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Rare variable star 35 EP

HD 221650

RA 353.4165° · Dec 48.8183° · star

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Score breakdown

· 6 badges
35 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
  • A named variable star +3
Total score 35

15 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
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M2III + B1eq — 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 10.6 you'll want a small backyard telescope, over in Andromeda.
  • 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 September — that's when to go looking.

Could we get there?

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

Properties

absmag
0.846
bv
1.12
constellation
And
dist ly
2912.107
luminosity
39.9577
mag
10.6
name
HD 221650
spect
M2III + B1eq
var amplitude
0.55
var designation
Z
var max
10.361
var min
10.911

About HD 221650

HD 221650 is a rare variable star. It lies about 2,912.1 light-years from Earth, sits in the constellation And, shines at apparent magnitude 10.6 and has spectral type M2III + B1eq.

Its spectrum reads M2III + B1eq — 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 221650 in the constellation And. At apparent magnitude 10.6, a small backyard telescope will bring it into view.

Like any astronomical target, HD 221650 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 221650 is a rare variable star

HD 221650 scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Distant (over 1,000 light-years), 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.