K2-419 A b
K2-419 A b is a cold gas giant orbiting K2-419 A in the constellation Cancer. It lies about 876 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is K2-419 A b?
K2-419 A b has a radius of 10.55 times that of Earth, or 0.94 times the radius of Jupiter. Its mass is 196 times that of Earth, giving it a density of 0.92 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is K2-419 A b in the Habitable Zone?
K2-419 A b orbits inside the inner edge of the habitable zone of K2-419 A. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of K2-419 A: 0.188–0.482 AU (conservative: 0.238–0.457 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-419 A b
The equilibrium temperature of K2-419 A b is about 377 K (104 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 3.30 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on K2-419 A b — one full orbit around K2-419 A — lasts 20.4 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.121 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.042).
How Was K2-419 A b Discovered?
K2-419 A b was discovered in 2024 using the transit method, with observations from K2.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is K2-419 A b?
K2-419 A b is 876.3 light-years (268.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1150. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 15,422,880 years to make the journey.
The Host Star: K2-419 A
K2-419 A b belongs to a system of 2 stars; it orbits K2-419 A.
K2-419 A
- Surface temperature
- 3,711 K (Sun: 5,772 K)
- Mass
- 0.56 M☉
- Radius
- 0.54 R☉
- Luminosity
- 0.0529 L☉
- Age
- 7.4 billion years (Sun: 4.6)
Planetary System
K2-419 A b is the only planet known to orbit K2-419 A so far.
K2-419 A b — Complete Data
| Radius | 10.550 Earth radii (0.941 Jupiter radii) |
|---|---|
| Mass | 196.00 Earth masses (0.617 Jupiter masses) |
| Density | 0.92 g/cm³ (Earth: 5.51) |
| Orbital period | 20.36 days |
| Orbital distance | 0.121 AU |
| Eccentricity | 0.042 |
| Equilibrium temperature | 377 K (104 °C) |
| Stellar irradiation | 3.30× Earth |
| Distance from Earth | 876.3 light-years (268.7 parsecs) |
| Constellation | Cancer |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2024-09-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-419 A b
Is K2-419 A b habitable?
No — K2-419 A b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is K2-419 A b?
K2-419 A b is about 876 light-years from Earth in the constellation Cancer. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 15,422,880 years to get there.
How big is K2-419 A b compared to Earth?
K2-419 A b has 10.55 times the radius of Earth and about 196 times its mass.
How long is a year on K2-419 A b?
One orbit around K2-419 A takes 20.4 Earth days — short enough that 18 of its years would fit into one Earth year.
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