The Star Formation Newsletter#329, 15-21
島 和宏 (京都)2020/06

The Star Formation Newsletter #329 (15-21)
#15

#16

#17
#18

#19
#20

#21

#15

https://arxiv.org/abs/2004.08736

フォーマルハウトb・HSTによって観測された画像を解析
・可視光で直接発見された史上初の太陽系外惑星(と思っていた)

フォーマルハウト

・赤外では何も映らないため微惑星衝突後の dust cloud では？
・むしろ太陽系外で初めて捕らえられた微惑星の衝突現象

Table 1. Multi-roll HST coronagraphic observations of the Fomalhaut system
Program ID

Date

GO9862X
2004-May|Aug
GO10390X
2004-OctGO10598X
2006-Jul
GO11818
X
2010-Jun|Sep
STIS
combined
2010,
2012,
2014
GO12576
X 2013,2012-May
GO13037
2013-May
GO13726
2014-Sep

Instrument

Filters

Apertures

ACS
ACS
ACS
STIS
STIS
STIS
STIS

F814W
F606W,F814W
F435W,F606W,F814W
N/A
N/A
N/A
N/A

CORON1.8
CORON1.8
CORON1.8,CORON3.0
WEDGEB2.5ú
WEDGEB2.5
WEDGEB2.5
WEDGEB2.5ú

NImages

NRotations

PSF

5
32
53
19
48
48
24

2
3
4
7†
12†
12†
8

Vega
Vega
Vega
ADI
ADI
ADI
Vega & ADI

rograms marked with “ADI” were planned to use angular differential imaging and therefore did not observe a PSF source.

¶
The majority
STIS combined of rotations were separated by only a few degrees (Æ 25 ).
2010, 2012, 2013, 2014

XPreviously published data.

Observations were also taken at additional apertures (BAR10 for GO11818 and BAR5 for GO13726), but were not included due to low S/N

he position of Fomalhaut b.

E

The first possibility was judged to be unlikely to reproduce
lhaut, either with ACS or with STIS. Of these, only 7 were trN
he observations (see also Tamayo (2014)). The other two pos- high-contrast imaging, multiorbit, and multirotation-angle pbilities are constrained significantly by the assumption that grams as described in Table 1; the remaining 4 programs tohe dust system should persist in a state similar to its present only a single or a few images. Here, we describe the previou
ne for the main sequence lifetime of the star, i.e., ≥ 400 unpublished 2013 and 2014 observations of Fomalhaut b a
Myr. Lawler
et al. (2015) suggested
a possible solution
to theprovide a coherent
and independent
rereduction and analy
2004-06/ACS/F814W
2004-10/ACS/F814W
2004-10/ACS/F606W
2006/ACS/F435W
2006/ACS/F606W
fetime issues by attributing the source to a transient dust of all the useful HST data.
loud produced by a collision between planetesimals interior
Rereduction of Archival ACS Data. Three of the 11 HST coro the main debris belt around the star.
agraphic programs used ACS (PI: Paul G. Kalas) and provid
Wereport that Fomalhaut b differential
has grown
in extent and
10 from the occulter. We also registered the shifts between
imaging (ADI) technique, where a star becomes
2006/ACS/F814W
2010/STIS
2013/STIS
2014/STIS
the target
images in a similar manner. We found an average
its own PSF calibrator by combining2012/STIS
images of it taken at the discovery
imagesof
Fomalhautb (Kalas et al., 2008). W
aded
since
its
discoveryin
HubbleSpace
Telescope(HST)
offset in x and y pixel coordinates of x = ≠0.32 ± 0.21 and different roll angles. This approach works well for edge-on or
y = 0.35 ± 0.42, which is close to the nominal quarter pixel inclined narrow-belt disk systems, such as that of Fomalhaut.
mages
from 2004, with motion consistent
with an escaping first give a brief description of the observations and thevalue given in the Instrument Handbook for pointing preciThe STIS coronagraph consists of two occulting wedges,
sion. The fluxes of the PSFs were scaled for each pairing by and two occulting bars. The GO11818 program observed
withinthesein observations.
rajectory.
behavior
isof theconsistentwithexpectationsfora 2013,serving
Fig.
1. (Top)background
Mediancombined
imageof
all multi-roll(2010,
and 2014)techniquesof the Fomalhautemployedsystem. Fomalhautb is visible
the image within the W
determining
theThislevelsat the edges
fields.
Fomalhaut STIS
in 2010observations
using the 2.5 wide
position2012,
on the “B”
To pinpoint the location of Fomalhaut,defines wedge. Deeper images at the same occulting position were
white
rectangle,which
is 2ÕÕwe◊determined1ÕÕplanetesimalinthensize
and highlights the area andshowndispersing
in the postage-stamp
imagesbelow. The
postage-stamp
imagesthe individual
observations
thendescribe
ourrereduction
ofshow
thesedata, carriedout(seesoust
producedawhichthecloudderotation centerof the images,inthe rota- obtainedcollisionin 2012 (GO12576) and 2013 (GO13037) utilizingEN

