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Rare star 35 EP

HD 193443

RA 304.7154° · Dec 38.2796° · star

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Score breakdown

· 3 badges
35 pts · Rare
Rare 50 pts → Epic
  • Blazing O-type star +26
  • Giant star +6
  • Star +3
Total score 35

15 more points to reach Epic.

Badges

  • Star · +3
  • Blazing O-type star · +26
  • Giant star · +6

Trivia

What it actually is

  • Spectral class. Its spectrum reads O9III — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.
  • Where it is in life. It is a giant. It has already exhausted its core hydrogen and swollen up enormously in response.

Find it in the sky

  • How to spot it. At magnitude 7.3 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 July — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out yellow-white (B−V 0.3) — a shade brighter and crisper than our own Sun.
  • Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 7280 K, against the Sun's 5778 K.

Properties

absmag
-12.74
bv
0.33
constellation
Cyg
luminosity
10864256.2362
mag
7.26
name
HD 193443
spect
O9III

About HD 193443

HD 193443 is a rare star. It sits in the constellation Cyg, shines at apparent magnitude 7.26 and has spectral type O9III.

Its spectrum reads O9III — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.

How to see it

Look for HD 193443 in the constellation Cyg. At apparent magnitude 7.26, it is an easy target for binoculars.

Like any astronomical target, HD 193443 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 193443 is a rare star

HD 193443 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 3 science badges — Star, Blazing O-type star and Giant 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.