J/AJ/123/279 VI Photometry and Variables in NGC 3201 (von Braun+, 2002)
Variable stars in the field of the globular cluster NGC 3201
von Braun K., Mateo M.
<Astron. J., 123, 279 (2002)>
=2002AJ....123..279V 2002AJ....123..279V
ADC_Keywords: Clusters, globular ; Binaries, eclipsing ; Photometry, CCD ;
Stars, variable
Keywords: binaries; eclipsing - blue stragglers - color-magnitude diagrams -
dust, extinction - globular clusters: individual (NGC 3201) -
stars: variable: general
Description:
The Globular Cluster NGC 3201 was monitored for the existence of
variable stars with 16.5<V<20 and 0.2days<period<5days. The files
v*.dat contain time-series photometry data in V and I for the 14
variables detected in the field of NGC 3201. Only V6 (a blue straggler
contact binary) is a member of the cluster. Due to its low-latitude
position, interstellar extinction is present across the field of the
cluster. The file phot.dat contains VI photometry data on the
monitored stars. These data are NOT corrected for extinction. The
variables V7, V8, and V9 were discovered during a follow-up observing
run with a different telescope and therefore do not lie in the field
covered by phot.dat. Variables V1-V9 are contact system eclipsing
binaries, V10 is an RR Lyrae, V11 a semi-detached Algol type binary,
V12 a detached binary system, and V13 and V14 are unclassified variable
systems.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
phot.dat 66 22693 Color and magnitude information for stars in the
field of NGC 3201
table1.dat 71 14 Variable stars in the field of NGC 3201
var/* . 28 Light curves of the 14 variable stars
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Byte-by-byte Description of file: phot.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID Star ID number
8- 9 I2 h RAh Right ascension (J2000.0)
10 A1 --- --- [:]
11- 12 I2 min RAm Right ascension (J2000.0)
13 A1 --- --- [:]
14- 18 F5.2 s RAs Right ascension (J2000.0)
20 A1 --- DE- Declination sign
21- 22 I2 deg DEd Declination (J2000.0)
23 A1 --- --- [:]
24- 25 I2 arcmin DEm Declination (J2000.0)
26 A1 --- --- [:]
27- 30 F4.1 arcsec DEs Declination (J2000.0)
34- 39 F6.3 mag Imag Calibrated apparent I-band magnitude (1)
44- 48 F5.3 mag e_Imag I-band photometric error (1)
52- 57 F6.3 mag V-I Calibrated apparent (V-I) color (1)
62- 66 F5.3 mag e_V-I V-I color photometric error (1)
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Note (1): In order to obtain the final values for the magnitudes of the stars,
we averaged between 10 and 40 individual measurements for each star.
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Var Variable name (V1 to V14)
5- 14 A10 --- Type Type of variable
16- 17 I2 h RAh Right ascension (J2000.0)
19- 20 I2 min RAm Right ascension (J2000.0)
22- 26 F5.2 s RAs Right ascension (J2000.0)
28 A1 --- DE- Declination sign (J2000.0)
29- 30 I2 deg DEd Declination (J2000.0)
32- 33 I2 arcmin DEm Declination (J2000.0)
35- 38 F4.1 arcsec DEs Declination (J2000.0)
40- 47 F8.6 d Per Period
49- 50 I2 10-6d e_Per rms uncertainty on Per (1)
51 A1 -- n_Per [*] Note on Per (2)
53- 58 F6.3 mag Vbright V magnitude at maximum light
60- 61 I2 10-3mag e_Vbright rms uncertainty on Vbright (3)
63- 68 F6.3 mag Ibright I magnitude at maximum light
70- 71 I2 10-3mag e_Ibright rms uncertainty on Ibright (3)
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Note (1): The error in the period corresponds to the full width at half maximum
(FWHM) of the peak in the AOV power spectrum corresponding to the
correct frequency. For the determination of this error, only V data
were used, except for the cases of V7, V8, and V13, where we used I
data.
Note (2): *: In some instances, the peak in the power spectrum corresponding to
the correct period was assigned essentially the same power as
directly neighboring peaks (i.e., it would be hard to pick
"by eye." which one is the correct one). In these cases, we
estimated the period error to be the distance between the two
neighboring peaks (with the peak corresponding to the correct
period in the middle).
Note (3): Photometry errors are the result of adding in quadrature the DOPHOT
photometry error for the instrumental magnitude and the rms of the
standard star solution
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Byte-by-byte Description of file: var/v*_v.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d HJD Heliocentric Julian Date
18- 28 F11.6 d HJDshort Heliocentric Julian Date - 2450000 days
30- 35 F6.3 mag Vmag Calibrated apparent V-band magnitude (1)
37- 41 F5.3 mag e_Vmag V-band photometric error (1)
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Note (1): the magnitudes and errors are the values associated with individual
measurements, i.e., not averaged.
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Byte-by-byte Description of file: var/v*_i.dat
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Bytes Format Units Label Explanations
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1- 16 F16.8 d HJD Heliocentric Julian Date
18- 28 F11.6 d HJDshort Heliocentric Julian Date - 2450000 days
30- 35 F6.3 mag Imag Calibrated apparent I-band magnitude (1)
37- 41 F5.3 mag e_Imag I-band photometric error (1)
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Note (1): The magnitudes and errors are the values associated with individual
measurements, i.e., not averaged.
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Acknowledgements:
Kaspar von Braun
(End) Kaspar von Braun [U of Michigan], Patricia Bauer [CDS] 15-Feb-2002