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Common exoplanet 17 EP

HD 109246 b

RA 188.0272° · Dec 74.4893° · exoplanet

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Score breakdown

· 3 badges
17 pts · Common
Common 22 pts → Uncommon
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 17

5 more points to reach Uncommon.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • 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.

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 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • Best time of year. It stands highest in the middle of the night around March — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.559
diameter km
177311.18
discovery facility
Haute-Provence Observatory
discovery method
Radial Velocity
discovery year
2010
dist ly
221.2476
eccentricity
0.12
eq temp k
507.43
host star teff
5844
insolation
11.568
mag
8.751
mass earth
273.3338
name
HD 109246 b
orbital period days
68.27
radius earth
13.9
semi major au
0.33
spect
G0 V
sys num planets
1
sys num stars
1

Nearby objects

About HD 109246 b

HD 109246 b is a common exoplanet. It lies about 221.2 light-years from Earth, shines at apparent magnitude 8.75, has spectral type G0 V and has an equilibrium temperature near 507 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 8.75, it is an easy target for binoculars.

Like any astronomical target, HD 109246 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 HD 109246 b is a common exoplanet

HD 109246 b scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Gas giant 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.