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Common exoplanet 19 EP

HAT-P-20 b

RA 111.9164° · Dec 24.3361° · exoplanet

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Score breakdown

· 3 badges
19 pts · Common
Common 22 pts → Uncommon
  • Tidally locked +10
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 19

3 more points to reach Uncommon.

Badges

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

Trivia

Hard to believe

  • Denser than iron. It is packed tighter than solid iron — whatever it is made of, it is not ordinary rock.

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. Denser than Earth — a solid world of rock and iron, with no meaningful atmosphere to speak of by mass.

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 11.2 you'll want a small backyard telescope.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around January — that's when to go looking.

Could we get there?

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

Properties

density gcc
13.78
diameter km
123964.7516
discovery facility
HATNet
discovery method
Transit
discovery year
2010
dist ly
231.6927
eccentricity
0.015
eq temp k
970
host star teff
4595
inclination
86.8
insolation
85.1168
mag
11.231
mass earth
2302.899
name
HAT-P-20 b
orbital period days
2.8753
radius earth
9.718
semi major au
0.0361
spect
K3
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HAT-P-20 b

HAT-P-20 b is a common exoplanet. It lies about 231.7 light-years from Earth, shines at apparent magnitude 11.23, has spectral type K3 and has an equilibrium temperature near 970 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 11.23, a small backyard telescope will bring it into view.

Like any astronomical target, HAT-P-20 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 HAT-P-20 b is a common exoplanet

HAT-P-20 b scores 19 points on Spacedle's rarity scale, which places it in the common tier. Another 3 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, 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.