SkyTracko

TOI-715 b

Orbits TOI-715 · 138 light-years from Earth

Super-EarthTransit2023ESI 83 · Very Earth-like
Earth1.55 R⊕
Radius
1.55×
Earth
Mass
3.0×
Earth
Year
19d
Temp
234 K
-39°C
Gravity
1.3×
Earth
Distance
138
ly

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

Radius
1.55 R⊕
1.00 R⊕
Mass
3.02 M⊕
1.00 M⊕
Surface gravity
1.26g
1.00g
Year length
19.29 days
365.25 days
Eq. temperature
234 K (-39°C)
255 K (−18°C)
Orbital eccentricity
0.0167
Semi-major axis
0.083 AU
1.000 AU

Temperature in context

Liquid N₂Mars avgEarth eq.Earth sfc.Boiling H₂OVenus

Host star — TOI-715

Spectral type
M4

Red dwarf — the most common type of star. Cool and small.

Temperature
3,075 K

Very cool — a faint red dwarf.

Radius
0.24 R☉
Mass
0.23 M☉
Luminosity
0.005 L☉
Distance
42.4 pc (138 ly)

Discovery & orbit

Method
Transit

Detected by measuring the tiny dip in starlight as the planet crosses in front of its star.

Year
2023
Facility
Transiting Exoplanet Survey Satellite (TESS)
Semi-major axis
0.0830 AU
Period
19.29 days
Eccentricity
Density
4.46 g/cm³

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

83/100
0 — 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.