ACCREファイル

THE STAR FORMATION NEWS LETTER: No. 244 7 April 2013 担当 麻生 (東大) 2013/4/26
Forma&on and evolu&on of interstellar filaments; Hints from velocity dispersion mea-­‐ surements D. Arzoumanian, Ph. Andre, N. Pere3o, and V. Konyves D. Arzoumanian et al.: Formatio
l  Aquila, Polaris星間雲の速度分散を調べた。 l  T=10 K, 幅0.1 pcでは熱的臨界線密度Mline,crit=2cs2/G
は、中心柱密度8e+21 cm–2 (Av~8)に相当。 (cf. 星形
成threshold Av=6~9) l  IRAM 30 mでC18O 2–1, 13CO 2–1, N2H+ 1–0 à乱流を求めて水素の音速と合わせた。 l  NH2<8e+21 subcriZcal à cs<σtot<2cs (NH2に依らない) , unbound 乱流でフィラメントが支えられている。 l  NH2>8e+21 super criZcal l  à σtot∝NH2,obs0.35 , bound 重力収縮、Σ0が多くなるとσtotも大きくなり~0.1 pcを維持。 l  Σ0はevoluZonary indicatorになる。
0.3and0.1
0.05
3.4.RDensity
velocity
Pl (pc)
Qi
0.3
0.4
0.5
all models, the syste
Reverse dynamical evolu&on of Eta Chamaeleon&s For
Plummer
model
Christophe Becker, Estelle Moraux, Gaspard Duchene, Thomas ! distribut
3.4. Density and
velocity
3Nsys
ρPl (r) =
1 + (r/R
Maschberger and Warrick Lawson 3 systems arePl
For all models,
the
4πR
Plummer model
Pl
l  η ChameleonZs、6-­‐9 Myr, d=94 pc, 18 systems in r=0.5 pc where Nsys! is the initial
" nu
3Nsys
2 −5/2
ρPl (r) =The 3velocities
1 + (r/RPl )of eac
l  m<0.1 Mo, rbinary>50 AUが少ない。 4πRPl
separaZon 30 AU以下は18% (cf. TW Hydrae assoc. 58%) cording to this density dis
where
number
/Einitial
Eof
Qi N=sysEiskinthe
pot where
kin
l  universal IMFから力学進化だけで再現できるか？ The
velocities
of
each
individ
ter and Epot the gravitati
thiswith
density
distribution
l  モデルパラメーター(初期状態)はNsys, RPl, Qで指定。 cording
thustoleft
three
free p
A&A 552, A46 (2013)
Ekin is the to
Q = Ekin /E
potofwhere
Halo
stars
tems
N
,
the
Plummer
ra
sys
ter and Epot the gravitational 1.00
ener
thus left with three free parameter
tems Nsys , the Plummer radius RPl
i
Number of massive stars
Number of systems
l  成功率の分布を見ると最適
解がありそうだが、同時刻で
はないのでダメ。 l  binary選び方、brown drarfの
分布を変えてもダメ。 l  初めからm<0.1 Mo, rbinary>50 AUを少なくすると成功。 l  結論) 力学進化は重要では
ない 0.3
0.1
3.5. Parameter grid
0.05
0.03
3.5.From
Parameter
grid
the shape
0.01
0.005
R
N 20
30
40
50
60
70
20
70
20
Number of VLMOs
0.3
0.1
0.05
0.03
0.01
0.005
R
N 20
30
40
50
60
of the IM
N = 50 by the requirem
Fromsys
the shape of the IMF, 0.10
we
30 40 50 60 than
70 20 30
40 "50. To
60 70
1
M
cover
a
w
Nsys = 50 by the requirement to hav
Binary fraction weNumber
of wide
binaries
tested
Nsys
from
to
than 1 M
a wide20
range
" . To cover
to fit
we estimated
tested Nsys from
20 atoconstan
70. The
estimated
to of
fit astar
constant
surface
vations
forming
re
vations
of
star
forming
regions
(A
to 1.0 pc for 50 systems.
to 1.0 pc for 50 systems. The0.01
stu
showed
that
a
dense
initia
showed that a dense initial configu
to eject
enough
members
to eject
enough
members
from th
of VLMOs.
Todyn
fa
the the
lacklack
of VLMOs.
