Star	  Forma)on	
  Newsle0er	
  	
  #259	
  29-­‐33本目	
麻生 有佑	

Debris	  disc	  forma)on	
  induced	
  by	
  planetary	
  growth	
  H.	
  Kobayashi	
  and	  T.	
  Lohne	  (2014)	

Ø デブリ円盤進化モデルでG型星デブリ円盤のSpitzer観測を説明。	
  Ø 1	
  µm以下はblow	
  out、ガスやradial	
  driFのないデブリ円盤進化モデルを使う。	
  Ø まずモデル毎の進化の特徴を述べる。	
  Ø 初期微惑星の大きさs0,	
  微惑星が存在する半径rin-­‐rout,	
  面密度分布x,	
  pをパラメーターとして、観測されたデブリ円盤の年齢-­‐フラックス関係ををフィット。	
  Ø 30	
  AU付近に幅2	
  AUのnarrowな微惑星円盤が良さそう。	
  ß	  A型星でもnarrow	
  diskが良いという研究がある。	
  Debris Disc Formation Induced by Planetary Growth 9Ø gasは入れなかったが、ﬂuxの増大がgas入りの方が早い、collisional	
  cascadeの効率が悪くなる、など特に100	
  Myr以前で重要で、rgas	
  (snow	
  line)とrinの関係にも依る。	
  eters to observational data: For each initial planetesimal radius s0 , the inner and outer radii of the discy scaling factor x, the surface density radial slope −p, and the total mass Mtot of the initial planetesimalx and p are discussed in the main text.
s0 [km]rin [AU]

0.1
1
10
100
1000

70.6+1.3−0.04
39.6+0.7−0.8
34.3+0.1−0.8
30.5+0.7−1.3
26.3+0.4−1.2←初期微惑星半径s0毎のベストモデル	  半径はフラックスから推定されたものとお13.5+0.03
0.23
1.1
5.7+0.5−5.1−0.2
1.47+1.33
0.40
0.56
14+0.01
よそ合う。	
  
−0.77
−1.5
+1.53
+2.9
2.23−0.12
1.34
0.04
33−1.8質量はフラックスから推定された値~0.01	
  1.75+1.48
2.6
0.0
45+49
−0.07
−13
1.16+1.29
79
1.9
122+50
MEより3桁大きい(赤外フラックスは小さい
−0.43
−71
粒子しか見えない)。	
  Kobayashi, Ormel, & Ida 2012).	
After gas depletion, colli-rout − rin [AU]

24µm
10km
1000kmxp

Mtot [M⊕ ]sional cascades can produce smaller bodies and then debris
disc fluxes increase. If planet formation occurs inside a radius rgas prior to gas depletion, planets are subsequently
formed beyond rgas in a gas-free disc. If rgas corresponds

6

0

8

10

m
1k

1

10

1

Fdisk,ν / F*,ν

10

0

10

24µm
10km

0.1km

1000km

0

10

100km

−1

10

−1

10

70µm

Fdisk,ν / F*,ν

0.1km
2

10

0

10

100km

1k

2

m

10

1000km
0

10

10km
0

10

2

10

4

10

1

10

2

10

3

10

4

10

Age [Myr]
Figure 11. Temporal evolution of the flux ratios using best-fit
parameter sets listed in Table 1 for initial planetesimal radii of
0.1, 1, 10, 100, 1000 km.

eﬀects of gas even in early times. Even starting with similar
initial planetesimals, the time when disc fluxes increase isearlier for our simulation. This means that gas drag plays
an important role in flux evolution before 100 million years.
Indeed, since collisional cascades cannot eﬀectively produce
1 µm-sized bodies in a gaseous disc (Kobayashi et al. 2010),
disc fluxes may not rise before gas depletion occurs.
If gas depletion is taken into account, the inner edgeof a disc may also be naturally explained. If discs still
have as much gas as the minimum-mass solar nebula, collisional fragmentation between bodies smaller than about

Kobayashisional cascdisc fluxes
dius rgas p
formed beto the inn
assume insimilar: Th
lated to thother handclean up a
the format

Planetbecause raof dust inplanetesim(Okuzumi
in a cluste
ing their ecounter tru
expected iedge of pl2001) andobjects (Ketesimal fo
explain the

In thebefore theand Neptu
Planet formyond 10–2
tion of theyield the50 AU (Koplanetesim
100 km) th
similar todepletion,
dress in fu

