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Uncommon exoplanet 23 EP

HD 109271 c

RA 188.3974° · Dec -11.6215° · exoplanet

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Score breakdown

· 4 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Orbits a Sun-like star +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Neptune-like +4
Total score 23

11 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Neptune-like · +4
  • Multi-planet system · +6
  • Orbits a Sun-like star · +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 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 8 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 March — that's when to go looking.

Properties

density gcc
0.907
diameter km
67225.174
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2013
dist ly
182.2286
eccentricity
0.15
eq temp k
716.68
host star teff
5783
insolation
52.058
mag
8.04
mass earth
24.154
name
HD 109271 c
orbital period days
30.93
radius earth
5.27
semi major au
0.196
spect
G5 V
sys num planets
2
sys num stars
1

Nearby objects

About HD 109271 c

HD 109271 c is an uncommon exoplanet. It lies about 182.2 light-years from Earth, shines at apparent magnitude 8.04, has spectral type G5 V and has an equilibrium temperature near 717 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 8.04, it is an easy target for binoculars.

Like any astronomical target, HD 109271 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 109271 c is an uncommon exoplanet

HD 109271 c scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Neptune-like, Multi-planet system 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.