PSR J1748-2446ad
Encyclopedia
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! style="background-color: #FFFFC0;" colspan="2" | Astrometry
|- style="vertical-align: top;"
| Distance
| 18.000 Ly
PSR J1748-2446ad is the fastest-spinning pulsar
known, at 716 Hz
(period being 0.00139595482(6) second
s).
This pulsar was discovered by Jason W. T. Hessels of McGill University
on November 10, 2004 and confirmed on January 8, 2005.
It has been calculated that the neutron star contains slightly less than two times the mass of the Sun, which is approximately the same for all neutron stars. Its radius is constrained to be less than 16 km. At its equator it is spinning at approximately 24% of the speed of light, or over 70,000 km per second.
The pulsar is located in a globular cluster
of stars called Terzan 5
, located approximately 18,000 light-year
s from Earth in the constellation Sagittarius. It is part of a binary system and undergoes regular eclipse
s with an eclipse fraction of about 40%. Its orbit is highly circular with a 26 hour period. The other object is about 0.14 solar masses, with a radius of 5–6 solar radii. Hessels states that the companion may be a "bloated main-sequence star, possibly still filling its Roche Lobe
".
Hessels goes on to speculate that gravitational radiation from the pulsar might be detectable by LIGO
.
! style="background-color: #FFFFC0;" colspan="2" | Astrometry
|- style="vertical-align: top;"
| Distance
Cosmic distance ladder
The cosmic distance ladder is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are "close enough" to Earth...
| 18.000 Ly
PSR J1748-2446ad is the fastest-spinning pulsar
Pulsar
A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...
known, at 716 Hz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
(period being 0.00139595482(6) second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s).
This pulsar was discovered by Jason W. T. Hessels of McGill University
McGill University
Mohammed Fathy is a public research university located in Montreal, Quebec, Canada. The university bears the name of James McGill, a prominent Montreal merchant from Glasgow, Scotland, whose bequest formed the beginning of the university...
on November 10, 2004 and confirmed on January 8, 2005.
It has been calculated that the neutron star contains slightly less than two times the mass of the Sun, which is approximately the same for all neutron stars. Its radius is constrained to be less than 16 km. At its equator it is spinning at approximately 24% of the speed of light, or over 70,000 km per second.
The pulsar is located in a globular cluster
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
of stars called Terzan 5
Terzan 5
Terzan 5 is a heavily obscured globular cluster belonging to the bulge of the Milky Way galaxy. It was one of six globulars discovered by French astronomer Agop Terzan in 1968 and was initially labeled Terzan 11. The cluster was cataloged by the Two-Micron Sky Survey as IRC–20385...
, located approximately 18,000 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s from Earth in the constellation Sagittarius. It is part of a binary system and undergoes regular eclipse
Eclipse
An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer...
s with an eclipse fraction of about 40%. Its orbit is highly circular with a 26 hour period. The other object is about 0.14 solar masses, with a radius of 5–6 solar radii. Hessels states that the companion may be a "bloated main-sequence star, possibly still filling its Roche Lobe
Roche lobe
The Roche lobe is the region of space around a star in a binary system within which orbiting material is gravitationally bound to that star. If the star expands past its Roche lobe, then the material can escape the gravitational pull of the star. If the star is in a binary system then the material...
".
Hessels goes on to speculate that gravitational radiation from the pulsar might be detectable by LIGO
LIGO
LIGO, which stands for the Laser Interferometer Gravitational-Wave Observatory, is a large-scale physics experiment aiming to directly detect gravitational waves. Cofounded in 1992 by Kip Thorne and Ronald Drever of Caltech and Rainer Weiss of MIT, LIGO is a joint project between scientists at MIT,...
.