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Uncommon exoplanet 25 EP

HATS-77 b

RA 149.8237° · Dec -27.3928° · exoplanet

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Score breakdown

· 4 badges
25 pts · Uncommon
Uncommon 34 pts → Rare
  • Tidally locked +10
  • Distant (over 1,000 light-years) +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 25

9 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Distant (over 1,000 light-years) · +6
  • Gas giant · +4
  • Tidally locked · +10

Trivia

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 16.2 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • 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 February — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

  • Aboard Voyager 1. ≈ 25 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
1.077
diameter km
166576.3596
discovery facility
HATSouth
discovery method
Transit
discovery year
2021
dist ly
1422.6142
eccentricity
0.045
eq temp k
828.3
host star teff
4071
inclination
88.44
insolation
78.37
mag
16.195
mass earth
436.6962
name
HATS-77 b
orbital period days
3.0876
radius earth
13.0585
semi major au
0.0361
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HATS-77 b

HATS-77 b is an uncommon exoplanet. It lies about 1,422.6 light-years from Earth, shines at apparent magnitude 16.2, has an equilibrium temperature near 828 K and spans roughly 13.06 Earth radii.

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 16.2, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, HATS-77 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 HATS-77 b is an uncommon exoplanet

HATS-77 b scores 25 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 9 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant and Tidally locked — 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.