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Rare exoplanet 39 EP

HD 142 A d

RA 1.5837° · Dec -49.0754° · exoplanet

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Score breakdown

· 5 badges
39 pts · Rare
Rare 50 pts → Epic
  • Its star is visible to the naked eye +12
  • Two suns in its sky +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
  • Multi-planet system · +6
  • Its star is visible to the naked eye · +12
  • Two suns in its sky · +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. 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 5.7 you can see it with your own eyes from a dark site.
  • 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 September — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.351
diameter km
139042.58
discovery facility
Multiple Observatories
discovery method
Radial Velocity
discovery year
2022
dist ly
85.4049
eccentricity
0.13
eq temp k
530.32
host star teff
6245
insolation
13.2625
mag
5.7
mass earth
82.6354
multi star system
yes
name
HD 142 A d
orbital period days
108.453
radius earth
10.9
semi major au
0.474
spect
F7V
sys num planets
3
sys num stars
2

About HD 142 A d

HD 142 A d is a rare exoplanet. It lies about 85.4 light-years from Earth, shines at apparent magnitude 5.7, has spectral type F7V and has an equilibrium temperature near 530 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 5.7, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HD 142 A 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 142 A d is a rare exoplanet

HD 142 A 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, Multi-planet system, Its star is visible to the naked eye and Two suns in its sky — 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.