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Uncommon variable star 33 EP

84 UMa

RA 206.6486° · Dec 54.4327° · star

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Score breakdown

· 7 badges
33 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Variable star +5
  • Blue-white star +5
  • Never sets (northern circumpolar) +4
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 33

1 more point to reach Rare.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Never sets (northern circumpolar) · +4
  • Hot blue B-type star · +6
  • Blue-white star · +5
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9p EuCr — 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.
  • It changes. This star does not hold still: its brightness rises and falls on a rhythm of hours, days or years, either pulsing in size or being eclipsed by a companion.

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 5.7 you can see it with your own eyes from a dark site, over in Ursa Major.
  • 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 April — 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. ≈ 5.1 million years at Voyager 1's speed (17 km/s).

Properties

absmag
0.932
bv
-0.039
constellation
UMa
dist ly
290.4328
luminosity
36.9148
mag
5.68
name
84 UMa
spect
B9p EuCr
var amplitude
0.03
var designation
CR
var max
5.666
var min
5.696

About 84 UMa

84 UMa is an uncommon variable star. It lies about 290.4 light-years from Earth, sits in the constellation UMa, shines at apparent magnitude 5.68 and has spectral type B9p EuCr.

Its spectrum reads B9p EuCr — 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 84 UMa in the constellation UMa. At apparent magnitude 5.68, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 84 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 84 UMa is an uncommon variable star

84 UMa scores 33 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 1 point would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Naked-eye visible, Never sets (northern circumpolar), Hot blue B-type star, Blue-white star, Barely variable (under 0.05 mag) and A named variable 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.