Collisions of small ice particles under microgravity conditions
C. R. Hill1, D. Heißelmann2,3, J. Blum2, and H. J. Fraser1•ミリメートルサイズ(4.7-10.8mm)の氷ダストの衝突実験論文 (ドイツ)•microgravity実験 (低速度衝突を実現するために必要)•放物軌道の飛行機の中で22sの無重力状態 (0.01g0)•研究の目的：パラメータ(衝突前後の速度比ε、インパクトファクターb、衝突速度)によって衝突がどう変わるか調べる。
サンプル選び(丸いものを持ってくる)
A&A 573, A49 (2015)

ぶつける
C. R. Hill et al.: Collisions of small ice particles under microgravity conditions

retained in the colosseum, and further kept from radiative heating by a fully enclosed U-shaped copper heat shield, which isalso attached to the copper cooling block. The colosseum moves
within this assembly to initiate a collision. The colosseum must
be rotated until two of the holes in the colosseum are aligned diametrically opposite each other, and with two accelerating pistons(positioned outside the heat shield and vacuum chamber), as wellas the exit guides (attached to the inner heat shield), which lead
into the collision volume. As liquid nitrogen is not permitted on
board the parabolic flight aircraft, during flight campaigns thecooling is stopped prior to flight and the copper block then acts
as a heat sink (and a cryopump for any water vapour left in thevacuum chamber – leaving the actual vacuum dominated by H2 ,CO and N2 gas, Fraser et al. 2002). Inevitably there is a slow risein temperature over the course of the flight (see Sect. 4.4), typically meaning collisions are studied in the range of 130–160 K.
Since the whole system is encased in a vacuum chamber, thispressure-temperature regime is well below the range at whichsurface melting, sublimation or desorption of the ice would beanticipated(180–200 K; Ehrenfreund et al. 2003).
Fig. 3. Examples of ice particles produced by syringing
water droplets
into liquid nitrogen. The polycrystalline nature of the ice is Once
evident thefromcolosseum is aligned, particle collisions are initisequence of two ice spheres colliding at a relative velocity
the physical appearance of the particles, as is the anisotropy
and roughated using
the hydraulic piston assembly. The piston heads are Fig. 2. Image−1of0.42ms.
The images were captured using mirror optics with theness of the surfaces. The particles indicated by a solid
circleareexattached to the piston assembly outside the vacuum chamber,
amples of the sort of particle that was selected for the experiments. Fig. 4. Image sequence of two ice fragments colliding at a relative
viewve-on the left separated from the view shown on the right by 60◦ . The
feedbecausethrough a differentiallypumped translational flange, so
Particles such as the ones indicated by a cross were andrejectedfour
successively numbered images were taken 1/107 s apart. The twolocity of 0.36 m s−1 . The images were captured using mirror optics
withthatat restbythea headtips
retractfromthe rotating
colosseumof their irregular shape and particles such as the ones
indicatedthe view on the left separated
from the viewshown onto
thesitright viewsby 60◦ .appear to be offset due to the set up of the mirror optics.
dashed circle were rejected due to their hemisphericalwithinshape. the outer The
regionthe U-shaped
copper
Thes apart. The
four ofsuccessively
numbered
imagesheat
wereshield.
taken 1/107
two views
appearto be offset
due tothe set up of
the mirror
piston tips are madeof gold
coatedcopper,
providinglarge
ther- optics.
malofconductivity
and heat capacity. They are mounted at the end strobes were started, the colosseum would be rotated to align theThis can be seen in Fig. 3, which shows a sample
ice partinextofset of stored particles, and the pistons then fired; repeatinga hollowstainlessrod of low
thermalpro-number
cles produced by this method, tipped out of theirofliquidN2 bathdue tosteel
the sphericalnatureof theconductivity
particles, a large
注：サンプルは、上記の丸いもの(spheres)と、砕いて作った凸凹な破片(fragments)の２種類を用意
whole collision process.
into air. It is clear that the polycrystalline ice particles
areneverthemrolledoutof
theirholders
duringflight.
This
meantviding the mechanical coupling to the accelerator. Between the thethat
transparent (see the examples marked with a solidcircle).
Of
few
good
collisions
wereobtained
and
sofor
theremainingtwo
Due to these procedures we are therefore reassured that overexperiments the piston heads were retracted in the cold environ-•結果•衝突の結果基本的に跳ね返る。全くくっつかない。時々破片は出る。
•ε(衝突前後の速度比)はバラけるので、一定の値を使ってはいけない•εは0.08-0.65まで広がっているが、平均は0.36•→衝突によって失うエネルギー少なくとも58%(=1-0.65^2)•εと衝突速度やインパクトファクターに相関はない

