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Common exoplanet 19 EP

HD 103720 b

RA 179.1713° · Dec -2.7791° · 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

  • 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 9.5 you'll want a small backyard telescope.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around March — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.386
diameter km
179862.42
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2014
dist ly
148.5158
eccentricity
0.086
eq temp k
926.24
host star teff
5017
insolation
140.3478
mag
9.5
mass earth
197.046
name
HD 103720 b
orbital period days
4.5557
radius earth
14.1
semi major au
0.0498
spect
K3 V
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HD 103720 b

HD 103720 b is a common exoplanet. It lies about 148.5 light-years from Earth, shines at apparent magnitude 9.5, has spectral type K3 V and has an equilibrium temperature near 926 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 9.5, a small backyard telescope will bring it into view.

Like any astronomical target, HD 103720 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 103720 b is a common exoplanet

HD 103720 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.