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Common star 20 EP

18 Com

RA 187.3627° · Dec 24.1089° · star

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Score breakdown

· 4 badges
20 pts · Common
Common 22 pts → Uncommon
  • Naked-eye visible +8
  • Giant star +6
  • Star +3
  • Yellow-white F-type star +3
Total score 20

2 more points to reach Uncommon.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • Yellow-white F-type star · +3
  • Giant star · +6

Trivia

What it actually is

  • Spectral class. Its spectrum reads F5III — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • 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 Coma Berenices.
  • 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 March — 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. ≈ 3.5 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.522
bv
0.445
constellation
Com
dist ly
200.9587
luminosity
21.4388
mag
5.47
name
18 Com
spect
F5III

About 18 Com

18 Com is a common star. It lies about 201 light-years from Earth, sits in the constellation Com, shines at apparent magnitude 5.47 and has spectral type F5III.

Its spectrum reads F5III — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for 18 Com in the constellation Com. At apparent magnitude 5.47, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 18 Com 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 18 Com is a common star

18 Com scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, Naked-eye visible, Yellow-white F-type star and Giant 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.