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Uncommon star 28 EP

22 Eri

RA 55.1597° · Dec -5.2107° · star

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Score breakdown

· 5 badges
28 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Giant star +6
  • Blue-white star +5
  • Star +3
Total score 28

6 more points to reach Rare.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • Hot blue B-type star · +6
  • Giant star · +6
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9IIIp Si — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • Where it is in life. It is a giant. It has already exhausted its core hydrogen and swollen up enormously in response.

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 5.5 you can see it with your own eyes from a dark site, over in Eridanus.
  • 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 November — 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. ≈ 8.7 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-0.382
bv
-0.145
constellation
Eri
dist ly
496.4323
luminosity
123.8226
mag
5.53
name
22 Eri
spect
B9IIIp Si

About 22 Eri

22 Eri is an uncommon star. It lies about 496.4 light-years from Earth, sits in the constellation Eri, shines at apparent magnitude 5.53 and has spectral type B9IIIp Si.

Its spectrum reads B9IIIp Si — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for 22 Eri in the constellation Eri. At apparent magnitude 5.53, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 22 Eri 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 22 Eri is an uncommon star

22 Eri scores 28 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 6 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Naked-eye visible, Hot blue B-type star, Giant star and Blue-white 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.