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Rare variable star 39 EP

31Omi Aqr

RA 330.8285° · Dec -2.1554° · star

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Score breakdown

· 8 badges
39 pts · Rare
Rare 50 pts → Epic
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Variable star +5
  • Subgiant (leaving the main sequence) +5
  • Blue-white star +5
  • Gently variable +4
  • On the zodiac +3
  • A named variable star +3
Total score 39

11 more points to reach Epic.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Subgiant (leaving the main sequence) · +5
  • Blue-white star · +5
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B7IVe — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.
  • 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 Aquarius.
  • 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 August — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

absmag
-0.888
bv
-0.1
constellation
Aqr
dist ly
435.4551
luminosity
197.3331
mag
4.74
name
31Omi Aqr
spect
B7IVe
var amplitude
0.25
var designation
Omi
var max
4.715
var min
4.965

About 31Omi Aqr

31Omi Aqr is a rare variable star. It lies about 435.5 light-years from Earth, sits in the constellation Aqr, shines at apparent magnitude 4.74 and has spectral type B7IVe.

Its spectrum reads B7IVe — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for 31Omi Aqr in the constellation Aqr. At apparent magnitude 4.74, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 31Omi Aqr 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 31Omi Aqr is a rare variable star

31Omi Aqr scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Naked-eye visible, On the zodiac, Hot blue B-type star, Subgiant (leaving the main sequence), Blue-white 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.