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Trash star 12 EP

HD 209004

RA 329.3772° · Dec 67.5915° · star

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Score breakdown

· 3 badges
12 pts · Trash
Trash 15 pts → Common
  • White A-type star +5
  • Never sets (northern circumpolar) +4
  • Star +3
Total score 12

3 more points to reach Common.

Badges

  • Star · +3
  • Never sets (northern circumpolar) · +4
  • White A-type star · +5

Trivia

Hard to believe

  • True brightness. It pours out about 2.2 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 A — 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.

Find it in the sky

  • How to spot it. At magnitude 9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cepheus.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • 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 brilliant white (B−V 0.2) — 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 8420 K, against the Sun's 5778 K.

Properties

absmag
-11.03
bv
0.168
constellation
Cep
luminosity
2249054.6058
mag
8.97
name
HD 209004
spect
A

Nearby objects

About HD 209004

HD 209004 is a trash star. It sits in the constellation Cep, shines at apparent magnitude 8.97 and has spectral type A.

Its spectrum reads A — 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 209004 in the constellation Cep. At apparent magnitude 8.97, it is an easy target for binoculars.

Like any astronomical target, HD 209004 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 209004 is a trash star

HD 209004 scores 12 points on Spacedle's rarity scale, which places it in the trash tier. Another 3 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Never sets (northern circumpolar) and White A-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.