A (More) Dynamic View of A (More) Dynamic View of Star FormationStar Formation

Alyssa A. GoodmanAlyssa A. GoodmanHarvard-Smithsonian Center for AstrophysicsHarvard-Smithsonian Center for Astrophysics

Physicist’s Glossaryfor Alyssa Goodman’s Talk at Rochester, 10/15/03

1 parsec = 1 pc = 3 x 1018 cm ≈ 3 light years = typical size scale for a “dark cloud”

1 solar mass = 2 x 1033 gage of the Sun (and ~the Earth) ~3 x 109 yrage of the Universe ~15 x 109 yr“extinction” = absorption+scattering (measure of how many photons

are “missing”)“molecular cloud” = condensation of molecular hydrogen (H2) 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 starCOMPLETE = 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 lig

ht y

ears

Molecular or Dark Clouds

"Cores" and Outflows

Quasi-Static

Jets and Disks

Extrasolar System

3 lig

ht y

ears

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

TheoryObservatio

n

Shu, Adams & Lizano 1987

“Quiet” Taurus

E.E

. B

arna

rd,

5.5

hour

exp

osur

e at

Yer

kes

Obs

erva

tory

, 19

07

Jan

. 9

Next slide shows near-IR 1000x zoom on blobs like these

Hubble Space Telescope Near-IR Images of Disks/Jets(c. 1998)

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DG Tau B

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IRAS 04302+2247

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Haro 6-5B

Barnard’s TaurusColor shows far-IR Dust Emission from IRAS

E.E

. B

arn

ard

~5.5

. hou

r exp

osu

re a

t Yerk

es

Obse

rvato

ry,

c. 1

90

7

Barnard’s TaurusColor 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 Spectral Line Observations

Velocity from Spectroscopy

1.5

1.0

0.5

0.0

-0.5

Inte

nsit

y

400350300250200150100

"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. 1995 13CO(1-0) integrated intensity map from Nagoya 4-mYoung star positions courtesy L. Hartmann

Size of wholemap shown in

next slide

“Coherent Dense Cores”Islands of Calm in a Turbulent Sea

Goodman, Barranco, Wilner & Heyer 1998

Size of wholemap shown in

next slide

Islands (a.k.a. Dense Cores)

Berkeley Astrophysical Fluid Dynamics Grouphttp://astron.berkeley.edu/~cmckee/bafd/results.html Barranco & Goodman 1998

AMR Simulation

Simulated NH3 Map

Goodman, Barranco, Wilner & Heyer 1998

Coherent Cores: 0.1 pc Islands of (Relative) Calm

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5

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8

9

1

v [

km s-1

]

3 4 5 6 7 8 91

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TA [K]

TMC-1C, OH 1667 MHz

v=(0.67±0.02)TA-0.6±0.1

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v

intr

insi

c[k

m s

-1]

6 7 8 90.1

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TA [K]

TMC-1C, NH3 (1, 1)

vintrinsic=(0.25±0.02)T A-0.10±0.05

“Coherent Core”“Dark Cloud”

Size Scale

Velo

city

Dis

pers

ion

Notice typical velocity disperson on pc scales

is ~1 km s-1

Order from Chaos

Order; N~R0.9

~0.1 pc(in Taurus)

Chaos; N~R0.1

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 lig

ht y

ears

Young Stellar Outflows in General

and PV Ceph in particular

Spectral Line Outflow Mapping

Usually…

In Extreme Cases… 1.0

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0.2

0.0 120100806040200

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0.0120100806040200 12010080604020 0

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0.0120100806040200

(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

(All the) Maps of “Giant” Outflows, c. 2002

See references in H. Arce’s Thesis 2001

L1448

Bach

iller

et

al. 1

990

B5

Yu, B

illaw

ala

& B

ally

1999

Lada &

Fic

h 1

99

6

Bach

iller,

Tafa

lla &

Cern

icharo

19

94

YSO Outflows are Highly Episodic

Outflow Episodes:Position-Velocity Diagrams

Figure

fro

m A

rce &

Goodm

an 2

00

1

HH300

NGC2264

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

PV Ceph

Episodic ejections from a

precessing or wobbling

moving moving source

Goodman & Arce 2003

PV Ceph is moving at ~20 km s-1

Goodman & Arce 2003

1 pc

The “Plasmon” Model for Deceleration

Assumes each jet burst begins at 350 km s-1

Precession is neglected, so model executed in v*-vjet 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 2003

1 pc

?

Ejected?!!

gap

DSS Image of NGC 7023

100 m IRAS Image of NGC 7023-PV Ceph Region

Goodman & Arce 2003

How Much Gas Could Be Pulled Along for the Ride?

108

109

1010

1011

1012

GM*

/RBH

= σeff

2

[cm2 s-2]

0.0012 3 4 5 6 7 8 9

0.012 3 4 5 6 7 8 9

0.1RBH [ ]pc

5 6 7 8 91

2 3 4 5 6 7 8 910

2 3 4

RBH [ 500 ]arcsec at pc

10

50 MSun

5

σeff

2=(1 km s-1 )2

20

2 1 M Sun

- Effective Bondi Hoyle 7 Radius for MSun in

σeff=5 km s-1 Gas

σeff

2=(5 km s-1 )2

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!

Dynamic Star

Formation

Bate, Bonnell & Bromm 2002

•MHD turbulence gives “t=0” conditions; Jeans mass=1 Msun

•50 Msun, 0.38 pc, navg=3 x 105 ptcls/cc

•forms ~50 objects

•T=10 K

•SPH, no B or •movie=1.4 free-fall times

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“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.

2MASS/NICER Extinction Map of Orion

Un(coordinated) Molecular-Probe Line,

Extinction and Thermal Emission Observations

5:41:0040 20 40 42:00

2:00

55

50

05

10

15

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R.A. (2000)

1 pc

SCUBA

5:40:003041:003042:00

2:00

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20

30

40

R.A. (2000)

1 pc

SCUBA

Molecular Line Map

Nagahama et al. 1998 13CO (1-0) Survey

Lombardi & Alves 2001Johnstone et al. 2001 Johnstone et al. 2001

The Lesson of Coordination: B68

C18ODust EmissionOptical 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 C18O 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…?

10-4

10-3

10-2

10-1

100

101

102

103

Time (hours)

20152010200520001995199019851980

Year

1 Hour

1 Minute

1 Day

1 Second

1 Week

SCUBA-2

SEQUOIA+

NICER/8-m

NICER/SIRTFNICER/2MASS

AV~5 mag, Resolution~1'

AV~30 mag, Resolution~10"

13CO Spectra for 32 Positions in a Dark Cloud (S/N~3)

Sub-mm Map of a Dense Core at 450 and 850 m

1 day for a 13CO map when

the 3 wise men were 40

1 minute for the same

13CO 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)

COMPLETE Perseus

IRAS + FCRAO

(73,000 13CO Spectra)

Perseus

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Total Dust Column (0 to 15 mag AV) (Based on 60/100 microns)

Dust Temperature (25 to 45 K)(Based on 60/100 microns)

Hot Source in a Warm Shell

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Column Density Temperatur

e

The action of multiple

bipolar outflows in NGC 1333?

SCUBA 850 mm Image shows Ndust (Sandell &

Knee 2001)

Dotted lines show CO outflow orientations (Knee & Sandell 2000)

A (More) Dynamic View of A (More) Dynamic View of Star FormationStar Formation

Alyssa A. GoodmanAlyssa A. GoodmanHarvard-Smithsonian Center for AstrophysicsHarvard-Smithsonian Center for Astrophysics