A&A 573, A, A49 (2015)

1.0

ε limit for ice spheres(d = 1.5 cm,v = 0.06−0.22 m s−1)
ε limit for this data

0.5

2.0

0.1

0.2
0.3
0.4
Relative impact velocity (m s−1)

2.0
Coefficient of restitution, ε1.5

0.00.0icient of restitution, εII

Spheres
Fragments

Spheres

Fragments＊最近のarXivに関連論文 http://arxiv.org/abs/1501.00830

Spheres
Fragments

Average error1.5

1.00.50.0
0.00.5ent of restitution, εII

Coefficient of restitution, ε2.0

2.0

0.2

0.4
0.60.8
Normalised impact parameter, b/RSpheres
Fragments

Collisionsof small ice particles under microgravity conditions (II): Does the chemical composition of the ice change
1.5
1.5
the collisional properties? C. R. Hill, D. Heißelmann, J. Blum, H. J. Fraser
メタノール5%やギ酸5%を混ぜても結果は変わらない
1.0

1.0

CHONDRULE DESTRUCTION IN NEBULAR SHOCKS
Emmanuel Jacquet and Christopher Thompson(片岡) この論文読んでも何がいいたいのか、何が新規性なのかわかりませんでした。すいません•背景•隕石にはコンドリュールと呼ばれる1mmくらいの粒構造が見つかっていて、これは高温溶融過程を経ないとできない。円盤のショックなどで過熱することが考えられている。

•サイズの違う溶ける前の天体同士が速度差がついてぶつかり壊れる•結果•gas-dominatedな時•減速中にミクロンサイズのダストは溶けきらない•solid/gas>0.1ならば高速衝突で壊れるかもしれない(でもその速度がいくつか書いてない)•solid-dominatedな時•より小さな速度で温度が上がる

THE STRUCTURAL EVOLUTION OF FORMING AND EARLY STAGE STAR CLUSTERS
Karl O. Jaehnig , Nicola Da Rio , Jonathan C. Tan2

•angular dispersion parameter (δADP,N)•星団の星の分布にsubstructureがあるかを調べる量。以前の自分たちの論文で定義•18の星団で δADP,N を測った。MYStIXというサーベイデータ。
•Chandra X線とUKIRT 赤外線、スピッツァーのデータ•結果•等方ではない (δADP,N>1)•δADP,Nと星団中心からの距離に相関があった
Fig. 2.— Continued from Figure 1.
•面密度高いor年齢が高いとよりスムーズな分布だった
of equal area, each containing ni stars. ADP,N is the•dynamical processでsubstructureが消えるのはかなり若い段階で進んでいる
Jaehnig
computed
as: et al. 2014vu
N=6のときNuX
1t(niADP,N =(N 1)n̄ i=1n̄)2 =s2.
2P oisson(1This parameteris subject to a statistical error, whic
１つの領域にni個の星がいる
does not depend only on the number of sectors N
and can be decreased further by averaging all possibl
等方に星が並んでいる時: δADP,N=1
orientations of the sector pattern (see DTJ14). Fo>1
ansubstructureがある時:
isotropic centrallyδADP,N
concentrated
cluster, ADP,N ' 1

TABLE 1
Cluster•等方ではない (δADP,6>1)

