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Trash star 13 EP

HD 202031

RA 317.7992° · Dec 56.3412° · star

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Score breakdown

· 3 badges
13 pts · Trash
Trash 15 pts → Common
  • Hot blue B-type star +6
  • Never sets (northern circumpolar) +4
  • Star +3
Total score 13

2 more points to reach Common.

Badges

  • Star · +3
  • Never sets (northern circumpolar) · +4
  • Hot blue B-type star · +6

Trivia

Hard to believe

  • True brightness. It pours out about 3.6 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 B9 — 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 8.4 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cepheus.
  • 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 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 7340 K, against the Sun's 5778 K.

Properties

absmag
-11.56
bv
0.319
constellation
Cep
luminosity
3664375.7465
mag
8.44
name
HD 202031
spect
B9

Nearby objects

About HD 202031

HD 202031 is a trash star. It sits in the constellation Cep, shines at apparent magnitude 8.44 and has spectral type B9.

Its spectrum reads B9 — 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 202031 in the constellation Cep. At apparent magnitude 8.44, it is an easy target for binoculars.

Like any astronomical target, HD 202031 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 202031 is a trash star

HD 202031 scores 13 points on Spacedle's rarity scale, which places it in the trash tier. Another 2 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Never sets (northern circumpolar) and Hot blue B-type 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.