the planet-forming zones of disks around solar- mass stars: a crires evolutionary study vlt large...
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The planet-forming zones of disks around solar-mass stars: a CRIRES evolutionary study
VLT Large Program 24 nights
Major questions
Structure of disks? E.g., size, flat vs. flared, inner holes
How and when is gas lost from disks => timescale for giant planet formation? Mechanisms: photoevaporation, winds, …
How and when is dust lost from disks? How, when and where are planets formed? Chemical composition of material for forming
planets (H2O, biogenic molecules, …)?
Inspiration and guidance from Keck
Cold gas Hot gas
CO v=1-0 band at 4.7 m in disks around Herbig stars
Blake & Boogert 2004
R=25000
CO vibration-rotation spectra
Inspiration from VLT-ISAAC
Pontoppidan et al 2003
CO ice
CO gas
- Increase in CO gas/solid ratios- Change in solid CO band profile
VLT-ISAACR=10,000
T
Q: what are gas-phase abundances? CO emission from young disks?
Importance of velocity information
- Hot HCN and CO blue-shifted by 25 km/s =>Base of MHD wind?
Keck HCN 3 m and CO 4.7 m
IRS 46
Lahuis, Boogertet al. 2006
CRIRES on VLT
1-5 m spectroscopy up to R=100000 with 0.2’’ slit, AO assistedFour 1024 x 512 InSb Aladdin III arrays => large instantaneous wavelength coverage
CRIRES goals and questions Do all disks show hot gas in the inner AU?
Gas dissipation timescales and mechanism Gas temperature and turbulent width CO emitting layer? Departures from Keplerian rotation on <10 AU scales? Comparison gas disk structures (size, position, inclination) with dust
disk CO excitation mechanism as function of radius (UV vs. thermal) Temperature structure of inner envelope and disks in embedded
phase? CO isotope selective photodissociation H3
+ as probe of ionization
Hot chemistry in inner disk? H2O, CH4, HCN, H2CO, …
CO kinematics in disksNeed for high spectral resolution and instrument stability
12CO low J 12CO low J
13CO low J
Note different profiles andnarrow absorption of coldgas in outer disk
CO excitation
Spectroastrometry works!SR 21 disk
-Note accuracy: down to 0.1 AU rms (~200 arcsec, comparable or better than VLTI!)
-Offset is relative to continuum at 4.7m
P lines
Need to work on press release
Pontoppidan et al. 2008
Asymmetries
- slight asymmetries in gas, or in underlying dust continuum in opposite direction
CRIRES sources
Classical T Tauri stars (35) Largely drawn from Keck M-band survey Spectroastrometry on subsample
Cold / transitional disks (20) Bruno’s sample Lucas wTT sample
Embedded Class I sources (20) Largely drawn from VLT-ISAAC survey
Absorption + emission sources Chemistry on subsample
Goals of today
Inventory of results from first four observing runs
Status of data reduction pipeline Status of modeling tools Plans for final runs
Which projects to emphasize? For which sources do we need 2 epochs?
Science analysis + papers Next papers Who will work on what
CO in disks: first results
Edge-on disk: i~60 Face-on disk: i~15o