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Rare exoplanet 49 EP

HD 212301 b

RA 336.8804° · Dec -77.7183° · exoplanet

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Score breakdown

· 6 badges
49 pts · Rare
Rare 50 pts → Epic
  • Lava world +14
  • Two suns in its sky +12
  • Tidally locked +10
  • Confirmed exoplanet +5
  • Gas giant +4
  • Blasted by starlight +4
Total score 49

1 more point to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Lava world · +14
  • Tidally locked · +10
  • Blasted by starlight · +4
  • 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.

Hard to believe

  • It would float. It is less dense than water. Drop it in a big enough ocean and the whole world would bob on the surface.

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. Lighter than Neptune — a puffed-up ball of hydrogen and helium with no surface anywhere on it to stand on.

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.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around August — that's when to go looking.

Properties

density gcc
0.311
diameter km
181138.04
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2005
dist ly
176.8757
eccentricity
0
eq temp k
1870.75
host star teff
6239
insolation
1944.4444
mag
7.76
mass earth
162.0933
multi star system
yes
name
HD 212301 b
orbital period days
2.2457
radius earth
14.2
semi major au
0.03
spect
F8 V
sys num planets
1
sys num stars
2
tidally locked
yes
tidally locked inferred
yes

About HD 212301 b

HD 212301 b is a rare exoplanet. It lies about 176.9 light-years from Earth, shines at apparent magnitude 7.76, has spectral type F8 V and has an equilibrium temperature near 1,871 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 7.76, it is an easy target for binoculars.

Like any astronomical target, HD 212301 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 HD 212301 b is a rare exoplanet

HD 212301 b scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Gas giant, Lava world, Tidally locked, Blasted by starlight 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.