PSR J1719-1438 b
PSR J1719-1438 b is a pulsar planet most likely composed largely of crystalline carbon, or diamond. PSR J1719-1438 b and PSR J1719-1438 were formerly two stars in a binary star system, but after PSR J1719-1438 went supernova and became a pulsar, PSR J1719-1438 b expanded into its red giant phase and diminished into a white dwarf. The intense conditions of the system converted the white dwarf into a planet composed largely of heavy elements like carbon and oxygen. PSR J1719-1438 b orbits very closely to its host star.
Formation
The pulsar was formed when the primary member of a binary star system experienced a supernova, leaving behind its rapidly spinning core, which became the pulsar itself. The secondary, less prominent companion was a main sequence star that became a red giant before shrinking into a white dwarf. During its life, the pulsar siphoned gases from the secondary star, speeding up as more matter was added to it.
The white dwarf, however, did not enter an unstable orbit and merge with the pulsar, which happens to a significant minority of star-pulsar binary systems. Instead, the white dwarf stabilized very close to the pulsar. The proximity caused the white dwarf to lose the majority of its remaining matter, leaving behind a bare core. The intense gravitational pressure caused by the proximity crystallized the carbon-composed planet (because all fusion reactions had stopped, it was reclassified), forming a substance similar to that of diamond.
Host star
- Main article: PSR J1719-1438
PSR J1719-1438 is a pulsar thatcompletes more than 10,000 rotations a minute. It is approximately 12 miles across, but has a mass that is 1.4 astronomical masses. The pulsar was originally part of a binary star system, with the other star being PSR J1719-1438 b (when it still completed fusion reactions).
Characteristics
PSR J1719-1438 b is one of the densest planets in the Galaxy. It may be partially composed of degenerate matter. Because it is hypothesized to be the remnant of a white dwarf, it is believed to be composed of oxygen and carbon (as opposed to hydrogen and helium, the main components of gas giants. However, all known white dwarfs have densities that are on the order of millions of times the density of water and are composed of electron-degenerate matter, which makes this object extremely non-dense for a white dwarf. Also, white dwarfs emit light due to their temperature based on trapped heat from gravitational collapse. It is unknown why this hypothesized white dwarf remnant does not retain enough temperature to emit light.
The oxygen is most likely on the surface of the planet, with increasingly higher quantities of carbon deeper inside the planet. The intense pressure acting upon the planet suggests that the carbon is crystallized, much like diamond is.
PSR J1719-1438 b orbits its host star with a period of 2.177 hours.
See also
- WASP-12b, a "diamond planet"
- BPM 37093, a "diamond star"
- EF Eridani, a star system with a compact star and a degraded planetary-mass former star
