Nagayoshi Ohashi, ASIAANagayoshi Ohashi, ASIAAKyoto Univ. 09.11.2009

Observations of Observations of Circumstellar Disks Circumstellar Disks

around YSOsaround YSOs

Observations of Observations of Circumstellar Disks Circumstellar Disks

around YSOsaround YSOs

Outline of TalkOutline of Talk

Brief introduction of the SMA Project Star formation and disk formation/evolution

Overview Disks around PMSs; HD 142527 Disks around protostars; B335

Brief introduction of the SMA Project Star formation and disk formation/evolution

Overview Disks around PMSs; HD 142527 Disks around protostars; B335

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SMA ProjectSMA Project Joint project of the SAO and ASIAA.

ASIAA joined the project in 1996. SMA consists of eight 6-m telescopes operating at

submm wavelengths (1mm to 350 m) at the top of Mauna Kea. ASIAA has delivered two telescopes with receiver

systems. Currently 230, 345, and 690 GHz bands are under

regular operation. The SMA was dedicated in November 2003. The SMA is the fore-runner to ALMA.

Joint project of the SAO and ASIAA. ASIAA joined the project in 1996.

SMA consists of eight 6-m telescopes operating at submm wavelengths (1mm to 350 m) at the top of Mauna Kea. ASIAA has delivered two telescopes with receiver

systems. Currently 230, 345, and 690 GHz bands are under

regular operation. The SMA was dedicated in November 2003. The SMA is the fore-runner to ALMA.

Kyoto Univ. 09.11.2009 3

Science using SMAScience using SMA Star formationStar formation

Jet/outflowJet/outflow Circumstellar disksCircumstellar disks Magnetic fieldMagnetic field

ExtragalacticExtragalactic Nearby galaxies/AGNNearby galaxies/AGN High-z galaxiesHigh-z galaxies

Evolved starsEvolved stars AstrochemistryAstrochemistry Solar systemSolar system

Star formationStar formation Jet/outflowJet/outflow Circumstellar disksCircumstellar disks Magnetic fieldMagnetic field

ExtragalacticExtragalactic Nearby galaxies/AGNNearby galaxies/AGN High-z galaxiesHigh-z galaxies

Evolved starsEvolved stars AstrochemistryAstrochemistry Solar systemSolar system

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Syfert/AGNSyfert/AGN OutflowOutflow

Magnetic fieldMagnetic field Solar systemSolar system

Star and Planet Formation: Overview

Star and Planet Formation: Overview

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Dense molecular cloudDense molecular cloud

A low-mass star (protostar) is formed in a dense molecular cloud core through its gravitational collapse.

The dense cloud becomes flatted (along the associated magnetic field). The associated magnetic field is also dragged inward.

A circumstellar disk is also formed around a YSO.

A molecular outflow takes place at some point.

Infall is terminated and a dense core is dispersed. The central star becomes optically visible (T Tauri star).

Planets are formed in the circumstellar disk?

A low-mass star (protostar) is formed in a dense molecular cloud core through its gravitational collapse.

The dense cloud becomes flatted (along the associated magnetic field). The associated magnetic field is also dragged inward.

A circumstellar disk is also formed around a YSO.

A molecular outflow takes place at some point.

Infall is terminated and a dense core is dispersed. The central star becomes optically visible (T Tauri star).

Planets are formed in the circumstellar disk?

Takakuwa et al. 2003Lada et al. 2003, Alves et al. 2001

Optically invisible!Optically invisible!

Girart et al. 2006

Research on Protostellar Disks and Protoplanetary Disks

Research on Protostellar Disks and Protoplanetary Disks

Formation of protostellar/protoplanetary disks; early phase (class 0 or even younger protostars)

Evolution of PSD/PPD; intermediate phase (class I and II)

Dissipation of PPD/Planet formation; late phase (class II and III)

Disks around massive stars and brown dwarfs.

Formation of protostellar/protoplanetary disks; early phase (class 0 or even younger protostars)

Evolution of PSD/PPD; intermediate phase (class I and II)

Dissipation of PPD/Planet formation; late phase (class II and III)

Disks around massive stars and brown dwarfs.

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HH211 SiO 8–7 at 0.2” (60 AU) resolutionLee et al. ApJ in press

A possible velocity gradient across the innermost pair of knots

~0.5 km /s at ~10 AU

A possible velocity gradient across the innermost pair of knots

~0.5 km /s at ~10 AU

7LAB, France 07.01.2009

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NGC1333/IRAS4A 345 GHz

Total Intensity and Linear Polarization

(B field)

Dust Polarization & Magnetic FieldDust Polarization & Magnetic Field

Girart et al. 2006Crutcher (2006),

Science, 313, 771

Protoplanetary Disk:the site of planet formation

Protoplanetary Disk:the site of planet formation

Protoplanetary disks (PPDs) are most probable sites for planet formation. Important to understand their physical conditions. Common characteristics or more variety?

