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Uncommon star 23 EP

23 UMa

RA 142.8818° · Dec 63.0619° · star

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Score breakdown

· 5 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Subgiant (leaving the main sequence) +5
  • Never sets (northern circumpolar) +4
  • Star +3
  • Yellow-white F-type star +3
Total score 23

11 more points to reach Rare.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • Never sets (northern circumpolar) · +4
  • Yellow-white F-type star · +3
  • Subgiant (leaving the main sequence) · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads F0IV — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.

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 3.6 you can see it with your own eyes from a dark site, over in Ursa Major.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • Best time of year. It stands highest in the middle of the night around February — 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. ≈ 1.4 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.766
bv
0.36
constellation
UMa
dist ly
77.6747
luminosity
17.1238
mag
3.65
name
23 UMa
spect
F0IV

About 23 UMa

23 UMa is an uncommon star. It lies about 77.7 light-years from Earth, sits in the constellation UMa, shines at apparent magnitude 3.65 and has spectral type F0IV.

Its spectrum reads F0IV — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for 23 UMa in the constellation UMa. At apparent magnitude 3.65, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 23 UMa 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 23 UMa is an uncommon star

23 UMa scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Naked-eye visible, Never sets (northern circumpolar), Yellow-white F-type star and Subgiant (leaving the main sequence) — 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.