5_Cancri
5 Cancri
Star in the constellation Cancer
5 Cancri is a single[9] star in the zodiac constellation of Cancer, located around 520 light years away from the Sun. It is just visible to the naked eye under good seeing conditions as a dim, blue-white hued star with an apparent visual magnitude of 5.99.[2] This object is moving closer to the Sun with a heliocentric radial velocity of −10 km/s.[5]
At one point this was thought to be a spectroscopic binary system. It is a Be star with a weak circumstellar disk of gas that has around three times the radius of the host star.[10] The stellar classification of 5 Cancri is B9.5 Vn,[4] matching a B-type main-sequence star with "nebulous" lines due to rapid rotation. It is 36[4] million years old with a high projected rotational velocity of 188 km/s.[3] The star has 2.9[3] times the mass of the Sun and about 3.1[7] times the Sun's radius. It is radiating 121[3] times the Sun's luminosity from its photosphere at an effective temperature of 9,727 K.[3]