J/ApJ/746/15 Runaway massive stars from R136 (Banerjee+, 2012)
Runaway massive stars from R136: VFTS 682 is very likely a "Slow runaway".
Banerjee S., Kroupa P., Oh S.
<Astrophys. J., 746, 15 (2012)>
=2012ApJ...746...15B 2012ApJ...746...15B
ADC_Keywords: Models ; Clusters, open ; Stars, masses ; Radial velocities
Keywords: galaxies: star clusters: general - methods: numerical -
open clusters and associations: individual (R136) -
stars: individual (VFTS 682, 30 Dor016) -
stars: kinematics and dynamics
Abstract:
We conduct a theoretical study on the ejection of runaway massive
stars from R136 -the central massive, starburst cluster in the 30
Doradus complex of the Large Magellanic Cloud. Specifically, we
investigate the possibility of the very massive star (VMS) VFTS 682
being a runaway member of R136. Recent observations of the above VMS,
by virtue of its isolated location and its moderate peculiar motion,
have raised the fundamental question of whether isolated massive star
formation is indeed possible. We perform the first realistic N-body
computations of fully mass-segregated R136-type star clusters in which
all the massive stars are in primordial binary systems. These
calculations confirm that the dynamical ejection of a VMS from an
R136-like cluster, with kinematic properties similar to those of VFTS
682, is common. Hence, the conjecture of isolated massive star
formation is unnecessary to account for this VMS. Our results are also
quite consistent with the ejection of 30 Dor 016, another suspected
runaway VMS from R136. We further note that during the clusters'
evolution, mergers of massive binaries produce a few single stars per
cluster with masses significantly exceeding the canonical upper limit
of 150 M☉. The observations of such single super-canonical stars
in R136, therefore, do not imply an initial mass function with an
upper limit greatly exceeding the accepted canonical 150M☉limit,
as has been suggested recently, and they are consistent with the
canonical upper limit.
Objects:
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RA (2000) DE Designation(s)
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05 38 42.40 -69 06 03.4 RMC136 = * 30 Dor
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 41 1955 Data for all the runaway stars as obtained from
all of our computations at 1Myr and 3Myr
table3.dat 58 1955 Additional data for all the runaway stars as
obtained from all of our computations
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See also:
J/MNRAS/410/190 : Young runaway stars within 3kpc (Tetzlaff+, 2011)
J/ApJ/707/1347 : HST F160W photometry in RMC 136 (Andersen+, 2009)
J/AJ/131/2164 : X-ray sources in RMC 136 (Townsley+, 2006)
J/ApJ/466/254 : NIR Imaging of R136 in 30 Dor (Brandl+ 1996)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 Myr Age [1/3] Age (1 or 3Myr)
3- 7 F5.1 Msun Mass [0.1/251.8] Star mass
9- 13 F5.1 km/s Vtan [0.1/399.2] Tangential velocity (1)
15- 20 F6.1 km/s Vrad [-263/210] Line-of-sight or radial velocity (2)
22- 26 F5.1 km/s Vel [0.2/419.7] 3-dimensional velocity
28- 32 F5.1 pc R [0.3/825.3] Projected distance (3)
34 I1 --- Type System type; 1=single, 2=binary
36- 41 I6 --- ID [1/170968] Star identifier
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Note (1): The reference frame is chosen fixed and originated at the cluster's
center of mass. Its axes are taken to be oriented arbitrarily as
there is no preferred directionality due to the absence of an
external field. All the projections are taken on the x-y plane.
Note (2): The velocity component normal to the plane of projection or the z
velocity component is simply taken to be the radial velocity due to
the arbitrariness in the choice of the coordinate axes. The
corrections due to the spatial extent is negligible for the distance
of R136.
Note (3): From cluster's center of density.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 I1 Myr Age [1/3] Age
3- 7 F5.1 Msun Mass [0.1/251.8] Mass
9- 14 I6 --- ID [1/170968] Star identifier
16- 21 F6.1 pc X The X position component (4)
23- 28 F6.1 pc Y The Y position component (4)
30- 35 F6.1 pc Z The Z position component (4)
37- 42 F6.1 km/s Vx [-107.8/398.5] The X velocity component (5)
44- 49 F6.1 km/s Vy [-216.9/175.9] The Y velocity component (5)
51- 56 F6.1 km/s Vz [-262.8/209.9] The Z velocity component (5)
58 I1 --- Type System type; 1=single, 2=binary
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Note (4): Relative to the cluster's center of density. The reference frame is
chosen fixed and originated at the cluster's center of mass. Its axes
are taken to be oriented arbitrarily as there is no preferred
directionality due to the absence of an external field.
Note (5): Relative to the cluster's center of mass.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 02-Aug-2013