IRS_Disks and C2D

Identifying the commonalities and differences in the combined

dataset

C2D/CRIRES Team Meeting – 29 Oct – 2 Nov, 2009, Garching

Joel Green (University of Texas at Austin)

On behalf of Neal Evans (University of Texas at Austin), Dan Watson, and Manoj Puravankara (University of

Rochester)

Talk Outline1. IRS_Disks vital statistics2. Disks3. Embedded Sources4. Followup

3

IRS_Disks (and IRS_Amazing8) summary

Cla

ss 0

pro

tost

ars:

35

, 9.

4 hr

FU Oris 6, 1.4 hr

IC 34820, 6 hr

Cha I-II 104, 20.2 hr

106 y 107 y 108 y 109 y

Debris disks 116, 31.3 hr

Oph157, 29.6 hr)

TW Hya 14, 4.8 hr

Taurus: 152, 42.8 hr

Pleiades 9, 2.1 hr

105 y

Total: 690, 169 hours.

Tr 37/N 7160 20, 15.1 hr

Young BDs 19, 15.1 hr

Lower Cen-Crux 8, 2.1 hr

With IRS_DimSuns

Still to be observed

IRS_Disks (and IRS_Amazing8) summary Part 2

Total: ~ 3200

While first half sample was selected from ground-based catalogs, the second half focused heavily on Orion, using targets from GTO IRAC surveys (Megeath et al.), mostly high res staring clusters, but large survey of SL-LL sources as wellAdding 250 YSOs in Orion A alreadyProduce spectra for ~ every YSO within 500 pcIncludes essentially all Orion Class 0 protostars with possible water detectionsCollaboration with outflows project mapping extended outflows from protostars

Non-Correlated Projects

IRS Disks: source typesDebris disk surveysBrown dwarf surveysClass 0 (low mass) surveys (followup in HOPS)Herbig stars? PAH analysis only (DIGIT will cover this, though)

C2D: observation modesIRAC/MIPS photometryGround-based observations (e.g. CRIRES), high res. spectra, and imaging

IRS survey of nearby star forming IRS survey of nearby star forming cloudsclouds12CO (FCRAO)

IRAS

IRAC + MIPS (Allen L. & D. Padgett)

IRS spectra of over 600 young stars in Taurus, Cha I, Oph & Orion A (L1641 & ONC) (IRS_disk team; PI Dan Watson)

Tau-Aur Cha I Oph Orion A

L1688 Off-core L1641 ONC

Distance (pc) 140 165 130 440

<age> (Myr) ~ 1 ~ 2 ~ 0.3 2 - 5 ~ 1 ~ 0.8

# of stars observed ~ 100 ~ 100 ~ 150 ~ 250

Kenyon et al. (1994), Kenyon & Hartmann (1995)Luhman (2008) , Wilking (2008) Muench et al. (2008) , Hirota et al. 2008)

IRS spectra of protoplanetary disks

strength and shape of the continuum vertical & radial disk structure sedimentation

dust emission features mostly silicate dust Si – O stretching modes in silicate grains dust composition crystallinity grain size & shape grain growth

IRS spectra probe the warm (400 – 100 K) dust in protoplanetary disks

Dust emission from protoplanetary disks

(Dullemond et al. 2007)

IRS spectra (5 - 40 m): 0.1 – 10 AUIRS spectra (5 - 40 m): 0.1 – 10 AU

Optically thin disk “photosphere”

Optically thickDisk mid-plane

(Dullemond et al. 2007)

IRS spectra

Disks Papers• Dust properties: Watson, Manoj, Furlan et al.

(2008-2009)• Some split by region (Tau, Oph, Cha) plus

Furlan overview paper• Specifically transitional disk properties: Manoj,

Kim, McClure et al.• Dust modeling with lab spectra: Sargent et al.

(2006, 2009a,b) (olivine/pyroxene and silica)• Extinction law: McClure et al.