TOWARD	  COMPLETE	  STATISTICS	
  OF	
  MASSIVE	
  BINARY	  STARS:	  
PENULTIMATE	
  RESULTS	
  FROM	  THE	
  CYGNUS	  OB2	
  RADIAL	  VELOCITY	
  SUVEY	
  Hernry	  A.	
  Kobulnicky	
  et	
  al.	  (2014)	

Ø Cybnus	
  OB2	  Associa)onにある48個の大質量連星系で軌道解析を行った。	
  Ø そのうち23個は新しい大質量二重連星である。	
  Ø Cyg	  OB2の大質量星は35%が連星系。	
  Ø 質量比は0.2-­‐1.0でおよそ一様に分布。	
  Ø 離心率は0.1-­‐0.6に一様分布と、e=0	
  (真円軌道)に別の分布がある。	
  Ø P<45	
  dには概ね一様に分布している(累積分布が線形)。	
  Ø P=1.4-­‐2000	
  dをsingle	
  powerでフィットすると冪は–0.22	
  (累積は0.78)。	
  Ø Galac)c	
  open	
  clusterなどの他の系と比べても分布が似ている(尤度91%)。	
  àP<25	
  dの二重連星の性質はdisk/clump	
  fragmenta)onの局所的物理で決まり、
環境や進化の影響が少ない。	
  Ø Cyg	  OB2には6d,	
  14d,	
  45	
  dつまり~0.2,	
  0.4,	
  1	
  AUに特徴的なスケール	  ←進化の影響？	
  – 94 –

Fig. 28.— Observed distribution of eccentricity for the sample of Cyg OB2 binaries. The
left-hand y-axis shows the cumulative probability, corresponding to the plotted points. The
right-hand y-axis provides the number of objects in each histogram bin. The distribution isapproximately uniform between e = 0 and e ≃0.6.

←離心率の分布	  e~0とe=0.1-­‐0.6の2成分。	
  	
  →質量比の分布	  q=0.2-­‐1.0に一様分布。	
	Fig. 29.— A statistical distribution of mass ratios for 48 known massive binaries in Cygnus
OB2, based on Monte Carlo realizations over allowed inclination angles.

n(s)=C·s ,
ch larger
than theWhile
blow-outsize
in Fomalhaut’s
main belt andinmodellingthe Herschel acolddebrissystems.
theslopeofissize.
thefragment
sizeofdistribution
and
ing
from
grain
collisions
essential
range
ofdisks.
ten atdust
some
small
fragment
To the whenbest
our knowledge,

size ofthe
thelargestfragment
wellrelevantcharacterized
andcan with 3 < ↵ < 4, and C
nt – thengs
interplanetarymedium– minorplanets,areasteroids:
general–forsolidthestate:
refractory
however,regimeoffragment
sizes
analysisA	
  dof
earth	  of	
  small	
  pmodels,ar)cles	  in	
  debris	  disks	  beusedconfidently
inthesmallest
fragment
size is lesspee sizethelargestfragment
arewellknown,
the behaviour
the is dominated by
below has not yet been probed by available experimental
dataof masswell
and isBasedusually
tofragment	  bewe
constantallcol- fragment
nt
An	
  
eunderstoodnergy-­‐constrained	
  mallest	
  
sfor
ize	
  
thus the surface
energyonexperiments,
adopt
the
standard
size
norpoorly
described
theoreticallyinsassumed
anastrophysicalcontext.
ntallyunderstood.
This
leads
debris
disk
codes
to
generallyWe
provideaframeworkforself-consistently
calculating
ra lisions.
S.	
  Krijt	
  