More than 150 extra-solar planets have been discovered. More systems with hot Jupiters and high eccentricity. How were these extra-solar planets formed?

Protoplanetary disks (PPDs) are most probable sites for planet formation. Important to understand their physical conditions. Common characteristics or more variety?

More than 150 extra-solar planets have been discovered. More systems with hot Jupiters and high eccentricity. How were these extra-solar planets formed?

9LAB, France 07.01.2009

MM High Resolution Images of PPDsMM High Resolution Images of PPDs

Geometry: compact, disklike structures Kinematics: Kepler motions

Geometry: compact, disklike structures Kinematics: Kepler motions

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1.3 mm cont1.3 mm cont

0.6” x 0.7” 0.6” x 0.7”

(~80 AU x 100 AU)(~80 AU x 100 AU)

GM Aur (Dutrey et al. GM Aur (Dutrey et al. 1998)1998)

Protoplanetary disks with spiral arms Protoplanetary disks with spiral arms

Fukagawa et al. 2004Fukagawa et al. 2004

AB Aur @ 1.6 micronAB Aur @ 1.6 micronHD 142527 @ 1.6 micronHD 142527 @ 1.6 micron

Fukagawa et al. 2006Fukagawa et al. 2006

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HD 142527 HD 142527 Herbig Ae star (F6 IIIe; M* ~ 2Mo) Subaru observations revealed that the disk

has a spiral arm (Fukagawa et al. 2006) Subaru observations at MIR revealed a hole

in the disk (Fujiwara et al. 2006). ASTE observations suggested existence of a

gas disk. There was no mm interferometric

observations due to its low declination.

Herbig Ae star (F6 IIIe; M* ~ 2Mo) Subaru observations revealed that the disk

has a spiral arm (Fukagawa et al. 2006) Subaru observations at MIR revealed a hole

in the disk (Fujiwara et al. 2006). ASTE observations suggested existence of a

gas disk. There was no mm interferometric

observations due to its low declination.

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HD142527: Subaru Infrared Images

HD142527: Subaru Infrared Images

1.6 m CIAO image

(Fukagawa et al. ‘06)

24.5 m COMICS image

(Fujiwara et al. ‘06)

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SMA Observations of HD142527

SMA Observations of HD142527

12CO 3-2 and 340 GHz continuum simultaneous observations One track with the compact configuration One track with the extended configuration

1.2” x 0.6” for dust continuum 2.1” x 1.1” for 12CO 3-2 Ohashi & Momose (‘09, submitted)

12CO 3-2 and 340 GHz continuum simultaneous observations One track with the compact configuration One track with the extended configuration

1.2” x 0.6” for dust continuum 2.1” x 1.1” for 12CO 3-2 Ohashi & Momose (‘09, submitted)

SMA is a joint project between the SAO and the ASIAA.14LAB, France 07.01.2009

SMA Results: 340 GHz Continuum

SMA Results: 340 GHz Continuum

340 GHz continuum distribution resembles to the 1.6 m scattered emission. An arc-like structure enclosing

the central star two peaks; one at the NE and

the other at the NW. Peak positions are shifted to the

N as compared to those seen at 1.6 m.

No clear emission on the southern side.

Total flux density ~1.2 Jy

340 GHz continuum distribution resembles to the 1.6 m scattered emission. An arc-like structure enclosing

the central star two peaks; one at the NE and

the other at the NW. Peak positions are shifted to the

N as compared to those seen at 1.6 m.

No clear emission on the southern side.

Total flux density ~1.2 Jy

HD 142527HD 142527

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SMA Result ： 12CO 3-2SMA Result ： 12CO 3-2

12CO also shows a central hole, with peak emissions coincident with the infrared features.

12CO also shows a central hole, with peak emissions coincident with the infrared features.

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SMA Results: Spiral arms in gas?SMA Results: Spiral arms in gas?

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12CO 3-2 Mean Velocity12CO 3-2 Mean Velocity

Clear velocity gradient from NW to SE, which is probably due to rotation. Roughly consistent with

Kepler rotation around a 2Mo star.

Disk axis is from NE to SW? Additional velocity gradient

suggestive of non-circular motion. Any relationship with gas

possibly associated with the spiral arm?

Clear velocity gradient from NW to SE, which is probably due to rotation. Roughly consistent with

Kepler rotation around a 2Mo star.