2004-06/ACS/F814W

2004-10/ACS/F814W

2004-10/ACS/F606W

2006/ACS/F435W

2006/ACS/F606W

2006/ACS/F814W

2010/STIS

2012/STIS

2013/STIS

2014/STIS

Fig. 1. (Top) Median combined image of all multi-roll STIS observations (2010, 2012, 2013, and 2014) of the Fomalhaut system. Fomalhaut b is visible in the image within thewhite rectangle, which is 2ÕÕ ◊ 1ÕÕ in size and highlights the area shown in the postage-stamp images below. The postage-stamp images show the individual observations (seetext for descriptions of each). The individual images are scaled to the same level per filter [0 to 0.1 counts per second (cts·s≠1 ) for the F606W and F435W ACS filters and for
STIS and 0 to 0.05 cts·s≠1 for the F814W ACS filter]. The green circles with crosses highlight the then current positions of Fomalhaut b, with 3‡ astrometric error radii, while
the smaller cyan color circles show the previous positions, to highlight the spatial motion of the source. For the 2014 image, we show the two locations predicted by the two
independent trajectory fits. The bright spot “near” the predicted locations is too far to be considered associated with Fomalhaut b.

ÕÕÕÕ

(cts s-1)

0.04
0.02
0

tric
-6

[1]
log10(F) (F x Jy-1)

xel
for

-6.2

ACS F435W
ACS F606W
ACS F814W
STIS(Model:(Model:(Model:(Model:

)
)
)
)

-6.4

-6.6

Spatial scale (au)

l of
-6.8
ith
red
-7
me
ere
-7.2
ned
2004
2006
2008
2010
2012
2014
2016
nts.
Date
to
ied Fig. 3. The photometry of Fomalhaut b at all observed epochs and wavelengths. The
for error bars shown are at 1‡. The offset between the ACS and STIS data is most likely
ons, an artifact, due to the larger STIS pixelsizes, the spatial expansion of the dust cloud,and the0.8
method of photometry that was necessary. The expansion of the dust cloud
meaal., over time,
α=0.05 au
yr-1the HST PSF, results in the central peak brightening. Thisconvolved
withσclouds in artifact 0.7
is further enhanced by the larger STIS pixel size. As we had to use larger
ical physical apertures for the STIS data than for the ACS data (same number of pixels),
sly
0.6
e to the object
seems to brighten artifically. Identical photometry of the cloud model ACS
ues
data, shown with empty circles, exhibits similar behavior.
age and STIS
0.5
ing
sital
a
0.4
ther
3V) color shift is a natural consequence of the dust cloud being
0.3
und
ent
slightly bluer than the central star. The offset between theonal
the ACS and
0.2 STIS data is most likely an artifact, brought on by
theJy)
the combinationof changes in two variables: 1) the source
0.1
the
ith
becomes extended over time and 2) the STIS photometry
olli0
for apertureis physically larger than the ACS one, due to thecity
our larger-0.1
projected pixel sizes of the detector (Fig. 3 legend). The
tver,
as
precision alignmentof the STIS
and lackof any2014
higher
2004
2006
2008 data
2010
2012
and
r of signal points near the predictedof the source (evenDatelocation(year)
andfor with a wide margin of astrometric error) gives high confidence
nch Fig. 8. The spatial evolution of the observed dust cloud and the best fitting slopeata
to our non-detection in 2014.
ST)
with a size increase of 0.05 ± 0.016 au·yr≠1 , which is approximately 6.2% of theeral

