J/A+A/624/A129 30 Dor red supergiant stars radial velocities (Patrick+, 2019)
The VLT-FLAMES Tarantula Survey.
XXXI. Radial velocities and multiplicity constraints of red supergiant stars
in 30 Doradus.
Patrick L.R, Lennon D.J., Britavskiy N., Evans C.J., Sana H., Taylor W.D.,
Herrero A., Almeida L.A., Clark J.S., Gieles M., Langer N.,
Schneider F.R.N., van Loon J.T.
<Astron. Astrophys. 624, A129 (2019)>
=2019A&A...624A.129P 2019A&A...624A.129P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, supergiant ; Radial velocities
Keywords: binaries: spectroscopic - stars: late-type - Magellanic Clouds -
galaxies: star clusters: individual: Hodge 301 -
galaxies: star clusters: individual: SL 639
Abstract:
The incidence of multiplicity in cool, luminous massive stars is
relatively unknown compared to their hotter counterparts.Here we
present radial velocity (RV) measurements and investigate the
multiplicity properties of red supergiants (RSGs) in the 30∼Doradus
region of the Large Magellanic Cloud using multi-epoch visible
spectroscopy from the VLT-FLAMES Tarantula Survey.
Exploiting the high density of absorption features in visible spectra
of cool stars, we use a novel slicing technique to estimate RVs of 17
candidate RSGs in 30 Doradus from cross-correlation of the
observations with model spectra.
We provide absolute RV measurements (precise to better than
±1km/s) for our sample and estimate line-of-sight velocities for
the Hodge 301 and SL 639 clusters, which agree well with those of
hot stars in the same clusters. By combining results for the RSGs with
those for nearby B-type stars, we estimate systemic velocities and
line-of-sight velocity dispersions for the two clusters, obtaining
estimates for their dynamical masses of
log(Mdyn/M☉)≃3.8±0.3 for Hodge 301, and an upper limit of
log(Mdyn/M☉)≲3.1±0.8 for SL 639, assuming Virial
equilibrium. Analysis of the multi-epoch data reveals one RV-variable,
potential binary candidate (VFTS 744), which is likely a semi-regular
variable asymptotic giant branch star. Calculations of semi-amplitude
velocities for a range of RSGs in model binary systems and literature
examples of binary RSGs were used to guide our RV variability
criteria. We estimate an upper limit on the observed binary fraction
for our sample of 0.3, where we are sensitive to maximum periods for
individual objects in the range of 1 to 10000-days and mass-ratios
above 0.3 depending on the data quality. From simulations of the RV
measurements from binary systems given the current data we conclude
that systems within the parameter range q>0.3, logP[days]<3.5, would
be detected by our variability criteria, at the 90% confidence level.
The intrinsic binary fraction, accounting for observational biases, is
estimated using simulations of binary systems with an empirically
defined distribution of parameters where orbital periods are uniformly
distributed in the 3.3<logP[days]<4.3 range. A range of intrinsic
binary fractions are considered; a binary fraction of 0.3 is found to
best reproduce the observed data.
We demonstrate that RSGs are effective extragalactic kinematic tracers
by estimating the kinematic properties, including the dynamical masses
of two LMC young massive clusters.
In the context of binary evolution models, we conclude that the large
majority of our sample consists of currently effectively single stars
(either single or in long period systems). Further observations at
greater spectral resolution and/or over a longer baseline are required
to search for such systems.
Description:
Radial velocities for each epoch in each grating estimated using the slice
technique defined here.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 86 17 Estimated mean radial velocities and associated
uncertainties from the three spectrograph settings
tablea1.dat 58 145 *Radial velocity (RV) estimates at each epoch
for candidate RSGs observed in the VFTS
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Note on tablea1.dat: Observations with the same spectrograph setting for each
target that were less than a day apart were coadded to improve signal-to-noise
(for which the quoted epochs are the average of the coadded observations).
