Outflow-Envelope Interactions at the Early Stages of Star Formation

1. Outflow-Envelope Interactions at the Early Stages of Star Formation Héctor G. Arce (AMNH) & Anneila I. Sargent (Caltech) Submillimeter Astronomy: in the era of the SMA June 2005 Cambridge, MA

2. Introduction Most, if not all, protostars produce outflows Circumstellar envelopes (~103-104AU) are primary mass reservoirs of forming stars Outflows interact with circumstellar envelope: -Injection of momentum and energy -Shocks-induced chemistry Outflows may be responsible for envelope’s dispersal, ending infall stage and playing important part in the mass-assembly process Circumstellar envelope angular size scales ~10-30”, with complex velocity structure. High angular and velocity resolution observations are needed.

3. Observations • Observed gas surrounding a sample of YSO with outflows at different evolutionary stages to study the morphology and kinematics of the molecular outflow and circumstellar envelope Owens Valley Radio Observatory Millimeter Array Using different molecular lines that trace different density (and kinematic) regimes: Simultaneously observe: 12CO(1-0): low-density, high-velocity outflow 13CO(1-0): “large-scale” (~0.05 pc) envelope C18O(1-0): inner (~0.02 pc) regions of envelope 2.7 mm continuum Simultaneously observe: HCO+(1-0): optically thick (infall)/shock chem. tracer HNC(1-0): high-density tracer H13CO+(1-0): high-density, optically thin tracer 3.4 mm continuum

4. 12CO(1-0) Outflow Survey HH114mms RNO43 IRAS3282 Class 0 104 AU 20” L1228 RNO129 HH300 Class I GKTAU RNO91 TTAU Class II

5. RNO91 Lee & Ho 2005 Ohashi et al. 1996 L1551 Langer et al. 1996 B5-IRS1 Lee et al. 2002 IRAM04191 HH211 Gueth & Guilloteau 1999 Opening Angle vs. Time RNO129 HH300 TTau L1228 IRAS3282 RNO43 HH114mms Time

6. C18O(1-0) Emission:probing the circumstellar envelope HH114mms RNO43 IRAS3282 5000 AU Class 0 10” HH300 L1228 RNO129 Class I GKTAU RNO91 TTAU Class II

7. C18O envelope kinematics HH114mms RNO43 IRAS3282 Class 0 ???? outflow outflow HH300 L1228 RNO129 Class I infall rotation/infall ? rotation Class II No structured kinematics, but C18O emission (when detected) mostly blueshifted and close to blue outflow lobe.

8. C18O envelope mass vs. time Time Consistent with single-dish studies: Ladd et al. 1998 Fuller & Ladd 2002

9. • Outflow lobe widening with time: Time Class I Class II Class 0 collimated wide-angle clumpy mess/ very wide • Change in envelope morphology and kinematics with time: • Decrease in envelope mass with time: Evidence for Outflow-Envelope Interactions

10. HCO+ (1-0) outflow emission: outflow chemical impact HH114mms RNO43 IRAS3282 Class 0 HH300 L1228 RNO129 Class I Other HCO+ outflow studies: • Hogerheijde et al. 1998; 1999 • Girart et al. 1999 TTAU Class II Consistent with chemical models: • Rawlings et al. 2000; 2004 • Viti et al. 2002

11. • Outflow impact on envelope’s dust using sub-mm dust continuum emission HH114mms PV Cep L1157 (Gueth et al. 2003) CO(2-1) 1.3mm 800mm Studying outflow-envelope interactions with the SMA • High transition lines will probe hot molecular gas closely related to shocks (at ~ 1”). • Potential for simultaneous multi-line observations e.g., 12CO + 13CO + C18O (2-1) 13CO + C18O (3-2) HCO+(3-2) + HCN(3-2) + 13CS(6-5)

12. Summary From observations of YSO sample: •widening of outflow cavities with time •change in envelope morphology and kinematics with time •decrease in envelope mass with time These are consistent with a picture where outflows play a major role in evolution of circumstellar envelope HCO+ observations show outflow-envelope interactions also affect the chemical composition of circumstellar environment, independent of outflow age. SMA observations will allow us to study the physical and chemical properties of gas closely related to shock, and impact of outflow on dust