J/MNRAS/468/2816 NGC6397 low-mass variable stars (Martinazzi+, 2017)
Low-mass variable stars in the globular cluster NGC 6397.
Martinazzi E., Kepler S.O., Costa J.E.S.
<Mon. Not. R. Astron. Soc., 468, 2816-2821 (2017)>
=2017MNRAS.468.2816M 2017MNRAS.468.2816M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, variable ; Magnitudes
Keywords: convection - methods: data analysis - techniques: photometric -
stars: chromospheres - stars: low-mass - stars: variables: general
Abstract:
We have conducted a photometric survey of the globular cluster
NGC 6397 in a search for variable stars. We obtained ∼11h of
time-resolved photometric images with one European Southern
Observatory-Very Large Telescope using the FOcal Reducer and low
dispersion Spectrograph imager distributed over two consecutive
nights. We analysed 8391 light curves of stars brighter than magnitude
23 with the 465-nm filter, and we identified 412 variable stars,
reaching ∼4.8±0.2 per cent of variability with time-scales between
0.004 and 2d, with amplitudes variation greater than ±0.2mag.
Description:
The images used in this work were obtained from the ESO program ID
083.D-0653(A) P.I. Barbara Castanheira. They were taken in 2009 July
27-28, with 8.4-m ESO-VLT-UT1 telescope (Very Large Telescope), using
the FORS2 (FOcal Reducer and low dispersion Spectrograph) imager
composed by two CCDs with a total of 2048x2068 pixels and
0.25arcsec/pix scale, with a usable portion total of 1670x1677pixels.
We obtained images B_HIGH and V_HIGH filters, with exposure times of
1, 10, 120, 300s each.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 65 405 Variable stars in NGC 6397 with 99.9 per cent
confidence level
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See also:
J/A+A/527/A148 : NGC6397 red giants chemical composition (Lind+, 2011)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Star Star designation, N/NNNN
9- 10 I2 h RAh Right ascension (J2000)
12- 13 I2 min RAm Right ascension (J2000)
15- 19 F5.2 s RAs Right ascension (J2000)
21 A1 --- DE- Declination sign (J2000)
22- 23 I2 deg DEd Declination (J2000)
25- 26 I2 arcmin DEm Declination (J2000)
28- 32 F5.2 arcsec DEs Declination (J2000)
34- 37 F4.2 --- chi2r Reduced chi2 value
39- 43 F5.2 mag F465-250 Filt465250 magnitude
(central wavelength = 4650Å, dl=250Å)
45- 49 F5.2 mag Bmag HIGH B magnitude
51- 54 F4.2 mag e_Bmag HIGH B magnitude error
56- 60 F5.2 mag Vmag HIGH V magnitude
62- 65 F4.2 mag e_Vmag HIGH V magnitude error
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 13-Mar-2020