System 58
W Ursa Majoris K class
The heart of this system is a contact binary of two main sequence stars of spectral class K. In such systems, one star is typically much
more massive than the other, though they have similar luminosities and often identical spectral classes due to atmospheric mixing. The
stars have both filled, or slightly overfilled, their Roche lobes, causing their atmospheres to fuse. Mass is constantly being transferred
between the stars. In this case, however, the mass differential is less than typical. The contact binary is orbited by a class M dwarf and a
class G dwarf. There are no planets in this system, they may have been ejected as a result of complex orbital dynamics during the
evolution of this system.
A low mass contact binary of this type is also classed as a W UMa (W Ursa Majoris) variable of type W. These stars are variable stars
since the light level as perceived by a remote observer may vary as the stars orbit about their common centre of mass. In this instance
they orbit once every 3.8 hours. Both the component stars have convective photospheres. This is an opportunity to further refine
models on plasma transfer and to examine the effects of the proximity of the M and G dwarfs on the stability of this process.

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