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Rare variable star 43 EP

HD 205733

RA 324.1409° · Dec 32.1028° · star

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Score breakdown

· 7 badges
43 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
  • A named variable star +3
Total score 43

7 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
  • Deep red star · +8
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M4:IIIvar — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • 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 Cygnus.
  • 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 August — that's when to go looking.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 19.8 million years at Voyager 1's speed (17 km/s).

Properties

absmag
0.294
bv
1.859
constellation
Cyg
dist ly
1128.5676
luminosity
66.4355
mag
7.99
name
HD 205733
spect
M4:IIIvar
var amplitude
0.51
var designation
AB
var max
7.699
var min
8.209

About HD 205733

HD 205733 is a rare variable star. It lies about 1,128.6 light-years from Earth, sits in the constellation Cyg, shines at apparent magnitude 7.99 and has spectral type M4:IIIvar.

Its spectrum reads M4:IIIvar — 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 205733 in the constellation Cyg. At apparent magnitude 7.99, it is an easy target for binoculars.

Like any astronomical target, HD 205733 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 205733 is a rare variable star

HD 205733 scores 43 points on Spacedle's rarity scale, which places it in the rare tier. Another 7 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Distant (over 1,000 light-years), 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.