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Trash star 13 EP

HD 55755

RA 108.4771° · Dec -10.2213° · star

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Score breakdown

· 3 badges
13 pts · Trash
Trash 15 pts → Common
  • White A-type star +5
  • Blue-white star +5
  • Star +3
Total score 13

2 more points to reach Common.

Badges

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

Trivia

Hard to believe

  • True brightness. It pours out about 990.8 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 Ap — 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 9.8 you'll want a small backyard telescope, over in Monoceros.
  • 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.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 11220 K, against the Sun's 5778 K.

Properties

absmag
-10.16
bv
-0.078
constellation
Mon
luminosity
1009252.8861
mag
9.84
name
HD 55755
spect
Ap

About HD 55755

HD 55755 is a trash star. It sits in the constellation Mon, shines at apparent magnitude 9.84 and has spectral type Ap.

Its spectrum reads Ap — 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 55755 in the constellation Mon. At apparent magnitude 9.84, a small backyard telescope will bring it into view.

Like any astronomical target, HD 55755 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 55755 is a trash star

HD 55755 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, White A-type 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.