36．Young andembedded clusters inCygnus-X: evidence forbuilding up the initial
mass function?
MNRAS 458, 3027–3046(2016)
Francisco F. S. Maia,Estelle Moraux andIsabelle Joncour
Cygnus-X north 領域
Cyg OB2

Cygnus-X north 領域、低質量星0.1M8までclusterごとのIMF を比較。
Wide-Field Infrared Camera (WIRCam) @ CFHT
JHKs3色測光

Membership 推定

星間吸収と距離M>0.7M8

Log t?

M<0.7M8

Rieke & Lebofskyのextinction law
PARSEC 星の進化 0.1M8~300M8
Avは2値：選択
年齢とdistant modulus 分散が小さくなるように？

MSAvは2値

若い星団 α~1.xx
4Myr以上の星団 α~2.xx Salpeterと一致
解釈
初期<3Myrに形成済みの低質量星がガスの効果で星団に落下しSalpeter的べきを作る。
ガスが4Myr程度で晴れ、その後は進化しなくなる。

On the Formation of Super-Earths with Implications for the Solar System
Rebecca G. Martin and Mario Livio
We first consider how the level of turbulence in a protoplanetary disk affects the formation locations for the observed close-in super-Earths in
exosolar systems. We find that a protoplanetary disk that includes a dead zone (a region of low turbulence) has substantially more material in theinner parts of the disk, possibly allowing for in situ formation. For the dead zone to last the entire lifetime of the disk requires the active layer
surface density to be sufficiently small, <100 g/cm^2. Migration through a dead zone may be very slow and thus super-Earth formation followedby migration towards the star through the dead zone is less likely. For fully turbulent disks, there is not enough material for in situ formation.
However, in this case, super-Earths can form farther out in the disk and migrate inwards on a reasonable timescale. We suggest that both ofthese formation mechanisms operate in different planetary systems. This can help to explain the observed large range in densities of super-Earths
because the formation location determines the composition. Furthermore, we speculate that super-Earths could have formed in the inner partsof our solar system and cleared the material in the region inside of Mercury's orbit. The super-Earths could migrate through the gas disk and fall
into the Sun if the disk was sufficiently cool during the final gas disk accretion process. While it is definitely possible to meet all of theserequirements, we don't expect them to occur in all systems, which may explain why the solar system is somewhat special in its lack of superEarths.

ガス巨大惑星的𝜚<1.6gcm%&
太陽系àLack of super Earth 1~10 MeàLack of planets inside of Mercury’s orbit
形成モデル
planetesimal formation a few Myr
Terrestrial planet ~ 10 – 100 Myr after gas disk was dispersed
系外太陽質量星の1/2以上にスーパーアースが見つかる。
円軌道で月以下の公転周期。
地球型惑星的𝜚>4.9gcm%&

1,6gcm%& < 𝜚 <4.9gcm%&
質量と密度は無関係
密度と軌道長半径は少し関係ありそう。
ガス円盤が残っているうちに巨大惑星的スーパーアースが形成されたのか？
形成場所、（１）その場形成（２）雪線外部で形成され、内側に運ばれた。

𝑀(𝑅 < 40AU)

全乱流ディスク

𝛼 = 0.01ディスク
乱流ディスクではその場形成する固体成分は不十分、

モデル２

𝑀(𝑅 < 1AU)
Minimum-mass extrasolar nebula
Minimum-mass solar nebula𝑀(𝑅 < 1AU)モデル１
𝐶𝑅: Σ789: ~200g𝑐𝑚 %&𝑀(𝑅 < 40AU)
Dead-Zoneあり乱流ディスクモデル１
Σ< Σ789: あるいは𝑇 > 𝑇789:の時MRIがON。
Off領域がDead-zone
𝐶𝑅: Σ789: ~200g𝑐𝑚 %&Xray: さらに少。
全乱流

モデル２
レイノルズ数𝑅 =ならDead-zone

D7 EFG𝜂 = 234 𝑇7 /𝑥L cmM s %O を求め、𝑅 < 𝑅𝑐𝑟𝑖𝑡

𝑀(𝑅 < 1AU)モデル１
UV: Σ789: ~20g𝑐𝑚%&

Photo-reverberation Mapping of a Protoplanetary Accretion Disk around a T Tauri Star
Huan Y. A. Meng et al
Theoretical models and spectroscopic observations of newborn stars suggest that protoplantary disks have an inner "wall" at a distance set
by the disk interaction with the star. Around T Tauri stars, the size of this disk hole is expected to be on a 0.1-AU scale that is unresolved bycurrent adaptive optics imaging, though some model-dependent constraints have been obtained by near-infrared interferometry. Here wereport the first measurement of the inner disk wall around a solar-mass young stellar object, YLW 16B in the {¥rho} Ophiuchi star-forming
region, by detecting the light travel time of the variable radiation from the stellar surface to the disk. Consistent time lags were detected on
two nights, when the time series in H (1.6 {¥mu}m) and K (2.2 {¥mu}m) bands were synchronized while the 4.5 {¥mu}m emission lagged by
74.5 +/- 3.2 seconds. Considering the nearly edge-on geometry of the disk, the inner rim should be 0.084 AU from the protostar on average,
with an error of order 0.01 AU. This size is likely larger than the range of magnetospherictruncations, and consistent with an optically andgeometrically thick disk front at the dust sublimation radius at ~1500 K. The widths of the cross-correlation functions between the data in
different wavebands place possible new constraints on the geometry of the disk.

