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Common exoplanet 21 EP

alf Ari b

RA 31.7933° · Dec 23.4624° · exoplanet

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Score breakdown

· 3 badges
21 pts · Common
Common 22 pts → Uncommon
  • Its star is visible to the naked eye +12
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 21

1 more point to reach Uncommon.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Its star is visible to the naked eye · +12

Trivia

What it actually is

  • 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. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 2 you can see it with your own eyes from a dark site.
  • 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 October — 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. ≈ 1.2 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 102.9 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

density gcc
1.31
diameter km
170933.08
discovery facility
Bohyunsan Optical Astronomical Observatory
discovery method
Radial Velocity
discovery year
2010
dist ly
65.9167
eccentricity
0.25
eq temp k
747.22
host star teff
4553
insolation
59.6537
mag
2.0054
mass earth
572.07
name
alf Ari b
orbital period days
380.8
radius earth
13.4
semi major au
1.2
spect
K2III
sys num planets
1
sys num stars
1

About alf Ari b

alf Ari b is a common exoplanet. It lies about 65.9 light-years from Earth, shines at apparent magnitude 2.01, has spectral type K2III and has an equilibrium temperature near 747 K.

Lighter than Neptune — a puffed-up ball of hydrogen and helium with no surface anywhere on it to stand on.

How to see it

At apparent magnitude 2.01, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, alf Ari 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 alf Ari b is a common exoplanet

alf Ari b scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Gas giant and Its star is visible to the naked eye — 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.