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Rare variable star 47 EP

HIP 7755

RA 24.9653° · Dec 60.9023° · star

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Score breakdown

· 8 badges
47 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
  • Never sets (northern circumpolar) +4
  • A named variable star +3
Total score 47

3 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
  • 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 Cassiopeia.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • Best time of year. It stands highest in the middle of the night around October — that's when to go looking.

Could we get there?

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

Properties

absmag
-1.652
bv
2.21
constellation
Cas
dist ly
2740.8066
luminosity
398.8412
mag
7.97
name
HIP 7755
spect
M2III
var amplitude
0.68
var designation
V770
var max
7.822
var min
8.502

About HIP 7755

HIP 7755 is a rare variable star. It lies about 2,740.8 light-years from Earth, sits in the constellation Cas, shines at apparent magnitude 7.97 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 HIP 7755 in the constellation Cas. At apparent magnitude 7.97, it is an easy target for binoculars.

Like any astronomical target, HIP 7755 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 HIP 7755 is a rare variable star

HIP 7755 scores 47 points on Spacedle's rarity scale, which places it in the rare tier. Another 3 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Distant (over 1,000 light-years), Never sets (northern circumpolar), 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.