Kepler-1998 b
Kepler-1998 b is a terrestrial planet orbiting Kepler-1998 in the constellation Lyra. It lies about 1,112 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is Kepler-1998 b?
Kepler-1998 b has a radius of 0.60 times that of Earth.
Is Kepler-1998 b in the Habitable Zone?
Kepler-1998 b orbits inside the inner edge of the habitable zone of Kepler-1998. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Kepler-1998: 0.664–1.570 AU (conservative: 0.841–1.489 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-1998 b
The equilibrium temperature of Kepler-1998 b is about 1,187 K (914 °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 468 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-1998 b — one full orbit around Kepler-1998 — lasts 3.03 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.041 AU — closer to its star than Mercury is to the Sun.
How Was Kepler-1998 b Discovered?
Kepler-1998 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-1998 b?
Kepler-1998 b is 1,112.1 light-years (341.0 parsecs) from Earth. Light arriving here tonight left the planet about 1,112 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 19,572,960 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-1998 b scores 0.27, ranking #2,468 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-1998
Kepler-1998
- Surface temperature
- 5,640 K (Sun: 5,772 K)
- Mass
- 0.96 M☉
- Radius
- 0.92 R☉
Planetary System
Kepler-1998 b is the only planet known to orbit Kepler-1998 so far.
Kepler-1998 b — Complete Data
| Radius | 0.600 Earth radii (0.054 Jupiter radii) |
|---|---|
| Orbital period | 3.03 days |
| Orbital distance | 0.041 AU |
| Equilibrium temperature | 1,187 K (914 °C) |
| Stellar irradiation | 468.31× Earth |
| Earth Similarity Index | 0.27 |
| Distance from Earth | 1,112.1 light-years (341.0 parsecs) |
| Constellation | Lyra |
| 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-1998 b
Is Kepler-1998 b habitable?
No — Kepler-1998 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Kepler-1998 b?
Kepler-1998 b is about 1,112 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 19,572,960 years to get there.
How big is Kepler-1998 b compared to Earth?
Kepler-1998 b has 0.60 times the radius of Earth.
How long is a year on Kepler-1998 b?
One orbit around Kepler-1998 takes 3.0 Earth days — short enough that 120 of its years would fit into one Earth year.
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