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Rare variable star 45 EP

10Nu Cep

RA 326.3622° · Dec 61.1208° · star

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Score breakdown

· 7 badges
45 pts · Rare
Rare 50 pts → Epic
  • Supergiant +18
  • Naked-eye visible +8
  • Variable star +5
  • White A-type star +5
  • Never sets (northern circumpolar) +4
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 45

5 more points to reach Epic.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Never sets (northern circumpolar) · +4
  • White A-type star · +5
  • Supergiant · +18
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads A2Iavar — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
  • Where it is in life. It is a luminous supergiant — among the largest and rarest stars in the galaxy.
  • 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.

Find it in the sky

  • How to spot it. At magnitude 4.2 you can see it with your own eyes from a dark site, over in Cepheus.
  • 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 August — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out yellow-white (B−V 0.5) — a shade brighter and crisper than our own Sun.
  • Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

Properties

absmag
-15.75
bv
0.474
constellation
Cep
luminosity
173780082.8749
mag
4.25
name
10Nu Cep
spect
A2Iavar
var amplitude
0.05
var designation
Nu
var max
4.229
var min
4.279

About 10Nu Cep

10Nu Cep is a rare variable star. It sits in the constellation Cep, shines at apparent magnitude 4.25 and has spectral type A2Iavar.

Its spectrum reads A2Iavar — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for 10Nu Cep in the constellation Cep. At apparent magnitude 4.25, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 10Nu Cep 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 10Nu Cep is a rare variable star

10Nu Cep scores 45 points on Spacedle's rarity scale, which places it in the rare tier. Another 5 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Naked-eye visible, Never sets (northern circumpolar), White A-type star, Supergiant, 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.