Reverberation mapping
AGNの質量推定
𝑀TUV = 𝑅 WXY 𝑉 M /𝐺
R_BLRは、AGNからの連続光の変光からBLR 雲起源の輝線の変光までの時間差によって、推定する。
ρOph cloud 内YLW16B TTauri型星
ディスク中央穴の大きさは0.1pc程度、近赤外の干渉計でも測定できない。
同時観測
Spitzer IRAC è 4.5μm
Mayall 4mφ / FLAMINGOS
SOAR 4mφ / Spartan IR Camera è Hバンド
1.3mφ、1.5mφ è K バンド

HK

4.5μm

𝜋
𝑅9] (1 + )4c^ 𝑅9] 1 + 𝑠𝑖𝑛𝜃 𝑠𝑖𝑛𝜃𝑑𝜃d(((74.5 second * c) / AU) * π) / 4 =0.11725772

𝑅 9] = 0.084 ± 0.004AU
è Disk 昇華（1500K）半径ではないか𝜃

𝑅9]

Dynamical ejections of massive stars from young star clusters under diverse initial conditions
Seungkyung Oh and Pavel Kroupa
We study the effects of initial conditions of star clusters and their massive star population on dynamical ejections of stars from star clusters up to anage of 3 Myr, particularly focusing on massive systems, using a large set of direct N-body calculations for moderately massive star clusters(Mecl=$10^{3.5}$ Msun). We vary the initial conditions of the calculations such as the initial half-mass radius of the clusters, initial binary populations
for massive stars and initial mass segregation. We find that the initial density is the most influential parameter for the ejection fraction of the massivesystems. The clusters with an initial half-mass radius of 0.1 (0.3) pc can eject up to 50% (30)% of their O-star systems on average. Most of the models
show that the average ejection fraction decreases with decreasing stellar mass. For clusters efficient at ejecting O stars, the mass function of theejected stars is top-heavy compared to the given initial mass function (IMF), while the mass function of stars remaining in the cluster becomes slightly
steeper (top-light) than the IMF. The top-light mass functions of stars in 3 Myr old clusters in our N-body models are in good agreement with themean mass function of young intermediate mass clusters in M31 as found by Weisz et al.. We show that the multiplicity fraction of the ejectedmassive stars can be as high as 60%, that massive high-order multiple systems can be dynamically ejected, and that high-order multiples becomecommon especially in the cluster. Furthermore, binary populations of the ejected massive systems are discussed. When a large survey of thekinematics of the field massive stars becomes available, e.g through Gaia, our results may be used to constrain the birth configuration of massivestars in star clusters.

Mass segregation in star clusters is not energy equipartition
Richard J. Parker, Simon P. Goodwin, Nicholas J. Wright, Michael R. Meyer and Sascha P. Quanz
Mass segregation in star clusters is often thought to indicate the onset of energy equipartition, where the most massive stars impart kinetic
energy to the lower-mass stars and brown dwarfs/free floating planets. The predicted net result of this is that the centrally concentrated massivestars should have significantly lower velocities than fast-moving low-mass objects on the periphery of the cluster. We search for energyequipartition in initially spatially and kinematically substructured N-body simulations of star clusters with N = 1500 stars, evolved for 100 Myr. Inclusters that show significant mass segregation we find no differences in the proper motions or radial velocities as a function of mass. The kineticenergies of all stars decrease as the clusters relax, but the kinetic energies of the most massive stars do not decrease faster than those of lowermass stars. These results suggest that dynamical mass segregation - which is observed in many star clusters - is not a signature of energy
equipartition from two-body relaxation.

Mass segregation: 大質量星が中心に、小質量星が周辺に分布。
σ ∝ m^-0.5 ß mσ^2 ~ 一定 完全エネルギー等分配〃的部分エネルギー等分配
エネルギー等分配にかかる時間（Spitzer 1969）t_relax=(N/8 ln N) t_crosst_cross〜0.1Myr t_relax〜100 Myr N=1000
これが本当に起こっているかを調べた。
初期条件
fractal dimension D=1.6
ヴィリアル比αvir=K/|W|=0.3
0.01 M8 < M <50 M8N=1500 stars

εを1/2にすると、構造3倍増えるとき

質量分離
Mass segregation ratio
Λ_MSR =<l_ave> / <l_sub><l_sub>最大質量N_MST個の星の間の平均距離、<l_ave>任意のN_MST個の星の間の平均距離

最重量10星程度が強く質量分離

Λ_MSR=1 質量分離なし
Λ_MSR>>1 強い質量分離
質量分離なしOM

E= 𝑚𝑣 M

時間進化
初期
結論
質量分離は見えるが、エネルギー等分配には見えない
100Myr𝑚