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Common star 19 EP

HD 51056

RA 103.7589° · Dec -20.6743° · star

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Score breakdown

· 4 badges
19 pts · Common
Common 22 pts → Uncommon
  • Giant star +6
  • White A-type star +5
  • Blue-white star +5
  • Star +3
Total score 19

3 more points to reach Uncommon.

Badges

  • Star · +3
  • White A-type star · +5
  • Giant star · +6
  • Blue-white star · +5

Trivia

Hard to believe

  • True brightness. It pours out about 963.8 thousand 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 A2III — 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 giant. It has already exhausted its core hydrogen and swollen up enormously in response.

Find it in the sky

  • How to spot it. At magnitude 9.9 you'll want a small backyard telescope, over in Canis Major.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around January — 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.

Properties

absmag
-10.13
bv
-0.107
constellation
CMa
luminosity
981747.943
mag
9.87
name
HD 51056
spect
A2III

About HD 51056

HD 51056 is a common star. It sits in the constellation CMa, shines at apparent magnitude 9.87 and has spectral type A2III.

Its spectrum reads A2III — 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 51056 in the constellation CMa. At apparent magnitude 9.87, a small backyard telescope will bring it into view.

Like any astronomical target, HD 51056 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 51056 is a common star

HD 51056 scores 19 points on Spacedle's rarity scale, which places it in the common tier. Another 3 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, White A-type star, Giant 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.