Star Formation News Letter No. 370, #41-54：工藤哲洋

231•コアがフィラメントから分離しているところを発見した。
•分離速度­2 km/s，タイムスケール〜4000年。

•乱流のエネルギーは小さいので，異方性のコア収縮が原因か？

コアはほぼサブクリティカル
フィラメント全体もサブクリティカル

PV図H13CO+CCH

H13CN

著者が推測しているシナリオ(i)フィラメントは比較的低い乱流を持ち、コアに分裂。
(ii)フィラメントに沿った流れのため質量が大きく不安定になり、最終的には重力崩壊。
(iii)M1は重力崩壊によって強く圧縮され脱出運動を開始。残りのエネルギーはフィラメントに伝達され乱流を増加。

• 原始惑星円盤と惑星との相互作用の流体数値シミュレーション• 二つの大きな惑星ができた場合，その間に小さな惑星ができる可能性を示した。（標準モデルでは，恒星から遠くなると惑星質量が大きくなると予想しているが。）• 実際にそのような惑星系の観測結果も示す。

• 等温流体＋ダスト＋惑星の数値シミュレーション
ガス＋ダスト（面密度）

惑星（スケールハイト）
（α粘性）

惑星

恒星

恒星質量＝1M太陽内側惑星質量＝12 or 20 M地球
外側側惑星質量＝20 or 35 M地球ダストのストークス数：0.002, 0.02, 0.2

流体中を運動する微粒子について、流体への追従性を表す。St <<1 の場合にダストは流体と一緒に動く。

Wikipedia

Figure 2. Azimuthally averaged profiles of the four simulations presented in Table 1 with two planets that cause two points of inflections (Small-Small; left), an
inner pressure maximum and an outer point of inflection (Big-Small; second column), an inner point of inflection and an outer pressure maximum (Small-Big;third column) and two pressure maxima (Big-Big; right). The location of the two planets are represented by the vertical dotted lines. The simulations with onlya single planet (located at ' = 1) are shown in a red line for comparison. From top to bottom we present the gas surface density, the dust surface density for
St = 0.002, St = 0.02 and St = 0.2 and finally the pressure gradient through the quantity 3ln%/3ln', all in code units. In cases with a small outer planet(columns 1 and 2) little diﬀerence is seen in the interplanetary density profiles (rows 1-4) between the one- and two-planet cases, whereas the diﬀerence issubstantial for a large outer planet. In particular, for the case where there are two planets present that are massive enough to create two pressure maxima (rightcolumn) the amount of dust in the pressure maximum in between the two planets is reduced.

Big-Bigの場合
観測例

青色が大きな惑星の間にある小さな惑星• Ηカメレオン星団の中の原始惑星系円盤とデブリ円盤をサブミリ波でサーベイした。

• サブミリ波の観測と，これまでの観測結果をあわせて，円盤のスペクトルをモデルフィットして，円盤の物理量を見積もった。

• Gaiaのデータと星進化理論から星団の年齢（7-9My）を見積もった。

Roccatagliata V. et al.: APEX/LABOCA observations of the ⌘ Chamaeleontis Association

新しい観測：870μｍのサブミリ波

その観測結果と，これまでの観測結果をあわせて，スペクトルのモデルフィッティングを行った。

星＋原始惑星系円盤

Fig. 2. SED models for the protoplanetary disks. For all cases, the photometry data is marked by blue circles (empty symbols for marginal
detections). Spitzer/IRS spectra are plotted in black. The MARCS model stellar photospheres are marked by dotted grey lines, and the various
disk models are represented by colored lines and labeled according to their main characteristics (see Table 2). RECX-5: A large-scale gap is notneeded to reproduce the long wavelengths, which also means that SED alone cannot constrain among many diverse but equally plausible SEDstructures. RECX-9: A change in vertical scale height at 10-15 au is needed, which could be caused by a gap, wall, warp, or any other structurea↵ecting the density and the scale height probably created by the existing companion at 20 au. RECX-11: Best fit with relatively massive andflattened disks. A more pu↵ed innermost disk (either a pu↵ed-up rim or a more extended ⇠0.6 au region) is required, with the disk becoming
increasingly flattened and settled at larger radii. J0801 and J0820 appear to be examples of relatively massive transition disks with large, strongly
mass-depleted inner holes. ECHA J0841: Very flattened SED. ECHA J0843: Small gap or hole required. For ECHA J0844: Gap and/or change inthe vertical scale height needed to explain the far-IR flux.

星＋デブリ円盤星のスペクトル型と降着率星団の年齢推定

Fig. 4. Left: SED models for the debris disks. The photometry data are marked by red circles and triangles (the upper limits). Stellar photospheric,disk, and total emission (stellar photospheric + disk models) are represented by grey dotted lines, and red and blue continuous lines, respectively(see Table 2 for details on individual models). The blue dots in the SED of RX J1005.3-7749 show the detection from Murphy et al. (2010). Right:
Results of the SED modeling of the debris disks showing the mass of the disk as a function of the location of the narrow dust ring.

with an optically thin dust emission. With the same approximation as in the other debris systems, we find that ECHA J0841 is
the only source with a massive narrow ring of 1.6-1.7 ⇥ 10 6 M

at between 17 and 20 au from the central star.
It is very interesting to highlight that both approaches led to alarge gap of about 15 au and a very massive disk compared to

ダストの質量と降着率

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