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TOI-561 e

Super Earth Sextans

The parameters of this planet are disputed or ambiguous in the scientific literature.

TOI-561 e is a super-Earth orbiting TOI-561 in the constellation Sextans. It lies about 280 light-years from Earth and was discovered in 2020 using the transit method.

2.52×Earth radius
12.4×Earth mass
77 dOrbital period
416 KEquilibrium temp.
0.44Earth similarity
280 lyDistance
2020Discovered

How Big Is TOI-561 e?

Earth1.00 R⊕TOI-561 e2.52 R⊕
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TOI-561 e has a radius of 2.52 times that of Earth. Its mass is 12.4 times that of Earth, giving it a density of 4.30 g/cm³ — between that of rocky and gaseous planets.

Is TOI-561 e in the Habitable Zone?

The position of TOI-561 e relative to the habitable zone of TOI-561 cannot be precisely determined from the available orbital data.

Temperature on TOI-561 e

The equilibrium temperature of TOI-561 e is about 416 K (143 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 4.89 times the stellar energy that Earth gets from the Sun.

Orbit and Year Length

A year on TOI-561 e — one full orbit around TOI-561 — lasts 77.1 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.330 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.07).

How Was TOI-561 e Discovered?

TOI-561 e 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-561 e?

TOI-561 e is 279.8 light-years (85.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1747. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,924,480 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-561 e scores 0.44, ranking #368 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.

The Host Star: TOI-561

TOI-561

Mass
0.81 M☉
Radius
0.84 R☉

The TOI-561 Planetary System

TOI-561 e is one of 4 known planets in the TOI-561 system. Its siblings:

TOI-561 e — Complete Data

Radius2.517 Earth radii (0.225 Jupiter radii)
Mass12.40 Earth masses (0.039 Jupiter masses)
Density4.30 g/cm³ (Earth: 5.51)
Orbital period77.14 days
Orbital distance0.330 AU
Eccentricity0.074
Equilibrium temperature416 K (143 °C)
Stellar irradiation4.89× Earth
Earth Similarity Index0.44
Distance from Earth279.8 light-years (85.8 parsecs)
ConstellationSextans
Discovery methodTransit
Discovery facilityTransiting Exoplanet Survey Satellite (TESS)
Discovery year2020

Data: NASA Exoplanet Archive, last updated 2025-02-24. Earth Similarity Index: PHL @ UPR Arecibo.

Frequently Asked Questions About TOI-561 e

Is TOI-561 e habitable?

TOI-561 e is not known to orbit within the habitable zone of TOI-561, and as a super-Earth it is an unlikely candidate for life as we know it.

How far away is TOI-561 e?

TOI-561 e is about 280 light-years from Earth in the constellation Sextans. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,924,480 years to get there.

How big is TOI-561 e compared to Earth?

TOI-561 e has 2.52 times the radius of Earth and about 12.4 times its mass.

How long is a year on TOI-561 e?

One orbit around TOI-561 takes 77.1 Earth days.

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