Beta Cancri b

Beta Cancri b is a gas giant exoplanet that orbits the K-type giant Beta Cancri. Its mass is 7.8 Jupiter masses, it takes 1.7 years to complete one orbit of its star, and is 1.7 astronomical units from its star, on a nearly circular orbit.^[1][2]

Beta Cancri b

Discovery[1]
Discovered by	B-C Lee et al.
Discovery date	2014
Detection method	Doppler spectroscopy (Radial velocity)
Orbital characteristics[1]
Semi-major axis	1.7±0.1 AU
Eccentricity	0.08±0.02
Orbital period (sidereal)	605.2±4.0 days 1.66 years
Star	Beta Cancri
Physical characteristics[1]
Mean radius	1.12 RJ (estimate)[2]
Mass	≥7.8±0.8 MJ

Discovery

How the radial velocity method works

First evidence for a planet around Beta Cancri was presented in 2008, when variations of the host star's radial velocity with a period of 673 days, but at that time an explanation to the radial velocity variations (such as a planet) wasn't presented. In 2014, Lee et al. found further evidence for the planet's existence, finding a different period of 605.2 days. After ruling out alternative explanations for the radial velocity variations, such as stellar variability, its existence could be confirmed.^[1]

Beta Cancri b was discovered with doppler spectroscopy,^[3] also known as the radial velocity method, which consists on observing small variations in the star's spectrum, which are radial velocity variations and happen because the planet is able to gravitationally pull its host star.^[4]

Host star

Main article: Beta Cancri

Beta Cancri (Altarf), the brightest star in Cancer, is one of the largest stars known to host exoplanets.^[5] It is a K-type giant with 70% more mass than the Sun^[1] but a diameter 50 times larger. It cooled to an effective temperature of 4,100 K, which is 1,700 degrees cooler than the Sun, but is 700 times more luminous than the Sun.^[6] It can be seen close to Procyon, which outshine it.^[7]

See also

• Hamal, Beta Ursae Minoris, Mu Leonis and Gamma¹ Leonis, other giant stars with exoplanets