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Rare variable star 39 EP

HD 103681

RA 179.1259° · Dec 57.8716° · star

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Score breakdown

· 7 badges
39 pts · Rare
Rare 50 pts → Epic
  • Strongly variable +10
  • Distant (over 1,000 light-years) +6
  • Giant star +6
  • Variable star +5
  • Cool red M-type star +5
  • Never sets (northern circumpolar) +4
  • A named variable star +3
Total score 39

11 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • Never sets (northern circumpolar) · +4
  • Cool red M-type star · +5
  • Giant star · +6
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M5IIIvar — 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 7.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Ursa Major.
  • 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
-0.286
bv
1.335
constellation
UMa
dist ly
1160.6976
luminosity
113.3444
mag
7.47
name
HD 103681
spect
M5IIIvar
var amplitude
1.19
var designation
Z
var max
6.937
var min
8.127

About HD 103681

HD 103681 is a rare variable star. It lies about 1,160.7 light-years from Earth, sits in the constellation UMa, shines at apparent magnitude 7.47 and has spectral type M5IIIvar.

Its spectrum reads M5IIIvar — 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 103681 in the constellation UMa. At apparent magnitude 7.47, it is an easy target for binoculars.

Like any astronomical target, HD 103681 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 103681 is a rare variable star

HD 103681 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 7 science badges — Variable star, Distant (over 1,000 light-years), Never sets (northern circumpolar), Cool red M-type star, Giant 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.