J/PASP/121/104 BVRI differential photometry of GW Gem (Lee+, 2009)
Photometric properties of the near-contact binary GW Geminorum.
Lee J.W., Kim S.-L., Lee C.-U., Kim H.-I., Park J.-H., Park S.-R., Koch R.H.
<Publ. Astron. Soc. Pac., 121, 104-110 (2009)>
=2009PASP..121..104L 2009PASP..121..104L
ADC_Keywords: Stars, double and multiple ; Photometry, CCD ; Photometry, UBVRI
Abstract:
New multiband CCD photometry is presented for the eclipsing binary
GW Gem; the RI light curves are the first ever compiled. Four new
minimum timings have been determined. Our analysis of eclipse timings
observed during the past 79 years indicates a continuous period
increase at a fractional rate of +(1.2±0.1)x1010, in excellent
agreement with the value +1.1x10-10 calculated from the
Wilson-Devinney binary code. The new light curves display an inverse
O'Connell effect increasing toward longer wavelengths. Hot- and
cool-spot models are developed to describe these variations but we
prefer a cool spot on the secondary star. Our light-curve synthesis
reveals that GW Gem is in a semidetached, but near-contact,
configuration. It appears to consist of a near-main-sequence primary
star with a spectral type of about A7 and an evolved early K-type
secondary star that completely fills its inner Roche lobe. Mass
transfer from the secondary to the primary component is responsible
for the observed secular period change.
Description:
Our CCD photometry of GW Gem was performed on 13 nights during the
period 2007 December 20-2008 March 1 in order to obtain multicolor
light curves. The observations were taken with a SITe 2K CCD camera
and a BVRI filter set attached to the 61-cm reflector at Sobaeksan
Optical Astronomy Observatory (SOAO) in Korea.
Objects:
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RA (2000) DE Designation(s)
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07 52 29.0 +27 09 16 GW Gem = V* GW Gem
07 53 05.5 +27 16 55 2MASS J07530545+2716551 = UCAC2 41361532
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 83 532 CCD Photometric Observations of GW Gem
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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- 13 F13.5 d HJDB ? Heliocentric Julian date for B band
15- 20 F6.3 mag DBmag ? Differential B magnitude, Var - Comp (1)
22- 34 F13.5 d HJDV ? Heliocentric Julian date for V band
36- 41 F6.3 mag DVmag ? Differential V magnitude, Var - Comp (1)
43- 55 F13.5 d HJDR Heliocentric Julian date for R band
57- 62 F6.3 mag DRmag Differential R magnitude, Var - Comp (1)
64- 76 F13.5 d HJDI ? Heliocentric Julian date for I band
78- 83 F6.3 mag DImag ? Differential I magnitude, Var - Comp (1)
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Note (1): The comparison star is 2MASS 07530545+2716551
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-Apr-2009