J/MNRAS/298/753 Variables in Cygnus OB2 (Pigulski+ 1998)
Mapping the β Cephei instability strip: photometric variability of stars
in the central part of the Cygnus OB2 association.
Pigulski A., Kolaczkowski Z.
<Mon. Not. R. Astron. Soc. 298, 753 (1998)>
=1998MNRAS.298..753P 1998MNRAS.298..753P
ADC_Keywords: Associations, stellar ; Stars, B-type ; Photometry, CCD
Keywords: stars: oscillations - stars: variables: other - dust, extinction -
open clusters and associations: individual: Cygnus OB2
See also:
Description:
We present the results of the photometric CCD search for B-type
variables in the central region of the Cygnus OB2 association. We
discover 29 new variables including two Beta Cephei stars. The
photometric data in the Cousins I band are given in file photom.dat.
In addition, we present BV(RI)c and Hα photometry for stars in
the observed field. This is Table 4 of the paper, available only in
electronic form.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 108 288 Cross-identifications, positions, membership,
BV(RI)c and H_alpha photometry of stars in the
observed field
photom.dat 31 14328 Differential Ic-filter photometry
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Reddish Star number according to Reddish et al.
(1966PROE....5..111R 1966PROE....5..111R), <Ass Cyg ON 2-NNNN>
6- 9 A4 --- MT91 Star number according to Massey &
Thompson (1991AJ....101.1408M 1991AJ....101.1408M), see Note (1)
11- 13 A3 --- Schulte Star number according to Schulte numbering
system, see Note (2)
14 A1 --- phFlag [*] Flag set when photometry available
in file photom.dat
16- 21 F6.1 pix Xpos X coordinate of a star in Fig.2
23- 28 F6.1 pix Ypos Y coordinate of a star in Fig.2
31- 36 F6.3 mag Imag ? I magnitude, see Note (3)
38- 43 F6.3 mag R-I ? R-I colour index, see Note (3)
45- 50 F6.3 mag V-I ? V-I colour index, see Note (3)
52- 57 F6.3 mag B-V ? B-V colour index, see Note (3)
59- 64 F6.3 mag Alpha ? α colour index, see Note (4)
67- 69 A3 --- Memb Membershib flag, see text for explanation
72- 77 F6.3 mag I0 ? Dereddened I magnitude
79- 84 F6.3 mag (R-I)0 ? Dereddened R-I colour index
86- 87 I2 h RAh Right Ascension J2000 (hours) (5)
89- 90 I2 min RAm Right Ascension J2000 (minutes) (5)
92- 96 F5.2 s RAs Right Ascension J2000 (seconds) (5)
98 A1 --- DE- Declination J2000 (sign) (5)
99-100 I2 deg DEd Declination J2000 (degrees) (5)
102-103 I2 arcmin DEm Declination J2000 (minutes) (5)
105-108 F4.1 arcsec DEs Declination J2000 (seconds) (5)
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Note (1): The list of Massey & Thompson (1991AJ....101.1408M 1991AJ....101.1408M)
contains 799 stars. These stars are labeled with 'MT'. All stars with
numbers over 799 are new-designated ones extending above-mentioned
numbering system. We label them with 'MTE'.
Note (2): The details of Schulte's designation are explained
in Section 3 of the paper.
Note (3): For variable stars we use the following rules in listing
their BV(RI)c magnitudes: for periodic variables we list the mean
magnitude, while for the eclipsing binaries the magnitudes at the
phase of maximum light are given. For the remaining variables we give
the BV(RI)c magnitudes at one, arbitrarily chosen night,
namely HJD 2450319.
Note (4): The definition of the alpha index we used is given by
Pigulski et al. (1997AcA....47..365J 1997AcA....47..365J).
Note (5): the positions were computed mainly from the GSC by Brian Skiff,
Lowell Observatory ()
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Byte-by-byte Description of file: photom.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star name
12- 23 F12.4 d HJD Heliocentric Julian day
26- 31 F6.3 mag DeltaI Differential Ic magnitudes
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Acknowledgements:
Andrzej Pigulski
Brian Skiff for J2000 positions
(End) Patricia Bauer [CDS] 10-Aug-1998