Disk axis is from NE to SW? Additional velocity gradient

suggestive of non-circular motion. Any relationship with gas

possibly associated with the spiral arm?

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12CO 3-2 Channel Maps12CO 3-2 Channel Maps

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Is 12CO 3-2 emission optically thin?Is 12CO 3-2 emission optically thin?

12CO shows similar structures to the dust emission.

Low brightness temperature (8.5 K).

12CO shows similar structures to the dust emission.

Low brightness temperature (8.5 K).

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Chiang & Goldreich ‘97

12CO 3-2 emission may be optically thin.

HD142527: Disk MassHD142527: Disk Mass 345 GHz total flux ~ 1.2 Jy, corresponding to 4.1E-2 Mo

Gas/dust mass ratio 100; Tdust = 50K 12CO 3-2 integrated flux ~ 15 Jy km/s, corresponding

6.6E-6 Mo. [H2]/[12CO] = 104; Tex = 50 K

The disk mass derived from 12CO 3-2 is factor of 10000 smaller that that derived from 345 GHz dust. CO depletion factor ~10000? H2 dissipation factor ~10000? Combination of CO depletion and gas dissipation?

345 GHz total flux ~ 1.2 Jy, corresponding to 4.1E-2 Mo

Gas/dust mass ratio 100; Tdust = 50K 12CO 3-2 integrated flux ~ 15 Jy km/s, corresponding

6.6E-6 Mo. [H2]/[12CO] = 104; Tex = 50 K

The disk mass derived from 12CO 3-2 is factor of 10000 smaller that that derived from 345 GHz dust. CO depletion factor ~10000? H2 dissipation factor ~10000? Combination of CO depletion and gas dissipation?

22LAB, France 07.01.2009

Unknown factors to estimate massUnknown factors to estimate mass Dust temperature and CO excitation temperature

Even if we assume Td=Tex=100 K, the mass difference is still more than three orders of magnitude.

-index (mass opacity) Even if we assume a smaller -index, the mass derived

from dust becomes just a factor of 2 smaller. CO depletion factor, f(co)

Around TTSs, f(CO) has been estimated to be upto ~200. Since Td would be higher around Herbig Ae stars, f(CO) would be less than 200.

Dust temperature and CO excitation temperature Even if we assume Td=Tex=100 K, the mass difference

is still more than three orders of magnitude. -index (mass opacity)

Even if we assume a smaller -index, the mass derived from dust becomes just a factor of 2 smaller.

CO depletion factor, f(co) Around TTSs, f(CO) has been estimated to be upto

~200. Since Td would be higher around Herbig Ae stars, f(CO) would be less than 200.

Even if we take into account of these unknown factors, it Even if we take into account of these unknown factors, it still seems to be difficult to explain the mass difference still seems to be difficult to explain the mass difference of 4 orders of magnitude.of 4 orders of magnitude.

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Gas dispersal in disk by photoevaporation

Gas dispersal in disk by photoevaporation

Takeuchi et al. (‘05; see also Alexander & Armitage ‘07) studied disk clearing processes. using a model taking into account combined

effects of viscous evolution, photoevaporation, differential radial motion of dust grains and gas.

Around an Herbig Ae/Be star with more ionizing photon, a gas-poor dust ring will be formed in 106 yr.

Takeuchi et al. (‘05; see also Alexander & Armitage ‘07) studied disk clearing processes. using a model taking into account combined

effects of viscous evolution, photoevaporation, differential radial motion of dust grains and gas.

Around an Herbig Ae/Be star with more ionizing photon, a gas-poor dust ring will be formed in 106 yr.

24LAB, France 07.01.2009

Takeuchi et al. 2005Takeuchi et al. 2005 A gap is created at ~17

AU (rg) by photoevapolation

Inside the gap Both gas and dust accrete

onto star due to viscosity. Outside the gap

Gas is gradually evaporated from the inner edge, and the inner edge gets larger.

Dust accumulates at the inner edge.

A gap is created at ~17 AU (rg) by photoevapolation

Inside the gap Both gas and dust accrete

onto star due to viscosity. Outside the gap

Gas is gradually evaporated from the inner edge, and the inner edge gets larger.

Dust accumulates at the inner edge.