and	
  M.	
  Kama	  (2014)	
distribution
Assuming
spherical
fragments with sizes between smin and As the creation of infi
a
range
of
astrophysicalthesmallest
fragmentsize
as a functionof material
and arecollision infinite amount of ene
as s ( s ), the total fragment
↵
mass
and
surface
area
max
min
n(s)
Csize
· s distribution,its implications(1)
werboundaryofthefragment
forfora rangeof collider
ent size
distributionand2),
parameters(Sect.
and =discussmodellingreavailable in a collisionØ ダストサイズ分布の小さい端が未だ不明でblow-­‐out	
  sizeが仮定される。	
  ll characterizedandcan 3).
we
apply
the
methoddebris4⇡⇢Cdebrisdisks(Sect.
with3 < disks.
↵ < 4,4⇡C
and C 3a coefficient
we express below.
While
thesmall fragm
4to↵
↵
on
some
Mfrag
= size is lesssmax ,Afrag =
smin ·(2) ten atØ
質量は大きい粒子が決め、表面積(表面エネルギー)は小さい粒子が決める。	
  lest
fragment
ments isNumerous
founddependoniscollisionvelocity,materialparameters,
mass
dominatedbythe largest
particles,
the surface area andstudies
at thefragment
3(4 toexperimental↵)↵have
3 lookedns
however, the regime of
to beØ
constant
for all col- thus the surface energy is dominated by the smallest
無限小の粒子を作るには無限大のエネルギーがいるので必ず分布に端がある。	
  fragments.
size
distribution
destructive
collisions,focussingon
the slope
motivatedforof
thecalculationof ofthesizesmallest
fragment,
which
ebelow
has annot yet bee-consistently
calculating
Forγは単位面積辺りの表面エネルギーで物質に依る。	
  a recipe
collision
betweentwobodies
s
and
mass
M
=
Ø
0
0
As
the
creationofinfinitely
small
fragments
wouldrequire
of
the
power
law(s),
and
on
the
size
of
the
largestfragment3arystems.
Forparameters,implies
our results
the described theoreticof material
andplausible
collisionnor(4⇡/3)⇢s, mass conservation
Mfrag =are
2Mconsistentandamountthus withØ
ηは表面エネルギーに変換される運動エネルギーの割合。	
  
0 ,theinfiniteamountofenergy,whileofkinetic
energy0&modelling
Ryan 1990;
Ryan
etal.in1991;
Nakamuracold& Fujiwara
ysize(Davisin
Fomalhaut’s
main
belt
and
the
Herscheldebrisdisks.
plicationsfor
AssumingØ 等質量、等サイズの衝突を考える。	
  available in a collision is finite, the power law must stopor flat- spherica
3↵4Ryan↵)s2000).
The smaller end of the size distribution has s ( s ), the total f
ed 1991;
C = 2(40 smax . ten at some small fragment size. To the best(3)of ourmax
knowledge,minØ 初期サイズが小さいと運動エネルギーも小さく、粉砕して表面積を作ることができ
me– minor
planets,
asteroids:
general–solidstate:
refractory
receivedconsiderably
lessattention;
thesmallest
fragmentsaree lookedat thefragment
2 for the analysis
however,the regimeof fragment
relevantないàsThekinetic
energyis simply
UKhigh=sizes(1/2)µv,
4⇡⇢C 4 ↵max~smin~2^(–1/3)s0と分裂(split)する。	
  s, focussing
on
the
slope
hard
topre-collisioncountexperimentally,andrequireavery
resolution
rel
below
has
not
yet
been
probedbyavailable
experimental
dataM=smax ,fragØ
それが分布の小さい方の端である(分布形成を段階を追って考えている？)。	
  
where
µ
=
M
/2
denotesthereducedmass.
The
di↵erence0of thelargestfragment3(4 ↵)
to be captured in numericalsimulations.
Fragment
distributionscontext.
nor describedtheoreticallyin an astrophysical
Ø
このs
とs
の関係が計算できて、いくつかの観測(s
>10	
  
