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Epic exoplanet 69 EP

tau Cet h

RA 26.0093° · Dec -15.9338° · exoplanet

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Score breakdown

· 7 badges
69 pts · Epic
Epic 78 pts → Anomaly
  • Earth-sized +16
  • Nearby (<25 ly) +12
  • Its star is visible to the naked eye +12
  • Disputed — it may not be there at all +10
  • Orbits a Sun-like star +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
Total score 69

9 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Nearby (<25 ly) · +12
  • Earth-sized · +16
  • Multi-planet system · +6
  • Its star is visible to the naked eye · +12
  • Orbits a Sun-like star · +8
  • Disputed — it may not be there at all · +10

Trivia

What makes it special

  • Earth-sized. Genuinely comparable to Earth in size. Worlds in this narrow band are the ones every next-generation telescope is being pointed at.

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. Denser than Earth — a solid world of rock and iron, with no meaningful atmosphere to speak of by mass.
  • Crowded system. One of at least 3 planets orbiting its star.

Sense of scale

  • In perspective. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 3.5 you can see it with your own eyes from a dark site.
  • 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 October — that's when to go looking.

Properties

controversial
yes
density gcc
5.97
diameter km
15179.878
discovery facility
Multiple Observatories
discovery method
Radial Velocity
discovery year
2017
dist ly
11.7515
eccentricity
0.23
eq temp k
473.22
host star teff
5310
insolation
8.3829
mag
3.4961
mass earth
1.83
name
tau Cet h
orbital period days
49.41
radius earth
1.19
semi major au
0.243
spect
G8.5V
sys num planets
3
sys num stars
1

About tau Cet h

tau Cet h is an epic exoplanet. It lies about 11.8 light-years from Earth, shines at apparent magnitude 3.5, has spectral type G8.5V and has an equilibrium temperature near 473 K.

Genuinely comparable to Earth in size. Worlds in this narrow band are the ones every next-generation telescope is being pointed at.

How to see it

At apparent magnitude 3.5, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, tau Cet h 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 tau Cet h is an epic exoplanet

tau Cet h scores 69 points on Spacedle's rarity scale, which places it in the epic tier. Another 9 points would lift it into a rarer tier.

That score comes from 7 science badges — Confirmed exoplanet, Nearby (<25 ly), Earth-sized, Multi-planet system, Its star is visible to the naked eye, Orbits a Sun-like star and Disputed — it may not be there at all — 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.