4

Orion Nebula
Carina Nebula a)Carina Nebula b)
Carina Nebula c)Eagle Nebula
M 17
NGC 6357 a)
NGC 6357 b)
NGC 6357 c)
Lagoon Nebula
Rosette Nebula
W3
NGC 6334
NGC 1893
NGC 3576
NGC 2264
DR 21
RCW 38
W4NGC 2362
Flame Nebula
RCW 36d(pc)
414
2300
2300
2300
17502000
1700
1700
1700
1300
1330
2040
1700
3600
2800
913
1500
1700
2040
1480
414
700

t⇤
(Myr)
1.6
3.3
3.3
3.3
2.1
1.3
1.3
1.3
1.3
2.1
3.1
...
1.7
2.6
...
2.4
1.9
...
...
3.5
1.0
1.3

R60
(pc)
0.06
0.14
0.56
0.54
0.25
0.19
0.20
0.27
0.22
0.17
0.50
0.22
0.26
0.58
0.33
0.38
0.23
0.13
1.03
0.49
0.08
0.12

Jaehnig et al. 2014

Rh
(pc)
0.34
1.56
1.89
2.72
1.31
1.34
1.11
0.65
1.40
0.89
1.36
1.55
0.89
2.86
1.04
0.98
1.43
0.842.39
1.18
0.21
0.42

Rmax
(pc)
0.86
3.97
3.38
5.27
3.03
4.06
2.33
1.45
2.49
1.76
2.04
4.23
1.92
5.47
3.58
1.64
2.87
2.52
3.70
2.53
0.48
1.16

ntot

Na

1200
1800
960
1020
1260
1800
540
360
540
480
420
900
360
840
480
360
480
660
300
360
300
300

20
30
16
17
2130
9
6
98
715
614
8
68
11
5
6
5
5h ADP,6 i
R60
Rh
Rmax
0.74 1.42
1.57
1.01 1.30
1.41
0.82 1.27
1.43
1.36 1.55
1.64
1.35 1.52
1.77
1.01 1.49
1.78
1.36 1.34
1.56
1.10 1.36
1.38
1.30 2.06
2.06
1.65 1.66
2.24
1.07 1.10
1.20
1.55 1.61
1.39
1.25 1.40
1.64
1.23 1.72
2.27
1.00 1.59
1.38
1.41 1.73
1.93
1.53 1.74
1.61
0.81 1.20
1.29
1.24 0.97
1.20
0.61 0.86
1.36
2.00 1.73
1.58
1.06 1.14
1.16

MST Q
Rh
Rmax
0.83
0.89
0.79
0.90
0.76
0.82
0.74
0.83
0.79
0.90
0.81
0.99
0.83
0.88
0.80
0.89
0.89
0.84
0.86
0.84
0.80
0.80
0.86
0.92
0.82
0.76
0.81
0.79
0.82
0.86
0.78
0.76
0.80
0.80
0.89
0.95
0.81
0.85
0.81
0.87
0.74
0.93
0.88
0.99

0ADP =

Cluster

low res.

high res.

