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Rare exoplanet 39 EP

HD 184010 d

RA 292.8401° · Dec 26.6173° · exoplanet

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Score breakdown

· 5 badges
39 pts · Rare
Rare 50 pts → Epic
  • Puffy low-density world +12
  • Its star is visible to the naked eye +12
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 39

11 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Puffy low-density world · +12
  • Multi-planet system · +6
  • Its star is visible to the naked eye · +12

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 3 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 5.9 you can see it with your own eyes from a dark site.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.269
diameter km
182413.66
discovery facility
Okayama Astrophysical Observatory
discovery method
Radial Velocity
discovery year
2022
dist ly
198.3006
eccentricity
0
eq temp k
381.37
host star teff
4971
insolation
3.5509
mag
5.8864
mass earth
143.0228
name
HD 184010 d
orbital period days
836.4
radius earth
14.3
semi major au
1.92
spect
K0 III-IV
sys num planets
3
sys num stars
1

About HD 184010 d

HD 184010 d is a rare exoplanet. It lies about 198.3 light-years from Earth, shines at apparent magnitude 5.89, has spectral type K0 III-IV and has an equilibrium temperature near 381 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 5.89, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HD 184010 d 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 184010 d is a rare exoplanet

HD 184010 d scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Puffy low-density world, Multi-planet system and Its star is visible to the naked eye — 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.