Star Forma)on Newsle0er#285 11-15
麻生 有佑

Water around IRAS 15398–3359 observed with ALMAP. Bjerkeli1,2 , J. K. Jørgensen1 , E. A. Bergin3 , S. Frimann1 , D. Harsono4 , S. K. Jacobsen1 ,3
8
J. E. Lindberg5 , M. Persson4 , N. Sakai6 , E. F. van Dishoeck4,7 , R. Visser
P. Bjerkeli,, etS.
al.:Yamamoto
Water around IRAS 15398–3359 as observed with ALMAP. Bjerkeli, et al.: Water around IRAS 15398–3359 as observed with ALMA

Ø accre)on historyØster Voldgade 5–7, 1350 Copenhagen K., Denmarkß化学。冷却は100-1000年。
e-mail: per.bjerkeli@nbi.dk
2
Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
Ø FU 3Oriより若くてもバーストするか。
Department of Astronomy, University of Michigan, 1085 S. University Ave., Ann Arbor, MI 48109-1107, USA
4
Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, the Netherlands
Ø IRAS
15398-3359, Lupus I, Class0, 1.8 Lo,
5NASA Goddard Space Flight Center, Astrochemistry Laboratory, Mail Code 691, 8800 Greenbelt Road, Greenbelt, MD 20771,
USA
WCCC。H13CO+
3-2で今のLに対して大きい
6
The Institute of Physical and Chemical Research (RIKEN), 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan
7
Max-Planck-Institut für Extraterrestische Physik, Giessenbachstrasse 2, 85478, Garching, Germany
穴。分子流,にもイベントあり。
8.06158v1 [astro-ph.SR] 22 Aug 2016

spectrum represents the average of the emission within 100 from1
Centre for Star and Planet Formation, Niels Bohr Institute & Natural
History
the central
position. Museum of Denmark, University of Copenhagen,Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan

Received 26 April 2016 / Accepted 1 August 2016

Ø ALMA Cycle 2, HDO (101-000) 465 GHz Eu=22
ABSTRACTK, H218O (414-321) 391 GHz Eu=390 K, θ~0.5”,
Context. Understanding how protostars accrete their mass is one of the fundamental problems of star formation. High dust column~5”をカバー。
densities and complex kinematical structures make direct observations challenging. Moreover, direct observations only provide aspectrum represents the average of the emission within 1 from+の穴の中snapshot. 13
Chemicaltracers provide analternative to characterise the infall histories of protostars.
the central
position.
Ø HDOはH
CO&interesting
CH3OH分子流。
Aims. We aim to map the distribution and kinematics
of gaseous water towards the low-mass embedded protostar IRAS 15398–3359.
P. Bjerkeli, et al.: Water around IRAS 15398–3359 as observed with ALMA00

Fig. 2. All spectra within 200 (100 for HDO (101 000 )) from thecentre of the map, averaged together. The vertical dashed line
represents the source velocity at LSR = 5.5 km s 1 .

Previous observations of H13 CO+ showed a depression in the abundance towards IRAS 15398–3359. This is a sign of destruction ofP. Bjerkeli,
et al.: Water around
IRAS 15398–3359
as observedinwith+
HCO+ by an enhanced presence of gaseous water in an extended
region,relatedto Ha13 CO
recenttheALMA
accretion. Direct
HDO ispossibly
detected in theregion whereis not burst
detected
+
(see
Fig.
3,
and
Jørgensen
et
al.
2013,
their
Fig.
1),
but
an
extenobservations of water vapour can determine the exact extent of the emission
andconfirmthehypothesis
that
HCO
is indeed a goodsion of the HDO emission towards the south-west of the H13 CO+
tracer of the water snow-line.
ring is visible as well. The extent of this emission is ⇠300 AU
and follow the cavity walls of the blue-shifted outflow outlined
Methods. IRAS 15398–3359 was observed using the Atacama Large
Array(ALMA)
at 0.500 resolution
by theMillimeter/submillimeter
CH3 OH emission. Furthermore, a red-shiftedcomponent
Fig. maps
3. HDO emission(black)comparedto the H13 CO+ centre
emissioFig.
1.
Continuumandintegrated
line
emission
towards
IRAS
15398–3359,
18
the3
outflow
lobe atthe 4 level. This (brown,
panel) and the CH
in two setups at 390 and 460 GHz. Maps of HDO (101 000 ) and His2 observed
O=(4
taken
simultaneously
withupper
observationsof
3 OH emission
0red-shifted
1 (green, low
14in 0921 ) 00were
–34
06.7
.
The
lines
are
integratedoveravelocity
range
of
=
0.75
km
s
(exceptfo
2000
feature is spatially coincident with the emission knot observed panel) presented in Jørgensen et al. (2013). Contours are fro
the CS (8–7) and N2 H+ (5–4) lines and continuum at 0.65 and 0.75mm.
TheCOmaps
were
using
radiative
18 1 . The transfer
in high-velocity(2–1) (Bjerkeli
al. 2016,
3) and3 . insteps
continuum
peaklevel
is indicatedwithindic
a starhas
been used).
Contours
areet interpretedfrom
3 their
inFig.
stepsof 1dust
For
Hon
O
and
CS,
the
2
is
also
2
the separation to the central source is ⇠500 AU. In Fig. 4 we plot
calculations of the protostellar infalling envelope with an outflow cavity.
red
shadedonly
regionsmarkintegrated
the directions
the and
3.5 bluelevel contours
for emission
over di↵er-of the outflow cones (same geometry as in the mo
13+
ent
at higher
velocitywithto reported
90-percent
levelofEmission
the beamprofileis indicatedwitha circlein eachpanel.
Theatbeam
is shownth
Results. HDO is clearly detected and extended over the scales of the
Hvelocity
COintervals.
depression,
althoughitisrespect
displacedbyby⇠500
AU
theJørgensen
et al.in(2013)
345 GHz,
where theinbea
the systemic
velocity
are indicatedin this figureby
withdarker red
size wasfrom
similar.theThe largest
recoverable scales in the observ
The
continuummaps
are zoomed-ina factorofabsent
two.
direction of the outflow. H18
Oistentatively
detected
towards
thered-shifted
outflowlobe,
butotherwiseitismappedand blue than the lower velocity emission. Comparing di↵erent tions presented here range from 4 – 500 . We therefore cannot ex2velocityentirely
bins in this way
shows a possible
gradientorigin,in the mappedthat emission
the ambient envelope is resolved ou
region, which suggests that temperatures are low. Although we cannot
excludea shock
this clude
indicates
thatfromanotherregion.1.
In ALMA
general, emission
at higher velocities is detected at and some low-level extended emission is observed. The lowe
Tableobservations.
process is responsible for the water emission.
greater distances from the source than at lower velocities.
contours of the emission presented in Fig. 1 should therefore b
The H18321 ) line models,in contrast to we
HDOconclude
is not detected thatconsidered
as unreliablebecausespacing data.
2 O (414
Conclusions. Based on the temperature structure obtained from dusttowards
radiative
transfer
thefrequency
water
wasBandwidth
mostwe lack shortLine+
thewindow
protostar. There
are twooftentative
featuresin the out- Center
Spectral
Numberchannels/ resolution
The N
2 H (5–4) line at 465.825 GHz is detected towards thflow lobes,
but onlyat the 3 accretionlevel. The north-easternthese islikely released from the grains in an extended hour-glass configuration
duringa recent
burst. ofHDO
only
detectedinthecavity walls in the red-shifted outflow lobe and in a series oknots is located downstream of the feature detected in knots in the cavity wall and inner regions of the blue-shifted ou
HDO setting:region closest to the protostar, at distances of up to 500 AU. These emission
signatures
has recently
HDO(101 000 ). can only be explained if the luminosity+
flow lobe. GHz
No emission 234.375
is detectedMHz
towards theitsel
960 / 244.141 kHz
465.818
Nprotostar
2 H (5–4)
A clear velocity gradient is visible in this dataset, and higher v
been increased by orders of magnitudes. Additionally, the densities in01 the outflow conesmustbesufficiently
low.
960 / 244.141 kHz
464.928 GHz
234.375 MHz
HDO (101 0
3.2.
2 Continuum and other128lines/ 15625.000 kHz

