Study for Origin and Structureof Outflows from YSOs:[Fe II] 1.644 µm Spectroscopy
with High Angular Resolution
Tae-Soo Pyo (Subaru Telescope)pyo@subaru.naoj.org

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

AgendaI. Introductiona) Young Stellar Outflowsb) [Fe II] Emission lines
II. Observations
III. Resultsa) L1551 IRS 5 without AOb) DG Tau with AOc) HL Tau with AOd) RW Aur A with AO
IV. Discussion
V. Follow Up Observations:
L1551 IRS 5 & DG Tau
VI. Summary
Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

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I. Introduction: Young Stellar Outflows• Ubiquitous in star formation• Closely related to the accretion process• Play an important role for removing angularmomentum from a star-disk system
Studies of YSO outflows may provide
us with crucial information forunderstanding the physical process ofstar formation.
Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

I. Introduction: Observations of YSOs
We can resolve the structure
within 100 AU from the Taurus
source, where collimation
140 AUand acceleration areoccurred.
14 AU•Collimation Mechanism•Acceleration Mechanism•Launching Mechanism 1.4 AU
High (Spatial + Velocity)
Resolution
Æ AO + IRCS (Echelle)
Malbet (2003)

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

2I. Introduction: NIR [Fe II] Emission
Lines
1.The strongest forbidden lines in the near-infrared
2.Small extinction
3.Trace partially ionized region & shocked region(Ionization Energy of Fe I : 7.6 eV)

Near Infrared [Fe II] emission lines will be a good tracer
for outflows in the vicinity of the young stellar objects.

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

II ObservationsSubaru Telescope

NIR [Fe II] emission
High spatial resolution
High velocity resolution
Adaptive Optics system

Infrared Camera and Spectrograph
Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

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II Observations
ObjectObs. Date Exp.
(mm/dd/yyyy) Time(sec)

R (dV) Spatial P.A.
Res.
(km/s) (″)
(°)

AO

L1551
10/16/2000
IRS 5
DG Tau 10/31/2001

720

590.3074×32030

0.16

222

○

HL Tau12/25/2001

2100

600.5051○

RW Aur 11/26/2002

960

300.20120○

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

III. Results : (1) L1551 IRS 5
LVC5"(700 AU)

PWC

HVC
[ Dec. 15. 2000 ] H-cont : Blue[Fe II] : Green
K-cont : Red
LVC : d ~ 1.2 – 2.0” , V ~ -100 km/s,
FWHM ~ 100 – 200 km/s
HVC : narrow & extended, d > 1.36”
V~-300 km/s, FWHM ~ 60 km/s
PWC: velocity increase from LVC to HVC(Pyo et al. 2002)

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

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III. Results: (2) DG Tau
10“(1400 AU)0.7”*140 AU

H-cont, [Fe II], H2(Pyo et al. 2003)

Eislöffel & Mundt (1998)

HVC : narrow & long, d > 0.8”
V~-220 km/s, FWHM ~ 50 km/s
LVC : V ~ -100 km/s, FWHM ~ 100 – 200 km/s,
d ~ 0.4”
0.7” Gap & Redshifted Outflow

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

(2)DG Tau: Ejection of Knots

Proper motion~ 0.27 “/yr

DG TauEjection period~ 5 yrs

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

5III. Results: (3)HL Tau
Red. Jet

0.8”

2≥140 AU

Br12LVC
HVC

Close et al. (1997)(Pyo et al. 1994)

Scattering effect

HVC : Narrow and extended feature (V~-180 km/s, FWHM~ 60 km/s)
LVC : Weak and compact (V ~ -60 km/s), Peak at Y = 0”.1
Redshifted Jet : V~150 km/s, FWHM ~ 60 km/s , dAv ~ 9 mag.
Optically Thick
Disk : Rproject ~@100AU
Sub-arcsecond Workshop
NAOJ Feb.17-19. 2004

III. Results: (4)RW Aur

1997.Jan CFHT + PUEO

HVC

Dougados et al. (2000)

LVC

140 AU

Red. Jet(Pyo et al. 1994)

Blue Jet (HVC) : V~-190 – -160 km/s (decrease), FWHM ~ 60 km/s
Red Jet : V ~ 95 – 135 km/s (increase), FWHM ~ 40 km/s
LVC : Weak and compact (V ~ -100 – -20 km/s @ Y < 0”.4) (time variation)
Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

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Discussion: Velocity & Launching Points
HVC(km/s)

LVC(km/s)L1551
IRS 5~ 430~ 140~ 45(verystrong)(Stock et al. 1988)

DG Tau~ 260

HL Tau~ 250

RW Aur~ 250

Inclination
(º )

~ 140

~ 32(strong)(Eislöffel & Mundt
1998)

~ 80

~ 42±5(weak)(Lay et al. 1997)~ 100~46±3(very weak)(López-Martin et al.
2003)

Keplerian Radius(AU)HVCÆ0.05 – 0.1(~ a few x R*)
LVC
Æ0.2 – 0.4(~ Rin, disk)

Shibata & Uchida (1986); Kudoh & Shibata (1997)
V (outflow) ~ Keplerian velocity at their launching radius
Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

Discussion: Two V. comp
HVC : High velocity + Narrow velocity width
A well collimated jet launched from the star surface or its vicinity

LVC : Low velocity + Broad velocity width
Widely opened disk wind launched from the inner edge of the accreting disk

Two V components are clearly distinct in space and velocity

Two outflows Mechanisms? ( + YSOs are X-ray sources.)
HVC Å reconnection of the stellar magnetic fieldanchored to the disk
(Hayashi et al. 1996; Hirose et al. 1996;Goodson et al. 1997, 1999)

LVC Å magnetocentrifugal force(Shu & Shang 1997:X-wind, Ferriera,1997:Disk wind)
Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

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Follow Up Observation: L1551 IRS 5
PHK1

PHK1
HVC

PHK2
HVC

LVCCont.

PHK2(Pyo et al. 2004, in preparation)
LVC = Widely Opened Fast Wind
Two V components belong to the northern Jet

2002. Nov

Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

Summary
1. [Fe II] λ 1.644 µm emission line observations toward
L1551 IRS 5, DG Tau, HL Tau, RW Aur.
2. For All objects we detected two distinct velocity
components (HVC and LVC) in space and velocity.
3. We confirmed that LVC of L1551 is spatially widelyopened fast wind.
4. Velocity Structure ≠ Onion-like Structure
5. Disks: DG Tau and HL Tau Rproject ~ 100 AU
6. Redshifted Jet : DG Tau and HL Tau within d < 1”.57. Ejection events of knots every 5 years in DG Tauoutflows
8. HVC : a well-collimated jet accelerated by thereconnection of dipole stellar magnetic fields anchoredto the disk
LVC : a disk wind with large opening angle driven bymagnetocentrifugal force
Sub-arcsecond Workshop @ NAOJ Feb.17-19. 2004

Thank you8