PSR J1719−1438

The location of PSR J1719-1438 (circled in red)
Observation data EpochMJD 55411.0      EquinoxJ2000
Constellation	Serpens[1]
Right ascension	17h 19m 10.0730(1)s[2]
Declination	−14° 38′ 00.96(2)″[2]
Characteristics
Spectral type	Millisecond pulsar[2]
Astrometry
Distance	~3,900 ly (~1,200[2] pc)
Orbit[2]
Primary	PSR J1719−1438
Companion	PSR J1719−1438 b
Period (P)	2 hours 10 minutes 37.0237 ±0.0002 seconds
Semi-major axis (a)	${\displaystyle a_P\sin i=}$0.001819(1)light seconds
Eccentricity (e)	<0.06
Periastronepoch (T)	MJD 55411.0
Details
Mass	1.44[3] M☉
Radius	19[3] km
Surface gravity (log g)	13.69 cgs
Rotation	5.7901517700238ms[4]
Age	11.4 Gyr
Other designations
PSR J1719−1438
Database references
SIMBAD	data

PSR J1719−1438 is amillisecond pulsar with a spin period of 5.7901ms and is characteristic age of 11.4 billion years old located about 3,900light years (1,200parsecs) from Earth in the direction ofSerpens Cauda,^[2][5] 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 abinary companion.

PSR J1719−1438 was discovered in 2011 by the High Time Resolution Survey, aradio astronomy search for astronomical objects that rapidly vary in radio brightness, such as pulsars.^[2] Timing measurements using theParkes Telescope andLovell Telescope showed that it has a low-mass companion:PSR J1719−1438 b.^[2] The companion has a mass similar to that ofJupiter, 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 (0.89solar radii).^[2] 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–oxygenwhite dwarf.^[2]

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".^[5][6][7]

It has been suggested in 2012 that PSR J1719−1438 b may not be the remnant of a white dwarf, but a lump ofquark matter with a size of just 1 kilometer and the mass of Jupiter,^[8] that would have been born in the collision and merger of two previousquark stars, part of the ejected matter ending orbiting the merger remnant we see as the pulsar PSR J1719−1438.^[9]

• Black widow pulsar – Millisecond pulsar in the constellation SagittaPages displaying short descriptions of redirect targets
• EF Eridani, a star system with a compact star and a degraded planetary-mass former star
• PSR J1544+4937 – Millisecond pulsar in the constellation Boötes

• Astronomical objects discovered in 2011
• Millisecond pulsars
• Planetary systems with one confirmed planet
• Serpens

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• Use dmy dates from September 2014
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