THE STAR FORMATIONNEWSLETTER
No. 257
塚越崇 (茨城大)
13 Jun. 2014

A Test of Star Formation Laws in Disk Galaxies. II.
Dependence on dynamical properties
C. Suwannajak et al.
• 銀河スケールのstar formation lawsをテスト• 6つのSFL• Kennicutt-Schmidt law• Constant Molecular law• turbulence-requlated star formation model (KM05 law)
• turbulence-requlated star formation model (KM09 law)
• Gas-Omega law• shear-driven GMC collision law• 各法則から導出される星形成率分布と、観測結果(近傍銀河16個)を比較• 各法則のパラメータと星形成効率の比例係数をchi-squareフィット• 他の細かいパラメータは固定• どのモデルも良く観測を再現• 領域によって、GMC collision、Constant Molecular lawが最適解

• どのモデルも良く観測を再現• 領域によって、GMC collision、Constant Molecular lawが最適解
4• 銀河運動に絡む3つの量とKS検定による比較
4. results

βFormation Laws
• rotation curve4.1.gradient
Test of StarFirst, we examine how well the star formation laws described in §2 do in predicting the SFR as a function of galactocentricrotationradius, given their required
inputs. speed
Note that these input requirements diﬀer: e.g. the Constant Molecular law only needs
the surface density of molecular gas, while some of the other laws require multiple inputs, each of which has inherent
observational uncertainties.
Thus, while
presenceofthe
a relative
bar accuracy with which the laws can predict SFRs is still interesting (e.g.,
if one is concerned with how accurate the use of given law will be in a model of galaxy evolution), this relative ordering
may not necessarily distinguish between which physical mechanism(s) is responsible for setting SFRs. In addition, there••• =>どれも大きな違いなし。後者二つはGMC collision lawでわずかな違いあり？

Reflection nebula

A very young, compact bipolar H2O maser outﬂow in theNW 1LkHȘ 234

intermediate-mass star-forming LkHa234 regionC (IRS 2)5"
17.6 µm

J.M. Torrelles et al.

NW 2
NW 1
LkHȘ234• 中型星周りのdisk-YSO-jet system
はまだ良く分かっていない

5"• VLBAを用いた複数エポックのH2O

66 06 59

メーザー観測• 0.1mas resolution• 4つのYSOからメーザーを検出• LkHa234本体は未検出• VLA2周りで対象なメーザースポッ
ト -> 今回はこれに着目• ジェット起源• 中心星情報無し

DECLINATION (J2000)• HBe型星LkHa234周辺のYSOが対象

VLA 1
5857

56

VLA 2 (NW2)

VLA 3 (NW1)55

LkH 23454
21 43 06.806.7

06.6

06.5
06.4
06.3
06.2
RIGHT ASCENSION (J2000)

06.1

06.0

• VLA2 - intermediate mass star
• 500L⦿, 6M⦿ : 3.6 cmがHII region起源なら• 50L⦿, a few M⦿: 3.6 cmがジェットのショック起源なら• 高分解能観測で3.6cmの向きを分解する事が必要• H2O maser spot• bipolar jet起源 - CO outﬂowや[SII]とコンシステント• dynamical time ~40 yrs - episodic ejectionの一つかも• momentum rate: 1E-6 ~ 1E-3 M⦿/yr km/s

• FUOriのような非定常降着の証拠の中型星版

H2 O maser outflow in the LkHα 234 region7

is derived to decrease.
Near-infrared
fromsublimatingin collisionally
10 Tau,⇠ Boo, and  CrB, the emission
possibility that theobserved
NIR excess is due todust
a low-masscompanion within theR. van Lieshout et al.: NIR emission from sublimating dust in debris disks
xcluded (Absil et al. 2013).

