J/AJ/145/16 Differential BVRI light curves of NSVS 02502726 (Lee+, 2013)
Physical properties of the low-mass eclipsing binary NSVS 02502726.
Lee J.W., Youn J.-H., Kim S.-L., Lee C.-U.
<Astron. J., 145, 16 (2013)>
=2013AJ....145...16L 2013AJ....145...16L
ADC_Keywords: Binaries, eclipsing ; Photometry, UBVRI
Keywords: binaries: eclipsing - stars: fundamental parameters -
stars: individual: NSVS 02502726 - stars: low-mass - starspots
Abstract:
NSVS 02502726 has been known as a double-lined, detached eclipsing
binary that consists of two low-mass stars. We obtained BVRI
photometric follow-up observations in 2009 and 2011 to measure
improved physical properties of the binary star. Each set of light
curves, including the 2008 data given by Cakirli et al., was
simultaneously analyzed with the previously published radial velocity
curves using the Wilson-Devinney binary code. The conspicuous seasonal
light variations of the system are satisfactorily modeled by a
two-spot model with one starspot on each component and by changes of
the spot parameters with time. Based on 23 eclipse timings calculated
from the synthetic model and one ephemeris epoch, an orbital period
study of NSVS 02502726 reveals that the period has experienced a
continuous decrease of -5.9x10-7day/yr or a sinusoidal variation
with a period and semi-amplitude of 2.51yr and 0.0011days,
respectively. The timing variations could be interpreted as either the
light-travel-time effect due to the presence of an unseen third body,
or as the combination of this effect and angular momentum loss via
magnetic stellar wind braking. Individual masses and radii of both
components are determined to be M1=0.689±0.016M☉,
M2=0.341±0.009M☉, R1=0.707±0.007R☉, and
R2=0.657±0.008R☉. The results are very different from those
of Cakirli et al. with the primary's radius (0.674±0.006R☉)
smaller the secondary's (0.763±0.007R☉). We compared the
physical parameters presented in this paper with current low-mass
stellar models and found that the measured values of the primary star
are best fitted to a 79Myr isochrone. The primary is in good agreement
with the empirical mass-radius relation from low-mass binaries, but
the secondary is oversized by about 85%.
Description:
We carried out CCD photometric observations of NSVS 02502726 (NSVS =
Northern Sky Variability Survey) during two observing seasons, using
BVRI filters attached to the 1.0m reflector at the Mt. Lemmon Optical
Astronomy Observatory (LOAO) in Arizona, USA. The observations of the
first season were made on 14 nights from 2009 March to May using an
FLI IMG4301E CCD camera and those of the second season were made on 16
nights from 2011 March to April using an ARC 4K CCD camera. The
instruments and reduction methods were the same as those described by
Lee et al. (2009, cat. J/AJ/138/478; 2012, cat. J/AJ/143/95) in the
same order. The comparison (C) and check (K) stars were chosen to be
GSC 3798-1250 (2MASS J08440529+5422332) and GSC 3798-1240.
Objects:
------------------------------------------------------------------------
RA (2000) DE Designation(s) (Period)
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08 44 11.04 +54 23 47.3 NSVS 2502726 = GSC 03798-01207 (P=0.559778)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 22 4753 CCD photometric data of NSVS 02502726 observed
in 2009 and 2011
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/AJ/143/95 : Transit light curves of HAT-P-12 (Lee+, 2012)
J/AJ/137/3181 : HW Vir differential VR light curves (Lee+, 2009)
J/AJ/138/478 : AR Boo differential BVR photometry (Lee+, 2009)
J/AJ/138/466 : NSVS variables automated classification (Hoffman+, 2009)
J/AJ/136/1067 : New beta Lyrae and Algol candidates in NSVS (Hoffman+, 2008)
J/AJ/128/2965 : Red variables in the NSVS (Williams+, 2004)
http://skydot.lanl.gov/ : NSVS database
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD Heliocentric Julian Date of observation
15- 20 F6.4 mag Dmag Differential magnitude
22 A1 --- Flt [BVRI] Filter (B, V, R or I)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 05-Mar-2014