J/MNRAS/419/2379 NGC 6866 variables V and I light curves (Joshi+, 2012)
Photometric study and detection of variable stars in the open clusters.
I. NGC 6866.
Joshi Y.C., Joshi S., Kumar B., Mondal S., Balona L.A.
<Mon. Not. R. Astron. Soc., 419, 2379-2390 (2012)>
=2012MNRAS.419.2379J 2012MNRAS.419.2379J
ADC_Keywords: Clusters, open ; Stars, variable ; Photometry, UBVRI
Keywords: techniques: photometric - stars: variables: general -
open clusters and associations: individual: NGC 6866
Abstract:
We present results of a variability search in the intermediate-age
open cluster NGC 6866 from 29 nights over two observing seasons. We
find 28 periodic variables, of which 19 are newly identified. The
periods of these variables, which have V magnitudes from 11.5 to
19.3mag, range from ∼48min to 37d. We detected several δ
Scuti stars, some of which are of high amplitude, as well as γ
Doradus and rotational variables, and eclipsing binaries. In order to
study the physical properties of the cluster, we obtained UBVRI
photometry of all the stars on a good photometric night. The radial
distribution of the stellar surface density shows that the cluster has
a radial extent of about 7-arcmin ( ∼3pc) with a peak density of
5.7±0.7stars/arcmin2 at the cluster centre. The colour-colour
diagram indicates a reddening of E(B-V)=0.10mag towards NGC 6866. A
distance of ∼1.47kpc and an age of ∼630Myr are estimated from the
colour-magnitude diagram using the theoretical isochrones of solar
metallicity.
Description:
Time-series observations of stars in NGC 6866 were obtained in the
Johnson V and Cousin I bands using the 1.04-m Sampurnanand telescope
at Manora Peak, Nainital. We used a 2kx2k CCD camera covering a
field of view of about 13x13arcmin2. The cluster was observed for
29 nights between 2008 September 26 and 2011 January 10 over two
observing seasons.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 100 2473 UBVRI photometric catalogue of 2473 stars
detected in the field of cluster NGC 6866
lc/* . 56 *Individual V and I light curves
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Note on lc/*: Individual light curves files are starNNNNV.dat for V band,
starNNNNI.dat for I band, where NNNN is the ID number of table1.
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See also:
J/MNRAS/437/804 : UBVRI photometry of NGC559 stars (Joshi+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I04 --- ID [1/2473] Sequential ID number
6- 7 I2 h RAh Right ascension (J2000)
9- 10 I2 min RAm Right ascension (J2000)
12- 16 F5.2 s RAs Right ascension (J2000)
18 A1 --- DE- Declination sign (J2000)
19- 20 I2 deg DEd Declination (J2000)
22- 23 I2 arcmin DEm Declination (J2000)
25- 28 F4.1 arcsec DEs Declination (J2000)
30- 34 F5.2 mag Umag ?=- Johnson U magnitude
36- 39 F4.2 mag e_Umag ? rms uncertainty on Umag (1)
41- 45 F5.2 mag Bmag Johnson B magnitude
47- 50 F4.2 mag e_Bmag rms uncertainty on Bmag (1)
52- 56 F5.2 mag Vmag Johnson V magnitude
58- 61 F4.2 mag e_Vmag rms uncertainty on Vmag (1)
63- 67 F5.2 mag Rmag ?=- Cousins R magnitude
69- 72 F4.2 mag e_Rmag ? rms uncertainty on Rmag (1)
74- 78 F5.2 mag Imag ?=- Cousins I magnitude
80- 83 F4.2 mag e_Imag ? rms uncertainty on Imag (1)
85- 88 F4.2 --- Msp [0/1] Membership probability based on the
spatial distribution
90- 93 F4.2 --- Mph [0/1] Membership probability based on the
position in the color-magnitude diagram (CMD)
95- 98 F4.2 --- Mpm [0/1]?=- Membership probability based on the
proper motion
100 A1 --- LC [*] * indicates individual V and I light
curves in subdirectory lc
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Note (1): The error in magnitudes indicates the internal photometric error in
the measurement.
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Byte-by-byte Description of file: lc/*.dat
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Bytes Format Units Label Explanations
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1- 11 F11.6 d HJD Heliocentric Julian date (HJD-2450000)
15- 20 F6.3 mag mag I or V magnitude
25- 29 F5.3 mag e_mag rms uncertainty on mag
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History:
From electronic version of the journal
References:
Joshi et al., Paper II 2014MNRAS.437..804J 2014MNRAS.437..804J, Cat. J/MNRAS/437/804
(End) Patricia Vannier [CDS] 08-Nov-2014