J/A+A/598/A108 Variability survey of brightest stars (Laur+, 2017)
Variability survey of brightest stars in selected OB associations.
Laur J., Kolka I., Eenmae T., Tuvikene T., Leedjarv L.
<Astron. Astrophys. 598, A108 (2017)>
=2017A&A...598A.108L 2017A&A...598A.108L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Stars, OB ; Binaries, eclipsing ;
Stars, Be ; Stars, variable
Keywords: stars: variables: general - stars: massive - surveys -
open clusters and associations: general
Abstract:
The stellar evolution theory of massive stars remains uncalibrated
with high-precision photometric observational data mainly due to small
number of luminous stars monitored from space. Automated all-sky
surveys have revealed numerous variable stars but most luminous stars
are often overexposed. Targeted campaigns can improve the time base of
photometric data for those objects.
The aim of this investigation is to study the variability of luminous
stars at different time-scales in young open clusters and OB
associations. We monitored 22 open clusters and associations from 2011
to 2013 using a 0.25-m telescope. Variable stars were detected by
comparing the overall light-curve scatter with measurement
uncertainties. Variability was analysed by the light curve feature
extraction tool FATS. Periods of pulsating stars were determined using
the discrete Fourier transform code SigSpec. We then classified the
variable stars based on their pulsation periods and available spectral
information.
We obtained light curves for more than 20000 sources of which 354 were
found to be variable. Amongst them we find 80 eclipsing binaries, 31
α Cyg, 13 β Cep, 62 Be, 16 slowly pulsating B, 7 Cepheid,
1 γ Doradus, 3 Wolf-Rayet and 63 late-type variable stars. Up to
55% of these stars are potential new discoveries as they are not
present in the Variable Star Index (VSX) database. We find the cluster
membership fraction for variable stars to be 13% with an upper limit
of 35%.
Description:
We monitored 22 open clusters and associations from 2011 to 2013 using
a 0.25-m telescope. We obtained light curves for more than 20000
sources of which 354 were found to be variable. The data set has a
limiting magnitude ∼14mag with 0.044mag mean precision at limiting
magnitude. Here we list our detected variable stars separated into
their variability types. Periods of pulsating stars were determined
using SigSpec code. In addition, information from Variable Star Index
(VSX) is presented.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 132 80 Observed eclipsing binaries
table2.dat 132 13 Observed β Cephei variables
table3.dat 132 16 Observed SPB variables
table4.dat 132 7 Observed Cepheid variables
table5.dat 132 1 Observed γ Doradus variables
table6.dat 132 3 Observed WR variables
table7.dat 132 30 Observed α Cyg variables
table8.dat 132 62 Observed variable Be stars
table9.dat 132 63 Observed variable late-type stars
table10.dat 132 80 Observed unclassified variable stars
tablea11.dat 116 221 Variable stars not in VSX
table11.dat 43 204141 Light curves of variable stars
lc/* . 354 Individual light curves
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
Byte-by-byte Description of file: table?.dat table10.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Field Field name
13- 16 I4 --- ID Internal ID
18- 41 A24 --- Name Star name
43- 44 I2 h RAh Right ascension (J2000.0)
46- 47 I2 min RAm Right ascension (J2000.0)
49- 52 F4.1 s RAs Right ascension (J2000.0)
54 A1 --- DE- Declination sign (J2000.0)
55- 56 I2 deg DEd Declination (J2000.0)
58- 59 I2 arcmin DEm Declination (J2000.0)
61- 62 I2 arcsec DEs Declination (J2000.0)
64- 75 A12 --- Member Cluster membership
77- 89 A13 --- SPType MK Spectral Type (G1)
91- 96 F6.3 mag Vmag Mean magnitude (apparent) in V filter
98-102 F5.3 mag Amp Amplitude of the light curve
104-111 F8.4 d Per ?=- Period from this work (1)
113-122 A10 --- VSXinfo Variability type in VSX (2)
123-132 F10.4 d VSXPer ?=- Period in VSX (2)
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Note (1): "-" means no period found
Note (2): "-" means information missing in the VSX catalogue
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Byte-by-byte Description of file: tablea11.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Field Field name
13- 16 I4 --- ID Internal ID
18- 41 A24 --- Name Star name
43- 44 I2 h RAh Right ascension (J2000.0)
46- 47 I2 min RAm Right ascension (J2000.0)
49- 52 F4.1 s RAs Right ascension (J2000.0)
54 A1 --- DE- Declination sign (J2000.0)
55- 56 I2 deg DEd Declination (J2000.0)
58- 59 I2 arcmin DEm Declination (J2000.0)
61- 62 I2 arcsec DEs Declination (J2000.0)
64- 75 A12 --- Member Cluster membership
77- 89 A13 --- SPType MK Spectral Type (G1)
91- 96 F6.3 mag Vmag Mean magnitude (apparent) in V filter
98-102 F5.3 mag Amp Amplitude of the light curve
104-111 F8.4 d Per ?=- Period from this work (1)
113-116 A4 --- Type Variability type (2)
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Note (1): "-" means no period found
Note (2): Variability type as follows:
E = Eclipsing binary
BE = Be star
BCEP = betaCephei type star
SPB = Slowly pulsating B star
ACYG = alpha Cygni type star
CEP = Cepheid
WR = Wolf-Rayet star
SR = late-type star
"-" = unclassified
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Field Field name
13- 16 I4 --- ID Internal ID
18- 28 F11.5 d Obs.date Heliocentric Julian date (HJD-2400000)
30- 36 F7.4 mag mag Differential magnitude in V passband
38- 43 F6.4 mag e_mag Uncertainty in magnitude
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Byte-by-byte Description of file: lc/*
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Bytes Format Units Label Explanations
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1- 11 F11.5 d Obs.date Heliocentric Julian date (HJD-2400000)
13- 19 F7.4 mag mag Differential magnitude in V passband
21- 26 F6.4 mag e_mag Uncertainty in magnitude
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Global notes:
Note (G1): Spectral types are compiled from literature with 10 new
classifications acquired with the 1.5 meter AZT-12 telescope at Tartu
Observatory, Estonia (Table 4 of the paper).
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Acknowledgements:
Jaan Laur, jaanlaur(at)ut.ee
(End) Jaan Laur [TO, Estonia], Patricia Vannier [CDS] 02-Nov-2016