J/PASP/130/C4201 BVR light curves of UZ Leo (Lee+, 2018)
Physical nature and orbital behavior of the eclipsing system UZ Leonis.
Lee J.W., Park J.-H.
<Publ. Astron. Soc. Pac. 130, C4201 (2018)>
=2018PASP..130c4201L 2018PASP..130c4201L (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Photometry, UBVRI
Keywords: binaries: close - binaries: eclipsing - stars: individual: UX Leo -
stars: fundamental parameters - starspots
Abstract:
New CCD photometric observations of UZ Leo were obtained between 2012
February and 2013 April, and on 2017 February. Its physical properties
were derived from detailed analyses of our light curves and existing
radial velocities. The results indicate that this system is a totally
eclipsing A-subtype overcontact binary with both a high fill-out
factor of 76% and a third light source contributing 12% light in the B
bandpass, 10% in V, and 7% in R. The light residuals between
observations and theoretical models are satisfactorily fitted by
adopting a magnetic cool spot on the more massive primary star.
Including our 12 measurements, a total of 172 eclipse times were used
for ephemeris computations. We found that the orbital period of UZ Leo
has varied due to a periodic oscillation superposed on an upward
parabolic variation. The observed period increase at a rate of
+3.49x10-7day/yr can be plausibly explained by some combination of
non-conservative mass transfer from the secondary to the primary
component and angular momentum loss due to magnetic braking. The
period and semi-amplitude of the oscillation are about 139 years and
0.0225 days, respectively, which is interpreted as a light-time effect
due to a third component with a mass of M3sini3=0.30M{sun.
Because the third lights of 7%-12% indicate that the circumbinary
object is very overluminous for its mass, it would possibly match a
white dwarf, rather than an M-type main sequence.
Description:
We performed new CCD photometry of UZ Leo during two observing seasons
between 2012 February and 2013 April, using a PIXIS: 2048B CCD and a
BVR filter set attached to the 61 cm reflector at Sobaeksan Optical
Astronomy Observatory (SOAO) in Korea. The CCD chip has
2048x2048pixels and a pixel size of 13.5um, so the field of view of
a CCD frame is 17.6'x17.6'.
Objects:
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RA (2000) DE Designation(s)
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10 40 33.18 +13 34 00.9 UZ Leo = HIP 52249
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 3733 CCD photometric data of UZ Leo observed in 2012
and 2013
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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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2- 14 F13.5 d HJD-B B band Heliocentric Julian date of observation
18- 24 F7.4 mag DBmag Differential B magnitude
30- 42 F13.5 d HJD-V ? V band Heliocentric Julian date of observation
46- 52 F7.4 mag DVmag ? Differential V magnitude
58- 70 F13.5 d HJD-R ? R band Heliocentric Julian date of observation
74- 80 F7.4 mag DRmag ? Differential R magnitude
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 20-Apr-2018