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See also:
J/A+A/530/A108 : VLT-FLAMES Tarantula Survey (Evans+, 2011)
J/A+A/550/A107 : RV catalogue of O stars in 30 Doradus (Sana+, 2013)
J/A+A/550/A108 : DIB in VLT-FLAMES Tarantula Survey (van Loon+, 2013)
J/A+A/550/A109 : VLT-FLAMES Tarantula Survey: vsini measures (Dufton+ 2013)
J/A+A/558/A134 : VLTS. 30 Dor luminous stars (Doran+, 2013)
J/A+A/560/A29 : O-stars in VLT-FLAMES Tarantula Survey (Ramirez-Agudelo+ 2013)
J/A+A/564/A39 : VLTS. OVz stars in 30 Dor (Sabin-Sanjulian+, 2014)
J/A+A/564/A40 : VLTS. O-type stellar content of 30 Dor (Walborn+, 2014)
J/A+A/564/L7 : VLT-FLAMES Tarantula Survey: VFTS 822 (Kalari+, 2014)
J/A+A/574/A13 : VLTS. B-type stars classification and RV (Evans+, 2015)
J/A+A/575/A70 : VLT-FLAMES Tarantula Survey: B supergiants (McEvoy+, 2015)
J/A+A/580/A93 : VLTS. B stars multiplicity (Dunstall+, 2015)
J/A+A/600/A81 : VLTS. 30Dor O giants and supergiants (Ramirez-Agudelo+, 2017)
J/A+A/600/A82 : VLTS. O giants & supergiants nitrogen abundances (Grin+, 2017)
J/A+A/603/A91 : VLTS. B-type main-sequence binary systems (Garland+, 2017)
J/A+A/601/A79 : VLTS. Properties of O dwarf in 30 Dor (Sabin-Sanjulian+, 2017)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- VFTS Star VFTS identification number
6 A1 --- Field Field
7 A1 --- n_Field [*] *: estimates corrected for instrumental
variation
9- 13 F5.1 km/s RVLR02 LR02 radial velocity
15- 17 F3.1 km/s e_RVLR02 rms uncertainty on RVLR02
18 A1 --- neRVLR02 [a] Note on e_RVLR02 (1)
20- 24 F5.1 km/s RVLR03 LR03 radial velocity
26- 28 F3.1 km/s e_RVLR03 rms uncertainty on RVLR03
29 A1 --- neRVLR03 [b] Note on e_RVLR03 (1)
31- 35 F5.1 km/s RVHR15N HR15N radial velocity
37- 39 F3.1 km/s e_RVHR15N rms uncertainty on RVHR15N
40 A1 --- neRVHR15N [b] Note on e_RVHR15N (1)
42- 46 F5.1 km/s V1D Adopted line-of-sight velocity, a weighted
average of the individual epochs in the
LR02 and LR03 settings
48- 50 F3.1 km/s e_V1D rms uncertainty on V1D
52- 86 A35 --- Notes Notes (2)
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Note (1): Notes as follows:
a = Observations of Field C on 2009-10-08 were discarded as a result of low S/N
b = estimates from only one epoch
Note (2): Published RVs are indicated in the final column from Massey & Olsen
(MO03, 2003, Cat. J/AJ/126/2867) and Gonzalez-Fernandez et al.
(GF15, 2015, Cat. J/A+A/578/A3).
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Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- VFTS Star VFTS identification number
10- 18 F9.3 d HJD Heliocentric Julian date (HJD-2400000)
26- 31 F6.2 km/s RV Radial velocity measurement
42- 45 F4.2 km/s e_RV Error in RV
54- 58 A5 --- gratID [LR02 LR03 HR15N] Grating ID
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Acknowledgements:
Lee Patrick, lpatrick(at)iac.es
References:
Evans et al., Paper I 2011A&A...530A.108E 2011A&A...530A.108E, Cat. J/A+A/530/108
Taylor et al., Paper II 2011A&A...530L..10T 2011A&A...530L..10T
Bestenlehner et al., Paper III 2011A&A...530L..14B 2011A&A...530L..14B
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Sabin-Sanjulian et al., Paper XXVI 2017A&A...601A..79S 2017A&A...601A..79S, Cat. J/A+A/601/A79
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Dufton et al., Paper XXVIII 2018A&A...615A.101D 2018A&A...615A.101D
Schneider et al., Paper XXIX 2018A&A...618A..73S 2018A&A...618A..73S
(End) Patricia Vannier [CDS] 07-Mar-2019