locities are detected farther away from the central source tha

465.000 GHz

2000.000 MHz

Continuum

close to the outflow launching region (Fig. 4).
Key words. ISM: individual objects: IRAS 15398 – ISM: molecules– ISM:is detectedjets and– Stars:formation– isStars:
18continuumThewith aoutflows
peak flux of 36±1
mJy beam 1
CS (8–7)
detectedwinds,
towards IRAS 15398–3359, and th

Water around IRAS 15398–3359 observed with ALMAP. Bjerkeli1,2 , J. K. Jørgensen1 , E. A. Bergin3 , S. Frimann1 , D. Harsono4 , S. K. Jacobsen1 ,J. E. Lindberg5 , M. Persson4 , N. Sakai6 , E. F. van Dishoeck4,7 , R. Visser3 , S. Yamamoto8.06158v1 [astro-ph.SR] 22 Aug 2016

1の続き

P. Bjerkeli, et al.: Water around IRAS 15398–3359 as observed with ALMA

Centre for Star and Planet Formation, Niels Bohr Institute & Natural History Museum of Denmark, University of Copenhagen,Øster Voldgade 5–7, 1350 Copenhagen K., Denmark
e-mail: per.bjerkeli@nbi.dk
2
Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
3
Department of Astronomy, University of Michigan, 1085 S. University Ave., Ann Arbor, MI 48109-1107, USA
4
Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, the Netherlands
5NASA Goddard Space Flight Center, Astrochemistry Laboratory, Mail Code 691, 8800 Greenbelt Road, Greenbelt, MD 20771,
USA
6
The Institute of Physical and Chemical Research (RIKEN), 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan
7
Max-Planck-Institut für Extraterrestische Physik, Giessenbachstrasse 2, 85478, Garching, Germany
8
Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
Received 26 April 2016 / Accepted 1 August 2016
ABSTRACTFig. 4. 3.5 levelin di↵erent
velocity intervals
from theaccrete
systemictheirvelocity
the lowest problems
velocities areContext.
Understanding
howo↵set
protostars
mass(seeis inset).
one ofFortheHDO,
fundamentalof star formation. High dust column
towards the central
regionandand complex
slightly displaced
into thestructures
blue-shiftedmake
outflow.
Highervelocities arechallenging.
furtheroutaroundin bothP.detected
Bjerkeli, etal.: Water
IRAS
15398–3359
as observed with
ALMA
densities
kinematicaldirectobservations
Moreover,directobservations
only
provide aoutflow lobes.snapshot.
The 465 GHz(for HDO)
and 403
GHz (forand N2 H+ )alternative
continuum istoplottedwith black
contours.
The extentof
of protostars.
Chemicaltracers
provideanCSinteresting
characterise
theinfallhistories
noise ratio attained for HDO) assume that this is an underestithe outflow is indicated in gray.

Aims. We aim to map the distribution and kinematics
ofbygaseous
water
towardsare
thestilllow-massembedded
protostar IRAS 15398–3359.
mationa factor of
two, velocities
on the lowerend.

We therefore
concludethat this towards
is most likely
not themain cause
Previous observations of H13 CO+ showed a depression
in theabundance
IRAS
15398–3359.
This is a sign of destruction of
the anextendedemission.
HCO+ by an enhanced presence of gaseous waterof inextendedregion, possibly related to a recent burst in the accretion. Direct
observations of water vapour can determine the exact extent of the emission and confirm the hypothesis that HCO+ is indeed a good
4.2.3. Water sublimation in low-density outflow
tracer of the water snow-line.
anotherpossibility
is thatMillimeter/submillimeterwater was released from the grainsArray (ALMA) at 0.500 resolution
Methods. IRAS 15398–3359 was observed usingYetthe
AtacamaLarge
at the time when the protostar
18 underwent a luminosity burst, but
in two setups at 390 and 460 GHz. Maps of HDO(1the000 ) out
andto H
(414occurred
321 )waswere
taken
simultaneously with observations of
01 distance
that
where
changedsignifi2 Othis
the CS (8–7) and N2 H+ (5–4) lines and continuumat compared
0.65 and
0.75is expected
mm. Thewere interpretedusing dust radiative transfer
cantlyto whatfor amaps
simple power-law
density profile.
If densities
are lower in the inner parts of the outflow
calculations of the protostellar infalling envelope withan outflow
cavity.
cavity, then the 100 K radius13can be+ changed significantly comResults. HDO is clearly detected and extended overthescalesof theonly
H anCO
depression,
althoughpared
to thecase whereenvelope
is present. To
test that, it is displaced by ⇠500 AU in the18
we adopted
a modelsimilar to the one
presented
in Bjerkeli
et al.
direction of the outflow. H2 O is tentatively detected
towards
the red-shifted
outflowlobe,
but otherwise
it is absent from the mapped
Model M3).
geometryof the model
presented
in that origin, this indicates that anotherregion, which suggests that temperatures are low.(2016,
AlthoughweThecannotentirely
excludea shock
paper resembles the structure of the emission and the observed
process is responsible for the water emission.
line profiles well, both the large-scale CO outflow and the smallC2 H emission,
tracing
the outflow
cavity walls(Jørgensen
Conclusions. Based on the temperature structure scaleobtainedfrom dust
radiative
transfermodels,we conclude that the water was mostet al. 2013).
The infalling envelope
profileaccretionin this caseburst. HDO is only detected in thelikely released from the grains in an extended hour-glass
configuration
duringdensity
a recent
is the same as before, but we also included an outflow that isregion closest to the protostar, at distances of up describedto 500 AU.
These signatures
onlytheir
beFig.
explained
if the luminosity has recently
by a wind-driven
shell (Lee etcan
al. 2000,
21).
The details
this system.
model
beoutflow
found inshow
Bjerkelietal. (2016).
been increased
by ordersmagnitudes.
Additionally,
the densities
incan
the
cones
beatsufficiently low.
Fig. 5. 100 K distancefrom the protostar
as aoffunctionof the angle
to the mid-planeof theThe
curvesthe must
distance
on theavailable
data towards
IRAS 15398–3359
we canwhich the temperature drops below 100 K for three di↵erent scenarios. InBasedthe first
scenario(blue),
a pure envelope
density profile5
not estimate
density
the–added
gas
insidethemodel.
outflowcone,and – Stars:formation – Stars: winds,
ISM: (black),
individual
objects:–density
ISM:theISM:
jets
and outflows
is considered. Key
In the words.
second scenario
an outflow
coneIRAS
with a 15398
constant
atmolecules
10
cm of3 isto theThe
third