a + b( RR )ha + b log( NN⇤ )⇤hN

a + b log( N dyn )dyn,hNdyn = t⇤ /tdyn

p-valueabp-valueabp-value
ab
R60
Rh
Rmax
Orion Nebula
0.009 0.77
0.19
0.007 1.02 -0.24
0.006 0.89 -0.32 24.4 5.84
2.06
Carina Nebula a)
0.002 0.76
0.22
0.002 1.02 -0.22
0.002 0.90 -0.29 14.2 1.52
0.53
Carina Nebula b)
0.003 0.59
0.390.002 1.00 -0.44
0.003 0.84 -0.57 1.83 0.83
0.49
Carina Nebula c)0.509 1.00 -0.01
0.316 1.00 -0.06
0.309 0.98 -0.08 1.95 0.51
0.26
Eagle Nebula
0.005 0.73
0.25
0.002 1.02 -0.31
0.002 0.86 -0.41 3.83 1.08
0.42
M 17
0.051 0.85
0.13
0.003 1.01 -0.26
0.003 0.85 -0.35 3.60 0.75
0.20
NGC 6357 a)
0.039 0.55
0.44
0.088 1.05 -0.34
0.092 0.94 -0.43 3.35 0.57
0.25
NGC 6357 b)
0.273 0.88
0.09
0.214 0.98 -0.180.209 0.95 -0.23 2.16 0.99
0.42NGC 6357 c)
0.450 0.98
0.02
0.233 1.03 -0.13
0.213 0.98 -0.17 2.96 0.40
0.23
Lagoon Nebula
0.012 0.46
0.50
0.025 1.06 -0.45
0.024 0.93 -0.58 6.70 1.15
0.59
Rosette Nebula
0.100 0.55
0.47
0.116 1.03 -0.50
0.121 0.93 -0.60 2.04 0.91
0.65
W30.713 1.10 -0.08
0.806 0.99
0.14
0.814 1.05
0.18 4.50 0.68
0.21
NGC 6334
0.050 0.69
0.26
0.089 1.01 -0.27
0.079 0.95 -0.35 2.90 0.81
0.36
NGC 18930.001 0.35
0.62
0.001 1.03 -0.62
0.001 0.82 -0.79 1.37 0.33
0.18
NGC 3576
0.933 1.21 -0.13
0.843 1.02
0.15
0.842 1.06
0.19 2.47 0.87
0.19
NGC 2264
0.175 0.65
0.32
0.194 1.03 -0.37
0.192 0.94 -0.46 2.34 0.99
0.65
DR 21
0.805 1.12 -0.11
0.708 1.00
0.07
0.696 1.01
0.08 4.01 0.52
0.26
RCW 380.324 0.94
0.05
0.246 1.01 -0.09
0.240 0.97 -0.12 9.63 1.48
0.38
W40.132 0.44
0.57
0.165 1.06 -0.59
0.173 0.94 -0.72 0.44 0.22
0.15
NGC 2362
0.040 0.29
0.58
0.037 0.96 -0.83
0.035 0.79 -1.07 2.39 1.10
0.49
Flame Nebula
0.722 1.19 -0.16
0.755 1.00
0.26
0.755 1.06
0.35 9.79 4.22
1.55
RCW 36
0.423 0.99
0.01
0.313 1.00 -0.04
0.310 0.99 -0.05 7.38 1.90
0.54
Fig. 3.— ADP vs R for all MYStIX regions of our analysis. Top panels indicate our low-resolution profiles (the average within 3 bins perNote.
— ntotis thetotal numberof stars within
Rmax, dividendin NThePearson’scorrelationcoe cient p-values
a annuli.
cluster: R60 , Rh and Rmax), bottom
panelsindicate
the high-resolution
profiles,wherefor eachcluster
all theradialbins fromthe centercluster
areassuming
thehighresolution
profileofandcircularsymmetry.
Values<0.5(green)
indicate
correlation in theADP,6(each containing 60 sources) are denoted. The right-hand panels show the correlations between the quantities in each axis is normalized asdirection.
Clusterages
tarefrom
Getmanetal.
(2014a).
The
dynamicalages
N
arelowerlimits(seetext).
dynindicated. The thick black line is the best fit to⇤the data, and the correlation p-value is reported in each panel.

Last, changing the numbers of sectors to 4 or 9 does

These results are amongst the first to probeindicated. The thick black line is the best fit to the data, and the correlation p-value is reported in each panel.

Fig. 4.— Same as Figure 3, forcorrelation evolutionof ADP,6 withsurface densityof starsN⇤ . star clusters
Thethestructuralof formingand earlystage

tical model inside each of them.
We measure the radial profile of ADP,6 for our identified MYStIX subclusters. Given the intrinsic di↵erencein their number of members (from ⇠ 300 to ⇠ 1800 members, see Table 1), we adopt two choices: a) the highresolution profile, in which for both circular and elliptical symmetry we divide the populations in all concentric
annuli containing 60 stars within Rmax , and b) the low
resolution profile, where we consider 3 radii: 1) R60 , i.e.,the smallest circle from each center containing 60 stars;
2) the mean of ADP,6 within the half-mass radius Rh ; 3)
the mean of ADP,6 within the cluster radius Rmax . Since
the MYStIX fields of view are not uniform, and becauseof our constraints (§2) to avoid overlapping of subclus-ters in regions with multiple central concentrations, bothRmax and Rh retain some arbitrariness. Also, the MYStIX cluster sample is heterogenous in that individual regions, depending on their distance and dust extinction,
have di↵erent levels of (in)completeness. As we show in§4, such limitations are insufficient to erase the general
qualitative trends we detect.
4. RESULTSIn Table 1 we report for each cluster the three radialbins of our low resolution profile, together with the total
number of stars, annuli, and the average h ADP,6 i within
Rmax , all assuming circular symmetry. In nearly all cases
ADP,6 > 1, indicating that none of these regions has5

