Survey for Dust Continuum Emissions toward Circumstellar Disks (I - - PowerPoint PPT Presentation

Survey for Dust Continuum Emissions toward Circumstellar Disks

(I will focus on nearby T Tauri stars)

Munetake MOMOSE (Ibaraki)

Strategy

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

ALMAʼs Goals

Understanding the formation of planetary systems “general scenario” (unified theory) ? when/how a planet is formed ? core-accretion vs. gravitational instability rocky planet / gaseous planet / icy planet how common the planet formation is ? YSO Disks = Initial condition for planet formation inner regions (< 102 AU) will critically be important survey will be essential (details are in a later slide)

Previous Trial

(e.g., Kitamura et al. 2002 with the NMA)

13 Single T Tauri stars Strong continuum emission at 1.3mm 1-2” (140-280AU) resolution imaging at λ = 2mm (Image + SED) ← Model Fitting Systematic Derivation of Disk Parameters such as Σ(r), T(r), β

Images : ~ 1” resolution

contour 1.5σ interval, starting at ±1.5σ

Radial Expansion

Evolution of Accretion Disks ?

Evolution

embedded protostars

Limitation of NMA survey

Inadequate angular resolution & sensitivity Derivation of Disk Parameters: Model dependent

Observations with the ALMA

“Direct” Derivation of Disk Structure Brightness distribution at multi-λs →Σ (surface density), T (Temperature), β (emissivity) directly at each position Comparison with Cont. at mid/far-IR and Line → Vertical Structure Higher Sensitivity → Detection of less massive disks Very-high resolution (~ 1AU) observations Better than (current) Optical/nIR telescopes ?

Why we shall need “survey” ?

Statistics to discuss ... disk evolution (how to proceed planet formation ?) diversity (related to diversity in planetary systems) “Highlights” = relatively short timescale ... dust growth / formation of planetesimals (e.g., Miyake & Nakagawa 1993, Wada et al. 2007, 2008) disk clearing by proto-planets photo-evaporation / gas dispersion (e.g.,Takeuchi et al. 2005; Ohashi & Momose submitted)

Wyatt et al. 2003

Dust Disk Mass evolution

Wyatt et al. 2003

Dust Disk Mass evolution

Gap ？

Why we shall need “survey” ?

Statistics to discuss ... disk evolution (how to proceed planet formation ?) diversity (related to diversity in planetary systems) “Highlights” = relatively short timescale ... dust growth / formation of planetesimals (e.g., Miyake & Nakagawa 1993, Wada et al. 2007, 2008) disk clearing by proto-planets photo-evaporation / gas dispersion (e.g.,Takeuchi et al. 2005; Ohashi & Momose submitted)

Initial Mass Distribution vs. Resultant Planetary Systems

※based on “Core-accretion” Scenario (Ida & Kokubo 2002)

• 1: Cores (= Protoplanets) can

grow above Mcrit 2: Core accretion timescale < gas disk lifetime Gas Planets Solar System type Earth-like planets only Distance from the star (AU)

Why we shall need “survey” ?

Statistics to discuss ... disk evolution (how to proceed planet formation ?) diversity (related to diversity in planetary systems) “Highlights” = relatively short timescale ... dust growth / formation of planetesimals (e.g., Miyake & Nakagawa 1993, Wada et al. 2007, 2008) disk clearing by proto-planets photo-evaporation / gas dispersion (e.g.,Takeuchi et al. 2005; Ohashi & Momose submitted)

Dust Growth

Wada et al. (2008) Dust Emissivity: β: 2 -> 1 as dust grows where νβ

Gap by Protoplanet

Why we shall need “survey” ?

Statistics to discuss ... disk evolution (how to proceed planet formation ?) diversity (related to diversity in planetary systems) “Highlights” = relatively short timescale ... dust growth / formation of planetesimals (e.g., Miyake & Nakagawa 1993, Wada et al. 2007, 2008) disk clearing by proto-planets photo-evaporation / gas dispersion (e.g.,Takeuchi et al. 2005; Ohashi & Momose submitted)

1-D Simple Model to examine survey strategy

内部構造：

• Axisymmetric, Physical parameters as a function of r

– Boundaries : rin, rout – Temperature: T(r) ∝ r−q. ∗ Source Function: Sν(r) = Bν(T(r)) – Surface Density: Σ(r) ∝ r−p. – Dust Emissivity: κν(r) ∝ νβ(r) ∗ Vertical Optical Depth: τν(r) = κν(r)Σ(r)

• Observer’s Parameters:

– Distance: d – Inclination; i

Beckwith et al. (1990)

Chiang & Goldreich (1997)

see also Dullemond et al. (2001)

Vertical Structure ?

