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A (More) Dynamic View of Star Formation Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics
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COMPLETE The COordinated Molecular Probe Line Extinction Thermal Emission Survey Alyssa A. Goodman, Principal Investigator (CfA) João Alves (ESA, Germany) Héctor Arce (Caltech) Paola Caselli (Arcetri, Italy) James DiFrancesco (HIA, Canada) Jonathan Foster (CfA, PhD student) Mark Heyer (UMASS/FCRAO) Di Li (CfA) Doug Johnstone (HIA, Canada) Naomi Ridge (CfA) Scott Schnee (CfA, PhD student) Mario Tafalla (OAS, Spain) Tom Wilson (MPIfR) cfa-www.harvard.edu/COMPLETE
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A Tale of Speeding Young Stars The quasi-static theory of star formation What stays still long enough for that? –not PV Ceph! Dynamic Star Formation How can we measure it (COMPLETE) What might it mean?
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Molecular or Dark Clouds "Cores" and Outflows Star Formation Jets and Disks Extrasolar System 3 light years
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Molecular or Dark Clouds "Cores" and Outflows “Quasi-Static” Jets and Disks Extrasolar System 3 light years Core formation time >> 1 Myr Outflow is steady, and lasts >>0.1 Myr Accretion onto disk lasts~same time as flow (>>0.1 Myr) Planet formation time ~1 Myr
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TheoryObservation Shu, Adams & Lizano 1987
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“Quiet” Taurus E.E. Barnard, 5.5 hour exposure at Yerkes Observatory, 1907 Jan. 9 Next slide shows near-IR 1000x zoom on blobs like these
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Hubble Space Telescope Near-IR Images of Disks/Jets (c. 1998) DG Tau B IRAS 04302+2247 Haro 6-5B
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Barnard’s Taurus Color shows far-IR Dust Emission from IRAS E.E. Barnard ~5.5. hour exposure at Yerkes Observatory, c. 1907
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Barnard’s Taurus Color shows far-IR Dust Emission from IRAS
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How do we see this move? Red Plate, Digitized Palomar Observatory Sky Survey The Oschin telescope, 48-inch aperture wide-field Schmidt camera at Palomar
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Velocity from Spectroscopy 1.5 1.0 0.5 0.0 -0.5 Intensity 400350300250200150100 "Velocity" Observed Spectrum All thanks to Doppler Telescope Spectrometer
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Measuring Motions: Molecular Line Maps
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Alves, Lada & Lada 1999 Radio Spectral-Line Survey Integrated Intensity Does Not Show Velocity Information
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Simulated spectral-line map, based on work of Padoan, Nordlund, Juvela, et al. Excerpt from realization used in Padoan, Goodman &Juvela 2003 Watching the Gas Move: Spectral Line Mapping Displays of “position-position- velocity-intensity space” are difficult Measurable with spectral line mapping –centroid velocity –line width (velocity dispersion) –rotation –infall –outflow –higher-order statistical properties of the flow (e.g. SCF)
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The Taurus Dark Cloud Complex Mizuno et al. 1995 13 CO(1-0) integrated intensity map from Nagoya 4-m Young star positions courtesy L. Hartmann Size of whole map shown in next slide
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“Coherent Dense Cores” Islands of Calm in a Turbulent Sea Goodman, Barranco, Wilner & Heyer 1998 Size of whole map shown in next slide
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Islands (a.k.a. Dense Cores) Berkeley Astrophysical Fluid Dynamics Group http://astron.berkeley.edu/~cmckee/bafd/results.html Barranco & Goodman 1998 AMR Simulation Simulated NH 3 Map
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Goodman, Barranco, Wilner & Heyer 1998 Coherent Cores: 0.1 pc Islands of (Relative) Calm 2 3 4 5 6 7 8 9 1 v [km s ] 3456789 1 2 T A [K] TMC-1C, OH 1667 MHz v=(0.67±0.02)T A -0.6±0.1 2 3 4 5 6 7 8 9 1 v intrinsic [km s ] 6789 0.1 23456789 1 T A [K] TMC-1C, NH 3 (1, 1) v intrinsic =(0.25±0.02)T A -0.10±0.05 “Coherent Core”“Dark Cloud” Size Scale Velocity Dispersion Notice typical velocity disperson on pc scales is ~1 km s -1
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Stars Form in Islands of Calm in a Turbulent Sea "Rolling Waves" by KanO Tsunenobu © The Idemitsu Museum of Arts.
