TOI-544 b
TOI-544 b is a mini-Neptune orbiting TOI-544 in the constellation Orion. It lies about 134 light-years from Earth and was discovered in 2022 using the transit method.
How Big Is TOI-544 b?
TOI-544 b has a radius of 2.02 times that of Earth. Its mass is 2.9 times that of Earth, giving it a density of 1.93 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-544 b in the Habitable Zone?
TOI-544 b orbits inside the inner edge of the habitable zone of TOI-544. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-544: 0.262–0.658 AU (conservative: 0.332–0.623 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-544 b
The equilibrium temperature of TOI-544 b is about 999 K (726 °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-544 b — one full orbit around TOI-544 — lasts just 37.2 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.023 AU — closer to its star than Mercury is to the Sun.
How Was TOI-544 b Discovered?
TOI-544 b was discovered in 2022 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-544 b?
TOI-544 b is 134.1 light-years (41.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1892. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,360,160 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. TOI-544 b scores 0.26, ranking #2,883 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-544
TOI-544
- Surface temperature
- 4,169 K (Sun: 5,772 K)
- Mass
- 0.63 M☉
- Radius
- 0.62 R☉
- Age
- 9.0 billion years (Sun: 4.6)
The TOI-544 Planetary System
TOI-544 b is one of 2 known planets in the TOI-544 system. Its siblings:
- TOI-544 c (Neptune-like)
TOI-544 b — Complete Data
| Radius | 2.018 Earth radii (0.180 Jupiter radii) |
|---|---|
| Mass | 2.89 Earth masses (0.009 Jupiter masses) |
| Density | 1.93 g/cm³ (Earth: 5.51) |
| Orbital period | 1.55 days |
| Orbital distance | 0.023 AU |
| Equilibrium temperature | 999 K (726 °C) |
| Earth Similarity Index | 0.26 |
| Distance from Earth | 134.1 light-years (41.1 parsecs) |
| Constellation | Orion |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2023-12-18. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-544 b
Is TOI-544 b habitable?
No — TOI-544 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-544 b?
TOI-544 b is about 134 light-years from Earth in the constellation Orion. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,360,160 years to get there.
How big is TOI-544 b compared to Earth?
TOI-544 b has 2.02 times the radius of Earth and about 2.9 times its mass.
How long is a year on TOI-544 b?
One orbit around TOI-544 takes 1.5 Earth days — short enough that 236 of its years would fit into one Earth year.
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