Almost all the Submm - mm Continuum will come from interior part because

• f its lower opacity ...

→ “1-D” approx. is OK

Strategy

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

Best Frequency Bands for Detection Survey

Frequency [GHz] 100 1000 Relative Mass Sensitivity (1 at 110GHz) 1 10 T = 20 K = 50 K = 80 K –––– –––– ––––

β=1 case

Mean Temperature (Mass-weighted) ※ 23 K for the sample in Kitamura et al. (2002) ν = 345 or 675 GHz ?

円盤質量 で近似的に予想される を として， すべての場合，点源で検出として，ある時間での達成感度を とし，

• ∆Fν

κνBν( ¯ T)

が小さいほうが有利。

※ proportional to

¯ T ≡ rout

rin

2πrΣ(r)T(r)dr Md for the sample in Kitamura et al.

円盤質量 で近似的に予想される を として， すべての場合，点源で検出として，ある時間での達成感度を とし， が小さいほうが有利。

Point-Source Detection

Assuming ¯ T = 20 K and β = 1 ...

• ν = 345 GHz

∆Mdisk = 10−5M

• d

150 pc 2 tinteg 157 sec −1/2 . (3)

• ν = 675 GHz

∆Mdisk = 10−5M

• d

150 pc 2 tinteg 64 sec −1/2 . (4) c.f. MJupiter = 10−3M, MEarth = 3 × 10−6M.

Strategy

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

Strategy

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

“Typical” Disk Paramaters around CTTSs

• -- From Kitamura et al. (2002) ---

Σ(r) = 100

• r

1 AU −1 [g cm−2] rin = 0.03 [AU], rout = 300 [AU] (− → Md = 0.021 M)

• −

→

• T(r) = 200
• r

1 AU −0.6 [K] β = 1

d = 150 [pc] i = 60◦

for sensitivity calculation ...

← 0.1× Σ

• f the Hayashi Model

at r =1AU

• −

κν = 0.1 cm2 g−1 250µm λ β :

Frequency: 100 GHz 230 GHz 345 GHz 675 GHz 875 GHz –––– –––– –––– –––– –––– Radius [AU] 0.1 1.0 10.0 100 Emissivity 1 0.1 0.01

Radial Emissivity (opacity) Distribution

ǫ = 1 − exp(−τ)

d = 150 [pc] Σ(r) = 100

• r

1 AU −1 [g cm−2] T(r) = 200

• r

1 AU −0.6 [K] β = 1 rin = 0.03 [AU] rout = 300 [AU] Md = 0.021 M i = 60◦

3AU 10AU 30 AU 100AU 300AU r=1AU Brightness [erg/s/cm2/Hz/str] 10-10 10-12 10-14 10-16 10-18 Frequency [GHz] 100 1000

“Local” SEDs

代表的半径における輝度の周波数特性

• ν2 (RJ & τ 1) → ν2+β(τ 1) → flatter due to lower T

d = 150 [pc] Σ(r) = 100

• r

1 AU −1 [g cm−2] T(r) = 200

• r

1 AU −0.6 [K] β = 1 rin = 0.03 [AU] rout = 300 [AU] Md = 0.021 M i = 60◦

Effective Brightness Temperature Distribution

Frequency: 100 GHz 230 GHz 345 GHz 675 GHz 875 GHz –––– –––– –––– –––– –––– Radius [AU] 0.1 1.0 10.0 100 104 102 100 10-2 10-4 Effective Brightness Temperature [K]

d = 150 [pc] Σ(r) = 100

• r

1 AU −1 [g cm−2] T(r) = 200

• r

1 AU −0.6 [K] β = 1 rin = 0.03 [AU] rout = 300 [AU] Md = 0.021 M i = 60◦

k ≡ ν J(T) = hν k 1 exp hν

kT

• − 1

Frequency: 100 GHz 230 GHz 345 GHz 675 GHz 875 GHz –––– –––– –––– –––– –––– Radius [AU] 0.1 1.0 10.0 100 104 102 100 10-2 10-4 Effective Brightness Temperature [K]

d = 150 [pc] Σ(r) = 100

• r

1 AU −1 [g cm−2] T(r) = 200

• r

1 AU −0.6 [K] β = 1 rin = 0.03 [AU] rout = 300 [AU] Md = 0.021 M i = 60◦

k ≡ ν J(T) = hν k 1 exp hν

kT

• − 1
• Imaging at ν = 345 GHz ...

