PSR J1719-1438
Encyclopedia
PSR J1719-1438 is a millisecond pulsar
with a spin period of 5.7 ms located about 4000 ly from Earth in the direction of Serpens
Cauda, approximately 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.
search for astronomical objects which 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 at about 40% of the diameter. It orbits the pulsar with a period of 2.17 hours 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 is very dense, it may be similar to a very large diamond. In the science press, the object has been called the "Diamond Planet"
.
Millisecond pulsar
A millisecond pulsar is a pulsar with a rotational period in the range of about 1-10 milliseconds. Millisecond pulsars have been detected in the radio, X-ray, and gamma ray portions of the electromagnetic spectrum. The origin of millisecond pulsars is still unknown...
with a spin period of 5.7 ms located about 4000 ly from Earth in the direction of Serpens
Serpens
Serpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....
Cauda, approximately one minute
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....
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
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
companion.
Diamond planet
PSR J1719-1438 was discovered in 2011 by the High Time Resolution Survey, a radio astronomyRadio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
search for astronomical objects which rapidly vary in radio brightness, such as pulsars. Timing measurements using the Parkes Telescope and Lovell Telescope
Lovell Telescope
The Lovell Telescope is a radio telescope at Jodrell Bank Observatory, near Goostrey, Cheshire in the north-west of England. When it was constructed in 1955, the telescope was the largest steerable dish radio telescope in the world at 76.2 m in diameter;it is now the third largest, after the...
showed that it has a low-mass companion: PSR J1719-1438 b. The companion has a mass similar to that of Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, but at about 40% of the diameter. It orbits the pulsar with a period of 2.17 hours 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
White dwarf
A white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
.
Because the companion to PSR J1719-1438 is planet sized, made primarily of carbon (with an unknown amount of oxygen), and is very dense, it may be similar to a very large diamond. In the science press, the object has been called the "Diamond Planet"
Carbon planet
A carbon planet, also referred to as a diamond planet or carbide planet, is a theoretical type of planet proposed by Marc Kuchner that could form if protoplanetary discs are carbon-rich and oxygen-poor. According to planetary science, it would develop differently from Earth, Mars and Venus, planets...
.
See also
- EF EridaniEF EridaniEF Eridani is a variable star of the type known as polars, AM Herculis stars, or magnetic cataclysmic variable stars. Historically it has varied between apparent magnitudes 14.5 and 17.3, although since 1995 it has generally remained at the lower limit...
, a star system with a compact star and a degraded planetary-mass former star