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Rare exoplanet 49 EP

WASP-15 b

RA 208.9280° · Dec -32.1597° · exoplanet

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Score breakdown

· 6 badges
49 pts · Rare
Rare 50 pts → Epic
  • Lava world +14
  • Puffy low-density world +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
  • Puffy low-density world · +12
  • 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 11 you'll want a small backyard telescope.
  • 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 April — that's when to go looking.

Properties

density gcc
0.263
diameter km
201607.7866
discovery facility
SuperWASP
discovery method
Transit
discovery year
2009
dist ly
920.0567
eccentricity
0
eq temp k
1676
host star teff
6300
inclination
85.96
insolation
1237.7366
mag
10.972
mass earth
171.6282
name
WASP-15 b
orbital period days
3.7521
radius earth
15.8047
semi major au
0.0517
spect
F7
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About WASP-15 b

WASP-15 b is a rare exoplanet. It lies about 920.1 light-years from Earth, shines at apparent magnitude 10.97, has spectral type F7 and has an equilibrium temperature near 1,676 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 10.97, a small backyard telescope will bring it into view.

Like any astronomical target, WASP-15 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 WASP-15 b is a rare exoplanet

WASP-15 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, Puffy low-density world 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.