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TOI-700 c

Mini Neptune Dorado

TOI-700 c is a mini-Neptune orbiting the M2.5 V star TOI-700 in the constellation Dorado. It lies about 102 light-years from Earth and was discovered in 2020 using the transit method.

2.60×Earth radius
16 dOrbital period
0.55Earth similarity
102 lyDistance
2020Discovered

How Big Is TOI-700 c?

Earth1.00 R⊕TOI-700 c2.60 R⊕
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TOI-700 c has a radius of 2.60 times that of Earth.

Is TOI-700 c in the Habitable Zone?

TOI-700 c orbits inside the inner edge of the habitable zone of TOI-700. So close to its star, surface conditions are far too hot for liquid water.

TOI-700 c
Too hot Optimistic habitable zone Conservative habitable zone Too cold

Habitable zone of TOI-700: 0.124–0.322 AU (conservative: 0.157–0.305 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.

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Temperature on TOI-700 c

TOI-700 c receives 2.64 times the stellar energy that Earth gets from the Sun.

Orbit and Year Length

A year on TOI-700 c — one full orbit around TOI-700 — lasts 16.1 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.093 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.07).

How Was TOI-700 c Discovered?

TOI-700 c was discovered in 2020 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-700 c?

TOI-700 c is 101.5 light-years (31.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1925. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,786,400 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-700 c scores 0.55, ranking #192 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.

The Host Star: TOI-700

TOI-700

Spectral type
M2.5 V
Surface temperature
3,459 K (Sun: 5,772 K)
Mass
0.42 M☉
Radius
0.42 R☉
Luminosity
0.0229 L☉

The TOI-700 Planetary System

TOI-700 c is one of 4 known planets in the TOI-700 system. Its siblings:

TOI-700 c — Complete Data

Radius2.600 Earth radii (0.232 Jupiter radii)
Orbital period16.05 days
Orbital distance0.093 AU
Eccentricity0.068
Stellar irradiation2.64× Earth
Earth Similarity Index0.55
Distance from Earth101.5 light-years (31.1 parsecs)
ConstellationDorado
Discovery methodTransit
Discovery facilityTransiting Exoplanet Survey Satellite (TESS)
Discovery year2020

Data: NASA Exoplanet Archive, last updated 2023-01-18. Earth Similarity Index: PHL @ UPR Arecibo.

Frequently Asked Questions About TOI-700 c

Is TOI-700 c habitable?

No — TOI-700 c orbits too close to its star and is too hot for liquid water to exist on its surface.

How far away is TOI-700 c?

TOI-700 c is about 102 light-years from Earth in the constellation Dorado. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,786,400 years to get there.

How big is TOI-700 c compared to Earth?

TOI-700 c has 2.60 times the radius of Earth.

How long is a year on TOI-700 c?

One orbit around TOI-700 takes 16.1 Earth days — short enough that 23 of its years would fit into one Earth year.

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