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Rare exoplanet 49 EP

HD 109749 b

RA 189.3173° · Dec -40.8121° · exoplanet

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Score breakdown

· 6 badges
49 pts · Rare
Rare 50 pts → Epic
  • Two suns in its sky +12
  • Hot Jupiter +10
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 49

1 more point to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Hot Jupiter · +10
  • Tidally locked · +10
  • Orbits a Sun-like star · +8
  • Two suns in its sky · +12

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 8.1 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 March — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.345
diameter km
141593.82
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
discovery year
2005
dist ly
205.7461
eccentricity
0
eq temp k
1250.83
host star teff
5824
insolation
409.4961
mag
8.08
mass earth
85.8141
multi star system
yes
name
HD 109749 b
orbital period days
5.2399
radius earth
11.1
semi major au
0.0615
spect
G3 V
sys num planets
1
sys num stars
2
tidally locked
yes
tidally locked inferred
yes

Nearby objects

About HD 109749 b

HD 109749 b is a rare exoplanet. It lies about 205.7 light-years from Earth, shines at apparent magnitude 8.08, has spectral type G3 V and has an equilibrium temperature near 1,251 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 8.08, it is an easy target for binoculars.

Like any astronomical target, HD 109749 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 109749 b is a rare exoplanet

HD 109749 b scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Gas giant, Hot Jupiter, Tidally locked, Orbits a Sun-like star and Two suns in its sky — 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.