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Trash star 14 EP

HD 188972

RA 299.2764° · Dec 19.5641° · star

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Score breakdown

· 3 badges
14 pts · Trash
Trash 15 pts → Common
  • Hot blue B-type star +6
  • Blue-white star +5
  • Star +3
Total score 14

1 more point to reach Common.

Badges

  • Star · +3
  • Hot blue B-type star · +6
  • Blue-white star · +5

Trivia

Hard to believe

  • True brightness. It pours out about 3.4 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 B5 — 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.

Find it in the sky

  • How to spot it. At magnitude 8.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagitta.
  • 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 blue-white (B−V -0.1) — 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.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 11410 K, against the Sun's 5778 K.

Properties

absmag
-11.49
bv
-0.09
constellation
Sge
luminosity
3435579.479
mag
8.51
name
HD 188972
spect
B5

Nearby objects

About HD 188972

HD 188972 is a trash star. It sits in the constellation Sge, shines at apparent magnitude 8.51 and has spectral type B5.

Its spectrum reads B5 — 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 188972 in the constellation Sge. At apparent magnitude 8.51, it is an easy target for binoculars.

Like any astronomical target, HD 188972 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 188972 is a trash star

HD 188972 scores 14 points on Spacedle's rarity scale, which places it in the trash tier. Another 1 point would lift it into a rarer tier.

That score comes from 3 science badges — Star, Hot blue B-type star and Blue-white 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.