どんどん暗くなっている-> 微惑星同士の衝突で生まれた
dust cloud が膨張して減光

膨張速度の見積もり-> 最初の観測の39日前に衝突？

#16 https://arxiv.org/abs/2004.13920

Initial Mass Function (IMF)について-> low-mass 側が知りたい

The ONC IMF to planetary masses

Young massive clusters (YMCs)に注目

3-> 若くて十分な個数の星Orion Nebula Cluster (ONC)-> 1-3 Myr, ~2500Msun

HST (WFC3/IR)
F139M (1.4μm water absorption band)
F130N (adjacent line-free continuum)-> low-mass star を探す
Color-Magnitude Diagram (CMD)
Figure 1. Left: the observed color-magnitude diagram. The green shaded area highlights the region used for the IMF fit.

e
1)
,
⇠
t
ve
e
he
2
yr,
srht
ge
e2
ey
.

s
ce
s
he
e
a.
e
nis
es
e
he
cwe
-n
ce
n-

↵1

k12andm planetary, m01  m
< m12
extrapolated into the brown dwarf
mass↵0 the data.
regime while still providing a good
k01fitmto, m < m01
brokenpower-law(Kroupa
IMF
like)
The IMF
probabilitymodel
distributionfunctions,arepawith :rameterized as follows. For the broken power law:2 ↵1
k12 = m↵12
↵2
pBPL (m|↵0 , ↵1 , ↵2 , m01 , m12 ) / m , m m12
1 ↵0
k01 ↵= k12 m↵(2)
01
1
k12 m , m01  m < m12↵0Here the ↵’s represent the slopes
withink01 m, m each< m01segment,
and the mij are the breakor transition masses between
with :
di↵erent segments, or regimes, in solar↵mass
units. The
2 ↵1= mbreak
12 the12
kij constants ensure continuitykat
points. The
↵1 ↵0
k12to
m01
footers run from the low mass kend,
the high (2)mass
01 = 0,end, 2. For reference, the values reported by Kroupa
Here the ↵’s represent the slopes within each segment,(2001) are:and the mij are the break or transition masses betweendi↵erent segments, or regimes, in solar mass units. The(↵0 , ↵1 , ↵2 , m01 , m12 )Kroupa =kij constants
ensure continuity at the break points. The
0.3, end,
1.3,0, to
2.3,
0.08,
0.5)
footers run from the low( massthehigh
mass(3)log-normal
IMF like)
end, 2. For model
reference,(Chabrierthe values reported
by Kroupa
For the(2001)
are:log-normal parameterization we have:pLN (m|mc , , mhm , ↵hm ) / m↵hm , m > mhm(↵0 , ↵1 , ↵2 , m01 , m12 )Kroupa =1 log m log(mc ) 21e 2 (2.3, 0.08, 0.5)) (3)( 0.3,k 1.3,mwith :For the log-normal parameterization
we have:1
2⇣

log mhmlog(mc )hm
pLN (m|mc , , mhm , ↵hm ) / mk↵=, m↵hm
> +1
mhm
m
e
hm
1 log m log(mc ) 2
1(4))
k e 2(m
Here mc is the characteristic
mass in solar mass units
with :(the peak in logarithmic space),is the⇣ width of the
⌘2

⌘2

.

ennaro & Robberto

Figure 4. Broken Power Law IMF fit results, 1Myr case. Top row, left and center-left: color and magnitude
the observed stars (cyan), with superimposed the color and magnitude distributions from the best fit IMF paramfrom 1000 draws from the posteriors (yellow-orange). Note the overall good fit to the luminosity function. The
the simulated color distribution function show however that the simulations underestimate the existing color sp
center-right panel: masses drawn from the best-fit IMF (black) and from 1000 samples from the posterior (graycorresponding observable masses within the CMD fitting region, note the high-mass drop due to our high-mass sa
and the low-mass drop due to incompleteness. Top row, right panel, comparison of the best-fit IMF with the st(2001) and Chabrier (2003) Galactic Disk IMFs. Bottom: corner plot for the fit parameters. The median and t
68% credible interval (1 ) are reported for each variable.

e fit region using the catalog from Paper I. The data are shown in brown.
k the correction corresponding to using the average number of detection
Drass
al. (2016)
で報告されているような
bimodal peak はない
ee text for details),
while theetlighter
histograms correspondto 15 actualidea of the correction uncertainty. Left and right panels are separated for-3thee left and our best10
fit onusing a single burst 1Myr SFH.
Mright,sun まで伸びている

BPLモデルの方が合う？

#17 https://arxiv.org/abs/2004.04753

星の基本的な性質(mass, temperature, luminosity, ageなど)を知るには？
-> double-lined eclipsing binary (EB) stars だと直接求めることができる
今回はNGC2264(~3Myr)内のA new low-mass PMS EB in NGC 2264
young low-mass pre-main sequence (PMS) EB に注目

