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Outflows from Young Stars ... What Next?

Outflows from Young Stars ... What Next?. High resolution observations of the Central Engine. Wide-field studies - Outflow statistics; Feedback. Chris Davis, UKIRT/JAC. Low Mass Star Formation. OPTICAL Herbig-Haro Objects; discovered in the early 50s

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Outflows from Young Stars ... What Next?

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  1. Outflows from Young Stars ... What Next? High resolution observations of the Central Engine Wide-field studies - Outflow statistics; Feedback Chris Davis, UKIRT/JAC

  2. Low Mass Star Formation ...

  3. OPTICAL • Herbig-Haro Objects; discovered in the early 50s • First symposium in 1983 (Bohm, ed.) • 1980s - HH objects part of bipolar outflows • (Dopita; Mundt; Graham; Reipurth) • Spectroscopy; proper motion studies; modeling • 1990s - HST … the weather... the central engine (but only TTSs). 1994 Herbig & Jones 1981 Bally et al. 2002

  4. (SUB)-MILLIMETRE • Broad CO lines in Orion (Kwan & Scoville 1976) • 1980s - CO surveys in the (Snell, Bally, Edwards, Lada) • 1990s - Higher-energy lines (submm @ JCMT); isotopes; • shock chemistry in outflows; entrainment models • Interferometry @ Plateau de Bure, CARMA, SMA • - molecular “jets”; study of massive SF... Davis & Eisloeffel 1996 Gueth et al. 1998 Beltran et al. 2004

  5. NEAR-IR • H2 emission lines discovered in Orion; Gautier 1976 • High-resolution studies of outflows from more embedded • sources! • 1980s - spectroscopy; molecular shock physics (theory) • 1990s - First sub-arcsec images; high-resol. spec. (CGS4) • - kinematics and excitation • - numerical simulations; bows; entrainment Calar Alto 1993 UKIRT 1999 Davis et al. 1994, 2000

  6. Models are “largely” successful at producing: morphologies (bow shock shapes) kinematics (line profiles) excitation (optical/near-IR/mid-IR) entrainment (CO outflows) Simulation courtesy of Michael Smith Job done, then... (lets all go to the pub...)

  7. (Some) questions that remain to be answered... How are jets collimated or accelerated? (from the star, inner disk edge, disk) Do all protostars drive outflows? Ages - Lengths Feedback of energy; turbulent cloud support Massive star formation (O and B stars) outflows = disk accretion Binary/Multiple star formation Circumbinary disks; precessing jets.

  8. How to probe the central engine in the near-IR…(without a near-IR “STIS” on the HST) H2 1-0S(1) @ 2.12mm; CGS4 echelle data (Davis et al. 2001)

  9. Complement the H2 with [FeII] 1.64 mm observations... H2 - 2000K molecular gas [FeII] - 10,000K atomic/ionised gas

  10. Deeper spectra…. (Subaru) Takami et al. 2005, 2006 H2 excitation diagrams - distinguish between excitation mechanisms. [FeII] line ratios - constrain the density, temperature and ionisation fraction at the jet base.

  11. Higher Spatial Resolution with AO…. (VLT/NACO) Resolving components… … measuring proper motions

  12. Ultimately, we aim to understand the origin of the line emission, and constrain (or distinguish between) jet collimation and acceleration models Ejected bullet? Disk Wind? X-wind? H2 - entrained ambient gas, or cool, outer layers of a disk wind. H2 & [FeII] - excited in ejected bullets, or in a stationary collimation shock at the base of the flow...

  13. On much larger scales….. Stanke et al. 2002

  14. The T-A-P survey in the GPS

  15. H2 jets in NGC 1333 in Perseus Hodapp & Ladd 1995 150 sec total expos time!

  16. Not just philately…! • Do all young stars drive outflows? • (How does binarity/multiplicity affect jets?) • Ages, lengths… • Affect of/on environment • (e.g. clustering affect disks and therefore outflows?) • Global energy input by flows • (turbulent cloud support) Multi-wavelength approach... • WFCAM - H2 flows (warm) • CFHT/VISTA - Herbig-Haro jets (hot) • Harp-B - CO outflows (cool) • SCUBA-2 - the outflows sources (Class 0/I) • SCUBA-2 + Pol - magnetic fields

  17. Outflows from Young Stars …Still lots to do! Chris Davis, UKIRT/JAC

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