Epoch MJD 55411.0 Equinox J2000
|Spectral type||millisecond pulsar|
|Apparent magnitude (R)||>25.4|
|Apparent magnitude (g)||>24.1|
|Apparent magnitude (I)||>22.5|
|Period (P)||0.090706293(2) days|
|Semimajor axis (a)||0.001819(1) light seconds|
|Periastron epoch (T)||MJD 55411.0|
PSR J1719-1438 is a millisecond pulsar with a spin period of 5.8 ms located about 4000 ly from Earth in the direction of Serpens Cauda, one minute from the border with Ophiuchus. Millisecond pulsars are generally thought to begin as normal pulsars and then spin up by accreting matter from a binary companion.
Diamond planet 
PSR J1719-1438 was discovered in 2011 by the High Time Resolution Survey, a radio astronomy search for astronomical objects that rapidly vary in radio brightness, such as pulsars. Timing measurements using the Parkes Telescope and Lovell Telescope showed that it has a low-mass companion: PSR J1719-1438 b. The companion has a mass similar to that of Jupiter, but 40% of the diameter. It orbits the pulsar with a period of 2 hours 10 minutes and 37 seconds, at a distance of around 600,000 km (0.89 solar radii). The companion is likely the remnant of a star whose outer layers were siphoned off by the more massive pulsar. Calculations show the companion has a minimum density of 23 grams per cubic centimeter and is probably an ultra-low-mass carbon–oxygen white dwarf.
Because the companion to PSR J1719-1438 is planet-sized, made primarily of carbon (with an unknown amount of oxygen), and very dense, it may be similar to a large diamond. In the science press, the object has been called the "Diamond Planet".
See also 
- EF Eridani, a star system with a compact star and a degraded planetary-mass former star
- Bailes, M.; Bates, S. D.; Bhalerao, V.; Bhat, N. D. R.; Burgay, M.; Burke-Spolaor, S.; d'Amico, N.; Johnston, S. et al. (2011). "Transformation of a Star into a Planet in a Millisecond Pulsar Binary". Science 333 (6050): 1717–20. arXiv:1108.5201. Bibcode:2011Sci...333.1717B. doi:10.1126/science.1208890. PMID 21868629.
- "Star Transforms Into A Diamond Planet". Universe Today. Retrieved 2011-08-26.
- "Surprise! Alien Planet Made of Diamond Discovered". Space.com. Retrieved 2011-08-25.
- "A Planet made of Diamond". Max Planck Institut for Radio Astronomy. Retrieved 2011-08-26.