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Molecular or Dark Clouds "Cores" and Outflows Star Formation Jets and Disks Extrasolar System 3 light years
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Young Stellar Outflows in General and PV Ceph in particular
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Spectral Line Outflow Mapping Usually… In Extreme Cases… 1.0 0.8 0.6 0.4 0.2 0.0 120100806040200 1.0 0.8 0.6 0.4 0.2 0.0 120100806040200 120100806040200 1.0 0.8 0.6 0.4 0.2 0.0 120100806040200
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(All the) Maps of “Giant” Outflows, c. 2002 See references in H. Arce’s Thesis 2001 Greyscale shows ambient 1000 ptcl/cc gas Red shows 100 ptcl/cc gas moving away from us Blue shows 100 ptcl/cc gas moving toward us
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(All the) Maps of “Giant” Outflows, c. 2002 See references in H. Arce’s Thesis 2001
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L1448 Bachiller et al. 1990 B5 Yu, Billawala & Bally 1999 Lada & Fich 1996 Bachiller, Tafalla & Cernicharo 1994 YSO Outflows are Highly Episodic
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Outflow Episodes:Position-Velocity Diagrams Figure from Arce & Goodman 2001 HH300 NGC2264
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Episodic Outflows: Steep Mass-Velocity Slopes Result from Summed Bursts Observed Power-law Slope >2 (2=momentum-conserving shell) Arce & Goodman 2001
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Episodic Outflows: Steep Mass-Velocity Slopes Result from Summed Bursts Power-law Slope of Sum = -2.7 (arbitrarily <-2) Slope of Each Outburst = -2 as in Matzner & McKee 1999 Arce & Goodman 2001
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The Usual Questions About Outflows How, exactly, do they carry away angular momentum from the forming star? Can they “drive” turbulence in star- forming regions? How are “optical” HH flows & molecular outflows related? How long do they last? How many are there, really?
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Today’s Question What can outflows tell us about the motion of a star relative to its environment?
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1 pc “Giant” Herbig- Haro Flow from PV Ceph Image from Reipurth, Bally & Devine 1997
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moving PV Ceph Episodic ejections from a precessing or wobbling moving source Goodman & Arce 2003
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PV Ceph is moving at ~20 km s -1 Goodman & Arce 2003 1 pc
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The “Plasmon” Model for Deceleration Assumes each jet burst begins at 350 km s -1 Precession is neglected, so model executed in v * -v jet plane Goodman & Arce 2003
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The Most Subtle Evidence for PV Ceph’s Motion Goodman & Arce 2003 Each point shows position of emission peak in high-res molecular line map.
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Deceleration Means Outflows Lie About their Age Goodman & Arce 2003
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Backtracking Goodman & Arce 2003 1 pc ?
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Ejected?!! gap DSS Image of NGC 7023 100 m IRAS Image of NGC 7023-PV Ceph Region Goodman & Arce 2003
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How Much Gas Could Be Pulled Along for the Ride?
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How often does this happen? Direct Proper Motion –RW Aur 16 km s -1, Jones & Herbig 1979 –BN object w.r.t. “I” 50 km s -1, Plambeck et al. 1995 –IRAS 16293-2422 30 km s -1, Loinard 2002 –T-Tau Sb 20 km s -1, Loinard et al. 2003 Deduced from Outflow Morphology –B5 IRS1~10 km s -1, Bally et al. 1996* –PV Ceph 20 km s -1, Goodman & Arce 2003 *but the possibility of motion was dismissed! See Furlan et al. 2003?
