk > 200 AU Kalas 2004

18. Scattered Light Midplane Profiles both disks show broken power-law profiles with similar slopes Liu 2004 Golimowski et al. 2006 R -4 R -1  Pic break at R ~120 AU R -1 R -4 AU Mic break at R ~35 AU 18

19. The “Birth Ring” Paradigm a collisional ring of dust-producing planetesimals – small grains blown out by stellar radiation (  Pic) and winds (AU Mic) – large grains stay close to birth ring – size-dependent dust dynamics explains scattered light profile  = F * /F grav Krivov 2010 (see Wyatt 2006) Strubbe & Chiang 2006 (also see Augereau & Beust 2006) scattered light 19

20. SMA: 1.3 Millimeter Emission Belts Wilner et al. 2011  Pic contours: ±2,4,6,8 x 0.6 mJy 20 Wilner et al. 2012 AU Mic contours: ±2,4,6 x 0.4 mJy

21. Emission Models and Belt Locations  Pic R = 94±8 AU  R = 34 +44 AU F = 15±2 mJy -32 AU Mic R = 36 +7 AU  R = 10 +13 AU F = 8.2±1.2 mJy -16 -8 21

22. MacGregor et al. 2013 AU Mic ALMA Cycle 0 Observations >10x better sensitivity, >10x smaller beam area than SMA study 2011.0.00142.S PI Wilner 2011.0.00274.S PI Ertel 4 SB executions in 2012 April and June  = 1.3 mm (band 6) 16 to 20 antennas beam 0.8 x 0.7 arcsec (8 x 7 AU) rms = 30 μ Jy 22

23. Millimeter Emission Model Fitting contours: ±4,8,12,.. x 30 μ Jy outer belt + central peak 23

24. AU Mic Outer Dust Belt Properties extends to R=40 AU, to the break in scattered light profile – consistent with model based on size-dependent dust dynamics appears sharply truncated – reminiscent of the classical Kuiper Belt – initial condition? or result of dynamical interaction? surface density profile rises with radius,  (r) ~ r 2.8 – collisional depletion of inner disk by ongoing planet formation? no detectable asymmetries in structure or position – no significant clumps, e.g. due to resonances with orbiting planet – centroid offset limit compatible with presence of Uranus-like planet 24 Kennedy and Wyatt 2010 Mustill and Wyatt 2009

25. AU Mic Central Peak Emission stellar photosphere and additional unresolved emission – measure 320  Jy in central component – a NextGen stellar model (3720 K, 0.11 L  0.6 M  )  52  Jy stellar flares? – no detectable variability, hours to months stellar corona? – low radio flux density limits in quiescence from VLA (in early 1990s) – requires turnover frequency > 40 GHz, or time evolution – would be detectable by EVLA at centimeter wavelengths asteroid-like belt at a few AU? – compatible with absence of excess emission < 25 μ m – would be easy for ALMA to resolve in future Cycles 25

26. A new “Radio Era” for Disk Studies planets form in circumstellar disks major unknown is distribution/evolution of cold dust and gas at Solar System scales: key observables for ALMA and EVLA entering a new regime of decoupled gas and dust, size-dependent dust dynamics three examples -resolving grain growth and drift -imaging snow lines -revealing planetesimal belts 26 expect surprises!

27. 27 END

28. Next Generation Radio Telescopes 66 moveable 12m/7m antennas 5000 m site in northern Chile  = 300  m to 7 mm global collaboration (NA, EU, EA) to fund >$1B construction 27 moveable 25 m antennas 2000 m site in New Mexico  = 7 mm to 4 m modern electronics and signal processing, c. 1980 infrastructure Atacama Large Millimeter Array Expanded Very Large Array 10-100x better sensitivity, spectral capabilities, resolution 28

29. Planet-Disk Interactions viscous/tidal interactions make waves consequences – open a gap – create pressure bumps – planet migration 29 Goldreich & Tremaine 1980; e.g., Bryden et al 1999 Andrews et al 2011a Mathews et al 2012 Brown et al 2008 Hughes et al 2009 Andrews et al 2011a Andrews et al 2011b Andrews et al 2009

30. Transition Disk Issues mass flow across gap – gas: regulated by M p + viscosity – dust: size-dependent filtration particle trapping (and growth) – location of ring vs. planet orbit – azimuthal asymmetries 30 Lubow and D’Angelo 2006, Zhu et al. 2012, Dong et al. 2012 Pinilla et al. 2012, Birnstiel et al. 2013 ALMA Cycle 0 HD142527 Casassus et al. 2013

31. A New “Radio Era” for Planet Forming Disks K. Teramura UH IfA David J. Wilner Harvard-Smithsonian Center for Astrophysics thanks to S. Andrews, C. Qi, and many collaborators, www.cfa.harvard.edu/disks SMA ALMA HIA, Victoria, March 2013

32. Planetary Systems Form from Disks 32 Marois et al. 2010, Keck Observatory McCaughren & O’Dell 1995 Silhouette Disks in Orion Nebula around ~1 Myr-old stars planets orbiting HR 8799