∆T = 21mK

• BW

16 GHz −1/2 θbeam 0.1

• −2

tinteg 120 min −1/2 (13)

Measurements of β

Radius [AU] 0.1 1.0 10.0 100 Power-Law Index (I ) 270/230 GHz 145/130 GHz 130/100 GHz –––– –––– ––––

2 3 4 1

d = 150 [pc] Σ(r) = 100

• r

1 AU −1 [g cm−2] T(r) = 200

• r

1 AU −0.6 [K] β = 1 rin = 0.03 [AU] rout = 300 [AU] Md = 0.021 M i = 60◦

τ ≪ 1, Rayleigh-Jeans approx. − → Fν ∝ ν2+β

• Simultaneous Measurements at ν = 130 & 145 GHz

– ◎ Minimize the effect of T(r) – ◎ Avoid systematic error (similar beam, noise level ...)

× ×

Frequency: 100 GHz 230 GHz 345 GHz 675 GHz 875 GHz –––– –––– –––– –––– –––– Radius [AU] 0.1 1.0 10.0 100 104 102 100 10-2 10-4 Effective Brightness Temperature [K]

d = 150 [pc] Σ(r) = 100

• r

1 AU −1 [g cm−2] T(r) = 200

• r

1 AU −0.6 [K] β = 1 rin = 0.03 [AU] rout = 300 [AU] Md = 0.021 M i = 60◦

k ≡ ν J(T) = hν k 1 exp hν

kT

• − 1

◎ ◎ × ×

• Brightness Temperature J(T) inside r < 100 AU

– J(T) ≥ 100 mK at ν = 145 GHz for Md ≥ 10−2M

∆T = 90mK BW 8 GHz −1/2 θbeam 0.1

• −2

tinteg 2400 sec −1/2 (12)

Frequency: 100 GHz 230 GHz 345 GHz 675 GHz 875 GHz –––– –––– –––– –––– –––– Radius [AU] 0.1 1.0 10.0 100 104 102 100 10-2 10-4 Effective Brightness Temperature [K]

k ≡ ν J(T) = hν k 1 exp hν

kT

• − 1

How to derive T (r) ?

• Cont. at Mid-Infrared ?

Vertical Temperature Gradient (mIR: surface layer with higher temperature)

Some Line tracing interior regions (CO isotope ?)

Complex radiative transfer

Submm Continuum (if τ >>1)

Chiang & Goldreich 1997

Strategy

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

Summary

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

Summary

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

can do now !

e.g., AzTEC on ASTE Survey toward Cham/Lupus YSO catalogue (Disk Mass Function)

Summary

0.1" imaging at higher freq (=345 or 675GHz)

0.1

′′(

> 10−3M⊙) ∆T ∼ 20 mK Exposure Time ∼ 120 min. each Targets ∼ 30 − 50

0.01" Deep imaging at =345 or 675GHz

∆T ∼ 500 mK Exposure Time ∼ 9 hrs each Targets ∼ 5 − 10?

0.01" Snapshot at = 230 - 875 GHz for derivation of T(r) in the inner regions

∆T ∼ 5 K Exposure Time ∼

• 30min. each

Targets ∼ 30 × freq

Observations of Dust Disks in Star Forming Regions (d ~ 150 pc)

~ 1" ~ 0.1" ~ 0.01"

No Detection

Detection

Detection Survey at =345GHz

Detection Limit ∼ 0.11 mJy ∼ 10−5M⊙ Exposure Time ∼ 3 min. each Targets ∼ 100 − 200

Deep Detection Survey at =345 or 675GHz

Detection Limit ∼ 0.011 mJy ∼ 10−6M⊙ Exposure Time ∼ 5 hrs each Targets ∼ 10 − 20

• index measurement in

Band 4 (=130/145GHz)

0.1

′′(

> 10−2M⊙)

• r 0.3

′′(

> 10−3M⊙) ∆T ∼ 90 mK Exposure Time ∼ 40 min. each Targets ∼ 30 − 50

can do now !

e.g., AzTEC on ASTE Survey toward Cham/Lupus YSO catalogue (Disk Mass Function)

can do also !

e.g., SMA Imaging Subaru SEEDS (something interesting sources)

GG Tau: Dust and Gas

2.2μm 散乱光 (Itoh et al. 2002) 1.3mm Dust + CO (Guilloteau et al. 1999)