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(All the) Maps of “Giant” Outflows, c. 2002 See references in H. Arce’s Thesis 2001
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Dynamic Star Formation Bate, Bonnell & Bromm 2002 MHD turbulence gives “t=0” conditions; Jeans mass=1 M sun 50 M sun, 0.38 pc, n avg =3 x 10 5 ptcls/cc forms ~50 objects T=10 K SPH, no B or movie=1.4 free-fall times
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“Early” Times
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“Later” Times
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How to measure dynamic star formation? Time is a key dimension but spatial statistics remain our best hope to understand it.
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The Lesson of Coordination: B68 C 18 O Dust Emission Optical Image NICER Extinction Map Radial Density Profile, with Critical Bonnor-Ebert Sphere Fit Coordinated Molecular-Probe Line, Extinction & Thermal Emission Observations of Barnard 68 This figure highlights the work of Senior Collaborator João Alves and his collaborators. The top left panel shows a deep VLT image (Alves, Lada & Lada 2001). The middle top panel shows the 850 m continuum emission (Visser, Richer & Chandler 2001) from the dust causing the extinction seen optically. The top right panel highlights the extreme depletion seen at high extinctions in C 18 O emission (Lada et al. 2001). The inset on the bottom right panel shows the extinction map derived from applying the NICER method applied to NTT near-infrared observations of the most extinguished portion of B68. The graph in the bottom right panel shows the incredible radial-density profile derived from the NICER extinction map (Alves, Lada & Lada 2001). Notice that the fit to this profile shows the inner portion of B68 to be essentially a perfect critical Bonner-Ebert sphere
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Un(coordinated) Molecular- Probe Line, Extinction and Thermal Emission Observations Molecular Line Map Nagahama et al. 1998 13 CO (1-0) Survey Lombardi & Alves 2001Johnstone et al. 2001
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Could we really…? 1 day for a 13 CO map when the 3 wise men were 40 1 minute for the same 13 CO map today
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COMPLETE The COordinated Molecular Probe Line Extinction Thermal Emission Survey Alyssa A. Goodman, Principal Investigator (CfA) João Alves (ESA, Germany) Héctor Arce (Caltech) Paola Caselli (Arcetri, Italy) James DiFrancesco (HIA, Canada) Jonathan Foster (CfA, PhD student) Mark Heyer (UMASS/FCRAO) Di Li (CfA) Doug Johnstone (HIA, Canada) Naomi Ridge (CfA) Scott Schnee (CfA, PhD student) Mario Tafalla (OAS, Spain) Tom Wilson (MPIfR)
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Perseus in (Coldish) Molecular Gas Map of 1200 13 CO Spectra from Bachiller & Cernicharo 1986 (made with Bordeaux 2.5-m, Beam Area = 31 x FCRAO) COMPLETE/FCRAO noise is twice as low, and velocity resolution is 6 x higher
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COMPLETE Warm Dust Emission shows Great Bubble in Perseus 2 x 10 51 erg SN into 10 4 cm -3 5 pc in 1 Myr T=30K v exp =1.5 km s -1
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COMPLET E Perseus IRAS + FCRAO (73,000 13 CO Spectra)
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Perseus Total Dust Column (0 to 15 mag A V ) (Based on 60/100 microns) Dust Temperature (25 to 45 K) (Based on 60/100 microns)
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Hot Source in a Warm Shell + = Column Density Temperature
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The action of multiple bipolar outflows in NGC 1333? SCUBA 850 mm Image shows N dust (Sandell & Knee 2001) Dotted lines show CO outflow orientations (Knee & Sandell 2000)
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A (More) Dynamic View of Star Formation Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics
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JCMT/SCUBA COMPLETE >10 mag A V 2 4 6 8 Perseus Ophiuchus 10 pc ~100 hours at SCUBA = in SCUBA archive = observed Spring ‘03 NGC1333 Map All at >5 mag, by 2004
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