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Trash exoplanet 9 EP

HD 205739 b

RA 324.5351° · Dec -31.7378° · exoplanet

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Score breakdown

· 2 badges
9 pts · Trash
Trash 15 pts → Common
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 9

6 more points to reach Common.

Badges

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

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. 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 8.6 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 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. ≈ 5.3 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
0.951
diameter km
173484.32
discovery facility
Las Campanas Observatory
discovery method
Radial Velocity
discovery year
2008
dist ly
301.7227
eccentricity
0.27
eq temp k
362.84
host star teff
6176
insolation
2.8535
mag
8.56
mass earth
435.41
name
HD 205739 b
orbital period days
279.8
radius earth
13.6
semi major au
0.896
spect
F7 V
sys num planets
1
sys num stars
1

Nearby objects

About HD 205739 b

HD 205739 b is a trash exoplanet. It lies about 301.7 light-years from Earth, shines at apparent magnitude 8.56, has spectral type F7 V and has an equilibrium temperature near 363 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 8.56, it is an easy target for binoculars.

Like any astronomical target, HD 205739 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 205739 b is a trash exoplanet

HD 205739 b scores 9 points on Spacedle's rarity scale, which places it in the trash tier. Another 6 points would lift it into a rarer tier.

That score comes from 2 science badges — Confirmed exoplanet and Gas giant — 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.