(Sub)mm & Infrared Spectroscopy of Circumstellar Disks Geoffrey A. Blake Div. Geological & Planetary Sciences 59 th OSU Symposium 25June2004 HD A (HST ACS)

People Really Doing the Work! Caltech: -Jacqueline Kessler (now at UT Austin), Joanna Brown -Adwin Boogert, Chunhua Qi (now at the SMA/CfA) Leiden w/Ewine van Dishoeck & Michiel Hogerheijde: -Klaus Pontoppidan, Gerd Jan van Zadelhoff, Wing-Fai Thi (now at ESO) 25June2004 I.Why study disks? II.Mm-wave interferometry of protoplanetary disks. III.High resolution IR spectroscopy of disks. IV.Conclusions

Cloud collapseRotating disk infall outflow Planet formationMature solar system x1000 in scale Adapted from McCaughrean How are isolated Sun-like stars formed? Picture largely derived from indirect tracers, especially SEDs.

Spitzer Space Telescope - IRAC (mid-IR cameras, , 5.8, 8.0  m) - MIPS (far-IR cameras, 24,  m, R=20 SED mode) - IRS (5-40  m long slit,R=150,  m echelle, R=600) August 2003 launch, >5 year lifetime. - GTO observations - Legacy program - General observations 25June2004 Evans et al., c2d ~170 YSOs first look + follow up of mapping. Meyer et al. Photometry~350 sources, IRS follow up (Class III).

Boogert et al. 2004, ApJS special issue 25June2004 HH 46 w/IRAC, IRS Ices toward young low mass stars Keck/VLT +Spitzer

Study Isolated Disks (Weak/No Outflow) 25June2004 Beckwith & Sargent 1996, Nature 383, Planet building phase

Why study disks? Star-disk-planet interactions: Radial velocity surveys are sensitive to ~Jupiter/Saturn mass planets out to >5 AU. From whence hot-Jupiters?

Disk-star- and protoplanet interactions lead to migration while the disk is present. The answer lies at earlier times… Theory Observation? 1 AU at 140 pc subtends 0.’’007. Jupiter (5 AU): V_doppler = 13 m/s V_orbit = 13 km/s Simulation G. Bryden

Spectroscopy of “Disk Atmospheres” 25June2004 IR disk surface within several – several tens of AU (sub)mm disk surface at large radii, disk interior G.J. van Zadelhoff 2002 Chiang & Goldreich 1997

The 1-Baseline Heterodyne Interferometer: HST resolution at 1mm D=10 km! Use array. Can’t directly process 100 – 1000 GHz signals. Heterodyne receivers detect |V| and , noise defined by the quantum limit of h /k. Positional information is carried by the PHASE. Spectral coverage depends on the receivers, while the kinematic resolution is determined by correlator. 25June2004 Geometrical delay

The n-Element Heterodyne Interferometer: n(n-1)/2 baselines, imaging performance depends on the array geometry, but For small to moderate n, the (u,v) plane is sparsely filled. For a given array, the minimum detectable temperature varies as (resolution =  S ) -2 : 25June2004  P = primary telescope beam

CO 3-2CO 2-1 CO traces disk geometry, velocity field: Qi et al. 2004, ApJL, in press. TW Hydra w/SMA

Disk properties vary widely with radius, height; and depend on accretion rate, etc. (Aikawa et al. 2002, w/ D’Alessio et al. disk models). Currently sensitive only to R>80 AU in gas tracers, R<80 AU dust. CO clearly optically thick, isotopes reveal extensive depletion, poor mass tracer! The fractional ionization is >10 -8, easily sufficient for MRI transport. HD & H 2 D + (Ceccarelli et al. 2004) in midplane? Disk Ionization Structure: CO and Ions

CO well mixed, while [CN]/[HCN] traces enhanced UV fields. Is LkCa 15 unusual? Photodesorption? Qi et al & in prep Chemical Imaging of Outer Disk? HDO formed via H 2 D +, possible tracer of H 3 + ? Kessler et al. 2004, in prep (6 transits)

R o =50AUR o =300AU R o =200AU R o =100AU For models: Using scaled H density distribution with varying inner radius cutoff R0R0 R out NTNT LkCa 15 HCN observations Molecular Distribution Models

CO 2-1 from HD J.-C. Augereau & A. Dutrey astro-ph/ Transitional/Debris Disks? HD & Vega w/PdBI: Vega, Wilner et al. 2002

Future of the U.S. University Arrays – CARMA CARMA = OVRO (6 10.4m) + BIMA (9 6.1m) + SZ Array (8 3.5m) telescopes. SUP approved! 2004 SZA at OVRO 2004 move 6.1m 2004 move 10.4m 2005 full operations Cedar Flat 7300 ft. June 15 th, 2004 March 27 th, 2004

