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Epic exoplanet 51 EP

NGTS-17 b

RA 72.9006° · Dec -34.2262° · exoplanet

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Score breakdown

· 7 badges
51 pts · Epic
Epic 78 pts → Anomaly
  • Lava world +14
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Distant (over 1,000 light-years) +6
  • Confirmed exoplanet +5
  • Gas giant +4
  • Blasted by starlight +4
Total score 51

27 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Distant (over 1,000 light-years) · +6
  • Gas giant · +4
  • Lava world · +14
  • Tidally locked · +10
  • Blasted by starlight · +4
  • Orbits a Sun-like star · +8

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 14.4 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • 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 December — that's when to go looking.

Properties

density gcc
0.5
diameter km
177300.1595
discovery facility
Next-Generation Transit Survey (NGTS)
discovery method
Transit
discovery year
2021
dist ly
3392.9356
eccentricity
0
eq temp k
1457
host star teff
5650
insolation
1160
mag
14.412
mass earth
242.8209
name
NGTS-17 b
orbital period days
3.2425
radius earth
13.8991
semi major au
0.0391
spect
G4 V
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About NGTS-17 b

NGTS-17 b is an epic exoplanet. It lies about 3,392.9 light-years from Earth, shines at apparent magnitude 14.41, has spectral type G4 V and has an equilibrium temperature near 1,457 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 14.41, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, NGTS-17 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 NGTS-17 b is an epic exoplanet

NGTS-17 b scores 51 points on Spacedle's rarity scale, which places it in the epic tier. Another 27 points would lift it into a rarer tier.

That score comes from 7 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant, Lava world, Tidally locked, Blasted by starlight and Orbits a Sun-like star — 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.