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Rare variable star 37 EP

HD 233930

RA 185.7129° · Dec 50.0460° · star

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Score breakdown

· 7 badges
37 pts · Rare
Rare 50 pts → Epic
  • Deep red star +8
  • Distant (over 1,000 light-years) +6
  • Giant star +6
  • Variable star +5
  • Cool red M-type star +5
  • Gently variable +4
  • A named variable star +3
Total score 37

13 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • Cool red M-type star · +5
  • Giant star · +6
  • Deep red star · +8
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M2III — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • 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 9.2 you'll want a small backyard telescope, 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 March — that's when to go looking.

Could we get there?

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

Properties

absmag
-0.465
bv
1.676
constellation
CVn
dist ly
2861.0176
luminosity
133.6596
mag
9.25
name
HD 233930
spect
M2III
var amplitude
0.16
var designation
BT
var max
9.182
var min
9.342

About HD 233930

HD 233930 is a rare variable star. It lies about 2,861 light-years from Earth, sits in the constellation CVn, shines at apparent magnitude 9.25 and has spectral type M2III.

Its spectrum reads M2III — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

How to see it

Look for HD 233930 in the constellation CVn. At apparent magnitude 9.25, a small backyard telescope will bring it into view.

Like any astronomical target, HD 233930 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 HD 233930 is a rare variable star

HD 233930 scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Distant (over 1,000 light-years), Cool red M-type star, Giant star, Deep red 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.