IGR J18293-1213 is an eclipsing cataclysmic variable

Clavel, M.M.ClavelTomsick, J. A.J. A.TomsickBodaghee, A.A.BodagheeChiu, J. L.J. L.ChiuFornasini, F. M.F. M.FornasiniHong, J.J.HongKrivonos, R.R.KrivonosPONTI, GABRIELEGABRIELEPONTIRahoui, F.F.RahouiStern, D.D.Stern2020-07-172020-07-1720160035-8711http://hdl.handle.net/20.500.12386/26486Studying the population of faint hard X-ray sources along the plane of the Galaxy is challenging because of high extinction and crowding, which make the identification of individual sources more difficult. IGR J18293-1213 is part of the population of persistent sources which have been discovered by the INTEGRAL satellite. We report on NuSTAR and Swift/XRT observations of this source, performed on 2015 September 11. We detected three eclipsing intervals in the NuSTAR light curve, allowing us to constrain the duration of these eclipses, ∆ t= 30.8^{+6.3}_{-0.0} min, and the orbital period of the system, T = 6.92 ± 0.01 h. Even though we only report an upper limit on the amplitude of a putative spin modulation, the orbital period and the hard thermal bremsstrahlung spectrum of IGR J18293-1213 provide strong evidence that this source is a magnetic cataclysmic variable. Our NuSTAR and Swift/XRT joint spectral analysis places strong constraints on the white dwarf mass M_wd = 0.78^{+0.10}_{-0.09} M☉. Assuming that the mass to radius ratio of the companion star M⋆/R⋆ = 1 (solar units) and using T, ∆t, and Mwd, we derived the mass of the companion star M⋆ = 0.82 ± 0.01 M☉, the orbital separation of the binary system a = 2.14 ± 0.04 R☉, and its orbital inclination compared to the line of sight I=(72.2°^{+2.4}_{-0.0})± 1.0°.STAMPAenIGR J18293-1213 is an eclipsing cataclysmic variableArticle10.1093/mnras/stw13302-s2.0-84988812644000383272500026https://academic.oup.com/mnras/article/461/1/304/25952912016MNRAS.461..304CFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_6 Stars and stellar systems