A (More) Dynamic View of Star Formation Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics

Physicist’s Glossary for Alyssa Goodman’s Talk at Rochester, 10/15/03 1 parsec = 1 pc = 3 x cm ≈ 3 light years = typical size scale for a “dark cloud” 1 solar mass = 2 x g age of the Sun (and ~the Earth) ~3 x 10 9 yr age of the Universe ~15 x 10 9 yr “extinction” = absorption+scattering (measure of how many photons are “missing”) “molecular cloud” = condensation of molecular hydrogen (H 2 ) in the interstellar medium (typically colder & denser than surroundings) “H II region” blob of ionized hydrogen (free protons & electrons, a.k.a. H II) surrounding hot young star COMPLETE = COordinated Molecular Probe Line Extinction Thermal Emission Survey (begun 2001) IRAS = Infrared Astronomy Satellite (1983) SIRTF = Space Infrared Telescope Facility (launched 8/03)

“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?

Molecular or Dark Clouds "Cores" and Outflows Star Formation Jets and Disks Extrasolar System 3 light years

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

TheoryObservation Shu, Adams & Lizano 1987

“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

Hubble Space Telescope Near-IR Images of Disks/Jets (c. 1998) DG Tau B IRAS Haro 6-5B

Barnard’s Taurus Color shows far-IR Dust Emission from IRAS E.E. Barnard ~5.5. hour exposure at Yerkes Observatory, c. 1907

Barnard’s Taurus Color shows far-IR Dust Emission from IRAS

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

Measuring Motions: Molecular Line Maps

Velocity from Spectroscopy Intensity "Velocity" Observed Spectrum All thanks to Doppler Telescope  Spectrometer

Watching the Gas Move: Spectral Line Mapping Data cubes are in position-position-velocity- intensity space –Very hard to visualize Measurable with spectral line mapping –centroid velocity –line width (velocity dispersion) –rotation –infall –outflow –higher-order statistical properties of the flow (e.g. SCF)

Simulated spectral-line map, based on work of Padoan, Nordlund, Juvela, et al. Excerpt from realization used in Padoan, Goodman &Juvela 2003 “Spectral-Line Map” color in background shows “integrated” intensity

Alves, Lada & Lada 1999 Radio Spectral-Line Survey Integrated Intensity Does not Show Velocity Information

Watching the Gas Move: Spectral Line Mapping Data cubes are in position-position-velocity-intensity space –Very hard to visualize Measurable with spectral line mapping –centroid velocity –line width (velocity dispersion) –rotation –infall –outflow –higher-order statistical properties of the flow (e.g. SCF)

The Taurus Dark Cloud Complex Mizuno et al CO(1-0) integrated intensity map from Nagoya 4-m Young star positions courtesy L. Hartmann Size of whole map shown in next slide

“Coherent Dense Cores” Islands of Calm in a Turbulent Sea Goodman, Barranco, Wilner & Heyer 1998 Size of whole map shown in next slide

Islands (a.k.a. Dense Cores) Berkeley Astrophysical Fluid Dynamics Group Barranco & Goodman 1998 AMR Simulation Simulated NH 3 Map

Goodman, Barranco, Wilner & Heyer 1998 Coherent Cores: 0.1 pc Islands of (Relative) Calm  v [km s ] T A [K] TMC-1C, OH 1667 MHz  v=(0.67±0.02)T A -0.6±  v intrinsic [km s ] 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

Order from Chaos Order; N~R 0.9 ~0.1 pc (in Taurus) Chaos; N~R 0.1 Goodman et al. 1998

Stars Form in Islands of Calm in a Turbulent Sea "Rolling Waves" by KanO Tsunenobu © The Idemitsu Museum of Arts.

Molecular or Dark Clouds "Cores" and Outflows Star Formation Jets and Disks Extrasolar System 3 light years

Young Stellar Outflows in General and PV Ceph in particular

Spectral Line Outflow Mapping Usually… In Extreme Cases…

(All the) Maps of “Giant” Outflows, c 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

(All the) Maps of “Giant” Outflows, c See references in H. Arce’s Thesis 2001

L1448 Bachiller et al B5 Yu, Billawala & Bally 1999 Lada & Fich 1996 Bachiller, Tafalla & Cernicharo 1994 YSO Outflows are Highly Episodic

Outflow Episodes:Position-Velocity Diagrams Figure from Arce & Goodman 2001 HH300 NGC2264

Episodic Outflows: Steep Mass-Velocity Slopes Result from Summed Bursts Observed Power-law Slope >2 (2=momentum-conserving shell) Arce & Goodman 2001

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

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?

Today’s Question What can outflows tell us about the motion of a star relative to its environment?

1 pc “Giant” Herbig- Haro Flow from PV Ceph Image from Reipurth, Bally & Devine 1997

moving PV Ceph Episodic ejections from a precessing or wobbling moving source Goodman & Arce 2003

PV Ceph is moving at ~20 km s -1 Goodman & Arce pc

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

The Most Subtle Evidence for PV Ceph’s Motion Goodman & Arce 2003

Deceleration Means Outflows Lie About their Age Goodman & Arce 2003

Backtracking Goodman & Arce pc ?

Ejected?!! gap DSS Image of NGC  m IRAS Image of NGC 7023-PV Ceph Region Goodman & Arce 2003

How Much Gas Could Be Pulled Along for the Ride?

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 –IRAS km s -1, Loinard 2002 –T-Tau Sb 20 km s -1, Loinard et al 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!

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

“Early” Times

“Later” Times

How to measure dynamic star formation? Time is a key dimension but spatial statistics remain our best hope to understand it.

Un(coordinated) Molecular- Probe Line, Extinction and Thermal Emission Observations Molecular Line Map Nagahama et al CO (1-0) Survey Lombardi & Alves 2001Johnstone et al. 2001

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

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

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)

Perseus in (Coldish) Molecular Gas Map of 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

COMPLETE Warm Dust Emission shows Great Bubble in Perseus 2 x erg SN into 10 4 cm -3 5 pc in 1 Myr T=30K v exp =1.5 km s -1

COMPLET E Perseus IRAS + FCRAO (73, CO Spectra)

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)

Hot Source in a Warm Shell + = Column Density Temperature

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)

A (More) Dynamic View of Star Formation Alyssa A. Goodman Harvard-Smithsonian Center for Astrophysics

JCMT/SCUBA COMPLETE >10 mag A V Perseus Ophiuchus 10 pc ~100 hours at SCUBA = in SCUBA archive = observed Spring ‘03 NGC1333 Map All at >5 mag, by 2004