Spitzer/IRAC 3.6 and 4.5 μm observation により EB の発見

5

E. Gillen et al.
6

E. Gillen et al.

1.0
0.8
0.6
0.025
0.000
0.025
0.2

0.0

0.2

0.4

0.6

1.0
0.9
0.8
0.7
0.6
0.025
0.000
0.025
0.05 0.00

0.05

Figure 3. Phase-folded Spitzer IRAC 3.6 and 4.5 µm light curves (left and right, respectively). Top panels: full phase-folded light curves
that have been detrended with respect to the Gaussian process model, with residuals immediately below. The red line represents the
Figure5. andSpectralenergydistribution
median posterior EB model, i.e. the median path of individual draws computed inphase space,
the pink shaded
regions
indicate the (SED) of Mon-735. Cyan
1 & 2 confidence
is defined relative
to primary
eclipse centre.
Bottomrepresent
panels: zooms
on theprimary andsecondarypointstheobserved
broadband
magnitudes reported inigure 4. Phase-folded
RVintervals.
orbitTheof phase
Mon-735.
The lines
andeclipses (left and right, respectively, for each light curve), with residuals immediately below. The eclipses are grazing with near equal
Table 2, which together comprise the observed SED. The horihaded regions depths
indicate
the medianand 1 & 2 confidence inof ⇠36–37%
on both stars.

-> primary も secondary も大体同じ大きさ

大体同じSEDzontal cyan error bars indicate the spectral range of each band.
ervals of the posterior RV orbits (blue and green for the priSEDs constructed from BT-Settl model atmospheres for the primary and secondarystars, respectively), with Keck/HIRES RV Darkening
between the radius ratio, surface brightness ratio and inclitoolkit) because the specific intensities of themary
andsecondary
arewhichshown
measurements shownasblack
points.
The
greyhorizontal
dottedPHOENIX model
spectra(Husser etstars
al. 2013),
LDtkin blue and green, respecnation when modelling the data. Details of the modelling
SED isshown
in black with its prediction
are systemic
given in §3.1–3.3
below. The two panels below show is based tively.
on, onlyTheirextend combined
up to a wavelengthof 2.6µm, sone indicates thevelocity.
IRAC
and observed
4.5 µm bandpasses
are not covered.
We
in 3.6eachband indicatedby magenta
triangles. Residuals
he residuals of the primary and secondary RV model orbits (top theassumed Teff = 3200 K and log g = 4.0 for both the primary
are shown below. The radii and e↵ective temperatures of the two
3.1 Light curvesnd bottom, respectively).
The primary star’s orbit has a slightly

Keck
で follow-up
4 HIRESE. Gillen spectrographet al.
H

H

Li 6708 Å

2015 -10 -27
0.81

Relative flux

2015 -12 -24
0.172015 -12 -29
0.65

2016 -12 -22
0.38

8

1.5

6

2017 -01 -13
0.45

1.0

4

3

0
4860

4864

0

0.5
6560

6564

6568

0.0

6704

6708

6712

Wavelength (Å)
Figure 1. H , H↵ and Li 6708 Å profiles of Mon-735 (columns, left-to-right) for di↵erent epochs (rows, top-to-bottom). The epoch andorbital phase are given in the H plots. The vertical blue and green lines indicate the radial velocities of the primary and secondarystars, respectively, at each epoch. Both stars present H and H↵ emission profiles, and Li 6708 Å absorption profiles, which suggest that
Mon-735 is a chromospherically active young system.

-> young system を示唆

able 4. Fitted and derived parameters for Mon-735.

Parameter

Symbol

Value

Unit

1.9751388 ± 0.0000050
2456408.9725 ± 0.0013
0.2767 ± 0.0017
0.981 ± 0.054
0.0621 ± 0.0015
0.0006 ± 0.0048
0.083 +0.072
0.037
18.47 ± 0.60
66.5 ± 1.1
72.9 ± 1.1
718 ± 270.105 +0.150
0.078
+73
3260 63
3213 +73
64

days
HJD

Fitted physical parameters
Orbital period
Time of primary eclipse centre
Sum of radii
Radius ratio
Cosine of orbital inclination
Eccentricity and argument of-periastron combination terms
Systemic velocity
Primary RV semi-amplitude
Secondary RV semi-amplitude
Distance
Reddening
Primary e↵ective temperature
Secondary e↵ective temperatureP
Tprim(Rpri + Rsec )/a
Rsec /Rpricos ipe cos !
pe sin !
Vsys
Kpri
Ksec
d
AV
Tpri
Tsec

km s 1km s 1km s 1pc
K
K

Derived fundamental parameters
Primary mass
Secondary mass
Primary radius
Secondary radiusPrimary luminosity
Secondary luminosity
Primary surface gravity
Secondary surface gravity
Mass sum
Radius sum

