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Rare variable star 41 EP

31 Ori

RA 82.4333° · Dec -1.0922° · star

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Score breakdown

· 8 badges
41 pts · Rare
Rare 50 pts → Epic
  • Naked-eye visible +8
  • Deep red star +8
  • In Orion's hunting ground +6
  • Giant star +6
  • Variable star +5
  • Orange K-type star +3
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 41

9 more points to reach Epic.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • In Orion's hunting ground · +6
  • Orange K-type star · +3
  • Giant star · +6
  • Deep red star · +8
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads K5III — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.
  • 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 Orion.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • 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. Hopelessly far for any craft humanity can build today.

Properties

absmag
-1.252
bv
1.592
constellation
Ori
dist ly
508.031
luminosity
275.9307
mag
4.71
name
31 Ori
spect
K5III
var amplitude
0.03
var designation
CI
var max
4.694
var min
4.724

About 31 Ori

31 Ori is a rare variable star. It lies about 508 light-years from Earth, sits in the constellation Ori, shines at apparent magnitude 4.71 and has spectral type K5III.

Its spectrum reads K5III — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.

How to see it

Look for 31 Ori in the constellation Ori. At apparent magnitude 4.71, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 31 Ori 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 31 Ori is a rare variable star

31 Ori scores 41 points on Spacedle's rarity scale, which places it in the rare tier. Another 9 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Naked-eye visible, In Orion's hunting ground, Orange K-type star, Giant star, Deep red 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.