To favour
30 40 50 60 70 20 30 40 50 60 70
Physical proper&es of ou>lows: Comparing CO-­‐ and H2O-­‐based parameters in Class 0 sources P. Bjerkeli, R. Liseau, B. Nisini, M. Tafalla, P. Bergman, G. Melnick and G. Rydbeck アウトフローのejecZon mechanismはCO以外で調べても同じなのか？ Herchel、H20(110–101) 557 GHz, H20 212–101 1670 GHz Class0天体、L1448, L1157, VLA 1623 COはcold entrained ambient gas H2, H2Oはshocked gas (H2OはCOよりH2をtraceできる) td=Llob/vmax (mom1速度だとtdを過大評価、vmaxは過去のCOに一致) P. Bjerkeli et al.: Physical properties of outflows from Class 0 sources
oullow age ~103 yr (衝撃波散逸より長く、freeze-­‐outより短い) 運動量P、運動エネルギーE
も推定。 l  dP/dt, dE/dtはCOと同じくら
いだが、2-­‐3倍大きい。 l  mass loss rate ~106 Mo yr–1 l  結論) CO地上観測で十分 l 
l 
l 
l 
l 
l 
l 
l 
L1157
200
VLA1623
L1448
150
Dec offset (")
100
50
0
−50
−100
−150
100
50
0
−50
RA offset (")
−100
100
50
0
−50
RA offset (")
−100
150
100
50
0
−50
RA offset (")
−100
−150
X-­‐Ray Determina&on of the Variable Rate of Mass Accre&on onto TW Hydrae N. S. Brickhouse, S. R. Cranmer, A. K. Dupree, H. M. Guenther, G. J. M. Luna and S. J. Wolk The Astrophysical Journal Letters, 760:L21 (5pp), 2012 December 1
1.2
1
G-Ratio [(f+i)/r]
l  TW HyaからのNe IX吸収線を観測し、星への
1.1
accreZon rateを直接調べる。 l  3つの時刻のデータ 1.0
l  Mg XI, Ne X, Ne IX, O VIII, Fe XVII (cooling column 0.9
of the shock) l  Mg XII, Si XIII, Si XIV (stellar corona) 0.8
1.5x10
l  O VII (post shock) 1.2
l  à 時刻3でTeが高く、N
Hが小さい。 neは一定。 8
1
l  NHの変化はaccreZon preshock streamがX線を吸
1.1
7
収していることを支持。 2
1.0
l  Teは距離(truncated radius)のみで変わり、Mdot, 6
B*で決まる。 0.9
3
l  モデルでMdot, B*, f (hot spot filling factor)を振っ 5
0.8
て、Te, ne, NHを合わせた 1.5x10
2.0x10
2.5x10
3.0x10
3.5x10
4.0x10
T (K)
l  時刻3ではB*は変わらず、Mdotとfが小さくなった。 l  X線を使うとMdotは過小評価されがちだが、可視
光の結果を合った。 6
The Astrophysical Journal Letters, 760:L21 (5pp), 2012 December 1
2
3
2.0x106
2.5x106
3.0x106
Te (K)
3.5x106
4.0x106
Brickhouse et al.
He α/He β
G-Ratio [(f+i)/r]
Figure 1. Theoretical G-ratio (i.e., ratio of forbidden plus intercombination t
6.4
resonance line fluxes) for Ne ix as a 6.3
function of Te 6.2
(solid curve) from AtomDB
(Foster et al. 2012; Chen et al. 2006). Overplotted are the observed ratios wit
1σ errors (vertical error
bars) for the individual observations (open circles
3
numbered in time order) and for the summed spectrum (solid circle). Horizonta
error bars (dashed lines) show how the errors on the observed ratios translate t
the errors on Te .
Ion
6
6
6
6
6
6
e
Figure 1. Theoretical G-ratio (i.e., ratio of forbidden plus intercombination to
resonance line fluxes) for Ne ix as a function of Te (solid curve) from AtomDB
(Foster et al. 2012; Chen et al. 2006). Overplotted are the observed ratios with
1σ errors (vertical error bars) for the individual observations (open circles,
numbered in time order) and for the summed spectrum (solid circle). Horizontal
error bars (dashed lines) show how the errors on the observed ratios translate to
the errors on Te .
1
Table 1
Emission Line Fluxes
2
λref a
(Å)
Flux (Uncorrected for Absorption)
6.6
(10−6 photons cm−2 s−1 )
Pointing 1b
6.5
Pointing 2b
Pointing 3b
Mg xi
9.17 21
2.5 ±210.4
1.7
2.4 ± 0.
21 ± 0.5
21
1x10
2x10
Ne x
9.71
1.8
± 0.8 -2 3x103.1 ± 0.5 4x10
2.8 ± 0.
NH (cm )
Ne x
10.24
7.0 ± 0.7
9.0 ± 2.0
8.7 ± 0.
Ne ix 2. Ratio of11.00
7.3 ± 0.7 line (Heα)6.6
± 1.0
7.9 ± 1.
Figure
the flux of the resonance
to that
of Heβ as a function
ofNe
hydrogen
column
for given
6.21.
ix
11.54density (dashed
19.9 ± curves)
1.5
23.7 ±log
1.8[Te ] (K) from
24.2 ±
toNe
6.6xas labeled.12.13
Absorption models
McCammon
(1983)
63.8 ±are
3.1from Morrison
74.1 ±&3.3
77.2
± 3.
and
are from Foster
al. (2012). Overplotted
Feline
xviiemissivities
12.27
3.2 ±et0.8
4.7 ± 1.0 are the observed
2.1 ± 0.
ratios
error ±
bars)
observations
(open
Ne ixwith 1σ errors
13.45(vertical128.3
6.9for the individual
144.7 ± 7.0
187.8
± 8.
circles, numbered in time order) and for the summed spectrum (solid circle).
