Exoplanet · gas giant
KELT-21 b
KELT-21 b is a gas giant orbiting the star KELT-21. Its year lasts 3.61 Earth days. It was discovered in 2018 by the Transit method.
| Host star | KELT-21 |
|---|---|
| Distance | 1,536 light-years (470.9 pc) |
| Orbital period | 3.61 days |
| Orbital radius | 0.0522 AU |
| Eccentricity | 0.000 |
| Radius | 17.8 R⊕ · 1.59 R♃ |
| Mass | 1,240 M⊕ · 3.91 M♃ |
| Density | 1.24 g/cm³ |
| Surface gravity | 3.93 × Earth |
| Equilibrium temperature | 2,051 K (1,778 °C) |
| Stellar flux received | 2,950 × Earth |
| Discovery method | Transit |
| Discovery year | 2018 |
| Discovered by | KELT-North |
Habitable zone
Inside the inner edge of the habitable zone: it receives 2,950 times the light the Earth does, too hot to keep liquid water on its surface.
Its star in the sky
In the planet's sky its star is a disc 17° across: 31 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 10.52. Visible from the whole Northern Hemisphere and south to latitude 57° S. North of latitude 57° N it never sets. It stands highest at midnight in July, the best time to observe it.
Light's journey
The light you see tonight set out around the year 490. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 27 million years.
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.