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Uncommon star 22 EP

HD 225519

RA 295.8689° · Dec 35.0744° · star

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Score breakdown

· 4 badges
22 pts · Uncommon
Uncommon 34 pts → Rare
  • Deep red star +8
  • Red dwarf +6
  • Cool red M-type star +5
  • Star +3
Total score 22

12 more points to reach Rare.

Badges

  • Star · +3
  • Cool red M-type star · +5
  • Deep red star · +8
  • Red dwarf · +6

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 M0 — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

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 Cygnus.
  • 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 deep orange-red (B−V 1.6) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3610 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-11.3
bv
1.625
constellation
Cyg
luminosity
2884031.5031
mag
8.7
name
HD 225519
spect
M0

About HD 225519

HD 225519 is an uncommon star. It sits in the constellation Cyg, shines at apparent magnitude 8.7 and has spectral type M0.

Its spectrum reads M0 — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

How to see it

Look for HD 225519 in the constellation Cyg. At apparent magnitude 8.7, it is an easy target for binoculars.

Like any astronomical target, HD 225519 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 225519 is an uncommon star

HD 225519 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 4 science badges — Star, Cool red M-type star, Deep red star and Red dwarf — 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.