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Epic exoplanet 64 EP

HD 217786 c

RA 345.7838° · Dec -0.4304° · exoplanet

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Score breakdown

· 8 badges
64 pts · Epic
Epic 78 pts → Anomaly
  • Lava world +14
  • Two suns in its sky +12
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Sub-Neptune +5
  • Blasted by starlight +4
Total score 64

14 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Sub-Neptune · +5
  • Lava world · +14
  • Tidally locked · +10
  • Multi-planet system · +6
  • Blasted by starlight · +4
  • Orbits a Sun-like star · +8
  • Two suns in its sky · +12

Trivia

What makes it special

  • Lava world. Its surface is almost certainly an ocean of molten rock, kept liquid by the star it hugs.

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 7.8 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around September — that's when to go looking.

Properties

density gcc
2.26
diameter km
33293.682
discovery facility
Multiple Observatories
discovery method
Radial Velocity
discovery year
2022
dist ly
180.9667
eccentricity
0.399
eq temp k
1663.13
host star teff
5966
insolation
1308.8643
mag
7.78
mass earth
7.3101
multi star system
yes
name
HD 217786 c
orbital period days
2.5222
radius earth
2.61
semi major au
0.038
spect
F8 V
sys num planets
2
sys num stars
2
tidally locked
yes
tidally locked inferred
yes

About HD 217786 c

HD 217786 c is an epic exoplanet. It lies about 181 light-years from Earth, shines at apparent magnitude 7.78, has spectral type F8 V and has an equilibrium temperature near 1,663 K.

Its surface is almost certainly an ocean of molten rock, kept liquid by the star it hugs.

How to see it

At apparent magnitude 7.78, it is an easy target for binoculars.

Like any astronomical target, HD 217786 c 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 HD 217786 c is an epic exoplanet

HD 217786 c scores 64 points on Spacedle's rarity scale, which places it in the epic tier. Another 14 points would lift it into a rarer tier.

That score comes from 8 science badges — Confirmed exoplanet, Sub-Neptune, Lava world, Tidally locked, Multi-planet system, Blasted by starlight, 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.