May 24, 2005ly 26, 2004 Astrobiology, McMaster University1 Protoplanetary Disks David J. Wilner Harvard-Smithsonian Center for Astrophysics

May 24, 2005ly 26, 2004 Astrobiology, McMaster University2 Solar System Characteristics planet orbits lie in a plane planet orbits nearly circular Sun’s rotational equator coincides with this plane planets and Sun revolve in same west-east direction Copernicus: De Revolutionibus (1543) Galileo: Sunspot Drawings (1613)

May 24, 2005ly 26, 2004 Astrobiology, McMaster University3 Equivalence of the Sun and Stars Principia Philosophiae (1644): Stars and Sun are the same and formed from rotating vortices. Rene Decartes

May 24, 2005ly 26, 2004 Astrobiology, McMaster University4 Kant/Laplace Nebular Hypothesis Gravitational contraction of a slowly rotating gaseous nebula makes a flat, spinning disk that forms (rings then) planets. Kant Laplace

May 24, 2005ly 26, 2004 Astrobiology, McMaster University5 Basic Questions How do disks form? What affects disk properties? How is angular momentum transported in disks? How do planets form in disks? Does environment influence disk evolution? Observables: size, mass, density, temperature, ionization, composition, gas chemistry, dust mineralogy, structure (flaring, warps, gaps),...

May 24, 2005ly 26, 2004 Astrobiology, McMaster University6 Stars Form in Molecular Cloud Cores Taurus Molecular Cloud (optical) Barnard (1906) Benson & Myers 1989 Dense Cores (radio) (infrared) Padgett et al AU

May 24, 2005ly 26, 2004 Astrobiology, McMaster University7 Schematic Solar System Formation

May 24, 2005ly 26, 2004 Astrobiology, McMaster University8 Size Scales to Consider nearest star forming regions with large samples of young stars: 150 pc (Taurus, Ophiucus, Chameleon, Lupus,...) –R ~ 400 AU disk ~ 3 arcsec –R ~ 40 AU Kuiper Belt ~ 0.3 arcsec –dR ~ 0.4 AU disk gap ~ arcsec subarcsecond angular scales are challenging to resolve –“normal” optical/near-ir telescope, e.g. CFHT  ~ 0.5 arcsec –large submm telescope, e.g. JCMT  ~ 7 arcsec ( /450  m) Dutrey 2004

May 24, 2005ly 26, 2004 Astrobiology, McMaster University9 disks are natural multi- objects due to radial and vertical gradients (n,T,...) optical: scattered light –contrast, illumination infrared: warm dust & gas –near-ir: inner disk –far-ir: only from space submm: cold dust & gas Disk Observations TW Hya Weinberger et al star optical infrared submm dust (1% of disk mass) TW Hya HST/STIS (G. Schneider) 4’’

May 24, 2005ly 26, 2004 Astrobiology, McMaster University10 Infrared “Excess” Emission If the planetary material of the Solar System were crushed to ~  m sized dust and spread out in a disk, then its surface area increases by ~10 13 x and becomes easy to detect as ir “excess”. Barnard (1906) Taurus Disks Hartmann et al Spitzer Space Telescope

May 24, 2005ly 26, 2004 Astrobiology, McMaster University11 Disk Frequency and Lifetime most (all) stars born with circumstellar disks (e.g. 3.4  m excess) ~ 50% gone by 3 Myr ~ 90% gone by 5 Myr circumstellar dust removed? or evolved? Spitzer will improve statistics dramatically (c2d and FEPS Legacy Programs) Barnard (1906) Haisch, Lada, Lada 2001

May 24, 2005ly 26, 2004 Astrobiology, McMaster University12 Disk around a Brown Dwarf OTS44 (M9.5) M * ~15 M jup L * ~0.001 L  Spitzer: mid-ir excess  disk Do miniature Solar Systems form around brown dwarfs? Barnard (1906) Luhman et al. 2005

May 24, 2005ly 26, 2004 Astrobiology, McMaster University13 optical: scattered light –high resolution (coronographic) imaging of surface near and mid-infrared spectroscopy –rovibrational lines probe atmosphere < ~ few AU –solid state features probe dust mineralogy near and mid-infrared interferometry –detect dust emission at ~ AU scales (no imaging) far-infrared: no large apertures (in space) millimeter and submillimeter interferometry –image dust and gas where most of mass resides Resolved Disk Studies

May 24, 2005ly 26, 2004 Astrobiology, McMaster University14 Importance of Millimeter ’s bulk of disk material is “cold” H 2 –T k ~30 K at r ~100 AU for a typical T-Tauri star dust continuum emission has low opacity: –dF  = B (T)   dA, detect every dust particle –millimeter flux ~ mass, weighted by temperature –M disk ~ M  (Beckwith et al. 1990) spectral lines of many trace molecules –heterodyne  >10 6 : kinematics, chemistry many element interferometry enables imaging

May 24, 2005ly 26, 2004 Astrobiology, McMaster University15 Millimeter Interferometry OVRO BIMA NMA IRAM PdBI VLA SMA ATCA

May 24, 2005ly 26, 2004 Astrobiology, McMaster University16 Dust Continuum Surveys IRAM PdBI 2.7 mm & 1.3 mm –  ~ 0.5 arcsec, mass limit ~ M  –  model  ~r -p, T ~r -q  p+q ~1.5, R > 150 AU –resolve disk elongations –find “large” disk sizes –confirm low dust opacities –“shallow” density profiles (Dutrey, Guilloteau et al.)

