PSR J1719-1438 is a millisecond pulsar, not a main-sequence star. PSR J1719-1438 b is the so-called diamond planet: a Jupiter-mass, ultra-dense remnant, likely crystallized carbon, whipping around a millisecond pulsar every 2.2 hours. PSR J1719-1438 b is a 1.20-Jupiter-mass companion, with an orbital period of 2.2 hours, at 0.004 AU from its star, on an eccentric orbit (e ≈ 0.06), discovered in 2011 via pulsar timing.