PSR B1620-26

PSR B1620-26 is a binary star located at the distance of 12,400 light-years, It is located in the Globular cluster Messier 4. It is located in the constellation Scorpius. 

PSR B1620-26 b is a binary star system of two stars, a white dwarf and a pulsar. It has a confirmed exoplanet which is one of the oldest exoplanets discovered.

 System 
Viewed as a binary star system, PSR B1620-26 is very far away, being 3,800 parsecs (12,400 ˞˞˞˞˞˞˞˞˞˞light-years) outside the core of Messier 4. It consists if two stars, PSR B1620-26 A is a pulsar and PSR B1620-26 B is a white dwarf (which form a binary star system together) and a exoplanet PSR B1620-26 b which according to astronomers is the oldest planet in the universe.

White Dwarf
PSR B1620-26 B is 0.34 solar masses and orbits the pulsar every 191 days.

 Planetary system 
PSR B1620-26 b was discovered in the early 1990s. The planet was announced by Stephen Thorsett and his collaborators in 1993

+The PSR B1620-26 planetary systemCompanion
(in order from star)MassSemimajor axis
(AU)Orbital period
(days)EccentricityInclinationRadiusb2.5 ± 1 MJ23~36,500low55−8+14°—

Category:Binary stars