s
)が説明できる。	
  insurfaceenergybefore
and
after
the
collisionequalsU=
Basedonexperiments,
adopt
fragment; Nakamura&
Fujiwara
min
blow
min
S blowaretherefore
incomplete
belowwesizes
of 100theµm,standard
or masses
beAssuming
spherical
fragments
with
sizes
betweenssize
and betwee
min
For
a
collision
2
3
the size
distribution
has
(A
8⇡s
),
where
equalsthesurfaceenergyperunit
surfrag
distribution
0low
10 gr (Fujiwara
et A&Aal.
Takagial. 1984).
Molecularsmax( 1977;smin), thetotal etfragmentmass
and surface area
are 3 , mass conser(4⇡/3)⇢s566,
L2(2014)
fragments
are0
le smallest
face ofthematerial.
Assumingthat
onlyora smooth
fractionparticle⌘ of thehykidynamics(e.g.
Dominik& Tielens
1997)
4⇡⇢C
4⇡C
↵
4 surface,↵3 ↵re a very3 ↵ 4
netichighis usednewwecan combinen(s)=energy
Cresolution· s(Geretshauser, Mfor(1)(2)=et al. 2010)
s
,
A
=
s
·
dhe
fragcreating
fragdrodynamics
simulations
have
limited
C
=
2(4
↵)s
.
max
min silicate
Table
1.
Material
properties
for
and
ice
used
in
this
work.
0 smax3(4↵)↵
3s. Fragment
distributions
Eqs. (2) andto obtain
a lower
for the smallest
fragment
and(3)
tend
to focuson thelimit
fragmentationthresholdvenf1ir100resolutionµm,
ormassesbewith
3
<
↵
<
4,
and
C
a
coefficientwe
express
below.
While
the
The
pre-collisionkine
Forbetweentwo bodies
mass
M0 =
size. Forthethanspecificcasea collisionof ↵fragments.
= 3.5,
this reduces
to of size s0 and.
locityratherthesmallest
321984). Molecular (4⇡/3)⇢s3 , mass conservationMaterial
sgi et al.
⇢ (g cm ) , and thus
(Jµm =) M /2 den
impliesMsurfacefrag = 2M0where
0
1
0
mass
is
dominated
by
the
the
area
and
0 largest particles,2
7)orsmoothparticlehyBC
24s
Silicate
2.6
0.05-simulations
BBB surface0 energy
CCC 1is dominatedin surface energy befo
3 ↵ 4
thus
by
the
smallest
fragments.
s,(4)smin =the
have
C
=
2(4
↵)s
s
.
(3) 2
A
@ limited
max
Ice
1.0
0.748⇡s
0 max
2(A), where⌘⇢sv+
24
ggmentation
frag
0 rel
thresholdve- of infinitely
Aggregate would⇠10 1require⇠10 4an
102 3 0AsMinimumthecreationsmall
fragments
2.
fragmentsize
inasinglecollision
The pre-collision kinetic energy is simply UK face
= (1/2)µv,of therelmaterial.
As.