(pre-ALMA) The size scales are too small even for the largest current & near-term arrays. Spectroscopy to the rescue! How can we probe the planet-forming region? Theory Observation? Jupiter (5 AU): V_doppler = 13 m/s V_orbit = 13 km/s

High Resolution IR Spectroscopy & Disks CO M-band fundamental Keck NIRSPEC R=25000 R=10, ,000 (30-3 km/s) echelles (ISAAC,NIRSPEC, PHOENIX,TEXES) on 8-10 m telescopes can now probe “typical” T Tauri/Herbig Ae stars: AB Aur HD

L1489: Gas/Ice~10/1, accretion. CRBR2422.8: Gas/Ice~1/1, velocity field? Elias 18 Gas/Ice<1/10 (Shuping et al.) Edge-on absorption. Orientation is Pivotal in the IR! H 2, H 3 + in absorption? 25June2004

Spitzer Enables the Study of Edge-on Disks! 25June2004 VLT ISAACS Flux (Jy) The small molecules in ices are similar in protostars and disks.

What about other species w/echelles? 25June2004 NGC 7538 IRS9 Boogert et al. 2004, ApJ, in press

Edge-on Disks & Comets? IR studies of edge on disks will map out both gas phase & grain mantle composition, compare to that found in massive YSOs, comets. N7538 W33A Hale-Bopp Water CO CO CH H 2 CO CH 3 OH HCOOH NH OCS June2004

CO lines give distances slightly larger than K-band interferometry, broad H I traces gas much closer to star (see also Brittain & Rettig 2002, ApJ, 588, 535; Najita et al. 2003, ApJ, 589, 931). Can do ~30-40 objects/night. In older systems, CO disk emission is common: Herbig Ae stars, from ~face-on (AB Aur) to highly inclined (HD ). CO lines correlated with inclination and much narrower than those of H I Disk! Pf 

Systematic Line Width Trends: Objects thought to be ~face on have the narrowest line widths, highly inclined systems the largest. As the excitation energy increases, so does the line width (small effect). Consistent with disk emission, radii range from AU at high J. Low J lines also resonantly scatter 5  m photons to much larger distances. Asymmetries (VV Ser)? 25June2004 Blake & Boogert 2004, ApJL 606, L73.

CO and 13 CO rotation diagrams show curvature as a result of  >1. Still, small amounts of gas since N(H 2 )~5 x leads to dust opacities near unity. Collisional excitation important, but cannot explain line widths at low J values (too broad). Resonant IR scattering at larger radii! The vibrational excitation is highly variable, likely due to variations in the UV field. Disk shadowing? How is the CO excited in these disks? 25June2004 CO 13 CO

Explanation: Dust sublimation near the star exposes the inner disk to direct stellar radiation, heating the dust and “puffing up” the disk. Flared disk models often possess 2-5 micron deficiency in model SEDs, where a “bump” is often observed for Herbig Ae stars. Where does the CO emission come from? Dullemond et al June2004

Calvet et al For dust sublimation alone, the lines from T Tauri disks should be broader than those from Herbig Ae stars+disks. Often observed, but… CO Emission from Disks around T Tauri Stars The TW Hya lines are extremely narrow, even for a disk with i~7 degrees, imply R>2 AU. Gap tracer?

(Sub)mm-wave instruments can only study the outer reaches of large disks at present in lines; even at these wavelengths the disk mid-plane is largely inaccessible due to molecular depletion. Expanded arrays (CARMA, eSMA, ALMA) will provide access to much smaller scales, lines should selectively highlight regions of planet accretion/formation. Midplane w/H 2 D + ? High resolution IR spectroscopy just starting, is immensely powerful, and provides unique access to the AU disk surface before advent of ALMA, large IR interferometers. Spectra are esp. sensitive to disk geometry. Spitzer is providing beautiful spectrophotometric SEDs and many new targets! Disk Spectroscopy - Conclusions 25June2004 AB Aur HD

Arrays everywhere! 25June2004 PdBI VLA SMA BIMA OVRO ATCA Typically n tel ≤ 6-10.

