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Uncommon variable star 33 EP

10 CMa

RA 101.1186° · Dec -31.0705° · 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
  • Gently variable +4
  • A named variable star +3
  • Main-sequence star +2
Total score 33

1 more point to reach Rare.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • Blue-white star · +5
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B2V — 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.
  • 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 5.2 you can see it with your own eyes from a dark site, over in Canis Major.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around December — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out blue-white (B−V -0.1) — the hallmark of a surface far hotter than the Sun's.
  • 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
-14.77
bv
-0.127
constellation
CMa
luminosity
70469306.8967
mag
5.23
name
10 CMa
spect
B2V
var amplitude
0.11
var designation
FT
var max
5.166
var min
5.276

About 10 CMa

10 CMa is an uncommon variable star. It sits in the constellation CMa, shines at apparent magnitude 5.23 and has spectral type B2V.

Its spectrum reads B2V — 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 10 CMa in the constellation CMa. At apparent magnitude 5.23, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 10 CMa 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 10 CMa is an uncommon variable star

10 CMa 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, Hot blue B-type star, Main-sequence star, Blue-white star, Gently variable 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.