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Common star 20 EP

HD 100281

RA 172.9210° · Dec -66.4068° · star

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Score breakdown

· 3 badges
20 pts · Common
Common 22 pts → Uncommon
  • Bright giant +12
  • White A-type star +5
  • Star +3
Total score 20

2 more points to reach Uncommon.

Badges

  • Star · +3
  • White A-type star · +5
  • Bright giant · +12

Trivia

Hard to believe

  • True brightness. It pours out about 2.6 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 A7II — 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.
  • Where it is in life. It is a bright giant, well on its way to the largest stars there are.

Find it in the sky

  • How to spot it. At magnitude 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Musca.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around March — 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 0.5) — 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.

Properties

absmag
-11.22
bv
0.494
constellation
Mus
luminosity
2679168.3248
mag
8.78
name
HD 100281
spect
A7II

About HD 100281

HD 100281 is a common star. It sits in the constellation Mus, shines at apparent magnitude 8.78 and has spectral type A7II.

Its spectrum reads A7II — 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 100281 in the constellation Mus. At apparent magnitude 8.78, it is an easy target for binoculars.

Like any astronomical target, HD 100281 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 100281 is a common star

HD 100281 scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, White A-type star and Bright giant — 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.