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Uncommon star 28 EP

42 Cas

RA 25.7324° · Dec 70.6225° · star

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Score breakdown

· 6 badges
28 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Blue-white star +5
  • Never sets (northern circumpolar) +4
  • Star +3
  • Main-sequence star +2
Total score 28

6 more points to reach Rare.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • Never sets (northern circumpolar) · +4
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9V — 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 on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.

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 5.2 you can see it with your own eyes from a dark site, over in Cassiopeia.
  • 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 October — 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. ≈ 4.9 million years at Voyager 1's speed (17 km/s).

Properties

absmag
0.53
bv
-0.022
constellation
Cas
dist ly
277.5796
luminosity
53.4564
mag
5.18
name
42 Cas
spect
B9V

About 42 Cas

42 Cas is an uncommon star. It lies about 277.6 light-years from Earth, sits in the constellation Cas, shines at apparent magnitude 5.18 and has spectral type B9V.

Its spectrum reads B9V — 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 42 Cas in the constellation Cas. At apparent magnitude 5.18, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 42 Cas 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 42 Cas is an uncommon star

42 Cas 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 6 science badges — Star, Naked-eye visible, Never sets (northern circumpolar), Hot blue B-type star, Main-sequence 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.