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Uncommon variable star 27 EP

20 CVn

RA 199.3857° · Dec 40.5726° · star

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Score breakdown

· 6 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Giant star +6
  • Variable star +5
  • Yellow-white F-type star +3
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 27

7 more points to reach Rare.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Yellow-white F-type star · +3
  • Giant star · +6
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads F3III — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • Where it is in life. It is a giant. It has already exhausted its core hydrogen and swollen up enormously in response.
  • 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 4.7 you can see it with your own eyes from a dark site, over in Canes Venatici.
  • 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.

Properties

absmag
0.177
bv
0.306
constellation
CVn
dist ly
264.308
luminosity
73.9946
mag
4.72
name
20 CVn
spect
F3III
var amplitude
0.03
var designation
AO
var max
4.71
var min
4.74

About 20 CVn

20 CVn is an uncommon variable star. It lies about 264.3 light-years from Earth, sits in the constellation CVn, shines at apparent magnitude 4.72 and has spectral type F3III.

Its spectrum reads F3III — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for 20 CVn in the constellation CVn. At apparent magnitude 4.72, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 20 CVn 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 20 CVn is an uncommon variable star

20 CVn scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Naked-eye visible, Yellow-white F-type star, Giant 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.