Mid-IR spectra & disk evolution grain growth & dust settling

larger grains settle towards the mid-plane thereby depleting the dust in the surface layers

disk models incorporating evolutionary effects (D`Alessio et al. 2006)

dust depletion parameter:= dust-to-gas-ratio (upper layers) dust-to-gas-ratio (ISM)

( = 1, 0.1, 0.01, 0.001)

dust depletion affects disk structure higher depletion more settling flatter disks (less flared)

dust depletion & observed SEDeffects of dust settling conspicuous inthe mid-IRcontinuum slope probes disk structure & evolution

(D`Alessio et al. 2006; Furlan et al. 2006, Watson etal. 2009)

deple

tion

= 1

= 0.001

(D`Alessio et al. 2006)

(D`Alessio et al. 2006)

Continuum indices from IRS spectra

comparison with model predictions

continuum indices of the form F evaluated from the IRS spectra

Grain growth & crystallization in disks

The flux ratio F11.3/F9.8 is a good proxy for grain processing in the disk

Protoplanetary disks show varying degrees of grain processing (grain growth & crystallization)

Disk structure & silicate emissionAmount of optically thin dust per unit area of optically thick disk

Degree of dust settling

Disks Results

• SEDs Class II full disk: (compared to D'Alessio models; 0.2,0.5,0.8 Msun, Mdot ~ 10-(7-10) Msun/yr, 20, 40, 60 inclination), dust depletion 100, 1000, 10000

• n13-31 settling parameter: depleted micron-ish dust mass by factor of ~ 100

• flared disk ~ stronger silicate emission

• 11.3/9.8 - proxy for both grain growth and crystallinity (processing) ~ settling

• F20/F10 ~ n13-31 (more settled, less 20 um emission relative to 10 um -- geometric effect of probing larger disk area)

• mid-range binaries (1"/65 AU) has no effect on SED (unlike outwardly truncated/SR 20, or close/CoKuTau/4 -- closer in)

• gap formation indicates planets rather than binaries (mid-range)

F10 or F20 = integral of (Fλ-Fλ,c) for appropriate wavelength (total flux over continuum)

W10= integral of (Fλ-Fλ,c / Fλ,c) : equivalent width, measures dust above continuum (ratio of amount of optically thin dust above optically thick dust)

Disks Results (cont.)• Dust modeling: (Sargent)

• 11.3 um forsterite more common than 33 um forsterite, and they correlate

• silica indicates dust processing in disk

• tridymite or cristobalite -- two types of silica that best fit observations

• require temperatures greater than 1300 K but cooled very quickly or will revert to alpha or beta-quartz, which we don't see, have to be quickly transported to outer disk, or formed in-situ in outer disk due to transient events (e.g. spiral shocks, X-wind)

• Watson et al. quick parameters match up well with detailed fits

Disk Results (cont.)

Transitional disks (Manoj, Kim et al.):• 90% of Tau/Oph/Cha trans. disks have pristine silicates (vs. 10% of full

disks); UX Tau A and a few others do not (including crystals at 57 AU!)• Analyzing Orion sample as well

• n13-31 high compared to n2-6

• W10 high for given n13-31 (low continuum)

Transitional disks frequency TD frequency ~ 10% short timescale for disk clearing (Skrutskie et al. 1990; Simon & Prato 1995; Wolk & Water 1996)

TD frequency increases with age ? (Currie & Kenyon 2009)

TD frequency (disks with holes/gaps) ~ 5 – 20%

hole/gap opening is rapid, in ~ 0.1 Myr -- once it starts.

If disks are cleared this way, then disk dissipation happens quite fast the ‘two-timescale’ behavior of disk dissipation (Alexander et al. 2007)

Region Age # of Class II # of TDs TD fraction (%)

ONC ~ 0.8 124 20 16 4

L1641 ~ 1 114 24 21 4

Oph ~ 1 71 7 10 4

Tau-Aur ~ 1 85 4 5 2

Cha I ~ 2 71 8 11 4

Disk Results (cont.)

Extinction Law (McClure et al.):

• Main distinction after Av >~ 8

• All of these are fairly flat at mid-IR (IRAC/24 um), although correction for ice absorption has large effect on silicate feature (not continuum indices so much)

Embedded Sources• Watson et al. (2004), Zasowski et al. (2009) – 16 sources (Taurus)

• Ubiquitous presence of CO2 suggests comes from envelope

• Used Leiden ices database and various mixtures of ice components, spline continuum fits, to generate optical depths and column densities

• Notably disagrees on water ice column density by factor of ~ 2

• Abundances: 12% CO∼ 2 (relative to H2O), 2%–9% CH3OH, 14% NH∼ 3, 3%∼

• CH4, 2% H∼ 2CO, 0.6% HCOOH, and 0.5% SO∼ ∼ 2

• Differences due to fitting technique? Some difference on composition of 6.8 um feature as well

• Also FU Orionis objects (Green, Zhu et al.)

• One potential new contribution: I am working on fits to the 42 um feature in Class 0/I sources, which also predicts shape of the 63 um feature when observed with Herschel-PACS

42 um water ice?