The 2008 outburst in the Young Stellar System Z CMa
III - Multi-epoch high-angular resolution images and spectra of the components
in near-infrared
M. Bonnefoy1,2 , G. Chauvin1,2 , C. Dougados1,2 , Á. Kóspál3 , M. Benisty1,2 , G. Duchêne1,2,4 , J. Bouvier1,2 , P. J. V.
Garcia5 , E. Whelan6 , S. Antoniucci7 , and L. Podio7
1

Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France

CNRS, IPAG, F-38000 Grenoble, FranceØ CMa OB1 associa)onのPMS
binary Z CMa=FU Ori+Herbig Be (~0.11”), d=450-1100 pc,
e-mail: mickael.bonnefoy@obs.ujf-grenoble.fr
Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, PO Box 67, 1525
EX Ori burst(‘87, ‘00, ‘04, ‘08, ‘11, ‘15, ‘16)。
Budapest, Hungary
Astronomy Department, UC Berkeley, 501 Campbell Hall, Berkeley CA 94720-3411, USAØ Oumlow (3.9pc) ß
HBeのwiggling
jet。FUORにもtwinjet。HBeにdust
cocoon。
Universidade
do Porto,
Faculdade de Engenharia, Rua
Dr. Roberto Frias, s/n, P-4200-465 Porto,
Portugal
Department of Experimental Physics, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
Ø bipolar wind
vs.5, I-50125
cocoonの減光変化(偏光観測)à変光。
INAF (Brγ)àmass
- Osservatorio Astrofisico lossà変光di Arcetri - L.go E. Fermi
Firenze, Italy
Received April 12, 2016 ; acceptedKeck/NIRC2+OSIRIS,
June 22, 2016
Ø JHK, VLT/NACO+SINFONI,
R~4000。

rXiv:1608.08035v1 [astro-ph.SR] 29 Aug 2016

2
3
4
5
6
7

M. Bonnefoy et al.: Multi-epoch images and spectra of the components of Z CMa in the near-infrared during the 2008 outburst

Visual Magnitude

6

8

10

12

2004

2005

ABSTRACT
Context. Z CMa is a complex pre-main sequence binary with a current separation of 110 mas, known to consist of an FU Orionis

2006

star (SE component) and an embedded Herbig Be star (NW component). Although it represents a well-studied and characterized
system, the origin of photometric variabilities, the component properties, and the physical configuration of the system remain mostly
unknown.
Aims. Immediately when the late-2008 outburst of Z CMa was announced to the community, we initiated a high angular resolution
imaging campaign aimed at characterizing the outburst state of both components of the system in the near-infrared.
Methods. We used the VLT/NACO and the Keck/NIRC2 near-infrared adaptive optics instrument to monitor the astrometric position
and the near-infrared photometry of the Z CMa components during the outburst phase and one year after. The VLT/SINFONI and
Keck/OSIRIS integral field spectroscrographs were in addition used to characterize for the first time the resolved spectral properties
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016of the FU Orionis
and the Herbig Be component during and after the outburst.
Date (years)
Results. We confirm that the NW star dominates the system flux in the 1.1-3.8 µm range and is responsible for the photometricoutburst. We extract the first medium-resolution (R⇠2000-4000) near-infrared (1.1-2.4 µm) spectra of the individual components. The
SE component has a spectrum typical of FU Orionis objects. The NW component spectrum is characteristic of embedded outbursting
protostars and EX Or objects. It displays numerous emission lines whose intensity correlates with the system activity. In particular,
we find a correlation between the Br equivalent width and the system brightness. The bluing of the continuum of the NW component
along with the absolute flux and color-variation of the system during the outburst suggests that the outburst was caused by a complex
interplay between a variation of the extinction in the line of sight of the NW component on one hand, and the emission of shocked
regions close to the NW component on the other. We confirm the recently reported wiggling of the SE component jet from [FeII]line emission. We find a point-like structure associated with a peak emission at 2.098µm coincidental with the clump or arm seen inbroadband polarization di↵erential imaging as well as additional di↵use emission along a PA=214 . The origin of these two structuresis unclear and deserves further investigation.
Key words. Techniques: high angular resolution, Binaries: general, Stars: pre-main sequence, individual (Z CMa)

1. Introduction
Z Canis Majoris (Z CMa) is a complex pre-main sequence binary

authors were able to reproduce the UV-optical spectrum by amodel of an optically thick accretion disk surrounding an 13 M star with an accretion rate of 10 3 M .yr 1 . The model

The 2008 outburst in the Young Stellar System Z CMa
III - Multi-epoch high-angular resolution images and spectra of the components

Fig. 12. Profile of strong and weakly blended lines for the HBein near-infraredand FUOR components. The black solid lines correspond to the
1,2 , G.
1,2 , C.
SINFONI (outburst) data,M.
while
the golden
lines
correspondto Dougados1,2 , Á. Kóspál3 , M. Benisty1,2 , G. Duchêne1,2,4 , J. Bouvier1,2 , P. J. V.
Bonnefoy
Chauvinthe OSIRIS spectra (post-outburst).
Garcia5 , E. Whelan6 , S. Antoniucci7 , and L. Podio7
1

Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France
CNRS, IPAG, F-38000 Grenoble, France
e-mail: mickael.bonnefoy@obs.ujf-grenoble.fr
3
Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, PO Box 67, 1525
Budapest, Hungary
4
Astronomy Department, UC Berkeley, 501 Campbell Hall, Berkeley CA 94720-3411, USA
5
Universidade do Porto, Faculdade de Engenharia, Rua Dr. Roberto Frias, s/n, P-4200-465 Porto, Portugal
6
Department of Experimental Physics, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
7
INAF - Osservatorio Astrofisico di Arcetri - L.go E. Fermi 5, I-50125 Firenze, ItalyrXiv:1608.08035v1 [astro-ph.SR] 29 Aug 2016