May 24, 2005ly 26, 2004 Astrobiology, McMaster University17 T~r -0.5  ~r -1 h(r) SED Physical Models of Disk Structure replace power-law parameterizations with self-consistent disk models using radiative and hydrostatic equil. accretion ~10 -8 M  /yr  irradiated, flared D’Alessio et al. 1998, 2001, …

May 24, 2005ly 26, 2004 Astrobiology, McMaster University18 Testing Disk Models: TW Hya Qi et al irradiated accretion disk model matches SED, resolved data SMA 870  m VLA 7 mm residual model data Calvet et al SED

May 24, 2005ly 26, 2004 Astrobiology, McMaster University19 The Orion Proplyds “shadow” disks around low mass stars in Orion Nebula Cluster (distance 450 pc) dramatically imaged by HST, e.g. O’Dell et al. 1993, McCaughrean & Stauffer 1994,... UKIRT clusters are the common star formation environment proplyds ionized by  1 Ori C  evaporating optically opaque; lower limits on mass are they viable sites of Solar System formation?

May 24, 2005ly 26, 2004 Astrobiology, McMaster University20 The Orion Proplyds (cont.) measure disk masses at  long ’s where dust is optically thin interferometry essential: separate proplyds, filter out cloud previous nondetections (BIMA Mundy et al. 1995; OVRO Bally et al. 1998) new SMA 880  m results: four detections > 0.01 M  (standard assumptions) some proplyds have sufficient bound material to form Solar Systems Williams, Andrews, Wilner 2005

May 24, 2005ly 26, 2004 Astrobiology, McMaster University21 CO Line Observations CO is most abundant gas tracer of the “cold” H 2 low J rot. lines collisionally excited, thermalized optically thick: T k (r) ~ r -q  q = 0.5 (flared) detailed kinematics: disk rotation, turbulence 12 CO J=2-1 IRAM PdBI ~ 15 systems, Simon et al Doppler Shift

May 24, 2005ly 26, 2004 Astrobiology, McMaster University22 CO Line Modeling results for 9 young stars from Simon et al. (2000) motions are Keplerian: v(r/D) = (GM * /r) 0.5 sin i constrain M *, test stellar evolutionary tracks

May 24, 2005ly 26, 2004 Astrobiology, McMaster University23 CO Line Modeling (cont.) Keplerian velocity field disk size, inc., orientation  v turb < 0.05 km/s use multiple lines to probe T k (r,z); excitation, abundance TW Hya SMA 12 CO J=2-1, Wilner et al Model Data 500 AU

May 24, 2005ly 26, 2004 Astrobiology, McMaster University24 Protoplanetary Disk Origins Initial conditions from individual, isolated, dense cores –~few x M , <10 K, low turbulence (NH 3 lines, e.g. Myers) –centrally condensed: approach  ~r -2 (dust, e.g. Evans, Lada) –slowly rotating:  ~ < to s -1 (tracer  v, e.g Goodman) centrifugal barrier to collapse should be ~  2 t 3 –expect wide range of disk sizes and masses Caselli et al N 2 H+(1-0) survey

May 24, 2005ly 26, 2004 Astrobiology, McMaster University25 Observing Embedded Disks Surrounding envelope complicates observational study –where does envelope end and disk begin? –additional kinematic components: infall and bipolar outflow Can we detect the youngest, smallest, protostellar disks? JCMT 850  m 10,000 AU 30 AU VLA 7mm Rodriguez et al. 2004

May 24, 2005ly 26, 2004 Astrobiology, McMaster University26 Disks and Jets theory predicts intricate disk/jet connection –e.g. Magnetocentrifugal X-wind (Shu et al. 1994) DG Tau: direct evidence of connection – 13 CO(2-1) line wings show velocity gradient in same sense as observed in [SII]/[OI] optical jet Red Blue Bacciotti et al [SII] Testi et al. 2002

May 24, 2005ly 26, 2004 Astrobiology, McMaster University27 Towards Nebular Chemistry: Submm submm molecular high-J rot. lines and vibrational lines –well matched to disks, n~10 7 cm -3, T~ K –avoid confusion with envelope IRAS16293 with SMA: complex “hot core” organic molecules at < 400 AU Kuan et al. 2005

