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