Mpri
Msec
Rpri
Rsec
Lpri
Lsec
log gprilog gsec
Mpri + Msec
Rpri + Rsec

0.2918 ± 0.0099
0.2661 +0.0095
0.00890.762 ± 0.022
0.748 ± 0.023
0.0590 +0.0064
0.0052+0.0056
0.0536 0.0048
4.140 ± 0.025
4.116 ± 0.026
0.558 ± 0.019
1.508 ± 0.019

Derived radiative, orbital and rotational parameters

M
M
R
R
L
L
(cm s 2 )(cm s 2 )MR

A new low-mass PMS EB in NGC 2264

モデルとの比較

11

BHAC15
1 Myr
8 Myr

2 Myr
10 Myr

3 Myr
15 Myr

4 Myr
20 Myr

5 Myr

0.4

1.4

log (L/L )Radius (R )

0.6
1.2
1.0

1.0
1.2

0.8

1.4

0.6
0.15

0.8

0.30

0.45

0.60

0.75

3800

Mass (M )

3600

3400

3200

3000

Teff (K)CoRoT223992193
pri
sec

0

5

Mon-735
secpri

10

15

MRD Age (Myr)mass-radius diagram

Hertzsprung‒ Russell diagram

Figure 9. Comparison of the fundamental parameters of Mon-735 (green) and CoRoT 223992193 (blue) to the predictions of the BHAC15
stellar evolution models. Top row : mass–radius relation showing model isochrones between 1–20 Myr (left), and the Teff –log L relation
with the same set of model isochrones. Bottom row : corresponding age distributions for Mon-735 (green) and CoRoT 223992193 (blue)
based on their locations in the mass–radius diagram (MRD; left) and Teff –log L (i.e. Hertzsprung–Russell) diagram (HRD; right). The
individual plots in Figures 9–13 all share the same axes for ease of comparison.

・priとsecの年齢はほぼ一致

・MRDとHRD間では一致しない？
do and do not simultaneously model the SED, which gives
us confidence that incorporating the SED into the fittingfrom 1 Myr to 1 Gyr, and the data points show measurements for EBs in the field (grey) and in sub-Gyr open clus-

14

magnetic ﬁeld ありのモデル

E. Gillen et al.

Feiden (mag)
1 Myr
8 Myr

2 Myr
10 Myr

3 Myr
15 Myr

4 Myr
20 Myr

5 Myr

Radius (R )

1.4
1.2
1.0
0.8
0.6
0.15

0.30

0.45

0.60

0.75

Mass (M )prisecsecpripri
secprisec

0

5

10

15

MRD Age (Myr)

0

5

10

15

HRD Age (Myr)Figure 12. Same as Figure 9 but comparing to the magnetic Feiden models.

・MRDとHRD間では一致？
predict larger HRD-inferred masses than the non-magnetic
models. These are consistent with our dynamical masses forboth components of Mon-735, ⇠10% (⇠0.05 M ) larger forthe primary of CoRoT 223992193 (but consistent to within

range, with Mon-735 and CoRoT 223992193 having apparent
ages of ⇠7–9 and ⇠4–6 Myr, respectively (from their positions in the MRD). It is interesting to note that Upper Scorpius has typically been considered older than NGC 2264 with

#18 https://arxiv.org/abs/2004.12938

A&A proofs: manuscript no. 37455_corr_astro-phFig. 1. Left: Extended Orion Nebula (M42), part of the integral-shape filament in Orion A (reddish colors), and the Veil bubble (delineated by adotted circle) filled with ionized gas (greenish). Red: SPIRE 500 µm image (cold dust from the background molecular cloud). Blue: PACS 70 µm
image (warm dust). Green: H↵ image adapted from ESO’s Second Digitized Sky Survey (DSS2, see Pabst et al. 2020). The yellow star corresponds

#19 https://arxiv.org/abs/2004.13736

Accretion driven turbulence in filaments

5

#20 https://arxiv.org/abs/2004.05818?context=astro-ph.GA

22

#21 https://arxiv.org/abs/2004.07834