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Uncommon exoplanet 27 EP

HD 168746 b

RA 275.4573° · Dec -11.9230° · exoplanet

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Score breakdown

· 4 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 27

7 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Tidally locked · +10
  • 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

  • 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. 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 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 June — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.345
diameter km
141593.82
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2002
dist ly
135.5769
eccentricity
0.11
eq temp k
900
host star teff
5570
insolation
224.4898
mag
7.95
mass earth
85.8141
name
HD 168746 b
orbital period days
6.404
radius earth
11.1
semi major au
0.07
spect
G5
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HD 168746 b

HD 168746 b is an uncommon exoplanet. It lies about 135.6 light-years from Earth, shines at apparent magnitude 7.95, has spectral type G5 and has an equilibrium temperature near 900 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 7.95, it is an easy target for binoculars.

Like any astronomical target, HD 168746 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 168746 b is an uncommon exoplanet

HD 168746 b scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Tidally locked 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.