TOI-5789 c
TOI-5789 c is a puffy low-density planet orbiting the K1 V star TOI-5789 in the constellation Sagitta. It lies about 67 light-years from Earth.
How Big Is TOI-5789 c?
TOI-5789 c has a radius of 2.86 times that of Earth. Its mass is 5.0 times that of Earth, giving it a density of 1.16 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-5789 c in the Habitable Zone?
TOI-5789 c orbits inside the inner edge of the habitable zone of TOI-5789. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-5789: 0.531–1.276 AU (conservative: 0.673–1.210 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-5789 c
The equilibrium temperature of TOI-5789 c is about 718 K (445 °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.
Orbit and Year Length
A year on TOI-5789 c — one full orbit around TOI-5789 — lasts 12.9 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.101 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.07).
How Was TOI-5789 c Discovered?
TOI-5789 c was discovered using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
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 TOI-5789 c?
TOI-5789 c is 66.7 light-years (20.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1960. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,173,920 years to make the journey.
The Host Star: TOI-5789
TOI-5789
- Spectral type
- K1 V
- Surface temperature
- 5,185 K (Sun: 5,772 K)
- Mass
- 0.82 M☉
- Radius
- 0.83 R☉
- Luminosity
- 0.4690 L☉
- Age
- 9.4 billion years (Sun: 4.6)
The TOI-5789 Planetary System
TOI-5789 c is one of 4 known planets in the TOI-5789 system. Its siblings:
- TOI-5789 b (Super Earth)
- TOI-5789 d (Super Earth)
- TOI-5789 e (Neptune-like)
TOI-5789 c — Complete Data
| Radius | 2.860 Earth radii (0.255 Jupiter radii) |
|---|---|
| Mass | 5.00 Earth masses (0.016 Jupiter masses) |
| Density | 1.16 g/cm³ (Earth: 5.51) |
| Orbital period | 12.93 days |
| Orbital distance | 0.101 AU |
| Eccentricity | 0.067 |
| Equilibrium temperature | 718 K (445 °C) |
| Distance from Earth | 66.7 light-years (20.5 parsecs) |
| Constellation | Sagitta |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
Data: NASA Exoplanet Archive, last updated 2026-01-29. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-5789 c
Is TOI-5789 c habitable?
No — TOI-5789 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-5789 c?
TOI-5789 c is about 67 light-years from Earth in the constellation Sagitta. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,173,920 years to get there.
How big is TOI-5789 c compared to Earth?
TOI-5789 c has 2.86 times the radius of Earth and about 5.0 times its mass.
How long is a year on TOI-5789 c?
One orbit around TOI-5789 takes 12.9 Earth days — short enough that 28 of its years would fit into one Earth year.
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