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Keywords:

  • binaries: close;
  • binaries: eclipsing;
  • stars: late-type;
  • white dwarfs

ABSTRACT

We present a new eclipsing post-common-envelope binary, identified inside the Kepler field prior to the launch of the spacecraft. Multifilter photometry and radial velocity data are analysed with an eclipsing-binary modelling code to determine the physical parameters of the binary. Spectra of the system within the primary eclipse and uneclipsed allow us to identify the spectral characteristics of the primary and secondary components. The primary component of the binary is a DA white dwarf, with M≃ 0.61 M, log g≃ 7.95 and Teff≃ 20 500 K.

The detection of two flares and the emission signatures displayed in the spectra show that the secondary component of the system is chromospherically active and is classified as an active M4 main-sequence star. Its mass, radius and temperature are estimated as M≃ 0.39 M, R≃ 0.37 R and Teff≃ 3200 K. The ephemeris of the system is HJD = 245 3590.436 126(10) + 0.350 468 722(6) ×E.

This binary is a new post-common-envelope binary (PCEB), with physical parameters within the range found in other systems of this small group of evolved binaries.