TOI-1439 b
TOI-1439 b is a Neptune-like planet orbiting TOI-1439 in the constellation Draco. It lies about 751 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is TOI-1439 b?
TOI-1439 b has a radius of 4.24 times that of Earth. Its mass is 38.5 times that of Earth, giving it a density of 2.76 g/cm³ — between that of rocky and gaseous planets.
Is TOI-1439 b in the Habitable Zone?
TOI-1439 b orbits inside the inner edge of the habitable zone of TOI-1439. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1439: 1.242–2.921 AU (conservative: 1.573–2.770 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-1439 b
The equilibrium temperature of TOI-1439 b is about 748 K (475 °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-1439 b — one full orbit around TOI-1439 — lasts 27.6 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.192 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.16).
How Was TOI-1439 b Discovered?
TOI-1439 b was discovered in 2024 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-1439 b?
TOI-1439 b is 751.2 light-years (230.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1275. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 13,221,120 years to make the journey.
The Host Star: TOI-1439
TOI-1439
- Surface temperature
- 5,841 K (Sun: 5,772 K)
- Mass
- 1.23 M☉
- Radius
- 1.62 R☉
- Luminosity
- 2.7600 L☉
- Age
- 4.6 billion years (Sun: 4.6)
Planetary System
TOI-1439 b is the only planet known to orbit TOI-1439 so far.
TOI-1439 b — Complete Data
| Radius | 4.243 Earth radii (0.379 Jupiter radii) |
|---|---|
| Mass | 38.50 Earth masses (0.121 Jupiter masses) |
| Density | 2.76 g/cm³ (Earth: 5.51) |
| Orbital period | 27.64 days |
| Orbital distance | 0.192 AU |
| Eccentricity | 0.157 |
| Equilibrium temperature | 748 K (475 °C) |
| Distance from Earth | 751.2 light-years (230.3 parsecs) |
| Constellation | Draco |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2024-07-23. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1439 b
Is TOI-1439 b habitable?
No — TOI-1439 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1439 b?
TOI-1439 b is about 751 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 13,221,120 years to get there.
How big is TOI-1439 b compared to Earth?
TOI-1439 b has 4.24 times the radius of Earth and about 38.5 times its mass.
How long is a year on TOI-1439 b?
One orbit around TOI-1439 takes 27.6 Earth days — short enough that 13 of its years would fit into one Earth year.
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