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Rare variable star 43 EP

HD 31311

RA 73.1475° · Dec -43.0605° · star

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Score breakdown

· 7 badges
43 pts · Rare
Rare 50 pts → Epic
  • Strongly variable +10
  • Deep red star +8
  • Distant (over 1,000 light-years) +6
  • Giant star +6
  • Variable star +5
  • Cool red M-type star +5
  • A named variable star +3
Total score 43

7 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
  • Strongly variable · +10
  • 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 8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Caelum.
  • 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.

Could we get there?

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

Properties

absmag
-1.155
bv
1.564
constellation
Cae
dist ly
2159.9737
luminosity
252.3481
mag
7.95
name
HD 31311
spect
M2III
var amplitude
0.52
var designation
Z
var max
7.642
var min
8.162

About HD 31311

HD 31311 is a rare variable star. It lies about 2,160 light-years from Earth, sits in the constellation Cae, shines at apparent magnitude 7.95 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 31311 in the constellation Cae. At apparent magnitude 7.95, it is an easy target for binoculars.

Like any astronomical target, HD 31311 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 31311 is a rare variable star

HD 31311 scores 43 points on Spacedle's rarity scale, which places it in the rare tier. Another 7 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, Strongly 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.