How do we proceed?• Active areas of interest will overlap more as we want to

look at the full sample, and improve statistics and trends• Settling on data reduction procedure? (generically)

Incremental improvements remain to be taken (e.g. optimal point-source extraction, refining of roguemasks)

• There will eventually be a full IRS_Disks archive, but it is not ready yet (first half in ~ 0.5 – 1 yr?), but data can be traded

• Extinction/reddening correction applied before or after? Count large amorphous grains as processed?

C2D and DIGIT

Part of the Herschel Follow-up

C2D Team Meeting – 29 Oct – 2 Nov, 2009, Garching

Joel Green (University of Texas at Austin)

On behalf of Neal Evans (University of Texas at Austin), Jeroen Bouwman (MPIA – Heidelberg), Tim van

Kempen (CfA) and many others

Talk Outline1. DIGIT vital statistics2. Data Processing3. Herschel Status4. Expected Science Results

DIGIT (Dust, Ice, and Gas In Time)

A Herschel Open Time Key Project 250 hrs (first observations appear at the end of November!) 30 embedded protostars, plus 64 disk sources ranging from B to M in spectral type (intermediate and low mass), selected from nearby (a few x 100 pc) molecular clouds (Tau, Oph, Cha, Per, Ser, Lup) Full disks/ disks with gaps; crystalline dust vs. amorphous at Spitzer wavelengths; embedded objects will exhibit outflows, ice (water, carbon dioxide, and others); gas emissionPACS spectroscopy (53-212 um), PACS photometry (70, 100, 160 um) SPIRE photometry (to determine disk masses) HIFI spectroscopy for embedded sources not in the WISH guaranteed time project (to detect water)

DIGIT ProcessingJeroen Bouwman at MPIA is assisting in calibration and will help Tim van Kempen and Joel Green reduce the data, also include Greg and Lars – anyone else want to be in on these reduction calls/emails?Bruno Merin is our Herschel Science Center (HSC) contactBabar Ali is our NHSC contactDIGIT website will maintain an archive (Green) of data in addition to any ancillary observations for each source (http://peggysue.as.utexas.edu/DIGIT)Most sources have IRS spectra, and many have IRAC/MIPSMost sources have or will have mm data for SED fittingEmbedded ancillary data will include high J-CO lines, interstellar molecules, ice feature data, dust feature data (for silicates, PAHs, and the rest; Sturm)Models of gas-phase water, far-IR lab spectroscopyIce modelsDust models, radiative transfer models

Expected Features

Outer disk: less optically thick, andwe can detect larger grains (~ 20 um)

Herschel StatusGood news: SPIRE and PACS Photometry: already collecting science (SDP data); several teams have already received dataPACS spectroscopy:

Line spectroscopy mode to be released next week (very close) – high spectral resolutionRange spectroscopy definitely still needs work, at least 2 weeks worth, but is looking very good already (needs RSRFs improved, and cosmic ray removal is tricky, elongated PSF) – we are fairly sure we are seeing some real features in there though, and continuum level looks good: so DIGIT SDP would not likely receive data for at least 1 month

HIFI: will probably be turned on soon, and they think they know what happened? Ewine? Sounds like this will occur very soon, and may further delay DIGIT SDP, so it is definitely possible we will not have data in time for the Madrid workshop (Dec. 14-18), although AAS in Washington (Jan. 3-7) Herschel special session seems realistic – however if we have DIGIT data by Dec. 14th we should go, even if it just showed up in Neal’s inbox

Herschel Deadlines

Meetings: workshop in Madrid (Dec. 14-18th); AAS (Jan. 3-7); Pasadena NHSC workshop (Jan. 25-29); DIGIT team meeting in Austin in February (?); ESTEC May?Submission of SDP papers by end of February to make special issue; presumably DIGIT would then get ~ 8 hours of time back to select a few more observations (probably 2 more sources)Some chance we could get one of our SDP objects a few weeks earlier depending upon validation of calibration data

Science Goals of DIGIT

Embedded sources: characterize envelope, outflow (spatially resolve the envelope); put limits on disk mass, ice feature column densities, dust composition, penetrate deeper through envelope, water and high-J CO lines, cooling lines [O I], deuterium abundance via HD R(0) and R(1), etc.Disk sources: characterize outer disk; radial distribution of dust features, SED continuum, disk mass, maybe some vertical structure, gas linesCorrelate with features at other wavelengthsSerendipitous gas lines? (Connections with GASPS?)

A “Typical” T Tauri Disk