Host star — TOI-715
- Spectral type
- M4
- Temperature
- 3,075 K
- Radius
- 0.24 R☉
- Mass
- 0.23 M☉
- Luminosity
- 0.005 L☉
- Distance
- 42.4 pc (138 ly)
Red dwarf — the most common type of star. Cool and small.
Very cool — a faint red dwarf.
TOI-715 b
Orbits TOI-715 · 138 light-years from Earth
Super-EarthTransit2023ESI 83 · Very Earth-like
Radius
1.55×
Earth
Mass
3.0×
Earth
Year
19d
Temp
234 K
-39°C
Gravity
1.3×
Earth
Distance
138
ly
Could life exist here?
AI analysisTOI-715 b is a super-Earth roughly 1.55 times Earth's radius and three times Earth's mass, orbiting an M-dwarf star 138 light-years away. Its equilibrium temperature of 234 Kelvin—roughly 39 Kelvin colder than Earth—places it in the habitable zone of its small, cool host star, where liquid water could theoretically persist on the surface. The planet's density of 4.46 grams per cubic centimeter suggests a rocky composition similar to Earth's. However, serious uncertainties remain: we do not know whether TOI-715 b has retained an atmosphere capable of trapping heat, or whether it has a magnetic field to shield against stellar wind erosion. Its 19.3-day orbit around a low-mass star may also increase the likelihood of tidal locking, which could create extreme temperature swings between day and night sides. With a habitability score of 83 out of 100, this world ranks among the most promising exoplanet candidates for habitability, making it a prime target for future atmospheric characterization with next-generation telescopes.
What it would be like
TOI-715 b is a super-Earth — larger than our planet but likely still rocky or ice-rich. Whether it has a thin atmosphere like Mars or a crushing one like Venus remains unknown.
Surface gravity is about 1.3g — noticeably heavier what you're used to on Earth.
At -39°C, this world is cold — similar to Earth's polar regions or the surface of Mars. Water would likely be frozen, but subsurface liquid isn't ruled out.
An orbital period of 19 days makes the year 18.9× shorter than Earth's. You'd celebrate your birthday more often here.
Earth comparison
Logarithmic bars so Jupiter-class planets fit the same scale as Earth-size worlds.
Radius1.55R⊕
1/25×Earth = 125×
Mass3.02M⊕
1/10000×Earth = 110000×
Surface gravity1.26g
1/100×Earth = 1100×
Equilibrium temp234 K(-39°C)
0 KEarth 255 K2500 K
Side-by-side with Earth
Temperature in context
Liquid N₂Mars avgEarth eq.Earth sfc.Boiling H₂OVenus
Discovery & orbit
- Method
- Transit
- Year
- 2023
- Facility
- Transiting Exoplanet Survey Satellite (TESS)
- Semi-major axis
- 0.0830 AU
- Period
- 19.29 days
- Eccentricity
- —
- Density
- 4.46 g/cm³
Detected by measuring the tiny dip in starlight as the planet crosses in front of its star.
Rocky composition likely. Earth is 5.51 g/cm³.
Discovered via · Transit
Tiny dip in starlight as the planet crosses in front of its star
A transit photometer watches a star nonstop and measures its brightness to ~0.01%. When a planet passes between us and the star, the star dims briefly — the deeper the dip, the bigger the planet. This is how Kepler and TESS found most known exoplanets.
- Overall share
- ~75% of all confirmed worlds
- Best for
- Earth-to-Neptune-sized planets on short orbits
Hertzsprung–Russell Diagram
Where this host star sits among … exoplanet host stars. The main sequence band runs diagonally — giants and supergiants sit above, white dwarfs below.
OBAFGKMCurrent star
How far is 138 light-years?
- A light beam leaving Earth right now would arrive in 138 years.
- At Voyager 1's speed (17 km/s), the trip would take approximately 2.4 million years.
- A radio signal sent today would arrive in 138.3 years — and the reply wouldn't come back for twice that.
Earth Similarity Index
83/1000 — Nothing like Earth100 — Identical to Earth
ESI combines radius similarity and equilibrium temperature similarity. Earth = 100. Mars ≈ 73. Venus ≈ 44. This score reflects two physical parameters only — not atmosphere, water, or magnetic field.