the true
⌘. We
that
valid ,foryieldsonsmin⌧ value
sblow offor⌘566,=stressandour theory= 0.1isJ/m
but3 >sminand'⌘ = 10 2 for this com
A&A
L20.1
(2014)
3 not apply to models that use shallower power↵for> 4, and 3does
6µm. Thus,1theTabledi↵erence
betweenourand
1 ⌘ = 10
1. Material properties
for silicate
and results
ice used in thiswork.
.15Qpr (L? /L )(M? /M )laws,(⇢/gforcmexample) 1 (s/µm)
Sect. 4.2 of Krivov
et al. (2013).
K
type stars. Krivov efragmentsizes
ofKrivov
et
al.
may
be
substantial,
depending
the radiation andthe
gravitational
force.
Particles
The importance of the limit given by
Eq. (4)⇢dependson(JtheMaterial(g cm )m ) with a collisional cas
true
value
of
⌘.
We
stressthat
ourtheoryisvalid
for 3 >
are removed fromon
thethesystembyradiation
presparameters, and can vary per individualSilicate
collision, depending
on
2.6
0.05
proposed that the largvely, Gáspár et al.↵ (2012)
calculatea notcollision> 4,
doesvelocity
apply
to modelsuserestshallower
Icethat1.0
theandcollisionand choice
for smax. In theof this 0.74
sec-power
unstirred material. Ou
Aggregate⇠10⇠10 10from mass conservation,
not studythewedo
explorein which
this limit
relevant.
laws, tion,
forbutexampleSect.
4.2casesof Krivov
etisal.most(2013).
explained as the outco
Notes.
The
valuesforthetypicalaggregateareexplained inInadebrisdisk,aparticle
of
size
s
is
most
likelyformed0 Eq. (4) depends on model
is highly degen
TheEq.
importance
of
the
limit
given
by
the
AppendixA.
, for any relevant collision(4)
predictss>
min only slightly larger particles. In addition,
in a collision between
belt
and
can
per individual
collision,
dependingon properties ( f ) areting the fragmentparameters,
size distribution
down
tovarythesebetween
we focus oncollisions
equal-sizedparticles,asthesemaximum fragment that carries half of the initial collider
mass.
impacton smin .
ified. For example,thestarting
from
Eq.
(2)
of
Krivovcollision
velocity
andchoice
for
s
.
In
the
rest
of
this
secmaxGravity
is importantfor bodies
larger thanB).
100 m (see below).
aremostefficientatformingsmall
fragments(Appendix
In Fig. 2, we assu⇤
m-sized bodies have
' 5explore⇥ 106weerg/g.
In
Smallerbodiesare weaker,
and canproducefragments down totion,Q we
inuse
which
cases
this
limit
is
most
relevant.
Therefore,
Eq.the(6)asanindication
for
the
lower
limit
particles. In reindicated by the solid curve. For example,for
SiOall2 fragamework, a collision between
twosuch bodies
at the smin Quantitative
ofa theparticle
sizea distribution.
comparisonsreIn
debrisdisk,
particle
of
size
s
is
most
likelyformedments
smallerthanamicroncan,atthis
velocity,
only
beformed0
the eccentricities of sm
en result in fragmentation,
as relative
the kinetic
energyvelocities,
by collisionsof bodieslargerthan a fewbodies
centimetres. The shadedquirecollision
which
for
the
largest3 a collision between only slightly larger particles. In addition,eccentricity can be wr
ng ⇢ = 2.35 g/cmin) slightly
exceeds
theincriticalregion, top left, is forbidden, as there Mfrag > 2M0 and mass is
are
often
written
terms
of
the
Keplerianorbitalvelocityatthe⇤itynon-linearof such a radiationconserved.
Close to sminparticles,⇠ s0 , the solid curvesare
we focusequal-sized
asthese' 10 J), and fragments
willonbe collisions
createdfrombetween
afromnotthecorresponding
distance
centralobject.
For
bodiesonvB).
/ s 1 , while E
Fig.the1. Top:minimum fragment
size sof in
a 20 m/s etcollision(Eq. (4)) as the pre- and post-collision surface areas become comparable.
rel /
e to
impactor(Eq.
(21)
Krivov
al.
2006)
are
most
efficientatformingsmall
fragments(Appendix
Ø three
物質毎の式sの関係。	
  interesting
compareEq.
(6) withcan
the traditional
form of disk 1/2
formaterials, as a functionofcollidersize sidentical. We have assumed
withsemi-major
the torelative
0とsorbits
min
Fig.It2.isaxes,
Predicted
smin/sblowvelocity
in debrisdisks,
asa function
scalesas vrel / s0 rad.
ow-out
size.
For
this
particularcollision,
Eq.
(4)
of
the
catastrophic
fragmentationthresholdvelocityinequal⌘ = 10 and s=Therefore,
2 s . The grey weshadeduseareas areexcludedEq.
(6)ofasArrows
ancollisions:indication
for
the
lower
limit
Ø 上図垂直点線は分裂する半径。	
  thenandbe
written(right).
interms
orbitaleccentricity
inclination
Øv2 show
indicatethe
ratiochangeswith⇤and⇤ stellar luminosity, surfmin/s0の理論線と観測。	
  becauseThe dotsizedenergy,Qsmallest, has unitsparticles incr
sblow
forof ⌘mass= conservation
0.1 and (left),= 0.1self-gravity
J/m2 , but
smin' 2 energy,
f = 8Q . The critical