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Protostellar Disks around Protostars

Protostellar Disks around Protostars

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L1551 IRS5: Infalling EnvelopeL1551 IRS5: Infalling Envelope

Kyoto Univ 11.09.2009 27

C18O (1-0) with NMA

(Momose et al. 1998)

A1

A2

B1

B2

Mass ~0.08 M

Radius ~ 1200 AU

€

Vrot = 0.24 r700AU( )

−1

km/s

Vinfall = 2GMr( )

0.5

=1.59 M1M¢

⎛ ⎝ ⎜ ⎞

⎠ ⎟0.5

r700AU( )

−0.5

km/s

Freely infalling and slowly rotatingFreely infalling and slowly rotatingwith angular momentum conservedwith angular momentum conserved

P-V diagrams

0.1 Mo

L1551 IRS5: Formation of a protostellar disk

L1551 IRS5: Formation of a protostellar disk

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SMA CS7-6 mean velocity

SMA CS 7-6 Total Intensity

NMA C18O 1-0

Takakauwa, Ohashi + 2003

Specific Angular Momenta around YSOs

Specific Angular Momenta around YSOs

Kyoto Univ 11.09.2009 29

Ohashi et al. 1997

+ new data (Yen, Takakuwa, Ohashi 2009)

Specific angular momentum seems to be constant within a radius of ~6000 AU.

B335 (IRAS 19347+0727)B335 (IRAS 19347+0727)

Class 0 Protostar Lbol ~ 1.5 Lo, Tdust ~ 30 K Associated with a well developed outflow

(e.g., Hirano et al. ‘88, ‘92) Infall signatures were observed (Zhou et

al. ‘93; Choi et al. ’95; Saito et al. ‘99).

Class 0 Protostar Lbol ~ 1.5 Lo, Tdust ~ 30 K Associated with a well developed outflow

(e.g., Hirano et al. ‘88, ‘92) Infall signatures were observed (Zhou et

al. ‘93; Choi et al. ’95; Saito et al. ‘99).

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SMA Observations of B335SMA Observations of B335

12CO, 13CO, C18O 2-1 and 230 GHz continuum simultaneous observations One track with the compact configuration

3.9” x 3.3” for dust continuum 3.7” x 3.2” for C18O 2-1 (Yen, Takakuwa, Ohashi ‘09, submitted)

12CO, 13CO, C18O 2-1 and 230 GHz continuum simultaneous observations One track with the compact configuration

3.9” x 3.3” for dust continuum 3.7” x 3.2” for C18O 2-1 (Yen, Takakuwa, Ohashi ‘09, submitted)

SMA is a joint project between the SAO and the ASIAA.31LAB, France 07.01.2009

B335: 1.3 mm continuumB335: 1.3 mm continuum

Size ~ 740 AU x 350 AU Mass ~ 0.027 Mo

Size ~ 740 AU x 350 AU Mass ~ 0.027 Mo

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B335: C18O 2-1B335: C18O 2-1

Size ~ 1500 AU Partially affected by the

outflow. Mass ~ 5.2 x 10-3 Mo C18O depletion (fd ~10)

Size ~ 1500 AU Partially affected by the

outflow. Mass ~ 5.2 x 10-3 Mo C18O depletion (fd ~10)

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B335: C18O 2-1 kinematicsB335: C18O 2-1 kinematics

Kyoto Univ 11.09.2009 34

Vinfall ~ 0.31-0.44 km/s @ 370 AU, Mstar ~ 0.02-0.04 Mo, Mass infall rate ~ 4.8-6.9 x 10-6 Mo/yr

B335: C18O 2-1 Kinematics (II)B335: C18O 2-1 Kinematics (II)

Kyoto Univ 11.09.2009 35

No detectable velocity gradient along the N-S direction; Vrot < 0.04 km/s @ 370 AU

Specific Angular Momentum in B335Specific Angular Momentum in B335

4.6 x 10-3 km/s pc @ 20000 AU 5.4 x 10-4 km/s pc @ 1000 AU (Saito et al.’99) 7 x 10-5 km/s pc @ 370 AU (SMA results)

4.6 x 10-3 km/s pc @ 20000 AU 5.4 x 10-4 km/s pc @ 1000 AU (Saito et al.’99) 7 x 10-5 km/s pc @ 370 AU (SMA results)

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The specific angular momentum is not conserved outside R ~ 370 AU.

If the specific angular momentum is conserved within R ~370 AU, Rd ~ 6 AU

With ALMA?With ALMA?

Observations with spatially high dynamic range (10-10000 AU scale) Kepler disk formation; age estimation based on

the disk size? Observations with high sensitivity and

resolution Pick up the earliest phase of the disk formation. Signature of the planet formation/disk dissipation.

Observations with a large sample.

Observations with spatially high dynamic range (10-10000 AU scale) Kepler disk formation; age estimation based on

the disk size? Observations with high sensitivity and

resolution Pick up the earliest phase of the disk formation. Signature of the planet formation/disk dissipation.

Observations with a large sample.

Kyoto Univ 11.09.2009 37