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Uncommon star 32 EP

21 Ori

RA 79.7967° · Dec 2.5958° · star

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Score breakdown

· 5 badges
32 pts · Uncommon
Uncommon 34 pts → Rare
  • Bright giant +12
  • Naked-eye visible +8
  • In Orion's hunting ground +6
  • Star +3
  • Yellow-white F-type star +3
Total score 32

2 more points to reach Rare.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • In Orion's hunting ground · +6
  • Yellow-white F-type star · +3
  • Bright giant · +12

Trivia

What it actually is

  • Spectral class. Its spectrum reads F5IIvar — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • Where it is in life. It is a bright giant, well on its way to the largest stars there are.

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 5.3 you can see it with your own eyes from a dark site, over in Orion.
  • 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 December — 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. ≈ 3.6 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.38
bv
0.412
constellation
Ori
dist ly
202.0794
luminosity
24.4343
mag
5.34
name
21 Ori
spect
F5IIvar

About 21 Ori

21 Ori is an uncommon star. It lies about 202.1 light-years from Earth, sits in the constellation Ori, shines at apparent magnitude 5.34 and has spectral type F5IIvar.

Its spectrum reads F5IIvar — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for 21 Ori in the constellation Ori. At apparent magnitude 5.34, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 21 Ori 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 21 Ori is an uncommon star

21 Ori scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 2 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Naked-eye visible, In Orion's hunting ground, Yellow-white F-type star and Bright giant — 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.