active debris disks

2.3. Pile-up in a collisionally active disk

sublimation

6et al. (2006); (A08) Absil et al. (2008); (Ab09) Absil et al. (2009); (Ak09)10Akesonet al. (2009); (A13) Absil et al. (2013);
R.
vanLieshoutetal.
SoCiardi
far,
weetlooked
separately
the balance
between (C06)
P–R drag); (C01)al.
(2001);(C05)at Chenet al. (2005);
Chen et al. (2006); (D00) Dent et al. (2000); (D04) di Folco
5and(2007);collisions(withoutconsidering
sublimation),at the bal10(E13)co et al.
(D11)
Defrèreet al. (2011);(D12)and
Defrèreet al. (2012);
Eiroa et al. (2013); (G04) Greaves et al.
デブリ円盤の黄道帯ホットダスト
ance
between
P–Rdragandsublimation(withoutconsideringal. (2013); (K05) Kalas et al. (2005); (L94) Lagage & Pantin (1994); (L09)
Lawler et al. (2009);
ns (L13) Lebreton et al.
o4icollisions).
Wenow
investigate
underwhatconditions
thispair10 Plavchan et al. (2009);
llisal. (2009); (M13) Marshall et al. (2013); (P97) Pantin et al. (1997); (P09)(S13) Su et al. (2013);
ocの起源
wise approach is justified, and combine the previous findings to).
estimate the distribution of dust in a debris disk in which all three103

processes•areNIR干渉計で見つかっている超過成分
operational.

t [yr]•102

drag

limation can leadto a local enhancement 2. Analytical constraints
R
どのように供給しているか不明
1
2.3.1. Do•collisions
interfere with dust pile-up?
P10
tion zone, leading to radial distributions
In thissection
investigate the distribution of dust
collisions
might
interfere withmodthe processof dustpile- we analyticallythose Sincefoundbythemorphological010
in the inner
regions of debris disks. We focus on the radial distriup, •the ポインティング・ロバートソン効
results of Sect. 2.2 are only valid if collisions
do noty investigate
thispile-upe↵ectfordragplay an important role at distances where sublimationbutionbecomesof material, byassuming
rpile that (1) the disk is axisymmetric,
rcrit r010−1which significant.
collisions
areunimportant,
and
it
is
果によるダスト供給を計算
We now investigate whether collisions can indeed beand (2) all particles have0.01 the same
0.1 size. Throughout
1
10this work,100
neglected in the inner
regions ofare
debrisdisks by comparing theo the phenomenon
if collisions
taken
r[AU]
distributions
are expressed in terms of vertical geometricalcharacteristic
timescales of the three processes radial
as a functionof• 衝突とsublimationも入れる
optical depth, which
is definedas thesurface
densityof ofcrossradius.
Fig. 2. The
characteristictimescale
as function
radialdistance2
the case of a very dense parent belt (⌘0 section.
1), ⌧geo (r)is for(Eq. 15), P–R
drag above,(Eq. 2), andUnder
thesublimation
two assumptions
listedit ismutual
givencollisions
by- 連続方程式使って円盤内側の定常分布を解く•In 計算given by Eq. 5. Putting this in Eq. 3 results in the minimum
aminecollisional
whethertimescale
it is possible to maintain(minimum timescale, Eq. 23), for = 0.5 particles in a debris
disk around a solar-massn(r)star with a very dense (⌘01) parent⌧(r)=.
verticalgeometrical
opticaldepthによる記述:•geo
belt located at 30 AU. The
grey vertical lines indicate the(1)radiale sublimation zone of a crcollisionally
3/2 ⇣ p2⇡r
p ⌘acmina[tpile-upr0r the,r  r0 .
(23) distances used by the analytical model: rpile is the radius forwhether suchcoll (r)] = could explain• 流れ GM?
whichdistancethe sublimation
equalsthe P–R
dragcrosstimescale,Here, r is the radialfrom timescalethe centralstar,is theion observed very close to some stars. To
rcrit is theradius
the P–Rdrag timescaleequals thesectionof anda particle,andn(r)foriswhich
the onedimensional
numberIn Fig. 2 thistimescaleiscomparedwiththesublimation
he steady-state
distribution
of
dust
in
the
collisional timescale, and r0 is the location of the parent belt.
• 仮定を使って解析的に解く
density(i.e.,
theparticle number density integrated over disk
P–R
dragtimescales
foradebris
diskaroundasolar-massstar
For the sublimation timescale, we assume that the dust grains
ks, under
theinfluence
ofcollisions,P–R
with a dense parent
beltdrag,
at 30 AU,
consistingsublimationを入れてモデル生成。self-consistentに解く
of barelyand
boundheightazimuth).
are solid spheres of graphite (see Sec. 2.2.1 for the values of theP-R
collision,•by solving
thecontinuity
equation.
First,( = 0.5) dust grains, using the sublimation parametersofparameters)with a radiusof s = 0.64 µm(the size
We considersublimation
three processesa↵ecting
the evolutionof dustsolution,usingIn athis
numbersimplifying
graphite.
exampleofsystem,the collisional timescale is corresponding to = 0.5).
観測と比較
particles
debris disks: collisions, P–R drag, and sublimation.
• otherlonger than thetimescalesat rpile , implyingthat P–R indrag
Subsequently,
wesolvethe continuity

