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Rare exoplanet 34 EP

TOI-5817 b

RA 322.3778° · Dec 21.4745° · exoplanet

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Score breakdown

· 5 badges
34 pts · Rare
Rare 50 pts → Epic
  • Two suns in its sky +12
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Sub-Neptune +5
  • Found by TESS +4
Total score 34

16 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Sub-Neptune · +5
  • Found by TESS · +4
  • Orbits a Sun-like star · +8
  • Two suns in its sky · +12

Trivia

What it actually is

  • Hugging its star. It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.
  • What it is made of. Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 8.6 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around August — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 4.6 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
1.93
diameter km
39289.096
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2025
dist ly
263.3847
eccentricity
0.2
eq temp k
950
host star teff
5770
inclination
88.72
insolation
126.8632
mag
8.64
mass earth
10.3
multi star system
yes
name
TOI-5817 b
orbital period days
15.6103
radius earth
3.08
semi major au
0.1223
spect
G2 IV-V
sys num planets
1
sys num stars
2

About TOI-5817 b

TOI-5817 b is a rare exoplanet. It lies about 263.4 light-years from Earth, shines at apparent magnitude 8.64, has spectral type G2 IV-V and has an equilibrium temperature near 950 K.

It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.

How to see it

At apparent magnitude 8.64, it is an easy target for binoculars.

Like any astronomical target, TOI-5817 b is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.

Why TOI-5817 b is a rare exoplanet

TOI-5817 b scores 34 points on Spacedle's rarity scale, which places it in the rare tier. Another 16 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Sub-Neptune, Found by TESS, Orbits a Sun-like star and Two suns in its sky — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.