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Common star 15 EP

HD 193634

RA 304.9549° · Dec 38.3427° · star

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Score breakdown

· 3 badges
15 pts · Common
Common 22 pts → Uncommon
  • Hot blue B-type star +6
  • Giant star +6
  • Star +3
Total score 15

7 more points to reach Uncommon.

Badges

  • Star · +3
  • Hot blue B-type star · +6
  • Giant star · +6

Trivia

What it actually is

  • Spectral class. Its spectrum reads B3III — 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.

Find it in the sky

  • How to spot it. At magnitude 7.4 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 7400 K, against the Sun's 5778 K.

Properties

absmag
-12.6
bv
0.31
constellation
Cyg
luminosity
9549925.8602
mag
7.4
name
HD 193634
spect
B3III

About HD 193634

HD 193634 is a common star. It sits in the constellation Cyg, shines at apparent magnitude 7.4 and has spectral type B3III.

Its spectrum reads B3III — 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 193634 in the constellation Cyg. At apparent magnitude 7.4, it is an easy target for binoculars.

Like any astronomical target, HD 193634 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 193634 is a common star

HD 193634 scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 7 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Hot blue B-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.