Ne ix
13.55
93.5 ± 5.5
97.8 ± 5.9
115.4 ± 6.
Observed points are placed on the curve appropriate for their Te as determined
Ne ix
13.70Horizontal47.4
± bars
4.0 (dotted50.4
± show
3.4 how the
53.9
± 4.
from
their G-ratios.
error
lines)
errors
We have preferred to analyse the observed spectrum as it is, and
have tried to obtain information also from the secondary spectrum.
This was not trivial, mostly because no usual spectroscopic methods for the parameter determinations can be applied to the close
companion. In fact, neither hydrogen lines nor elements with lines
in two different ionization stages are independently observable. We
based our parameters for the secondary mostly on the Ca I line at
6122.21 Å which is a good luminosity indicator (Cayrel et al. 1996).
The two components for this line are rather well separated and free
of blends. Unfortunately, the other two lines of the Ca I triplet at
6102.73 Å and 6161.30 Å are blended.
The composite synthetic spectrum normalized to the continuum (PS) was computed according to the relation (Lyubimkov &
Samedov 1987)
The Herbig Ae SB2 System HD 104237 C.R. Cowley, F. Castelli, and S. Hubrig l 
l 
l 
l 
l 
分光連星Herbig Ae Hd 104237 (DX Cha) weak absorpZon lineからabundanceを測った。 モデル大気 (ATLAS9)から主星はTeff=8250 K, 重力加速度log g=4.2 F (P )R + F (S)R
F (P S)
=
.
(1)
F (P S)
F (P )R + F (S)R
観測された等価幅(連星同士が混ざる)とモデルからの真の等価幅を使うと
We use the subscript ‘λc’ to indicate the continuum at a wavelength
λ. F for the primary (P) and secondary (S) have units of energy per
星の半径比がわかる。 unit area per sec per Ångström. R are the stellar radii.
After some experimentation with alternate models and different
等価幅からabundanceもわかる。 radii ratios, we selected a ratio R /R = 1 (see Section 4.4), and
the parameters T = 4800 K and log (g) = 3.7 for the secondary.
was deduced from the
A rotational velocity v sin (i) = 12 km
25元素調べて、ほとんどsolar vsalue comparison of the observed and computed profiles. We thank the
referee, Barry Smalley, who pointed out that the same v sin (i) and
Zrが最もenhanced、Liもenhanced macroturbulence (8 and 9 km s , respectively) would have nearly
the same combined profile as a v sin (i) of 12 and no macroturbuLiは他のHerbig Aeでは見つかっていない。 lence. This would be the case if the stars were tidally locked.
A microturbulent velocity ξ = 1.0 km s and solar abundances
Herbig AeはmagneZc p/CP starになると考えられているが、化学的には
K, log (g) = 4.0 and assumed
were assumed. FBA
used
T = 4500
solar abundances and a microturbulent velocity ξ = 2 km s .
indicaZveではない。(solarまたはmild oo) with
the
Fig. 3 compares the observed Ca profile at 6122.21λÅ B
λ
λ
λc
λc
2
P
2
P
2
S
2
S
λ
λc
Figure 3. Observed (black) and calculated Ca I λ6122.21, with log (g) =
3.7 (light grey), and log (g) = 4.0 (dark grey). The main feature is due to the
primary. Absorption from the same line in the secondary star (see the text)
is to the violet.
S
P
Table 2. Adopted parameters for primary and secondary atmospheres.
eff
−1
−1
Primary
Secondary
−1
t
eff
t
−1
I
composite profiles computed for Teff = 8250 K and log (g) = 4.2
for the primary and for both Teff = 4800 K, and log (g) = 3.7 and
Teff = 4500 K and log (g) = 4.0 for the secondary. In the first case,
the ratio of radii is RS /RP = 1, in the second case it was deduced
from the relation
MS gP
RS2
=
·
.
MP gS
RP2
(2)
for a mass ratio MP /MS = 1.29 (Böhm et al. 2004). The too broad
wing of the secondary star profile computed for log(g) = 4.0 is
evident.
The adopted parameters for the two components (Table 2) were
well suited to reproduce several primary–secondary pairs of profiles
as Fe I at 4950.11, 4969.92, 5002.793, 5393.17, 5576.09, 6065.48,
6252.56, 6335.33 Å, Ca I 6717.68 Å, and several others.
Teff K
log (g)
ξ turb
8250 ± 200
4800 ± 200
4.2 ± 0.25
3.5− ≤ 3.7
2.5 ± 1
1.0 ± 1
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