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Uncommon star 31 EP

HD 200857

RA 315.9702° · Dec 55.2303° · star

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Score breakdown

· 5 badges
31 pts · Uncommon
Uncommon 34 pts → Rare
  • Intrinsically luminous (Mv < −2) +10
  • Distant (over 1,000 light-years) +6
  • Hot blue B-type star +6
  • Giant star +6
  • Star +3
Total score 31

3 more points to reach Rare.

Badges

  • Star · +3
  • Distant (over 1,000 light-years) · +6
  • Hot blue B-type star · +6
  • Giant star · +6
  • Intrinsically luminous (Mv < −2) · +10

Trivia

What it actually is

  • Spectral class. Its spectrum reads B3IIIvar — 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 giant. It has already exhausted its core hydrogen and swollen up enormously in response.

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 7.1 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. ≈ 46.6 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-2.41
bv
0.554
constellation
Cyg
dist ly
2651.6747
luminosity
801.6781
mag
7.14
name
HD 200857
spect
B3IIIvar

About HD 200857

HD 200857 is an uncommon star. It lies about 2,651.7 light-years from Earth, sits in the constellation Cyg, shines at apparent magnitude 7.14 and has spectral type B3IIIvar.

Its spectrum reads B3IIIvar — 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 HD 200857 in the constellation Cyg. At apparent magnitude 7.14, it is an easy target for binoculars.

Like any astronomical target, HD 200857 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 200857 is an uncommon star

HD 200857 scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Distant (over 1,000 light-years), Hot blue B-type star, Giant star and Intrinsically luminous (Mv < −2) — 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.