← Back to dex
Uncommon variable star 22 EP

HD 213918

RA 338.5303° · Dec 39.3355° · star

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 5 badges
22 pts · Uncommon
Uncommon 34 pts → Rare
  • Variable star +5
  • White A-type star +5
  • Blue-white star +5
  • Gently variable +4
  • A named variable star +3
Total score 22

12 more points to reach Rare.

Badges

  • Variable star · +5
  • White A-type star · +5
  • Blue-white star · +5
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 2.8 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 Ap — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
  • 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 8.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Lacerta.
  • 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.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out blue-white (B−V -0) — the hallmark of a surface far hotter than the Sun's.
  • 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
-11.29
bv
-0.046
constellation
Lac
luminosity
2857590.5434
mag
8.71
name
HD 213918
spect
Ap
var amplitude
0.13
var designation
V362
var max
8.635
var min
8.765

About HD 213918

HD 213918 is an uncommon variable star. It sits in the constellation Lac, shines at apparent magnitude 8.71 and has spectral type Ap.

Its spectrum reads Ap — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for HD 213918 in the constellation Lac. At apparent magnitude 8.71, it is an easy target for binoculars.

Like any astronomical target, HD 213918 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 213918 is an uncommon variable star

HD 213918 scores 22 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 12 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, White A-type star, Blue-white 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.