HD 63935 and Its Two Neptune-Like Planets

HD 63935 is a star located 160 light-years from Earth. It is host to two known planets, both discovered in 2021: HD 63935 b and HD 63935 c.

The host star is estimated to be 6.6 billion years old. Its reported mass is 0.941 solar masses, smaller than the Sun's, and its reported radius is 0.96 solar radii, also smaller than the Sun's. With a reported temperature of 5510 K, the star is cooler than the Sun.

HD 63935 b is a Neptune-like planet found by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it. Its mass is 10.5 Earth masses and its radius is 2.92 Earth radii, both larger than Earth's. It completes an orbit every 9.06 days, and its mean density is 2.33 g/cm³, 0.424 times Earth's.

HD 63935 c is also Neptune-like but was discovered by the radial velocity method, which measures the wobble a planet's gravity induces in its star's motion. Its mass is 11.1 Earth masses and its radius is 3.06 Earth radii, both larger than Earth's. It orbits once every 21.4 days, and its mean density is 2.13 g/cm³, 0.386 times Earth's.

Among the listed planets, HD 63935 b has the shortest year by reported estimates, at 9.06 days, while HD 63935 c has the longest, at 21.4 days. HD 63935 b also has the smallest radius, 2.92 Earth radii, and the smallest reported mass, 10.5 Earth masses. HD 63935 c has the largest radius, 3.06 Earth radii, and the largest reported mass, 11.1 Earth masses.