2 1/2 f , and ⌘.
1/2
Colouredregions
indicate
observational
constratedlines
indicate
the
limit
of
Eq.
(6).
Bottom:criticalenergies
versus
as
f
⌘
v
/v
=
(1.25e
+
i
)
,
with
v
=
(GM
/a)
the
of
the
particle
size
distribution.
Quantitative
comparisons
rerel
K
K
?
Ø
矢印は各パラメーターの依存性。	
  oferg/g,
andvarieswithparticle
mass.
For
small
bodies,the3Ø. Thus,
下図実線は粉砕に必要なエネルギー。	
  fragmentation.
As a r
0 sizethedi↵erence
betweenour
results
andfor equal-sized collisions. The energy needed to split a particle on
smin&/sforvarioussystems(seetext),
the diagonal solid li
strength
isDentdominatedby cohesion,and forlarge
onesandby gravity
blow
Keplerianorbitalvelocity(Wyatt2002).
Inadebrisdisk,
quire
relative
collision
velocities,
which
for
the
largestbodiesEq.
(6)) is shown⌘ =be10(dotted) and ⌘depending= 1 (dashed).
Øofdo0edはη=1e–3,	
  dsubstantial,
ashedはη=1の分裂に
Ø 1999).
sblowfor並みに小さいダストが観測
2
sizesoccurs
thisregime.
zes(e.g.
Krivov
et al. for
may
(Benz
& AsphaugFor
solid
thisWetransition
give
ourcalculations
each⇤bodies,system.
fix=in0.1Jm, f = Pa10
a rangefragmentationof eccentricities
inclinations
will
bepresent.
Fora
The solid curves correspond to catastrophicof aggregatesand
72around
100
m
in
size.
Values
of
Q
⇠
10
erg/g
are
often
taken
on
a
short
timescale.
Fue(Beitzof ⌘.
stressthat
ouris valid
forshowing
3 >of andarewrittenin1999),terms
the⌘Keplerian
orbitalvelocityat the
必要なエネルギー。	
  = 10
for されていないことを説明できる。	
thiscomparison.
et We
al. 2011),
and iceandoftenbasalttheory(Benz& Asphaugroughcomparison,
weuse
averagequantities
hei
and
hii
to
obas typical for asteroids, and experimentally obtained
values for for each parstrength-dominated(smallself-gravity dominatedevaluated
es bothnottheapply
to models
thatsizes)
useandshallower
power
corresponding
distancefrom
thecentralobject.
For
bodiesonØ
一般に粉砕の方がエネルギーを使うこと
small
grains(mm
tocm
sizes)
canbeseveralordersofmagnitude
tain
typicalcollision
velocities.
In
reality,
hei
and
hii
are
poorlyertiesof thethesematerial
pleregimes
Sect.(large
4.2sizes).
of Krivov et al. (2013).
smaller(Blum& Münch
1993;
Beitz
et
al.
Figureshows
3 were1 2011).
K
typeaxes,
stars.
Krivov
et al.
notable
to1 model
systeaorbitswith
identical
semi-major
therelative
velocity
canconstrained.
Estimates
range
from
hei
⇠
hii
⇠
10
10
,
deがわかる。	
  the critical energy for splitting predicted by Eq. (6) as a function
Aof smallance of the limit given by Eq. (4) depends on the withaforcollisionalcascadereaching
downto⌘ =dearths1.
3
min = 3 µm, aand gives the size of thesmallest
fragments
createdina collisionpending
on
the
level
of
stirring(Matthewsetal.
2014).
ofsize
thematerials
in
Table
1
assuming
⌘
=
10
and
then
be
writteninterms
oforbitaleccentricity
andinclination
dictedby Thébault &d can
per ↵individual
collision,on proposed
at vrelvary, assuming= 3.5 and smax
sminratio. dependingthat
the criticallargegrains
inand
these
The
indicate
fragmentationenergies
for basalt are primord
2 smallest
2 solid
1/2 lines
1/2 systems
The
between
the
grain
size
from
Eq.
(6)
as
fsmax⌘. Invdistribution,/vresti )ice (Benz, withvK Our=1999)(GM
thesminInsteadforminga fragment
we (1.25e
imaginethe +unstirredlocityand ofchoice
for
the
this
secon
. In
their
rel
K =of
? /a) aggregatesand& Asphaugand silicate(Beitzmaterial.
calculations
suggestthat
theycanscenaalso
theblow-outsize
thenbecomes
limiting
case
in
which
the
kinetic
energyjust
suffices
to
split
et
al.
2011).
The
criticalfragmentationenergies
exceedthesplite in which cases this
limit
is
most
relevant.
ofthesmallest
grains
Keplerian orbital
velocity&
Inofa adebris
disk,cascade. However,explainedas the2002).
outcomecollisional!(Wyatt! 2Dent
both colliders in half1 , i.e. ⌘UK = 2⇡s20 . Solvingfors0 , we1 ting energy,
✓
◆
✓
◆
✓
◆
indicatingthat
substantiallymoreenergyis required1
disk,
ss0minisofmost
likelydestructionrate
is deta formed
L? andmodelf⌘obtaina particle ofishighlydegenerate,asmaterial
properties
and)aa sizerange
eccentricities
inclinations
will
bepresent.
For
a for (⌘
to destroy – rather than split – colliders. ,Thevalues plotted
=
2.4
(7)
1 stirring. Wh
etweenonly
slightlylargerparticles.
In
addition,
fectedby222
icebasalt10
were(obtainedat Jcollisionvelocitiesof 3 kmands , all have a la
3
belt
propertiesf ) areusually
scomparison,
5 AUwe Luse
10and
0.1
mandpoorly
split
blow
rough
quantities
hei
hii toknown,
obs0 = between,(5) average
substantially higher than the velocities considered here,andQ⇤ollisionsequal-sizedparticles, asthese
2of blow-out
size, their
3

