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Uncommon exoplanet 27 EP

HD 221416 b

RA 353.0332° · Dec -21.8012° · exoplanet

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Score breakdown

· 4 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Lava world +14
  • Confirmed exoplanet +5
  • Gas giant +4
  • Found by TESS +4
Total score 27

7 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Lava world · +14
  • Found by TESS · +4

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 8.2 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • 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 September — that's when to go looking.

Properties

density gcc
0.431
diameter km
116974.354
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2019
dist ly
311.6365
eccentricity
0.115
eq temp k
1314.67
host star teff
5080
inclination
85.75
insolation
495.9065
mag
8.15
mass earth
60.5
name
HD 221416 b
orbital period days
14.2767
radius earth
9.17
semi major au
0.1228
spect
K0 IV/V
sys num planets
1
sys num stars
1

About HD 221416 b

HD 221416 b is an uncommon exoplanet. It lies about 311.6 light-years from Earth, shines at apparent magnitude 8.15, has spectral type K0 IV/V and has an equilibrium temperature near 1,315 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 8.15, it is an easy target for binoculars.

Like any astronomical target, HD 221416 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 221416 b is an uncommon exoplanet

HD 221416 b scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Lava world and Found by TESS — 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.