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Rare exoplanet 44 EP

Kepler-42 b

RA 292.2196° · Dec 44.6174° · exoplanet

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Score breakdown

· 6 badges
44 pts · Rare
Rare 50 pts → Epic
  • Puffy low-density world +12
  • Tidally locked +10
  • Orbits a red dwarf +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Found by Kepler +3
Total score 44

6 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Tidally locked · +10
  • Puffy low-density world · +12
  • Multi-planet system · +6
  • Found by Kepler · +3
  • Orbits a red dwarf · +8

Trivia

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.
  • Crowded system. One of at least 3 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 16.7 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Properties

density gcc
0.15
diameter km
9949.836
discovery facility
Kepler
discovery method
Transit
discovery year
2011
dist ly
130.6565
eccentricity
0.04
eq temp k
519
host star teff
3068
inclination
85.57
insolation
22.388
mag
16.7
mass earth
0.7059
name
Kepler-42 b
orbital period days
1.2138
radius earth
0.78
semi major au
0.0116
spect
M
sys num planets
3
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About Kepler-42 b

Kepler-42 b is a rare exoplanet. It lies about 130.7 light-years from Earth, shines at apparent magnitude 16.7, has spectral type M and has an equilibrium temperature near 519 K.

It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.

How to see it

At apparent magnitude 16.7, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, Kepler-42 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 Kepler-42 b is a rare exoplanet

Kepler-42 b scores 44 points on Spacedle's rarity scale, which places it in the rare tier. Another 6 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Tidally locked, Puffy low-density world, Multi-planet system, Found by Kepler and Orbits a red dwarf — 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.