1

2

4

3

min

2

max

1/3

0

0

3

⌘⇢vrelimpacton smin . on velocity (Leinhardt & Stewart 2012).
is known to depend

B. Kumar et al.: Stellar content in the Carina west region
0

V-I

1

2

3

4
0.0

0.5

1.0

1.5
B-V

2.0

2.5

3.0

5

B. Kumar et al.: Stellar content in the Carina west region

11

3

2

1

0
0

1

2

3

H-K

ntent in the Carina west region

15

3.0

Log Φ

2.5

2.0

1.5

1.0

-0.8

-0.6

-0.4

-0.2

0.0
Log MO•

0.2

0.4

0.6

Fig. 14. Plot of the mass function in the CrW region. Log Φ←Mass	  Func)on	  Ø 環境の影響はIMFのlow	
  mass	  endに見られるはず。	
  Ø IMFについて、l1	
  Moより軽い側でSalpeter	
  (Γ=–1.35)より浅くなって折れる、大質量形成領域では軽い側は
ﬁeld	
  IMFより少ない、などの予想がある。	
  Ø しかし、CrWでは軽い側で折れていない(Γ=-­‐1.13)。	
  àgalac)c	
  ﬁeld	  star	  popula)onは主にOB	
  associa)onsや大質量星団が決めているのではないか。	

A	
  search	
  for	
  ﬂares	
  and	
  mass	  ejec)ons	
  on	
  young	
  late-­‐type	
  stars	
  in	
  the	
  open	
  cluster	
  Blanco-­‐1	
  M.	
  Leitzinger	
  et	
  al.	  (2014)	
Ø coronal	
  mass	  ejec)on	  (CME)は星の最も高エネルギーな現象で、惑星大気などにも影響。	
  Ø 太陽では良く調べられているが他の星では点源なので難しい。	
  Ø 太陽ではCMEとフレアが相関しているので他の星でもそうだろう。	
  Ø Blanco-­‐1はメンバーが多い(メンバーである確率が高いものが多い)。	
  Ø 12個のM型星のうち7個でHα輝線、4個でHα吸収線	
  Ø 14個のK型星のうち1個で輝線、13個で吸収線	
  Ø 彩層が活発だと吸収線で、不活発だと輝線になる。	
  Ø フレアは4天体で検出。	
  Ø フレアのある天体で、CMEによるHαの時間変動を調べるも4天体とも3σレベルで検出できず、à検出限界を検証。	
  Ø フラックスの感度から、必要なCMEの質量が決まり、その質量のCMEが観測条件において検出される回数が決まるà1	
  イベント以下。	
  Ø FS1とFS4ではフレアの前にdipを検出(FS3は解析による人工物)	
  Ø FS1,	
  4ともにblue	
  wingが減っている.	
  ←太陽ではフィラメントやプロミネンスのような噴出現象がHαの吸収を起こすことが知られている。	
  Stellar activity in Blanco-1

FS1_2MASS J00032088−3004472

FS2_2MASS J00031154−2958103

average spectrum
single spectrum

11_9
11_8
11_7
11_6
11_5
11_4

spectrum number

spectrum number

11_3
11_2
11_1
10_9
10_8
10_7
10_6
10_5
10_4
10_3
10_2
10_1
−1000

10−13

11

OD = 2
OD = 5

10−14

10−15

10−16

10−17
10−18
α = 1.8
α = 2.3
log(LX) = 28.4 erg/slog(LX) = 30 erg/s

100.00

10.00

10.00

0.10

0.10

0.01
16

100.00

1.00

1.00

0.01

17

18
log(MC) [g]19number of CMEs during tobs with vproj>135 km s−1

number of CMEs (M>MC) per day

maximum expected Hα flux [erg cm−2 s−1]

Stellar activity in Blanco-1

20

−800

−600
−400
−200
velocity [km s−1]

0

200

−800

−600

−400
−200
velocity [km s−1]

0

200

−1000

−800

−600
−400
−200
velocity [km s−1]02007