Mass and period limits on the ringed companion transiting the young star J1407
M. A. Kenworthy,1‹ S. Lacour,2 A. Kraus,3 A. H. M. J. Triaud,4,5† E. E. Mamajek,6 E. L. Scott,6 D.
Se ́gransan,5 M. Ireland,7 F.-J. Hambsch,8 D. E. Reichart,9J. B. Haislip,9 A. P. LaCluyze,9 J. P. Moore9 and N. R. Frank•16Myrの前主系列星 J1407、2007年に54日間の食を起こしている•→リングをまとったsubstellar companionが通っていると思われている•このcompanionを見つけるためのfollow-up観測を行った•VLTとKeckの直接撮像観測+RV+測光観測•特に何も受からなかったが、色々と制限がついた•→e>0.7、Hill半径に対してdisk半径が大きく(0.5以上), ロッシュ半径を超えているので円盤の安定性が不思議

J1407 companion mass limits

425

Downloaded fr

424

M. A. Kenworthy et al.

(b)２回の直接撮像からの制限。
黒がOKの領域(c) RVからの制限。

(d) disk半径/Hill半径

Figure 14. Limits to the period and mass of J1407b for elliptical orbits with periastron at the time of the eclipse in 2007. Vertical grey bars are trial pehave been ruled out by photometric monitoring. (a) The minimum eccentricity of orbit required to get a periastron tangential velocity of 32 km s−1 .

NEW CANDIDATE ERUPTIVE YOUNG STARS IN LYNDS 1340
M. Kun1, D. Apai2, J. O’Linger-Luscusk3,7, A. Moo ́r1, B. Stecklum4, E. Szegedi-Elek1, and G.
Wolf-Chase5,•暗黒星雲L1340の中で3つのeruptive young star candidates を発見した。
•IRAS 02224+7227•FUor-like spectrum•2MASS 02263797+7304575,•SDSSで2005年に増高が確認•2MASS 02325605+7246055
hysical JournalLetters, 795:L26 (6pp), 2014 November 10
DSS1とDSS2のサーベイ間で増高•
2ters, 795:L26 (6pp), 2014 November 10Kun et al.

2log(λ Fλ) [Wm-2]

Normalized flux + C

3-13 02263797+7304575

0.7-14

CAFOS

Sr II

4000

HγFASTNOMAD
SDSSWISE
2MASSSpitzer-16-174500

Hβ-0.50.01516HD 47731 G5 Ib

0.5
1.05500log λ [µm]
6000

5000
Wavelength [Å]< 2000 (NOMAD)
2005 11 3 (SDSS)
2011 01-03
2011 07-2011 112012 06-2012 07
2013 06-2014 06

FU Ori G3 Ia-15
IRAS 02224+7227

10K414IC [mag]1AV = 1 mag

17
Hα Li I2.0
1.56500

0.6

0.8 1.0 1.2
RC - IC [mag]1.4

ft: spectral energy distribution of 2MASS 02263797+7304575. Crosses indicate the low-state fluxes, corrected for an extinct

e Astrophysical Journal Letters, 795:L26 (6pp), 2014 November 10

Kun et３[O I]Hα-13[S II]

02325605+7246055

log(λ Fλ) [Wm-2]

Normalized flux

1.0

0.5

0.0

6300

6400

6500
6600
Wavelength [Å]6700-14-152MASS Ks
MAGIC Ks
SpitzerWISE
Akari FIS

-16-0.5

0.0

0.5

1.0
1.5log λ [µm]2.0ure 3. Top left: three-color image, composed of RC (red), Hα (green), and [S ii] (blue) images of the environment of 2MASS 02325605+7246055 (located wired circle), obtained with the Tautenburg Schmidt Telescope. Green circles encompass the HH objects. Top right: IRAC 3.6 (blue), 4.5 (green), and 5.8 (