The first photometric and spectroscopic analysis of the neglected totally eclipsing contact binary NSVS 2536063

We firstly studied the neglected totally eclipsing contact binary NSVS 2536063 using the newly observed g'r'i' light curves of 60 cm Ningbo Bureau of Education and Xinjiang Observatory Telescope (NEXT) and some public data, which come from the Transiting Exoplanet Survey Satellite (TESS), the All-Sky Automated Survey for SuperNovae (ASAS-SN), the Zwicky Transient Facility (ZTF) survey, and the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST). NSVS 2536063 is determined as an A-type median contact binary with a mass ratio of q =0.308 +/- 0.001 and the contact degree of f =26 +/- 2%. The absolute parameters of the two components were calculated using the photometric parameters and Gaia distance. Then the diagrams of mass-radius and mass-luminosity indicate that the more massive star is a main sequence star and the less massive star is over-sized and over-luminous. Both the hot spot added on the primary star and magnetic emission lines of spectra indicate the possible magnetic activity of NSVS 2536063. The orbital period of NSVS 2536063 may be long-term increasing with a rate of dp/dt = 1.24(+/- 0.19) x 10(-7)d yr(-1), which is often explained by the mass transfer from the less massive star to the more massive one. Mass transfer may also be responsible for the hot spot on the primary star.