J/A+A/635/A29 Multiplicity of red supergiants in NGC 330 (Patrick+, 2020)
Multiplicity of the red supergiant population in the young massive cluster
NGC 330.
Patrick L.R, Lennon D.J., Evans C.J., Sana H., Bodensteiner J.,
Britavskiy N., Dorda R., Herrero A., Negueruela I., de Koter A.
<Astron. Astrophys. 635, A29 (2020)>
=2020A&A...635A..29P 2020A&A...635A..29P (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Clusters, open ; Stars, giant ;
Radial velocities
Keywords: binaries: spectroscopic - supergiants - stars: late-type -
Magellanic Clouds - galaxies: star clusters: individual: NGC 330
Abstract:
The multiplicity properties of massive stars are one of the important
outstanding issues in stellar evolution. Quantifying the binary
statistics of all evolutionary phases is essential to paint a complete
picture of how and when massive stars interact with their companions,
and to determine the consequences of these interactions.
We investigate the multiplicity of an almost complete census of red
supergiant stars (RSGs) in NGC 330, a young massive cluster in the
Small Magellanic Cloud.
Using a combination of multi-epoch HARPS and MUSE spectroscopy, we
estimate radial velocities and assess the kinematic and multiplicity
properties of 15 RSGs in NGC 330.
Radial velocities are estimated to better than ±100m/s for the HARPS
data. The line-of-sight velocity dispersion for the cluster is
estimated as σ1D=3.20+0.69-0.52km/s. When virial
equilibrium is assumed, the dynamical mass of the cluster is
log(Mdyn/M☉)=5.20±0.17, in good agreement with previous
upper limits. We detect significant radial velocity variability in our
multi-epoch observations and distinguish between variations caused by
atmospheric activity and those caused by binarity. The binary fraction
of NGC 330 RSGs is estimated by comparisons with simulated
observations of systems with a range of input binary fractions. In
this way, we account for observational biases and estimate the
intrinsic binary fraction for RSGs in NGC 330 as fRSG=0.3±0.1 for
orbital periods in the range 2.3<logP[days]<4.3, with q>0.1. Using
the distribution of the luminosities of the RSG population, we
estimate the age of NGC 330 to be 45±5Myr and estimate a red
straggler fraction of 50%.
We estimate the binary fraction of RSGs in NGC 330 and conclude that it
appears to be lower than that of main-sequence massive stars, which is
expected because interactions between an RSG and a companion are assumed
to effectively strip the RSG envelope.
Description:
Radial velocities for each epoch in each grating estimated using the
slice technique defined here. The spectroscopy comes from HARPS and
MUSE.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sources.dat 65 15 List of studied source
(from table B1 of the paper)
tablea1.dat 46 175 RV estimates at each epoch for RSGs in the
HARPS and MUSE samples
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See also:
J/A+A/634/A51 : NGC 330 seen by MUSE (Bodensteiner+, 2020)
Byte-by-byte Description of file: sources.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- IDR74 ID from Robertson (1974A&AS...15..261R 1974A&AS...15..261R),
Cl* NGC 330 Rob ANN in Simbad
5- 9 A5 --- IDArp59 ID from Arp (1959AJ.....64..254A 1959AJ.....64..254A),
Cl* NGC 330 ARP NNN in Simbad
11- 16 A6 --- IDBal92 ID from Balona (1992MNRAS.256..425B 1992MNRAS.256..425B),
Cl* NGC 330 Bal NNNN in Simbad
18- 36 I19 --- GaiaDR2 Gaia DR2 source name (Cat. I/345),
Gaia DR2 NNNNNNNNNNNNNNNNNNN in Simbad
38- 39 I2 h RAh Right ascension (ICRS) at Ep=2015.5
41- 42 I2 min RAm Right ascension (ICRS) at Ep=2015.5
44- 50 F7.4 s RAs Right ascension (ICRS) at Ep=2015.5
52 A1 --- DE- Declination sign (ICRS) at Ep=2015.5
53- 54 I2 deg DEd Declination (ICRS) at Ep=2015.5
56- 57 I2 arcmin DEm Declination (ICRS) at Ep=2015.5
59- 65 F7.4 arcsec DEs Declination (ICRS) at Ep=2015.5
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- ID Identification
5- 13 F9.1 d HJD Heliocentrc Julain date (HJD-2400000)
15- 20 F6.2 km/s RV Radial velocity measurement
22- 26 F5.2 km/s e_RV Error in RV
28- 46 A19 --- Inst/Ref Instrument or journal reference
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Acknowledgements:
Lee Patrick, lpatrick(at)iac.es
(End) Lee Patrick [IAC], Patricia Vannier [CDS] 21-Feb-2020