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TOI-1758 b

Sub Neptune Cepheus

TOI-1758 b is a sub-Neptune orbiting TOI-1758 in the constellation Cepheus. It lies about 315 light-years from Earth and was discovered in 2024 using the transit method.

3.62×Earth radius
21 dOrbital period
315 lyDistance
2024Discovered

How Big Is TOI-1758 b?

Earth1.00 R⊕TOI-1758 b3.62 R⊕
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TOI-1758 b has a radius of 3.62 times that of Earth.

Is TOI-1758 b in the Habitable Zone?

TOI-1758 b orbits inside the inner edge of the habitable zone of TOI-1758. So close to its star, surface conditions are far too hot for liquid water.

TOI-1758 b
Too hot Optimistic habitable zone Conservative habitable zone Too cold

Habitable zone of TOI-1758: 0.504–1.209 AU (conservative: 0.638–1.147 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.

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Temperature on TOI-1758 b

TOI-1758 b receives 21.05 times the stellar energy that Earth gets from the Sun.

Orbit and Year Length

A year on TOI-1758 b — one full orbit around TOI-1758 — lasts 20.7 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.141 AU — closer to its star than Mercury is to the Sun.

How Was TOI-1758 b Discovered?

TOI-1758 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-1758 b?

TOI-1758 b is 315.1 light-years (96.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1711. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,545,760 years to make the journey.

The Host Star: TOI-1758

TOI-1758

Surface temperature
5,169 K (Sun: 5,772 K)
Mass
0.88 M☉
Radius
0.81 R☉

Planetary System

TOI-1758 b is the only planet known to orbit TOI-1758 so far.

TOI-1758 b — Complete Data

Radius3.620 Earth radii (0.323 Jupiter radii)
Orbital period20.71 days
Orbital distance0.141 AU
Stellar irradiation21.05× Earth
Distance from Earth315.1 light-years (96.6 parsecs)
ConstellationCepheus
Discovery methodTransit
Discovery facilityTransiting Exoplanet Survey Satellite (TESS)
Discovery year2024

Data: NASA Exoplanet Archive, last updated 2024-12-10. Earth Similarity Index: PHL @ UPR Arecibo.

Frequently Asked Questions About TOI-1758 b

Is TOI-1758 b habitable?

No — TOI-1758 b orbits too close to its star and is too hot for liquid water to exist on its surface.

How far away is TOI-1758 b?

TOI-1758 b is about 315 light-years from Earth in the constellation Cepheus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,545,760 years to get there.

How big is TOI-1758 b compared to Earth?

TOI-1758 b has 3.62 times the radius of Earth.

How long is a year on TOI-1758 b?

One orbit around TOI-1758 takes 20.7 Earth days — short enough that 18 of its years would fit into one Earth year.

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