Kepler-1990 b
Kepler-1990 b is a sub-Neptune orbiting Kepler-1990 in the constellation Cygnus. It lies about 1,281 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is Kepler-1990 b?
Kepler-1990 b has a radius of 3.27 times that of Earth.
Is Kepler-1990 b in the Habitable Zone?
Kepler-1990 b orbits inside the inner edge of the habitable zone of Kepler-1990. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-1990: 0.798–1.880 AU (conservative: 1.010–1.783 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-1990 b
The equilibrium temperature of Kepler-1990 b is about 1,554 K (1,281 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 1,373 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-1990 b — one full orbit around Kepler-1990 — lasts just 41.6 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.029 AU — closer to its star than Mercury is to the Sun.
How Was Kepler-1990 b Discovered?
Kepler-1990 b was discovered in 2023 using the transit method, with observations from Kepler.
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 Kepler-1990 b?
Kepler-1990 b is 1,280.9 light-years (392.7 parsecs) from Earth. Light arriving here tonight left the planet about 1,281 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 22,543,840 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. Kepler-1990 b scores 0.20, ranking #3,879 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-1990
Kepler-1990
- Surface temperature
- 5,751 K (Sun: 5,772 K)
- Mass
- 1.03 M☉
- Radius
- 1.07 R☉
The Kepler-1990 Planetary System
Kepler-1990 b is one of 2 known planets in the Kepler-1990 system. Its siblings:
- Kepler-1990 c (Terrestrial)
Kepler-1990 b — Complete Data
| Radius | 3.270 Earth radii (0.292 Jupiter radii) |
|---|---|
| Orbital period | 1.74 days |
| Orbital distance | 0.029 AU |
| Equilibrium temperature | 1,554 K (1,281 °C) |
| Stellar irradiation | 1,372.87× Earth |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 1,280.9 light-years (392.7 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2017-05-08. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-1990 b
Is Kepler-1990 b habitable?
No — Kepler-1990 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-1990 b?
Kepler-1990 b is about 1,281 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 22,543,840 years to get there.
How big is Kepler-1990 b compared to Earth?
Kepler-1990 b has 3.27 times the radius of Earth.
How long is a year on Kepler-1990 b?
One orbit around Kepler-1990 takes 1.7 Earth days — short enough that 211 of its years would fit into one Earth year.
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