J/A+A/617/A66 Massive eclipsing SB2 in Arches cluster spectra (Lohr+, 2018)
The Arches cluster revisited:
II. A massive eclipsing spectroscopic binary in the Arches cluster.
Lohr M.E., Clark J.S., Najarro F., Patrick L.R., Crowther P.A., Evans C.J.
<Astron. Astrophys. 617, A66 (2018)>
=2018A&A...617A..66L 2018A&A...617A..66L (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Binaries, eclipsing ;
Photometry, infrared ; Spectra, infrared
Keywords: stars: individual: F2 - stars: massive - stars: Wolf-Rayet -
binaries: close - binaries: eclipsing - binaries: spectroscopic
Abstract:
We have carried out a spectroscopic variability survey of some of the
most massive stars in the Arches cluster, using K-band observations
obtained with SINFONI on the VLT. One target, F2, exhibits substantial
changes in radial velocity; in combination with new KMOS and archival
SINFONI spectra, its primary component is found to undergo radial
velocity variation with a period of 10.483±0.002d and an
amplitude of ∼350km/s. A secondary radial velocity curve is also
marginally detectable. We reanalyse archival NAOS-CONICA photometric
survey data in combination with our radial velocity results to confirm
this object as an eclipsing SB2 system, and the first binary
identified in the Arches. We model it as consisting of an
82±12M☉ WN8-9h primary and a 60±8M☉ O5-6 Ia+
secondary, and as having a slightly eccentric orbit, implying an
evolutionary stage prior to strong binary interaction. As one of four
X-ray bright Arches sources previously proposed as colliding-wind
massive binaries, it may be only the first of several binaries to be
discovered in this cluster, presenting potential challenges to recent
models for the Arches' age and composition. It also appears to be one
of the most massive binaries detected to date; the primary's
calculated initial mass of ≳120M☉ would arguably make this the
most massive binary known in the Galaxy.
Description:
K-band spectra covering 25 epochs between 1999 and 2014 taken with
Keck/NIRSPEC, VLT/SINFONI and VLT/KMOS are presented here for the
massive eclipsing SB2 system F2 in the Arches cluster (#2 in the list
of Figer+ 2002). All spectra have been fully reduced, with barycentric
velocity corrections made, rebinned to a common dispersion and
normalised to the continuum. In each case the file name is of the form
sYYMMDD.dat, referring to the date of observation, and the Barycentric
Julian Date in Barycentric Dynamical Time (BJD(TDB)) at
mid-observation is given in the explanations column of the file
summary. Two disentangled spectra for the individual components of the
binary are also presented; each has been rescaled using our preferred
derived flux ratio.
Objects:
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RA (2000) DE Designation(s)
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17 45 49.71 -28 49 25.4 F2 = [FNG2002] 2
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 60 27 List of spectra
f2prim.dat 17 1776 Disentangled spectrum of primary component
f2sec.dat 17 1776 Disentangled spectrum of secondary component
s990704.dat 17 506 Keck/NIRSPEC spectrum with BJD(TDB) 2451363.945
s050610.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2453531.755
s110414.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455665.819
s110419.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455670.716
s110425.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455676.808
s110504.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455685.820
s110521.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455702.648
s110623.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455735.816
s110626.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455738.726
s110629.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455741.735
s110630.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455742.683
s110824.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455797.561
s110827.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455800.544
s110828.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455801.590
s110829.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455802.550
s111002.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2455836.512
s130717.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2456490.715
s130808.dat 17 1776 VLT/SINFONI spectrum with BJD(TDB) 2456512.611
s140430.dat 17 1776 VLT/KMOS spectrum with BJD(TDB) 2456777.831
s140723.dat 17 1776 VLT/KMOS spectrum with BJD(TDB) 2456861.523
s140804.dat 17 1776 VLT/KMOS spectrum with BJD(TDB) 2456873.737
s140805.dat 17 1776 VLT/KMOS spectrum with BJD(TDB) 2456874.692
s140811.dat 17 1776 VLT/KMOS spectrum with BJD(TDB) 2456880.596
s140812.dat 17 1776 VLT/KMOS spectrum with BJD(TDB) 2456881.622
s140813.dat 17 1776 VLT/KMOS spectrum with BJD(TDB) 2456882.631
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See also:
J/ApJ/581/258 : Infrared photometry in the Arches Cluster (Figer+ 2002)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 48 A48 --- Title Title of the spectrum
50- 60 A11 --- FileName Name of the file with spectrum
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Byte-by-byte Description of file: f2*.dat s*.dat
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Bytes Format Units Label Explanations
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1- 8 F8.6 um lambda Wavelength in micrometres
10- 17 F8.6 -- Nflux Continuum-normalised flux
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Acknowledgements:
Marcus Lohr, Marcus.Lohr(at)open.ac.uk
References:
Clark et al., Paper I, 2018A&A...617A..65C 2018A&A...617A..65C
(End) Marcus Lohr [OU, UK], Patricia Vannier [CDS] 18-Apr-2018