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Common variable star 18 EP

HD 218325

RA 346.6373° · Dec 46.9236° · star

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Score breakdown

· 4 badges
18 pts · Common
Common 22 pts → Uncommon
  • Hot blue B-type star +6
  • Variable star +5
  • Gently variable +4
  • A named variable star +3
Total score 18

4 more points to reach Uncommon.

Badges

  • Variable star · +5
  • Hot blue B-type star · +6
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B3 — 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.
  • 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 7.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Andromeda.
  • 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 September — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out brilliant white (B−V 0) — hotter and whiter than the Sun, the colour of Sirius or Vega.
  • 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 10030 K, against the Sun's 5778 K.

Properties

absmag
-12.25
bv
0.008
constellation
And
luminosity
6918309.7092
mag
7.75
name
HD 218325
spect
B3
var amplitude
0.15
var designation
V379
var max
7.686
var min
7.836

About HD 218325

HD 218325 is a common variable star. It sits in the constellation And, shines at apparent magnitude 7.75 and has spectral type B3.

Its spectrum reads B3 — 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 218325 in the constellation And. At apparent magnitude 7.75, it is an easy target for binoculars.

Like any astronomical target, HD 218325 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 218325 is a common variable star

HD 218325 scores 18 points on Spacedle's rarity scale, which places it in the common tier. Another 4 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, Hot blue B-type star, 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.