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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
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: -------------------------------------------------------------------- RA (2000) DE Designation(s) -------------------------------------------------------------------- 07 52 29.0 +27 09 16 GW Gem = V* GW Gem 07 53 05.5 +27 16 55 2MASS J07530545+2716551 = UCAC2 41361532 -------------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 83 532 CCD Photometric Observations of GW Gem
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
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)
Note (1): The comparison star is 2MASS 07530545+2716551
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 26-Apr-2009
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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