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Common exoplanet 17 EP

HD 199509 b

RA 317.3446° · Dec -82.0275° · 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

  • 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. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 7 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around August — that's when to go looking.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 1.4 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
0.579
diameter km
94778.566
discovery facility
Multiple Observatories
discovery method
Radial Velocity
discovery year
2022
dist ly
79.2742
eccentricity
0.373
eq temp k
410.73
host star teff
5796.02
insolation
4.5393
mag
6.98
mass earth
43.2247
name
HD 199509 b
orbital period days
99.6217
radius earth
7.43
semi major au
0.426
spect
G3V
sys num planets
1
sys num stars
1

Nearby objects

About HD 199509 b

HD 199509 b is a common exoplanet. It lies about 79.3 light-years from Earth, shines at apparent magnitude 6.98, has spectral type G3V and has an equilibrium temperature near 411 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 6.98, it is an easy target for binoculars.

Like any astronomical target, HD 199509 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 199509 b is a common exoplanet

HD 199509 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.