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Rare exoplanet 36 EP

HD 190984 b

RA 302.8780° · Dec -64.6203° · exoplanet

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Score breakdown

· 5 badges
36 pts · Rare
Rare 50 pts → Epic
  • Long-period world +10
  • Eccentric orbit +9
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 36

14 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Long-period world · +10
  • Eccentric orbit · +9
  • Orbits a Sun-like star · +8

Trivia

What it actually is

  • What it is made of. Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.

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 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 8.5 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 754.7 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

density gcc
2.85
diameter km
165830.6
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2009
dist ly
483.3208
eccentricity
0.57
eq temp k
152.29
host star teff
5988
inclination
64
insolation
0.089
mag
8.76
mass earth
1137.8257
name
HD 190984 b
orbital period days
4885
radius earth
13
semi major au
5.5
spect
F8 V
sys num planets
1
sys num stars
1

About HD 190984 b

HD 190984 b is a rare exoplanet. It lies about 483.3 light-years from Earth, shines at apparent magnitude 8.76, has spectral type F8 V and has an equilibrium temperature near 152 K.

Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.

How to see it

At apparent magnitude 8.76, it is an easy target for binoculars.

Like any astronomical target, HD 190984 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 190984 b is a rare exoplanet

HD 190984 b scores 36 points on Spacedle's rarity scale, which places it in the rare tier. Another 14 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Long-period world, Eccentric orbit and Orbits a Sun-like star — 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.