Hamal

Hamal (also known as Alpha Arietis), is the brightest star in the zodiac constellation of Aries.HR 617 , database entry, The Bright Star Catalogue,  5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50.  Accessed on line December 16, 2008.Hamal , Stars, Jim Kaler.  Accessed on line December 16, 2008.

The star has an apparent magnitude of 2.0, it is the 50th brightest star in the night sky. Using the parallax measurements made with the Hipparcos astrometry satellite, Hamal is about 65.8 light years away from the Earth. It is a giant star that may have an planet with a mass greater than Jupiter orbiting around it.
Planetary system
In 2011, Byeong-Cheol Lee and others discovered a likely planet that might be in orbit around the star known as Hamal b (Alpha Arietis b). The planet was detected using the radial velocity method, using measurements that were made between 2003 and 2010 at the Bohyunsan Optical Astronomy Observatory in Korea. The planet has an orbital period of 381 days and an eccentricity of 0.25. The minimum value of this planet's mass is about 1.8 times the mass of Jupiter. The estimated semi-major axis of the orbit of the planet is 1.2 AU, which would give it a periapsis (closest) distance of 0.9 AU and an apoapsis (farthest) distance of 1.5 AU. By comparison, the star has a radius of 0.07 AU or about 10,471,850.9 km.

 References 

Category:Stars