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Uncommon exoplanet 27 EP

HD 215497 c

RA 341.6527° · Dec -56.5998° · exoplanet

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Score breakdown

· 4 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Puffy low-density world +12
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 27

7 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Puffy low-density world · +12
  • Multi-planet system · +6

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

  • 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 2 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 9 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.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

density gcc
0.278
diameter km
165830.6
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2009
dist ly
132.2458
eccentricity
0.47
eq temp k
198.6
host star teff
5113
inclination
90
insolation
0.2267
mag
8.96
mass earth
111.2399
name
HD 215497 c
orbital period days
566
radius earth
13
semi major au
1.31
spect
K3 V
sys num planets
2
sys num stars
1

Nearby objects

About HD 215497 c

HD 215497 c is an uncommon exoplanet. It lies about 132.2 light-years from Earth, shines at apparent magnitude 8.96, has spectral type K3 V and has an equilibrium temperature near 199 K.

Lighter than Neptune — a puffed-up ball of hydrogen and helium with no surface anywhere on it to stand on.

How to see it

At apparent magnitude 8.96, it is an easy target for binoculars.

Like any astronomical target, HD 215497 c 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 215497 c is an uncommon exoplanet

HD 215497 c 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, Puffy low-density world and Multi-planet system — 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.