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Outflows from Young Stars and the Interstellar Medium

Outflows from Young Stars and the Interstellar Medium. Alyssa A. Goodman & Héctor G. Arce Harvard University cfa-www.harvard.edu/~agoodman. Note: This talk is a special “preview” of Héctor Arce’s thesis, to be completed Summer 2001. Star Formation v. 2000. (a.k.a. GMC or Cloud Complex).

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Outflows from Young Stars and the Interstellar Medium

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  1. Outflows from Young Stars and the Interstellar Medium Alyssa A. Goodman & Héctor G. Arce Harvard University cfa-www.harvard.edu/~agoodman Note: This talk is a special “preview” of Héctor Arce’s thesis, to be completed Summer 2001.

  2. Star Formationv. 2000 (a.k.a. GMC or Cloud Complex)

  3. Star Formation v. 2000: The Bare Essentials 1. Stars form in molecular cloud complexes which range in size from ~10's to 100's of pc. 2. Molecular clouds can be characterized as turbulent, definitely supersonic, and perhaps super-Alfvénic. 3. Select "coherent" pieces of molecular clouds collapse and fragment to form stars. 4. Every star produces an outflow for during some (significant) fraction of its pre-main-sequence life. 5. Outflows can, and apparently often do, extend for several pc.

  4. "Cores" and Outflows Giant Molecular Clouds Jets and Disks Solar System Formation How the Recipe Works

  5. Do Outflows Ever “Create” Cloud Structures?If so, how does this effect future star formation & the “clump mass spectrum”? Today’s Proposal The “Standard Model”

  6. Radio Spectral-line Observations of Molecular Clouds

  7. 1.0 0.8 1.0 1.0 0.6 0.8 0.8 0.4 0.6 0.6 0.4 0.4 0.2 0.2 0.2 0.0 0.0 0.0 0 20 40 60 80 100 120 120 100 80 60 40 20 0 0 120 100 80 60 0 40 20 20 40 60 80 100 120 “Outflow” Spectra Traditionally... Today...

  8. +=dense core CS (21) “Clump” Mass Distribution Ω What is a clump? Structure-Finding Algorithms Typical Stellar IMF Salpeter 1955 Miller & Scalo 1979 What does the clump “IMF” look like? • CLUMPFIND (Williams et al. 1994) • Autocorrelations (e.g. Miesch & Bally 1994) • Structure Trees (Houlahan & Scalo 1990,92) • GAUSSCLUMPS (Stutzki & Güesten 1990) • Wavelets (e.g. Langer et al. 1993) • Complexity (Wiseman & Adams 1994) • IR Star-Counting (C. Lada et al. 1994) • PCA (Heyer & Schloerb 1997) • Spec. Corr. Function (Rosolowsky et al. 1999) E. Lada 1992 E. Lada et al. 1991

  9. Molecular Clouds "Created" by Supernovae 100 mm Emission in Cassiopeia Tóth et al. 1995 Keep in Mind...

  10. Examples that might convince you that YSO Outflows Move More Gas than You Thought 1. “Giant” Herbig-Haro Flows PV Cephei 2. The Effect of Outflows on their host Cores B5 3. Are Some Dark Clouds Created by Outflows? HH300 4. How much of a molecular cloud complex was “moved” to its present location by an outflow? Taurus

  11. “Giant” Herbig-Haro Flows:PV Ceph 1 pc Reipurth, Bally & Devine 1997

  12. MatchingEjectionAngles(assumes episodic ejections from precessing or wobbling stationery source)

  13. Matching Ejection Distance (preferred by Reipurth)

  14. A New Proposal: Episodic ejections from precessing or wobbling moving source Required motion of 0.25 pc (e.g. 2 km s-1 for 125,000 yr)

  15. “Giant” Herbig-Haro Flows

  16. 67:55 H H 3 1 5 C H H 3 1 5 B 67:50 H H 3 1 5 A H H 4 1 5 HH 215P2 ) 0 HH 215P1 5 9 1 ( PV Cephei d 67:45 HH 315D H H 3 1 5 E 67:40 H H 3 1 5 F 20:46 20:45 ( 1 9 5 0 ) a PV Ceph 12CO (2-1) OTF Map from NRAO 12-m Red: 3.0 to 6.9 km s-1 Blue: -3.5 to 0.4 km s-1 Arce & Goodman 2000

  17. “Ambient” Gas in PV Ceph 13CO (1-0) SEQUOIA Map from FCRAO Integrated over all velocities. Arce & Goodman 2000

  18. PV Ceph12CO (2-1) OutflowContours on 13CO (1-0) Map

  19. Position-Velocity Diagram for PV Ceph Outflow Gradient in Systemic Velocity! Blue Lobe Red Lobe 12CO (2-1) data from NRAO 12-m (Arce & Goodman 2000)