• 解析解• P-R dragによるinward ﬂow• sublimating dustの堆積• inner diskでは衝突よりP-R dragが支配的で、衝突成長は集積を妨げない• Numerical modeling• 特定のケースを計算し解析解と比較• radial distribution• 解析解に従う• 堆積メカニズムは解析解より非効率• size distribution• 観測と比較• P-R dragによって少量のダストが内側に運ばれるが、これによる赤外超過は極めて小さく、観測を説明出来ない。

h|BV |ittProtProtRo
Ro

0.79
0.81
0.54
0.72
0.80a
0.71a
0.64
0.81
0.79

< 0.01< 0.01< 0.01< 0.01< 0.01a< 0.01a< 0.01< 0.01< 0.010.655 ± 0.045
0.622 ± 0.042
1.32 ± 0.14
1.31 ± 0.11
1.38 ± 0.14a
1.19 ± 0.14a
1.80 ± 0.20
1.61 ± 0.15
1.82 ± 0.18

Stellar magnetism: empirical trends withage and rotationh|B |iV

V

A.A. Vidotto et al.

V

h|BV |iV• 低質量星のsurface Bと、年齢、回転、X-ray放射との関連を調査
h|B |i
LX
LX /LbolLX /LbolVVV0Fits considering only p• Zeeman Doppler Imaging(ZDI)によってmagnetic mapを取得してaいる論文から104天体をコンパイル

2.5
 |t• 0.1-2.0 M⦿, 1Myr-10Gyr

1.5• non-accreting object• surface Bは年齢,Prot等と相関あり• accreting object

109log(t [yr])2.0log(
 [G])• 
の導出<0.655 ±0.045

1.0

solar
solarlike
like
young
youngsuns
suns
H-J
hosts
H−J
host
early-dM
early−dM
SunSunT Tauri

80.5

70.0

1.96 ±0.15

t |Prot• non-accretingに比べて相関が見られない

678log(t [yr])96−0.5100.0loFigure 2. interactionによるもの
Correlation between the average large-scale field• magnetic ﬂuxとrotation periodに弱い相関->star-diskstrength derived from the ZDI technique h|BV |i and age t, forthe non-accreting stars in our sample. The trend found (solid line)
has a similar age dependence as the Skumanich law (⌦? / t 0.5 ).
This relation could be used as an alternative method to estimate
the age of stars (“magnetochronology”).

• ZDIとZeeman Broadening測定の結果がコンシステント-> small, large scale ﬁeldは共通のダイナモ生成過程

I|>の測定(large+small• ZDIは
の測定(large scaleに感度)、ZBは<|B
3.1.2
Correlation with rotation scale)periodStellar winds are believed to regulate the rotation of MS

Complex organic molecules in protoplanetary disks
C. Walsh et al.

• 円盤のcomplex organic molecules (COMs)の計算• アバンダンスと柱密度分布• 今後のALMA観測でのfeasibilityの見積もり• Model• 標準的なTTS周りの円盤, face-on• X-ray(TWHya), UV ﬁeld(中心星+ISM), cosmic-ray, mixed dust-gas• self-consistentに温度分布を解く• grain surface moleculeとgas-phase moleculeのアバンダンスを計算• LTEで輝線強度を計算• grain surfaceのほうがgas phaseよりアバンダンス/柱密度↗
• 複雑な分子ほどgas phaseのアバンダンスが減る• gas phase molecule(H2CO,HC3N)は円盤構造に依存しないgas phasegrain surface

surface densities

放射予想(d=140pc)

• 観測との比較• H2COやCH3OH(上限値)の柱密度は観測と合う• HC3Nは観測と合わない。恐らく検出天体が特殊(LkCa15, GOTau)な為• ALMAでの観測• 300GHzのメタノールは最も強い。重要なターゲットラインになる• grain surface chemistryを知る上での重要なライン• hot coreで受かっているCOMはfull-ALMAといえどもチャレンジングである• grain surface moleculeのアバンダンスはcometのものとコンシス
テント=>cometが円盤内のダスト集積によって生成されたことを示す