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Uncommon exoplanet 23 EP

HD 154857 b

RA 257.8162° · Dec -56.6810° · exoplanet

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Score breakdown

· 4 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Orbits a Sun-like star +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 23

11 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Multi-planet system · +6
  • Orbits a Sun-like star · +8

Trivia

What it actually is

  • What it is made of. Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.
  • Crowded system. One of at least 2 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 7.2 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.

Getting there

  • Aboard Voyager 1. ≈ 3.6 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
1.82
diameter km
169657.46
discovery facility
Anglo-Australian Telescope
discovery method
Radial Velocity
discovery year
2004
dist ly
206.9401
eccentricity
0.46
eq temp k
359.86
host star teff
5589
insolation
2.7638
mag
7.24
mass earth
778.6835
name
HD 154857 b
orbital period days
408.6
radius earth
13.3
semi major au
1.29
spect
G5 V
sys num planets
2
sys num stars
1

About HD 154857 b

HD 154857 b is an uncommon exoplanet. It lies about 206.9 light-years from Earth, shines at apparent magnitude 7.24, has spectral type G5 V and has an equilibrium temperature near 360 K.

Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.

How to see it

At apparent magnitude 7.24, it is an easy target for binoculars.

Like any astronomical target, HD 154857 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 154857 b is an uncommon exoplanet

HD 154857 b scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Multi-planet system 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.