| Abstract : | The multi-wavelength spectral energy distributions (SEDs) are indirect way to detect hot companions of binary systems as they emit a significant amount of their flux at UV wavelengths. Berkeley 39 is an old Galactic open cluster located at a distance of 4200 pc. Using the ML-MOC algorithm on Gaia EDR3 data, we identified 861 members and 20 BSS in this cluster. Here, we characterize 18 blue straggler stars (BSS) and 6 main-sequence (MS) stars of Berkeley 39 using their SEDs. For this, we use UV data from swift/UVOT, optical data from Gaia DR3, IR data from 2MASS, Spitzer/IRAC, and WISE. We found excess flux in UV data points of 3 BSS, implying the presence of hot companions. Therefore, we fit them with double-component SEDs. Of the 18 BSS, the remaining 15 are successfully fitted with single-component SED.
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