  20. 67:55 30-m Data H H 3 1 5 C H H 3 1 5 B 67:50 H H 3 1 5 A H H 4 1 5 HH 215P2 ) 0 HH 215P1 5 9 1 ( PV Cephei d 67:45 HH 315D H H 3 1 5 E 67:40 H H 3 1 5 F 20:46 20:45 ( 1 9 5 0 ) a Zooming in on the “Blue Lobe” of PV Ceph 12CO (2-1) OTF Map from NRAO 12-m Red: 3.0 to 6.9 km s-1 Blue: -3.5 to 0.4 km s-1 Arce & Goodman 2000

  21. PV C eph: CO (2-1) Spectra Near HH315 B Full-resolution IRAM 30-m Spectrum NRAO 12-m Spectrum Smoothed 30-m Spectrum

  22. PV C eph: CO (2-1) Spectra Near HH315 B Full-resolution IRAM 30-m Spectrum Note: Higher spatial resolution gives higher velocity resolution! NRAO 12-m Spectrum Smoothed 30-m Spectrum Arce & Goodman 2000

  23. PV C eph: CO (2-1) Spectra Near HH315 B Full-resolution IRAM 30-m Spectrum Most Blueshifted 14% Cloud Intermediate 35% Blueshift 11% NRAO 12-m Spectrum Smoothed 30-m Spectrum Least Blueshifted 40% Arce & Goodman 2000

  24. 68 05 30 HH 315C NRAO 12m Beam 00 IRAM 30m Beam 04 30 0.5 pc 00 HH 315B 03 30 00 02 30 00 20 45 45 30 15 00 RIGHT ASCENSION (J2000) The “Blue” Lobe of the PV Ceph Outflow least blueshifted intermediate blueshift most blueshifted 12CO (2-1) data from IRAM 30-m (Arce & Goodman 2000)

  25. Giant HH Flow: PV Ceph • Ejection is almost surely episodic, and gas from >1 episode present along some lines of sight • Souce may travel in addition to precessing or wobbling • Both Velocity and Density Structure of “Cloud” bear resemblance to Outflow

  26. 2. The Effect of Outflows on their host Cores Previous Suggestions • Increased Turbulence (in the area of the core coexisting with outflow) • Core Dispersal by Outflows New Slightly Radical Suggestion • Outflow Gas May Be a Significant Volume of a Core (accounts for increased line widths & can lead to core dispersal)

  27. FCRAO 13CO Observations Yu et al. (2000) 12CO (2-1) Observations, The Effect of Outflows on their host Cores

  28. B5 “Line Width-Intensity Plot” 1.8 1.6 Line Width [km s-1] 1.4 1.2 3.2 3.6 4.0 4.4 Tpeak Arce & Goodman 2000

  29. FCRAO 13CO Observations Yu et al. (2000) 12CO (2-1) Observations, The Effect of Outflows on their host Cores with Heyer et al. (1990) IR nebulosity superimposed near source Wide-angle wind? (See Langer et al. 1996)

  30. + = T [K] A B5-IRS 5:An “Outflow” Component? 1.8 1.6 1.4 1.2 3.2 3.6 4.0 4.4 Velocity (km/sec) T [K] A Model: Cloud component "Outflow" component T = 3.4 K T = 2.2 K A A D v=1.2 km/sec D v=1.2 km/sec v =10.5 km/sec v = 9.3 km/sec o o Velocity [km/sec] Velocity [km/sec] Sum of both components Velocity [km/sec] 13CO(1-0) Data from FCRAO to appear in Arce & Goodman 2000

  31. 04239+2436 D B C HH300 A 3. Are Some Dark Clouds Created by Outflows? 24:40 24:35 24:30 1 pc 24:25 24:20 24:15 04:24 04:23

  32. Roughly 1/4 of all mass within box is at “outflow” velocities HH300 & B18w in Taurus Contours show CO (2-1) emission from 7.3 to 9.9 km s-1(nearby “ambient” velocity is 6.7 km s-1 Greyscale shows extinction based on IRAS 60 & 100 micron emission

  33. The Taurus Dark Cloud Complex B18W/HH300 Mizuno et al. 1995 13CO(1-0) integrated intensity map from Nagoya 4-m

  34. 4. How much of a molecular cloud complex was “moved” to its present location by an outflow? • Movie of Taurus, Gas Only • Movie of Taurus, with Stars Key: Blue 34% "Cloud" 56% Red 10% (by mass)

  35. YSO Outflows Move More Gas than WeThought 1. “Giant” Herbig-Haro Flows PV Cephei shows density & velocity structure--at least at low density--controlled by flow. 2. The Effect of Outflows on their host Cores B5: Evidence for a "Core" Component in 13CO 3. Are Some Dark Clouds Created by Outflows? HH300: Is B18w an Outflow Lobe? 4. How much of a molecular cloud complex was “moved” to its present location by an outflow? Taurus: A Lot

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