2

Received April 12, 2016 ; accepted June 22, 2016
ABSTRACT
Context. Z CMa is a complex pre-main sequence binary with a current separation of 110 mas, known to consist of an FU Orionis

star (SE component) and an embedded Herbig Be star (NW component). Although it represents a well-studied and characterized
system, the origin of photometric variabilities, the component properties, and the physical configuration of the system remain mostly
unknown.
Immediately
when
Fig. 13. H band HI BrackettAims.
excitation
diagramforthethelate-2008
HBe of outburst of Z CMa was announced to the community, we initiated a high angular resolution
imaging
campaign
aimedatcharacterizing
ZCMa (circles). All line fluxes are normalized to the HI Brackett the outburst state of both components of the system in the near-infrared.
Methods. We used the VLT/NACO and the Keck/NIRC2 near-infrared adaptive optics instrument to monitor the astrometric position
11 line. Open circles show thelines that are probably contamiand the near-infrared photometry of the Z CMa components during the outburst phase and one year after. The VLT/SINFONI andnated. Blue triangles show theline ratiosintegral
detected
EX Lupi
Keck/OSIRIS
fieldinspectroscrographs
were in addition used to characterize for the first time the resolved spectral properties(Kóspál et al. 2011b). The ofgreen
curvesarepredictions
fromthe FU Orionis and the Herbig Be
component
during and after the outburst.
4case B recombination from Hummer& Storey
forNW
T=10
Results. We
confirm(1987)
that thestar dominates the system flux in the 1.1-3.8 µm range and is responsible for the photometric8
3
K and n=10 cm (lower curve)andT= the first medium-resolution (R⇠2000-4000) near-infrared (1.1-2.4 µm) spectra of the individual components. The
outburst.
Wefor
extract
SE component has a spectrum typical of FU Orionis objects. The NW component spectrum is characteristic of embedded outbursting
protostars and EX Or objects. It displays numerous emission lines whose intensity correlates with the system activity. In particular,
we find a correlation between the Br equivalent width and the system brightness. The bluing of the continuum of the NW component
along with the absolute flux and color-variation of the system during the outburst suggests that the outburst was caused by a complex
interplay between a variation of the extinction in the line of sight of the NW component on one hand, and the emission of shocked
regions close to the NW component on the other. We confirm the recently reported wiggling of the SE component jet from [FeII]line emission. We find a point-like structure associated with a peak emission at 2.098µm coincidental with the clump or arm seen inbroadband polarization di↵erential imaging as well as additional di↵use emission along a PA=214 . The origin of these two structuresis unclear and deserves further investigation.
Key words. Techniques: high angular resolution, Binaries: general, Stars: pre-main sequence, individual (Z CMa)

1. Introduction
Z Canis Majoris (Z CMa) is a complex pre-main sequence binary

authors were able to reproduce the UV-optical spectrum by amodel of an optically thick accretion disk surrounding an 13 M star with an accretion rate of 10 3 M .yr 1 . The modelの続き

BANYAN. VIII. NEW LOW-MASS STARS AND BROWN DWARFS WITH CANDIDATE CIRCUMSTELLARDISKS.
A NNE B OUCHER1 , DAVID L AFRENIÈRE 1, J ONATHAN G AGNÉ 2,3 , L ISON M ALO4 , JACQUELINE K. FAHERTY2,5,6, R ENÉ D OYON1 , AND
C HRISTINE H. C HEN7
1 Institut de Recherche sur les Exoplanètes (iREx), Université de Montréal, Département de Physique, C.P. 6128 Succ. Centre-ville, Montréal,

QC H3C 3J7, Canada. boucher@astro.umontreal.ca

v:1608.08259v1 [astro-ph.SR] 29 Aug 2016

2 Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USAØ デブリ円盤や遷移円盤は3 NASA Sagan Fellow
4
substellarで少ない。 Canada-France-Hawaii Telescope, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743, USA PT or WT
5 Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034
6 NASA Hubble Fellow andØ 惑星がいそう。星形成の7 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
lower limit。
Draft version August 31, 2016
TD的ABSTRACTØ Young Moving
Groupが対象。
We present
the results of a search for new circumstellar disks around low-mass stars and brown dwarfs with
spectral types >K5 that are confirmed or candidate members of nearby young moving groups. Our search input
Ø 10-250 Myr,
1600
sampleK5V-M5V,
was drawn fromthe BANYAN surveys of Malo et al. and Gagné et al. Two-Micron All-Sky Survey
andWide-field
Infrared
SurveyExplorer data were used to detect near- to mid-infrared excesses that would
天体, 2MASS,
WISE。
reveal the presence of circumstellar disks. A total of 13 targets
convincing excesses were identified:↙︎Wwith3とW4が2温度必要↗︎Ø WISEのW3,
four W4のexcessや目
are new and nine were already known in the literature. The new candidates are 2MASS J05010082–
4337102 (M4.5), J08561384–1342242 (M8 γ), J12474428–3816464 (M9 γ) and J02265658–5327032 (L0 δ),
視で13個円盤同定。
and are candidate members of the TW Hya (∼ 10 ± 3 Myr), Columba (∼ 42+6
−4 Myr) and Tucana-Horologium
(∼
45
±
4
Myr)
associations,withmasses
of
120
and
13–18
M
.
The
M8–L0
objects in Columba and TucanaJupØ そのうち4つは初、うち2つをHorologium are potentially among the first substellar disk systems aged ∼ 40 Myr. Estimates of the new
candidates’ mean disk temperatures and fractional luminosities are in the ranges ∼ 135−520 K and 0.021−0.15,
可視ESPaDOnS@CFHTと近赤
respectively. New optical spectroscopy of J0501–4337 reveals strong Hα emission, possibly indicating ongoing
FIRE@Magellan
Baadeで観
accretion, provides
a detection of lithium absorption
and a radial velocity measurement that is consistent
PT的TD orwithPTamembershiptoColumba.
We
also
presentanear-infrared
spectrumofJ0226–5327
thatreveals
Paschenβ測。
emission and shows signs of low surface gravity, consistent with accretion from a disk and a young age.
Subject headings: Circumstellar matter, Brown dwarfs, Stars: Low-mass, Protoplanetary disks, Infrared: Stars

Ø 4つともT Tauri的ではない。

1. INTRODUCTION

The presence of debris disks is a signpost of a past planetary formation (Zuckerman & Song 2004; Moór et al. 2011;
Raymond et al. 2011), whereas the presence of protoplanetaryor transition disks can be a sign of ongoing planetary formation (Espaillat et al. 2010; Kraus & Ireland 2011). Searchingfor circumstellar disks is thus an interesting way to identify
new exoplanets and study their formation. Disks are usuallymore amorphous (indicating a lesser amount of grain growth
and thermal processing). Since debris disks are colder (∼ 10–
100 K), their weaker excesses are mostly observable in the
mid-infrared (MIR) and beyond (> 20 µm; Rhee et al. 2007;
Schneider et al. 2012a; Liu et al. 2014). Transition disks (TD)are intermediate cases: they feature an inner region devoid ofwarm dust, and an outer region that still contains a significant
amount of dust. Transition disks display an excess startingBANYAN. VIII. NEW LOW-MASS STARS AND BROWN DWARFS WITH CANDIDATE CIRCUMSTELLARDISKS.
の続き
A NNE B OUCHER1 , DAVID L AFRENIÈRE 1, J ONATHAN G AGNÉ 2,3 , L ISON M ALO4 , JACQUELINE K. FAHERTY2,5,6, R ENÉ D OYON1 , AND
C HRISTINE H. C HEN7
1 Institut de Recherche sur les Exoplanètes (iREx), Université de Montréal, Département de Physique, C.P. 6128 Succ. Centre-ville, Montréal,

v:1608.08259v1 [astro-ph.SR] 29 Aug 2016

QC H3C 3J7, Canada. boucher@astro.umontreal.ca

2 Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA
3 NASA Sagan Fellow
4 Canada-France-Hawaii Telescope, 65-1238 Mamalahoa Hwy, Kamuela, HI 96743, USA
5 Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034
6 NASA Hubble Fellow and
7 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

