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Rare variable star 46 EP

HD 193928

RA 305.3822° · Dec 36.9202° · star

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Score breakdown

· 4 badges
46 pts · Rare
Rare 50 pts → Epic
  • Wolf-Rayet star (shedding itself) +34
  • Variable star +5
  • Gently variable +4
  • A named variable star +3
Total score 46

4 more points to reach Epic.

Badges

  • Variable star · +5
  • Wolf-Rayet star (shedding itself) · +34
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 1.1 million times as much light as the Sun. It only looks ordinary because it is so far away.

What it actually is

  • Spectral class. Its spectrum reads WN6 (SB1) — a Wolf-Rayet star: a stellar monster shedding its own outer layers in a ferocious wind, on its way to a supernova.
  • 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.

Find it in the sky

  • How to spot it. At magnitude 9.7 you'll want a small backyard telescope, 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 (B−V 0.8) — almost exactly the Sun's own shade — a stellar twin in colour, if not in size.
  • 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.

Properties

absmag
-10.28
bv
0.792
constellation
Cyg
luminosity
1127197.4562
mag
9.72
name
HD 193928
spect
WN6 (SB1)
var amplitude
0.12
var designation
V2183
var max
9.665
var min
9.785

About HD 193928

HD 193928 is a rare variable star. It sits in the constellation Cyg, shines at apparent magnitude 9.72 and has spectral type WN6 (SB1).

Its spectrum reads WN6 (SB1) — a Wolf-Rayet star: a stellar monster shedding its own outer layers in a ferocious wind, on its way to a supernova.

How to see it

Look for HD 193928 in the constellation Cyg. At apparent magnitude 9.72, a small backyard telescope will bring it into view.

Like any astronomical target, HD 193928 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 193928 is a rare variable star

HD 193928 scores 46 points on Spacedle's rarity scale, which places it in the rare tier. Another 4 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, Wolf-Rayet star (shedding itself), Gently 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.