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Trash star 9 EP

HD 77421

RA 135.1302° · Dec -48.9845° · star

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Score breakdown

· 2 badges
9 pts · Trash
Trash 15 pts → Common
  • Hot blue B-type star +6
  • Star +3
Total score 9

6 more points to reach Common.

Badges

  • Star · +3
  • Hot blue B-type star · +6

Trivia

Hard to believe

  • True brightness. It pours out about 1.7 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 B — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

Find it in the sky

  • How to spot it. At magnitude 9.3 you'll want a small backyard telescope, over in Vela.
  • 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 February — 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.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 6600 K, against the Sun's 5778 K.

Properties

absmag
-10.73
bv
0.455
constellation
Vel
luminosity
1706082.389
mag
9.27
name
HD 77421
spect
B

About HD 77421

HD 77421 is a trash star. It sits in the constellation Vel, shines at apparent magnitude 9.27 and has spectral type B.

Its spectrum reads B — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for HD 77421 in the constellation Vel. At apparent magnitude 9.27, a small backyard telescope will bring it into view.

Like any astronomical target, HD 77421 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 77421 is a trash star

HD 77421 scores 9 points on Spacedle's rarity scale, which places it in the trash tier. Another 6 points would lift it into a rarer tier.

That score comes from 2 science badges — Star and Hot blue B-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.