Draft version August 31, 2016

ABSTRACT
We present the results of a search for new circumstellar disks around low-mass stars and brown dwarfs with
spectral types >K5 that are confirmed or candidate members of nearby young moving groups. Our search input
sample was drawn from the BANYAN surveys of Malo et al. and Gagné et al. Two-Micron All-Sky Survey
and Wide-field Infrared Survey Explorer data were used to detect near- to mid-infrared excesses that would
reveal the presence of circumstellar disks. A total of 13 targets with convincing excesses were identified:
four are new and nine were already known in the literature. The new candidates are 2MASS J05010082–
4337102 (M4.5), J08561384–1342242 (M8 γ), J12474428–3816464 (M9 γ) and J02265658–5327032 (L0 δ),
and are candidate members of the TW Hya (∼ 10 ± 3 Myr), Columba (∼ 42+6
−4 Myr) and Tucana-Horologium(∼ 45 ± 4 Myr) associations, with masses of 120 and 13–18 MJup . The M8–L0 objects in Columba and TucanaHorologium are potentially among the first substellar disk systems aged ∼ 40 Myr. Estimates of the new
candidates’ mean disk temperatures and fractional luminosities are in the ranges ∼ 135−520 K and 0.021−0.15,
respectively. New optical spectroscopy of J0501–4337 reveals strong Hα emission, possibly indicating ongoingaccretion, provides a detection of lithium absorption and a radial velocity measurement that is consistent witha membership to Columba. We also present a near-infrared spectrum of J0226–5327 that reveals Paschen βemission and shows signs of low surface gravity, consistent with accretion from a disk and a young age.
Subject headings: Circumstellar matter, Brown dwarfs, Stars: Low-mass, Protoplanetary disks, Infrared: Stars
1. INTRODUCTION

The presence of debris disks is a signpost of a past planetary formation (Zuckerman & Song 2004; Moór et al. 2011;
Raymond et al. 2011), whereas the presence of protoplanetary
There are some discrepancies in the kinematics of this startransition
canmembershipbe a signof ongoing planetary formafrom that ofor
TWA,
explainingdisks
its modest
probability. Thisbrown
dwarf could
also
be a memberof a& Ireland 2011). Searchingtion(Espaillat
et
al.
2010;
Kraus
young association not yet included in the spatial and kinematdisks
is thusan interesting way to identify
ics models forfrom circumstellar
BANYAN II, such as
the Lower
Centaurus
Crux (LCC)new
association(Gagné et al.
2016,
submitted).
exoplanets
and
study
theirLCC
formation. Disks are usually
F IG . 3.— Top panel: Hα emission line of J05010082–4337102. Bottom
panel: lithium absorption line for J05010082–4337102. Both are consistent
with a young age. See Section 6.1 for more details.

members have similar UVW kinematics to those of TWA,

more amorphous (indicating a lesser amount of grain growth
and thermal processing). Since debris disks are colder (∼ 10–
100 K), their weaker excesses are mostly observable in the
mid-infrared (MIR) and beyond (> 20 µm; Rhee et al. 2007;
Schneider et al. 2012a; Liu et al. 2014). Transition disks (TD)are intermediate cases: they feature an inner region devoid ofwarm dust, and an outer region that still contains a significant
amount of dust. Transition disks display an excess startingConnecting low- and high-mass star formation: theintermediate-mass protostar IRAS 05373+2349 VLA 2

Connecting low- and high-mass star formatio

G. M. Brown,1? K. G. Johnston,1 M. G. Hoare1 and S. L. Lumsden1

Table 1. Summary of Continuum Observations.
1 School of Physics and Astronomy,
University of Leeds, West Yorkshire, Leeds LS2 9JT, UK
Wavelength

Array

Date ofNo. ofTime on-Synthesised

P.A

arXiv:1608.08677v1 [astro-ph.GA] 30 Aug 2016

observation
antennas source (hr) beam size (”) ( )1 September
2016
Ø 中質量星(2-8Mo)は橋渡し。
6 cm
VLA-C
12 Mar 2008 27 (24)
1.5
4.55 ⇥ 4.02
27
Ø energe)c collimated oumlows,
3.6 cmVLA-C
10 Mar 2008 26 (23)2.0
2.97 ⇥ 2.86
-13
ABSTRACT
1.3 cmVLA-C
10 Mar 2008 26 (21)
1.3
1.23 ⇥ 1.04
48
there havebeen few studies of the 15
protostellar
evolution ofintermediate中間的なinside out envelopes.Until recently,
2.7 mmCARMA-D 24 Apr 2007
5.7
4.92 ⇥ 4.28
78

Map rms(mJy beam 1 )
0.026
0.016
0.047
2.6

mass (IM) stars, which may bridge the low-and high-mass
regimes.lowThisandpaper
aims star formation 5
Connecting
high-mass
to investigate whether the properties of an IM protostar within the IRAS 05373+2349
embedded cluster are similar to that of low- and/or high-mass protostars. We carriedsmoothingand line length corrections w
out Very
Large andArray
as well as
for ResearchHanningin Millimeter
AstronTable
2. Assumed
determined
fluxCombined
and phase Arraycalibrator
12
plied
to
the
data
in
miriad,properties.
omy continuum and CO(J=1–0) observations, which uncover seven radio continuumwhich gave spectral resof 1.27
0.32protostar
km s 1 foristhe two narrow windo
sources (VLA 1–7). The spectral index of VLA 2, associatedwith andthe IM
12
ering
the
CO
(J=1–0)consistent with an ionised stellar wind or jet. The source VLA 3 is coincident with line
pre-emission. The data we
SourceFluxdensity(Jy)
Cal
exportedfromtheiroriginal
viously observed H2 emission line objects aligned in the north-south direction (P.A. -20format into casa where
6 cm
1.3an
cmionised
2.7 mmtype
ductionwere carried out. The source 05
to -12 ), which
may3.6becm
eitherjet emanatingfrom
VLA 2andor imaging(shock-)ionised
was used
to calibrate
and gain of thcavity walls in the large-scale outflow from VLA 2. The position
angle
between both
VLAamplitude
20137+331
5.52 misaligned
A outflow wevation;assumed flux
is listed in Table 2.
and
3 is slightly
withthe large-scale
map theat ⇠5-arcsec
resolu1331+305
5.22 ), which
2.58 in the -case of A
The imagesThecreatedfrom the millimetre continu
tion
in 12 CO (P.A.
⇠30
a jet suggests precession.
emission
120530+135
6.70
A+G
COestimate(J=1–0) its
linemass
emissionfromthe mm coreassociatedwith
VLA
2 is also
detected; weto be are presented in Sect
0559+238
0.41
0.37
G
TheFurthermore,
two continuumthe
spectral
12–23
M , dependingon the0.35
contribution
fromionised gas.
large-windows were cleaned t
0539+145G
producesingleimage with a central frequscale outflow has properties intermediate between outflowstofrom
low- aandhigh-mass
Briggs weighting with a robust
young stars.
Therefore,
concludethegainIM caliprotostar113.279
withinGHz,
IRASusing05373+2349
Absolute
flux calibrators
arewedenotedby ‘A’that
and the
eter
of
0.5.
The
synthesisedisphenomenologically
as
well
as
quantitatively
intermediate
betweenthelowandbeam size and noise, alo
brators are denoted by ‘G’ in the ‘cal type’ column.
the number of antennas and time spent on-sourcehigh-mass domains.

