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Rare exoplanet 42 EP

TOI-421 b

RA 81.8533° · Dec -14.2767° · exoplanet

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Score breakdown

· 6 badges
42 pts · Rare
Rare 50 pts → Epic
  • Two suns in its sky +12
  • Tidally locked +10
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Sub-Neptune +5
  • Found by TESS +4
Total score 42

8 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Sub-Neptune · +5
  • Tidally locked · +10
  • Multi-planet system · +6
  • Found by TESS · +4
  • 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.
  • Crowded system. One of at least 2 planets orbiting its star.

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 9.9 you'll want a small backyard telescope.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around December — that's when to go looking.

Could we get there?

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

Properties

density gcc
2.04
diameter km
33676.368
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2020
dist ly
243.9546
eccentricity
0.13
eq temp k
922
host star teff
5291
inclination
85.68
insolation
154.57
mag
9.931
mass earth
6.7
multi star system
yes
name
TOI-421 b
orbital period days
5.1976
radius earth
2.64
semi major au
0.0554
spect
G9 V
sys num planets
2
sys num stars
2
tidally locked
yes
tidally locked inferred
yes

About TOI-421 b

TOI-421 b is a rare exoplanet. It lies about 244 light-years from Earth, shines at apparent magnitude 9.93, has spectral type G9 V and has an equilibrium temperature near 922 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 9.93, a small backyard telescope will bring it into view.

Like any astronomical target, TOI-421 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-421 b is a rare exoplanet

TOI-421 b scores 42 points on Spacedle's rarity scale, which places it in the rare tier. Another 8 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Sub-Neptune, Tidally locked, Multi-planet system, Found by TESS 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.