ARTICLE IN PRESS JID: NEASPA [m5G;February 12, 2016;20:9] New Astronomy xxx (2016) xxx–xxx Contents lists available at ScienceDirect New Astronomy journal homepage: www.elsevier.com/locate/newast The first CCD photometric analysis and modeling for short period eclipsing binary system 1SWASPJ210423.7+073140.4. M.S. Saad b,c , M.S. Darwish b,c,∗ , M.A. Nasser a,b , M.A. Hamdy b,c , M.M. Beheary a , K. Gadallah a , Q1 D. Fouda b,c a Astronomy Department and Meteorology, Faculty of Science, Al-Azhar University, Cairo, Egypt b Astronomy Department, National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt c Kottamia Center of Scientific Excellence in Astronomy and Space Sciences (KCScE), Egypt highlights • The research present new CCD VRI observations for the new discovered eclipsing binary system J2104 • New timing of minima (3 primary and 3 secondary) were calculated for each filter. The observed light curves were analyzed using the 2009 version of the Wilson–Devinney code. • The solution indicated that the system is an overcontact one with fill-out factor f = 25% ± 6%. • The system has high mass ratio q = 0.85. The high mass ratio systems with q > 0.72 was first introduced by Csizmadia & Klagyivik (2004), they indicated that in H-type systems the energy transfer rate is less efficient than in other type at a given luminosity ratio. • The primary star is more massive and about 112K hotter than the secondary one. • The primary star belongs to spectral type K4 while the secondary belongs to K5. • According to the M-L and R-M relation we have an evolved eclipsing binary system with primary system above the ZAMS track and Secondary one on TAMS track. • The calculations lead to an average distance of 307 ± 21Pc article info Article history: Received 11 January 2016 Accepted 1 February 2016 Available online xxx Communicated by P.S. Conti Keywords: WUMa Eclipsing binaries Individual 1SWASP J2104 Light curve modeling abstract We present the first light curve analysis of the new eclipsing binary of WUMa type 1SWASP J2104. A detailed photometric analysis was carried out in VRI bands using the most recent version of Wilson– Devinney (WD) code. The absolute physical parameters of the system were obtained and the previously determined period was confirmed. The evolution state shows that the primary component is slightly evolved above the ZAMS track while the secondary is on TAMS track. Our results show that the spectral types of the primary and secondary stars of the studied system are K4 and K5, respectively. The distance to 1SWASP J2104 was calculated to be 307 ± 21pc. © 2016 Published by Elsevier B.V. 1. Introduction 1 Studying the short period eclipsing binary stars give valuable 2 information about the physical and absolute parameters of the 3 stars, such as masses and radii. The determination of absolute 4 parameters provides us with an important knowledge about the 5 stellar structure and evolution. These parameters can be obtained 6 ∗ Corresponding author at: Astronomy Department, National Research Insti- tute of Astronomy and Geophysics, Helwan, Cairo, Egypt. Tel.: +201009169305; fax: +225548020. E-mail addresses: saadmhsaad@gmail.com (M.S. Saad), m.darwish@nriag.sci.eg, darwish.msk@gmail.com (M.S. Darwish). by analyzing both the light and radial velocity curves. WUMa are 7 very important objects for studying the evolution state of close bi- 8 nary stars and a better characterizing of their formation. 1SWASP 9 J210423.7+073140.4, (J2104 hereafter) is one of the short period 10 eclipsing binary candidate stars (p<2 × 10 4 s i.e. 0.23 day) that 11 identified by SuperWASP project (Norton et al. 2011). The system 12 J2104 was classified as a short period WUMa star (P = 0. d 20908) 13 with apparent magnitude v max = 13.3mag. Studying short period 14 eclipsing binaries is important for understanding the evolution of 15 low mass stars and allow investigating the cause of the period cut- 16 off (Norton et al. 2011). In the present paper, we are going to per- 17 form a first photometric study for the eclipsing binary J2104 using 18 new CCD observations in VRI filters. The reduction of the observa- 19 tions were done using C-Munipack (Motl, 2007) package. 20 http://dx.doi.org/10.1016/j.newast.2016.02.001 1384-1076/© 2016 Published by Elsevier B.V. Please cite this article as: M.S. Saad et al., The first CCD photometric analysis and modeling for short period eclipsing binary system 1SWASPJ210423.7+073140.4., New Astronomy (2016), http://dx.doi.org/10.1016/j.newast.2016.02.001