← Back to dex
Epic variable star 67 EP

29 CMa

RA 109.6682° · Dec -24.5587° · star

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 8 badges
67 pts · Epic
Epic 78 pts → Anomaly
  • Blazing O-type star +26
  • Intrinsically luminous (Mv < −2) +10
  • Naked-eye visible +8
  • Distant (over 1,000 light-years) +6
  • Variable star +5
  • Blue-white star +5
  • Gently variable +4
  • A named variable star +3
Total score 67

11 more points to reach Anomaly.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • Naked-eye visible · +8
  • Blazing O-type star · +26
  • Blue-white star · +5
  • Intrinsically luminous (Mv < −2) · +10
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads O7f — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.
  • 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 4.9 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 January — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

  • Aboard Voyager 1. ≈ 33.5 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-3.955
bv
-0.16
constellation
CMa
dist ly
1907.345
luminosity
3326.5955
mag
4.88
name
29 CMa
spect
O7f
var amplitude
0.4
var designation
UW
var max
4.805
var min
5.205

About 29 CMa

29 CMa is an epic variable star. It lies about 1,907.3 light-years from Earth, sits in the constellation CMa, shines at apparent magnitude 4.88 and has spectral type O7f.

Its spectrum reads O7f — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.

How to see it

Look for 29 CMa in the constellation CMa. At apparent magnitude 4.88, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 29 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 29 CMa is an epic variable star

29 CMa scores 67 points on Spacedle's rarity scale, which places it in the epic tier. Another 11 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Distant (over 1,000 light-years), Naked-eye visible, Blazing O-type star, Blue-white star, Intrinsically luminous (Mv < −2), 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.