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Rare exoplanet 41 EP

HD 16417 b

RA 39.2441° · Dec -34.5791° · exoplanet

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Score breakdown

· 5 badges
41 pts · Rare
Rare 50 pts → Epic
  • Its star is visible to the naked eye +12
  • Two suns in its sky +12
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Neptune-like +4
Total score 41

9 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Neptune-like · +4
  • Its star is visible to the naked eye · +12
  • Orbits a Sun-like star · +8
  • 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

  • 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. 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 5.8 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 October — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.972
diameter km
63781
discovery facility
Anglo-Australian Telescope
discovery method
Radial Velocity
discovery year
2008
dist ly
82.8228
eccentricity
0.2
eq temp k
964
host star teff
5841
insolation
141.5514
mag
5.78
mass earth
22.1
multi star system
yes
name
HD 16417 b
orbital period days
17.24
radius earth
5
semi major au
0.14
spect
G1 V
sys num planets
1
sys num stars
2

About HD 16417 b

HD 16417 b is a rare exoplanet. It lies about 82.8 light-years from Earth, shines at apparent magnitude 5.78, has spectral type G1 V and has an equilibrium temperature near 964 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 5.78, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HD 16417 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 16417 b is a rare exoplanet

HD 16417 b scores 41 points on Spacedle's rarity scale, which places it in the rare tier. Another 9 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Neptune-like, Its star is visible to the naked eye, Orbits a Sun-like star 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.