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CRIRES observations of CO emission from disks around
embedded young stars
Gregory Herczeg (MPE)
Collaborators: Ewine van DishoeckKlaus Pontoppidan
Joanna BrownJeanette Bast
CRIRES Observations
• 10 sources:– IRS 43, IRS 44, IRS 63, Elias 23, Elias 29,
Elias 32, HH 100, WL 6, WL 12, CrA IRS 2– Several observed in multiple epochs– Usually a few wavelength settings– Need to add a few more (mostly non-
detections)
• NGS AO not possible– Limited spatial information
Goals:
• Do young disks emit in CO?– What else is CO probing?– Why do some disks show no CO?
• Does inner disk structure differ from CTTS disks?– Luminosity– Temperature/Excitation
Red: CRIRES black: ISAAC
IRS 44: resolved emission• 0.3 arcsec binary• 0.69 mag difference in M• Equal brightness in L
– (Duchêne et al. 2007)
• Primary is barely (or not) detected in K, never in J– Ratzka et al. 2005,
Terebey et al. 2001, Allen et al. 2002
• CO and H2 emission: only detected from secondary
• 13CO emission: blueshifted, offset from 12CO emission
H2 S(9) Emission
Variability?
• Seeing in Aug.: 0.33 arcsec• Seeing in Apr.: 0.56 arcsec
• Blueshifted CO emission from IRS 44 also variable in EW
Conclusions: CO emission from embedded objects
• CO absorption can make analysis difficult– Sometimes impossible, sometimes not so bad– Better than H2, which often probes extended material
• Most emission consistent with a disk origin– Double-peaked profile from Elias 23– Winds can also play a role (IRS 44)
• Two components– Narrow, colder, optically-thick– Hot, vibrationally excited broad component
• TO DO: Add a few sources, temps, luminosities, optical depths