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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 (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:
FileName Lrecl Records Explanations
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 table11.dat 43 203699 Light curves of variable stars lc/* 26 354 Individual light curves
See also: B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014) Byte-by-byte Description of file: table?.dat table10.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) 45 A1 --- --- [:] 46- 47 I2 min RAm Right ascension (J2000.0) 48 A1 --- --- [:] 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) 57 A1 --- --- [:] 58- 59 I2 arcmin DEm Declination (J2000.0) 60 A1 --- --- [:] 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)
Note (1): "-" means no period found Note (2): "-" means information missing in the VSX catalogue
Byte-by-byte Description of file: table11.dat
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
Byte-by-byte Description of file: lc/*
Bytes Format Units Label Explanations
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
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).
Acknowledgements: Jaan Laur, jaanlaur(at)ut.ee
(End) Jaan Laur [TO, Estonia], Patricia Vannier [CDS] 02-Nov-2016
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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