Embedded disks? Padgett et al 1999  3mm: HCO +, HCN, 13 CO, C 18 0 (1-0)  2000 AU radius, 0.02 M  disk  1mm: HCO + (3-2)  infall (disk not quite fully rotationally supported) 0.65 M   M   1.4 M  disk collapse to 300 AU in 2 x 10 4 yrs? L1489, a disk in transition? HCO + 3-2HCO See also: Hogerheijde et al 1997, 1998; Looney 2000; Chandler & Richer 2000, Shirley et al 2000 Hogerheijde 2001

OVRO CO(2-1) Survey of T Tauri stars stellar ages Myrs stellar masses ~ 1 M  selection by 1 mm flux, SED characteristics Taurus 19/19 detections Ophiuchus 4/6 detections resolution ~ 2” 20 objects radii  150 AU masses  0.02 M  (from SEDs) (Koerner & Sargent 2003) See also Dutrey, Guilloteau, & Simon, Ohashi

Chemical / Radiative Transfer Modeling Physical model : D'Alessio et al Chemical model : Willacy& Langer 2001 Radiative transfer : Hogerheijde & vander Tak 2000 Molecular line survey UV fields grain reactions disk ages and evolution Understanding Disk Chemistry

MM-Wave CO Traces Dynamics, Others? 25June2004 Dutrey et al. 1997, IRAM 30m D. Koerner & A. Sargent OVRO, in Qi et al. (2004). Measure: R_disk M_star Inclination w/resolved images. LkCa 15

The Sample (drawn from larger single dish + OVRO CO survey): Star Sp Type d(pc) Teff(K) R(Rsun) L(Lsun) M(Msun) Age(Myr) LkCa 15K5:V GM Aur K5V:e HD A MWC 480 A Mannings, Koerner & Sargent 1997 MWC 480 LkCa 15 Koerner & Sargent 1995 OVRO+CSO/JCMT MM-Wave Disk Survey 25June2004

Combine 3/1.3 mm array images w/higher J spectra to constrain OUTER disk properties, chemical networks. van Zadelhoff et al OVRO+CSO/JCMT MM-Wave Disk Survey II 25June2004

Source L * (L ) CN/HCN H dust /h gas LkCa ~ GM Aur 0.80 << MWC ~ HD >> 50 - [CN]/[HCN] traces enhanced UV fields ( Fuente et al. 1993, Chiang et al ) Molecular distribution ring-like? Photochemistry or desorption? Qi et al., in prep UV Fields: HCN and CN LkCa 15 25June2004 

Infinite resolution, complete UV coverage Observed UV sampling, uniform weighting CO 2-1 fit LkCa15 ___ model Model Parameters i = 58°, V turb = 0.1 km/s R o = 5 AU, R out = 430 AU n CO = n H (D'Alessio 2001)  syn = 3.6” x 3.6” Modeling the effects of (uv) Sampling

MM-continuum surveys do not reveal such large, massive disks in similarly aged clusters (IC348) and clouds (NGC 2024, MBM12). Environment? Need better (sub)mm-wave imaging capabilities. SMA! and… CO, HCO + (and NNH + ) chemistry well predicted by disk models. Other species, esp. CS, CN, HCN, much more intense, with unusual emission patterns in some cases (LkCa 15). Are these large disks unusual? 29Aprn03

CARMA – Site Monitoring

HDO: rms (3sigma) = K (CARMA w/D config. in 4 hrs) ALMACARMA M d =0.01M sun R out =120AU R o =20AU Disk Observations w/CARMA+ALMA Dust simulation (L.G. Mundy), unrealistic phase errors, but no CLEAN/MEM.

Atm. fluctuations (mostly H 2 O) can vary geom. delay. |V|e i f decorrelation if Ef>  each baseline). If the fluctuations vary systematically across the array, phase errors ensue. Problem is NOT solved. OVRO WLM System Atmospheric Phase Correction (mm Adaptive Optics)

Enter ALMA: Llano de Chajnantor; 5000 m, good for astronomy, tough for humans! Superb site & large array exceptional performance (64 12m telescopes, by 2012). Dust simulation (L.G. Mundy), unrealistic phase errors, but no CLEAN/MEM.

Ices in the disk of L1489 IRS Prominent band of solid CO detected toward L1489, originating in large, flaring disk. CO band consists of 3 components, explained by laboratory simulations as originating from CO in 3 distinct mixtures: 1'polar' H 2 O:CO 2'apolar' CO 2 :CO [NEW!] 3'apolar' pure CO (Boogert, Hogerheijde & Blake, ApJ 568,761, 2002)

Nearly all spectra observed to date have emission from very high J levels (J>30-35), but… Variations in CO M-band Spectra: 25June2004 The degree of vibrational excitation is highly variable!

This model can now be directly tested via YSO size determinations with K-band interferometry. Intense dust emission pumps CO, rim “shadowing” can produce moderate T_rot. Fits to AB Aur SED yield an inner radius of ~0.5 AU (and 0.06 AU for T Tau). SED Fits versus IR Interferometry (Monnier & Millan-Gabet 2002, ApJ) Dullemond et al. 2002

Many other species and disk types (transitional, debris, etc.) should be examined in both absorption (edge-on disks) and emission, but extremely high dynamic range will be needed. Protoplanet tracers? H 2, H 3 +, CH 4, H 2 O, OCS... Line profile asymmetries? Future “Near”-IR (1-5  m) Spectroscopy Brittain & Rettig 2002, Nature