PSR J1748-2446ad

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**PSR J1748-2446ad**
Observation data Epoch J2000
Constellation (pronunciation)	Sagittarius
Right ascension	17h 48m
Declination	−24° 48'
Apparent magnitude (V)	5.28
Characteristics
Spectral type	Pulsar
U-B color index	?
B-V color index	?
Variable type	None
Astrometry
Distance	28.000 Ly
Details
Mass	0.14 (doesn't match article) M_☉
Radius	5–6 (doesn't match article) R_☉
Luminosity	? L_☉
Temperature	? K
Metallicity	?
Rotation	0.00139595482(6) s
Age	? years
Database references
SIMBAD	data

In astronomy, and in particular the study of pulsars, PSR J1748-2446ad is the fastest known spinning pulsar, at 716 Hz, the period being 0.00139595482(6) seconds. The previous record was held by PSR B1937+21, discovered in 1982, spinning at 642 Hz.

This pulsar was discovered by Jason W. T. Hessels of McGill University on November 10, 2004 and confirmed its existence on January 8, 2005.

Scientists' calculation assume 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 28,000 light-years from Earth in the constellation Sagittarius. It is part of a binary system and undergoes regular eclipses with an eclipse fraction of about 40%. Its orbit is highly circular with a 26 hour period and a radius of 4–5 earth radii. 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.