Ø IRAS 05373+2349 (d=1.2 kpc)の初mm干渉計観測。
Ø VLA, CARMA (2.7 mm, 12CO 1-0)
Ø Δv=0.32 km/s, θ=5”x4”。

6 cm

3.6 cmØ VLA 2に注目。VLAはfree-free。
+: 2.7 mm
x: MHO (水素分子)Ø VLA 3を初検出。
Ø MHOはVLA 2からのジェット起源★: Class I ↓observation, can be found in Table 1.
words: COstars:
formationstars: protostars – ISM: jetsFor
and– radio
2.2KeyCARMA(J=1–0)
and–2.7-mm(PA=–20~–12°)。
theoutflows
CO (J=1–0)
line image, the two narrocontinuum:stars – techniques: interferometriccontinuum
tral windows were combined at 115.271 GHz using
Ø 2.7 mm, 27 Kàコア~12-23 Mo
weighting and a channel width of 1.3 km s ; uv–d
Combined Array for Research in Millimeter Astronomy
12

12

1

smaller than 3 k were excluded. The beam size
(CARMA2 ) observations at = 2.7 mm were taken on 24
12
CO (J=1–0) image was 4.92 ⇥ 4.28 arcsec P.A. 78
April 2007. The antenna array during the observation connoiseinranged
from ⇠0.07
beam 1 in an empty chan
1 INTRODUCTION
photons
becomes
easilyobservable
cm continuum
andJythesisted of fifteen antennas, six 10 m and nine 6 m in diameter1
to ⇠0.5 Jyphasebeamis notin theinner channels.
mass andabove
a pre-main
sequence
observprimarybeams sizes orof 64 arcsec
115whicharcsec,reAs much research has focusedwith
on either
distinguishingable(Beltrán&deWit2016).
spectively.
A mosaic
was created from nine pointing centres
unifying the formation of high-massstars and
their low-mass
high-mass bystars, whose descent onto the mainin (IM)a squarepattern.
were separated
counterparts, intermediate-massstars gridare ofinterestTheas pointingsUnlike
sequence
occurswhile
still deeply
embedded and actively
30
arcsec.
3 RESULTS
they provide a bridge between the two mass regimes. IM prowithin
their parent cores, IM stars have a longer
The CARMA
correlator
up with two
sidebands,
tostars – the precursors of Herbig Ae/Bestars – aredefinedwas setaccreting
6, 3.areand1.3-cm continuum
pre-mainsequence
timescale, so3.1
that VLA
their discs
revealed
placedeither
sidefinalof thechosen local
oscillator
frequency
as young stellar objects (YSOs)
that willreachmasses
for
part
of
their
formation,
similartotheirlow-masscounof113.280
GHz,
with
the
upper
bands
situatedtomeasureof 2–8 M and have luminosities between ⇠50–2000 L (BelIn this section, we present
the VLA images at eac
12
terparts.
Thisisaresultoftheiraccretion
timescales
beCO(J=1–0)line
emission.
Both
the
upper
and
lower
sidetrán 2015). The lower limit of 2 M originates from the fact
length and calculate spectral indices.

Connecting low- and high-mass star formation: theintermediate-mass protostar IRAS 05373+2349 VLA 2の続き

1 formation
1
low- 1andstar
7
G. M. Brown,1? K.8Connecting
G. G.
Johnston,M.
G.
and S. L. Lumsden
M. Brown
ethigh-massal. Hoare

1 School of Physics and Astronomy, University of Leeds, West Yorkshire, Leeds LS2 9JT, UK

Table 4. Derived properties of the blue- and red-shifted lobes ofthe outflow centred on VLA 2 traced by 12 CO (J=1–0) emission.

