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Rare exoplanet 48 EP

HD 128356 b

RA 219.2703° · Dec -25.8032° · exoplanet

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Score breakdown

· 4 badges
48 pts · Rare
Rare 50 pts → Epic
  • In the habitable zone +30
  • Eccentric orbit +9
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 48

2 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • In the habitable zone · +30
  • Gas giant · +4
  • Eccentric orbit · +9

Trivia

What makes it special

  • Goldilocks zone. Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

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.
  • What the zone means. The habitable zone is only about temperature: it is the band where liquid water could survive on a surface. It is a promising address, not evidence of anything living.

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 8.2 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 April — that's when to go looking.

Properties

density gcc
0.579
diameter km
177311.18
discovery facility
Multiple Observatories
discovery method
Radial Velocity
discovery year
2016
dist ly
85.3054
eccentricity
0.57
eq temp k
232.36
habitable zone
yes
host star teff
4875
insolation
0.4756
mag
8.2411
mass earth
282.8687
name
HD 128356 b
orbital period days
298.2
radius earth
13.9
semi major au
0.87
spect
K3 V
sys num planets
1
sys num stars
1

Nearby objects

About HD 128356 b

HD 128356 b is a rare exoplanet. It lies about 85.3 light-years from Earth, shines at apparent magnitude 8.24, has spectral type K3 V and has an equilibrium temperature near 232 K.

Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

How to see it

At apparent magnitude 8.24, it is an easy target for binoculars.

Like any astronomical target, HD 128356 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 128356 b is a rare exoplanet

HD 128356 b scores 48 points on Spacedle's rarity scale, which places it in the rare tier. Another 2 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, In the habitable zone, Gas giant and Eccentric orbit — 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.