2. Three generations of stars: a possible case of triggered star formation
M.B. Areal1, A. Buccino1,2, S. Paron1, C. Fari.a3,4 and M.E. Ortega1

Evidence of triggered star formation:
Example of three-generations:(1) W3/W4 Galactic star-forming complex.
(2) N11B nebula in the Large Magellanic Clouda distance of between
2.8 and 3.5 kpc.

HII regions:
Associated with a molecular cloud that
extends from 15.5 -28.5 km/s with amean velocity of about 20.8 km/s
D=2.5±1kpc

SpectroscopyWith 2.5 mIsaac Newton
Telescope at Roquede Los Muchachos
Observatory
on 2019 October 22Sh2-90(1) age <6.5 Myr(2) association containing an O9V star(3) 100 YSOs (0.2<M<3M8)

à B0IIIà D=2.68-3.04kpc
Spitzer/GLIMPSE 8 (G), 4.5 μm (B),MIPS/Spitzer at 24 μm(R)MIPSGAL bubble (MB)sources(1) emission-line stars,(2) supernova remnants(SNRs),(3) luminous bluevariables(4) planetary nebulae(PNe).
Obe starの周りに⾒られるものによく似ている。

H2 column density
13pc(D/2.8kpc)

主系列時のスペクトル型: O9VM=12~15 M8

τMS~10Myr
dM/dt=10-8 M8/yr
Vw=1300km/s
⼒学的エネルギー＝星間ガスに対してした仕事膨張則

λ=70-500μm
Chevalier 1999
è RB=13 (p/k/105)-1/3 pcè観測と無⽭盾である

4. Star-forming sites IC 446 and IC 447: an outcome of end-dominated collapse of Monoceros R1 filament
N. K. Bhadari1,2, L. K. Dewangan1, L. E. Pirogov3 and D. K. Ojha4the sites IC 446 (or IC 2167) and IC 447 (or IC 2169)
are seen at opposite ends of the lamentary structure.
Herschel temperature map

Herschelcolumn density map.
1) A curved geometry2) several high column
density regions.
3) eastern, central, andwestern parts.
Mf=1465M8,l~14pc
λ<105M8pc-1
East) more diffuse with asingle column density
peak,several subfilaments :Central=319M8, 64M8/pc
West=365M8, 91M8/pc
two sites IC 446 and IC 447 are connected by acurved section of dark nebulosity,

vs 105 M8/pc(1) Mon R1 filament is found to be thermally supercritical(2) more prone to fragment and able to collapse into coresdue to gravitational instability(3) possibility that the non-thermal microturbulent gas
motions can provide extra support?
1)the linewidth of 13CO spectra is observed to be 1.5 km/s2)μcrit=211~219 M/pc for a temperature range of 15-20 K.

Cs=0.23 km/s
μ=2cs2/Gに達する時間
τcri=1.1Myr(central λ=0.5pc)
τcri=0.4Myr(western λ=0.2pc)

dμ/dt= 2cs2/G/τcri
22M8/pc/Myr
60M8/pc/MyrPerturbation growth in accreting filaments
S. D. Clarke, A. P. Whitworth, D. A. Hubber

t = 0.15 Myr

t = 0.55 Myr

gλ/g0.05pcMonthly Notices of the Royal Astronomical Society, Volume 458, Issue 1, 01 May 2016, Pages 319‒324,

n=1

n=2
n=3amplitude
λA = 0.2, λ = 0.2 pc, TO = 40 K

and dμ/dt=70M⊙/pc/Myr
inflow(1)longer wavelength
perturbations tend to grow faster,(2) superimposed on this there isa series of peaks and troughsΤcrit=μcrit/(dμ/dt)
the time at which the first sink particle forms, τSINK
the perturbation growth rate as gλ = 1/τSINK

overstability½ periodCondition for the perturbation to growゆえ成⻑が促進される波⻑

前ページの例λ=0.33, 0.17, 0.11, … (n=1,2,3, …)
τ=λ/cs=0.5Myrn=1

ゆえ、半周期間隔で図⽰

end-dominated collapse
For a filament having an initial aspect ratio (A) = 5,
the collapse timescale at its edges is observed 2-3
times less compared to the central regions,
Here A is defined as L/R, where 2L is the length of
the filament and R is the radius of it.

τcrit=λ/2a
The homologous collapse is observed if A < 5, while
the end-dominated collapse is dominant if A > 5(Bastien 1983; Pon et al. 2011).

1. Chemical Variation among Protostellar Cores: Dependence on Prestellar Core Conditions
Yuri Aikawa, Kenji Furuya, Satoshi Yamamoto and Nami Sakai

3. An evolutionary study of volatile chemistry in protoplanetary disks
Jennifer B. Bergner1,2, KarinI. .berg3, Edwin A. Bergin4, Sean M. Andrews3, Geoffrey A. Blake5 et al.

5. Shape Analysis of Hii Regions ‒ II. Synthetic Observations
Justyn Campbell-White1,2, Ahmad A. Ali3, Dirk Froebrich2 and Alfred Kume4

6. The distances to molecular clouds in the fourth Galactic quadrant
Bingqiu Chen1, Shu Wang2, Ligang Hou2, Yihong Yang1,3, Zhiwen Li1,3 et al.

7. Evolutionary study of complex organic molecules in high-mass star-forming regions
Alessandro Coletta1, Francesco Fontani2, Victor Manuel Rivilla2, Chiara Mininni1,2, Laura Colzi1,2,Alvaro Sanchez-Monge3 and Maria T. Beltran2