kinetic energy, mean velocity, length, dyn
mass transfer rate, mechanical force and1 September 2016
nosity for the blue and red lobes of the ou
The velocity range shows the range ofParameter
Outflowthat were integrated over to produce the oABSTRACT
blue lobe
red lobe
Until recently, there have been few studies of the protostellar evolutionof intermediateThe inner,
low velocity channels were exc
massVelocity(IM) stars,
which
regimes.
This paper
aims flux; channels with irange (kms 1 ) may bridge-25.9 tothe-1.2low-and
5.3 high-mass
to 20.9
absorption
or missing
to investigate
the properties
within thesionIRAS(< 3 05373+2349) in the high-velocity wings weMass, M (Mwhether)
0.53of an IM protostar
0.26
embeddedclusterarekm
similarthat(4.82)
of low- and/or
high-mass protostars.
We carried
Momentum,P (Ms 1 ) to4.06
1.57 (1.87)
The outflow
mass, Moutflow , was deriv
Very Large
as Combined
Array
for Research in Millimeter AstronE (M Array
km2 s 2as) well 20.70(29.24)5.80 (8.19)
onnecting low- and high-mass star formation 7 out Energy,
following
Scovilleetal. (1986):
12
omyEnergy,
continuumandwhich
E (1044erg) CO(J=1–0)
4.14observations,(5.85)
1.16(1.64)uncover seven radio continuum
1)
vout f low(km s1–7).
7.61(9.04)
sources(VLA
The spectral
indexof VLA5.92
2, (7.03)
associated with the IM protostar is
Table 4. Derived properties of the blue- and red-shifted lobes ofconsistentwith
anionisedstellar
wind
or
jet.
The
sourceLength, L (au)35000 (41000)
43000 (51000)VLA 3 is coincident with pre- 5 (T + 0.926)⌧
the outflow centred on VLA 2 traced by 12 CO (J=1–0) emission.
(M ) = (P.A.
2.29 ⇥-20
10
viouslyobservedHemissionline
objectsalignedin(3.41)the north-south M
direction
42
tdyn (10 yr)
2.15 (2.15)
3.41
e 5.53/T ⌧ e ⌧to -12), whichmay
ionised
5 M yr1 ) be either anṀ (102.48(2.48)jet emanating
0.78 (0.78)from VLA 2 or (shock-)ionised
4 Min km1 yr 1 )cavitywalls
thes large-scale
outflowfrom VLA
2.(0.55)
The position angle between VLA 2
F (101.88 (2.24)
0.46
Parameter
Outflow
4 M kmmisaligned
2 s 2 yr 1 )and Ė3 (10is slightly
withlarge-scaleat ⇠5-arcsec
9.61the(13.56)
1.70outflow(2.40) we map
where⌧ is the resoluoptical depth, which we seblue lobe
red lobe
Figure 4. 12 CO (J=1–0) spectral profile measured at the position
tion Lin(L12 CO(P.A. ⇠30 ), which0.16
in thecase of 0.03
a jet(0.04)
suggests precession.
The emission)(0.22)
ingthesourcetobe optically thin, and t
of VLA 2: 05h 40m 24.s 22 +23 500 54.00 79 (J2000).
from the mm core associated with VLA 2 is also detected; we estimate
its
mass to4be
1
term
of
Equation
was set to unity. The d
Velocity range (km s )-25.9 to -1.2
5.3 to 20.9
12–23The
Mproperties, dependingon theparentheses
contribution
fromcorrectedionisedatgas. Furthermore,
the1.2largegiven withinhave been
assumedtobekpc.
S is the integrated
Mass, M (M )
0.53
0.26
Figure5.
Centredon VLA 2 (marked
by a between
white plus)
the
scale
outflow
hasintermediate
outflows
low- and high-mass v
an inclinationi = properties
57.3 , otherwise
no correction
was applied(i = from1
locitychannel,
v,
that
was
found by summin
12
Momentum, P (M km s )4.06 (4.82)
1.57 (1.87) contours
CO (J=1–0)
emissionover - within IRAS 05373+2349
youngstars. Therefore,
welineconcludethatintegrated
the IM protostar
0 ). show
Energy, E (M km2 s 2 )20.70 (29.24)
5.80 (8.19) 25.9 - 1.2 km s 1 (blue) and 5.3 - 20.9 km s 1 (red) and 2.7-mm
withinaregiondefinedbythe 1 = 0.5 Jy
is phenomenologically as well as quantitatively intermediate between the low- andEnergy,E (1044continuumerg)
4.14 (5.85)
1.16 (1.64)
3.2.1
2.7-mm(themaximalnoise
level
withinthe spec
continuum
emission(black). The contours are over-plotted onhigh-mass
domains.
vout f low (km s 1 )7.61 (9.04)
5.92 (7.03)
themillimetre
continuum
emission
was emission
calculatedbetween
using 12 CO
citation
temperatureoftheoutflowgas, wa
first
momentmapofthe(J=1–0)Continuum
emission at 2.7 mm
was only detected
towards
1stars:Length, L (au)35000 (41000)
43000 (51000) 25.9Key
words:
formation–2 Sstars:
protostars– ISM:
jets toandoutflows
– the
radio
d
to
20.9
km
s
velocity
channelswithpixelsmasked
be⌫
be
equal
to
full
Planckfunctiond
VLA 2. Fig.
3 shows the continuum emission from the reMdust = interferometric(3)stars – contours
techniques:tdyn (104 yr)
2.15 (2.15)
3.41 (3.41) lowcontinuum:
1
Jy.
Blue-shifted
are
-3,
3,
4,
5,
7,
10,
12,
14
⇥
B
(T
)

temperature,
given
as:
⌫
D
⌫
gion around
VLA1 2 at 111.1 GHz (⇠ 2.7 mm) with MHOs
5

arXiv:1608.08677v1 [astro-ph.GA] 30 Aug 201612CO at VLA 2

Ṁ (10 M yr )2.48 (2.48)
0.78 (0.78) 3.0 Jy beam 1 km s 1 , red-shifted contours are -3, 3, 4, 5, 7, 10,
where d = 1.2 kpc and T = 27 K are the distance and dust
745
A, B and C (K11) indicatedas crosses. The
morpholF (10 4 M km s 1 yr 1 )1.88 (2.24)
0.46 (0.55) 15, 20 ⇥ 2.0 Jy beam 1 km s 1D and the black contours are as intemperature (Molinari et al. 2000). S ⌫ is the integrated flux
ogy
of
the
emissionshowsacompact
core
with
an
exten42
2
1
Ė (10 M km s yr )9.61 (13.56)
1.70 (2.40)
Fig. 3.density
The synthesised
beam
cor-)
3.92 ⇥ 10 8 [measured in
the 1is shown
contourinatthe =bottom
2.7 mm.left
B⌫ (T
sion
from
the
south
of
the
sourceinthesouth–east
direcD
L (L )
0.16 (0.22)
0.03 (0.04)
Tcm= 0.048 and[⌫ (GHz)]ln 1 +
B (K)
ner
and
the
scale
bar
in
the
bottommiddle.
MHOs
are
shown
1
INTRODUCTION
photons
becomes
easilyobservableincontinuum
theis the value of the Planck function at T D . Finally the dusttion. The integrated and peak flux densities, measured in a
F⌫ (Jyas crosses.
A Class[see Fig.
12 (cd)]
and which
abyClass
II object sequence phase is not observabovea pre-main
opacity,⌫ = I0.1807
cm
g 1and
,mass
was
found
extrapolating
1 contour, were 53.7 ± 2.6 mJy
and
30.1± 1.6 mJy,
respecAs
muchresearchhas
focusedoneitherdistinguishingor
The properties given within parentheses have been corrected atreported by Gutermuth et al. (2009)
shown1994)
as de
a to
black
and
(Beltrán
&
Wit
model
opacity(Ossenkopfable&areHenning
2.72016).
mm,
tively. The peak position, measured
atthe
theformationbrightestofpixel,
where ✓ is the beamsize and F⌫ is the peunifying
stars respectively.
andtheir data
low-mass
an inclinationi = 57.3 , otherwise
no correction
was appliedhigh-mass(i =white star,
5
3
h
m s
0 00
Unlikestars, whose thedescent
ontoatthe
mainassuming
gasinterest
densityasof 1⇥10 g cm
andhigh-massthin ice mantles,
was(J2000).
outflow
frequency⌫. For the derived
intermediate-mass (IM)stars area of
0 ). 05 40 24.18 +23 50 55. 01counterparts,
sequence
occurswhile
stilldeeplyembeddedandactively
where
,
the
dust
opacityindex
withfrequency,
wasfittedA 2D-Gaussian was alsothey
fittedtothesource.
Howprovide a bridge between the two mass regimes. IM proin Table 4 the largest peak flux from eit
accretingwithintheir toparentto be-1.82.–Aaregas-to-dust
ratio
of 100 was
assumedinfer cores, IM stars have a longer
ever, we found that only the innercompactcore couldofpro12 stars
tostars– theprecursors
definedlobe was used to define the brightThe
COcore(J=1–0)emission
appears
to showa emission
bipolarso thatshifted
the millimetre continuum emission
wascalculatedusing Herbig Ae/Be
pre-mainsequence
timescale,
their discs are revealed
the
total
mass.
In
the
case
of
all
of
the
2.7
mm
duce a satisfactory fit; we derived
anintegrated
flux
denas youngstellar objects (YSOs)
that willreach onfinalVLA
massesforthat
outflow,counwhich we found to be 6
2
outflow
centred2,
appearing
in
the
same
orientafor part
theirisformation,
similar to their low-mass
d2–8
Sdensity
originating
fromLthe(Beldust, the total
coreofmass
23 M . Thissity of 53.7 ± 5.9 mJy, a peak offluxof have29.9 ±
3.3 mJy between⌫ M andluminosities⇠50–2000
1
Mdust =
(3)tion as previously
5.3
km
s
from
the
seen
by
Zhang
et
al.
(2005).
There
is
also
terparts.
in close fromagreementwith thevalue ofThis⇠26 isMa result
found ofbytheir accretion timescales be- red-shifted lobe. W
and a deconvolved source sizeB
by lower
2.9 ± 0.6
(T D4.1) ⌫± 0.4The
⌫of
trán
2015).
limitarcof 2 M isoriginates
the fact#

