The nature of the companion of PSR J1719-1438: a white dwarf or an   exotic object?
  We rise in this Letter the possibility that the very dense, compact companion of PSR J1719-1438, having a Jupiter-like mass is an exotic quark object rather than a light helium or carbon white dwarf. The exotic hypothesis explains naturally some of the observed features, and gives quite strong predictions for this system, to be confirmed or refuted in future feasible studies. 
J. E. Horvath
astro-ph.HE