[12] Based on its kinematic, rotational and lithium abundance properties, it is part of the Ursa Major Moving Group.

[4] HD 63433 is a G-type main sequence star with a radius of 0.912 R☉, a mass of 0.99 M☉, an effective temperature of 5640 K and a spectral type G5V.

[11] (light-years) HD 63433 belongs to the class of BY Draconis variables,[5][6] stars have variations in their luminosity due to their rotation together with sunspots and other chromospheric activities.

These values calculate an upper density limit of 13 g/cm3,[23] 2 times greater than that of Earth,[f] and similar to that of the chemical element Mercury.

HD 63433 b orbits its parent star at a distance of 0.0719 astronomical units (10,760,000 km) – about 5 times closer than Mercury is to the Sun – and completes one revolution every 7 days and 3 hours.

[28] However, if HD 63433 b were a rocky core, it would need to be unusually massive and, therefore, a water-rich composition in addition to an atmosphere with a high mean molecular weight could explain both the radius and the non-detection of the Ly-α.

[9] It is 2.7 times larger than Earth,[23] but 30% smaller than the Solar System's ice giants, Neptune and Uranus.

Orbiting its star at a distance of 0.145 astronomical units (21,700,000 km) in an orbital period of 20 days,[23] it is the outermost planet in its planetary system, but still close to its star, making it a warm planet, with a planetary equilibrium temperature estimated between 267 and 406 °C.

[23][h] Due to the high radiation received from its star, the atmosphere of HD 63433 c, made up of hydrogen, is slowly being stripped away and escaping from the planet, like a hot air balloon.

[4] The extreme proximity to its star makes it extremely hot, having a daytime temperature estimated at 1,260 °C (2,300 °F),[4][i] hot enough to melt all the minerals present on its surface,[30] as well as being tidally locked, meaning that one half of the planet is always facing towards its star, while the other is always facing away from it.

[33][34] Meanwhile, the nightside of the planet, which never faces its star, may be the opposite, resembling Pluto with glaciers of frozen nitrogen.

[25][36][4] Further investigation allowed researchers to confirm that this signal was from another orbiting exoplanet, now called HD 63433 d.[25] The discovery was announced on January 10, 2024, in The Astronomical Journal.