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3European#Southern#Observatory,#Santiago#de#Chile,#Chile##の続き#

The#famous,#very#young,#helium#rich,#magneticallyEactive,#radio#and#XE
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伴星予想範囲。
い。 a# close# lateEtype# stellar# companion,#
peculiar# star# σ# Ori# E# may# have#
which# could# explain# flaring#
activity#in# some#
σ# Ori#E# XEray#Ø Siess
etobserved#
al. models(3 Myr,
Z=Zo=0.02)からM*<2Mo,
light# curves.# In# 2009,# Bouy# et# al.# announced# the# detection# of# a# faint#Teﬀ<4960 K, Sp>K2。
Table#I#companion#candidate#in#the#Ks#band#at#0.330#arcsec#(130#AU)#to#the#B2#
Apparent#and#absolute#magnitudes#in#the#red#optical#and#near:infrared#of#σ#Ori#E#
Vp#primary.#Here,#we#carry#out#z’Eband#lucky#imaging#with#AstraLux#at#
and#its#close#companion#candidate###the#2.2#m#Calar#Alto#telescope#in#an#attempt#to#constrain#the#properties#
Ø 予想されたK-Mに矛盾はしない。
#
σ#Ori#E#
Companion#candidate#of#the#companion#candidate#to#σ#Ori#E.#We#impose#a#maximum#mass#of#
Band#
Apparent#
Absolute#
Apparent#
Absolute#
Ø Gaiaでも無理。NACO,SPHERE,
GPI, MagAOなら30
magnitude#
magnitude#
2.0+0.2E0.1# Msol# and# an# earliest# spectral# type# of#magnitude#
K2±1,# which#leaves# the#magnitude#[mag]#[mag]#[mag]#[mag]##
分の観測でわかるだろう。
door#open#to#a#new,#inexpensive,#nearEinfrared,#adaptiveEoptics#study.##
#
+0.08
R#
6.84±0.01#
−1.09
#
…#
…#
−0.15
# FIG.#2#
Limit#of#our#AstraLux#Norte#z’Eband#image:#magnitude#difference#Δz’#as#a#function#I#
7.08±0.01#−0.85+0.08−0.15#…#…#
of#angular#separation#ρ#to#σ#Ori#E#(2.5%#best#frames).#The#vertical#dotted#lines#indicate#the#z’#
7.04±0.04#−0.89+0.10−0.16#>10.0±0.3#>2.1±0.3#
expected#location#of#the#candidate#companion#to#σ#Ori#E,#at#ρ#=#0.33±0.03#arcsec.####J#6.974±0.026#
−0.96
…#
…#
−0.15#
Introduction#
Table#I#H#
6.954±0.031#−0.98+0.09−0.15#…#…##
Apparent#and#absolute#magnitudes#in#the#red#optical#and#near:infrared#of#σ#Ori#E##
The#heliumErich#peculiarity#of#the#spectrum#of#the#B2#Vp#star#σ#Ori#E#(48#and#its#close#companion#candidate###1#
Ori#E,#V1030#Ori,#HD#37479,#Mayrit#42062)#was#first#noticed#in#1956#by#Berger
Table#II# ,##σ#Ori#E#
Companion#candidate#2
Upper#limits#to#the#presence#of#resolved#companions#to#σ#Ori#E#
and#two#years#later#made#widely#public#by#Greenstein#&#Wallerstein.#Six#decades#
Band#
Apparent#
Absolute#
Apparent#
Absolute##
later,#
dedicated#works#
on#
σ#
Ori#
E#
have#
received#
over#
1000#
citations#from#magnitude#
magnitude#
magnitude#
magnitude#
ρ##
s##
z’#
Mmax##
Earliest##
3
approximately#50#dedicated#works#(e.g.,#The#magnetic#field#of#σ#Ori#E,#The#rigidly#[mag]#[mag]#[mag]#[mag]#[arcsec]#[AU]##[mag]#[M
sp.#type#sol]#rotating#
magnetosphere#of# σ# Ori#of# σ# Ori#10.0±0.3#
E# –# New# 2.0+0.2E0.1#
R#
6.84±0.01#−1.09+0.08−0.15#…#…# E4,# Shell# and#
0.33#photosphere#
130#
K2±1#
5,#A#new#phenomenon#in#the#spectrum#of#σ#Ori#E6,#I#
7.08±0.01#−0.85+0.08−0.15#…#…#
observations#and#improved#model
1.00#
385#
10.9±0.3#
0.65±0.15#
K4±1#
z’#
7.04±0.04#−0.89+0.10−0.16#>10.0±0.3#>2.1±0.3#etc.).#Actually,#for#decades#the#star#attracted#more#attention#than#the#rest#of#stars#in#
2.00#
770#
12.6±0.3#
0.69±0.09#
K7±1#
+0.08
J#
6.974±0.026#−0.963#…#…# which# is# now#
−0.15#
3.00# a# cornerstone#1160#
14.3±0.3# of# 0.25±0.04#
M3±1#
the#
MyrEold#σ#Orionis#cluster,#for#studies#H#
6.954±0.031#−0.98+0.09−0.15#…#…##
circumstellar#discs,#coronal#emission,#accretion,#and,#especially,#the#mass#function##
7E9
down# to# the# substellar# limit# and# beyond # .# With# an# early# B# spectral# type# and# a##
Acknowledgements#
mass# of#
7E8# Msol,# σ# Ori# E# is# one# of# the# most# massive# stars# in# the# homonymous#
Table#II##
Upper#limits#to#the#presence#of#resolved#companions#to#σ#Ori#E#
TrapeziumElike# system# σ# Ori,# which# also# gives# the# name# to# the# cluster# and##+0.08