May 24, 2005ly 26, 2004 Astrobiology, McMaster University28 Towards Nebular Chemistry: IR mid-infrared ’s –absorption: pencil beam for edge-on geometry –  ~10 3 –ices, silicates, PAHs, –molecules: H 2, CH 4, CO 2,... (a lot of) new data from Spitzer IRS

May 24, 2005ly 26, 2004 Astrobiology, McMaster University29 Protoplanetary Disk Chemistry single dish surveys of a handful of Keplerian disks detect most abundant simple species like HCO +, HCN, H 2 CO,... TW Hya JCMT & CSO Thi et al. (2004)

May 24, 2005ly 26, 2004 Astrobiology, McMaster University30 Protoplanetary Disk Chemistry (cont.) results of single dish surveys –low spatial resolution, only sensitive to ~50 AU scales –depletions 5 to >100x, at limits of current sensitivity –ion-molecule reactions: HCO+, N 2 H+ –photochemistry important: high CN/HCN, C 2 H –most emission arises in layer between photodissociated surface and cold, depleted midplane (e.g. van Zadelhoff et al. 2003) interferometric imaging –difficult but possible at 50 AU scales –low T B for  < 1,  v Doppler limited –e.g. TW Hya SMA HCN(3-2) Qi et al., in prep 150 AU

May 24, 2005ly 26, 2004 Astrobiology, McMaster University31 Effects of Stellar Multiplicity millimeter fluxes lower for binary systems disk masses lower tidal truncation: disks within Roche lobes (Jensen et al. 1996) e.g. UZ Tau quadruple –UZ Tau East 0.03 AU asin i binary: circumbinary emission (typical of single star) –UZ Tau West 50 AU binary: weak circumstellar emission –are disks aligned? coplanar? OVRO Mathieu et al. 2000

May 24, 2005ly 26, 2004 Astrobiology, McMaster University32 Disk Structure: Gaps and Holes infrared excess, accretion largely gone ~ few Myr spectral “gaps”: TW Hya, GM Aur, CoKu Tau 4,... clearing from inside-out? planet formation? Quillen et al AU CoKu Tau 4 D’Alessio et al  m “gap”

May 24, 2005ly 26, 2004 Astrobiology, McMaster University33 NASA Disk Evolution Movie

May 24, 2005ly 26, 2004 Astrobiology, McMaster University34 early science: 2008 full operation: 2012? Atacama Large Millimeter Array large! ~64 x 12m (+12 x 7m) telescopes; >10 km  < 0.02 arcsec at 870  m VertexRSI prototype antenna, Socorro, NM

May 24, 2005ly 26, 2004 Astrobiology, McMaster University35 Next Generation Submm Imaging hypothetical planet in TW Hya disk (Wolf & D’Angelo 2005) Model density distribution simulated ALMA image 5 AU

May 24, 2005ly 26, 2004 Astrobiology, McMaster University36 From Dust to Planets: Grain Growth The beginning: dust particles stick together Blum et al.

May 24, 2005ly 26, 2004 Astrobiology, McMaster University37 Millimeter Spectral Signatures observations at probe particle sizes ~O( ) F mm ~  dust -2 ~ -(  +2) ; if  < 1, then observe , diagnostic of size (shape, composition,...) small, a >,  = 0 observe  ~ 1 –large grains? or  >1? –need images to resolve Sargent & Beckwith 1991  < 1  > 1

May 24, 2005ly 26, 2004 Astrobiology, McMaster University38 F mm ~  dust -2 ~ -  VLA 7mm resolves emission w/low T B  < 1,  dust ~ -0.7  large grains more resolved disks with  <1 Natta et al Calvet et al a max = 1cm Millimeter Spectrum: TW Hya

May 24, 2005ly 26, 2004 Astrobiology, McMaster University39 ~cm sizes in midplane TW Hya: VLA 3.5cm Dust Grows and Settles Weidenschilling 1997 theory: expect particles to grow and settle to midplane, develop bimodel size distribubution Wilner et al. 2005

May 24, 2005ly 26, 2004 Astrobiology, McMaster University40 Summary gravity + angular momentum forms disks observations: complementary info  m’s to cm’s disk lifetime (infrared excess) ~ few Myr derived properties for ~1 Myr old disks –typical M disk ~0.01 M , (wide range)  protoplanetary –R disk to ~100’s of AU –velocity field is Keplerian (M disk << M * ) –structure consistent with irradiated accretion models –glimpses of nebular chemistry, dust evolution companions influence structure: truncation, gaps amazing prospects for the near future

May 24, 2005ly 26, 2004 Astrobiology, McMaster University41 Kepler and the Nature of Stars “You think that the stars are simple things, and pure. I think otherwise, that they are like our earth... in my opinion there is also water on the stars... and living creatures as well, who exist only because of these earthlike conditions. Both that unfortunate man Giordano Bruno, the same fellow who was burned at the stake in Rome over hot coals, and Brahe, of good memory, believed that there are living creatures on the stars.” Letter from Kepler to Johann Brengger, November 30, 1607 Johannes Kepler