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Rare exoplanet 37 EP

HD 143105 b

RA 238.4024° · Dec 68.7200° · exoplanet

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Score breakdown

· 5 badges
37 pts · Rare
Rare 50 pts → Epic
  • Lava world +14
  • Tidally locked +10
  • Confirmed exoplanet +5
  • Gas giant +4
  • Blasted by starlight +4
Total score 37

13 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Lava world · +14
  • Tidally locked · +10
  • Blasted by starlight · +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 6.8 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • Best time of year. It stands highest in the middle of the night around May — that's when to go looking.

Properties

density gcc
0.822
diameter km
174759.94
discovery facility
Haute-Provence Observatory
discovery method
Radial Velocity
discovery year
2016
dist ly
152.5722
eccentricity
0.07
eq temp k
2028.25
host star teff
6380
insolation
2502.0025
mag
6.7701
mass earth
384.5743
name
HD 143105 b
orbital period days
2.1974
radius earth
13.7
semi major au
0.0379
spect
F5
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HD 143105 b

HD 143105 b is a rare exoplanet. It lies about 152.6 light-years from Earth, shines at apparent magnitude 6.77, has spectral type F5 and has an equilibrium temperature near 2,028 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 6.77, it is an easy target for binoculars.

Like any astronomical target, HD 143105 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 143105 b is a rare exoplanet

HD 143105 b scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Lava world, Tidally locked and Blasted by starlight — 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.