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Common star 17 EP

HD 75750

RA 133.0834° · Dec 19.3508° · star

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Score breakdown

· 4 badges
17 pts · Common
Common 22 pts → Uncommon
  • Hot blue B-type star +6
  • Blue-white star +5
  • Star +3
  • On the zodiac +3
Total score 17

5 more points to reach Uncommon.

Badges

  • Star · +3
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Blue-white star · +5

Trivia

Hard to believe

  • True brightness. It pours out about 3.4 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 B5 — 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 8.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cancer.
  • 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 February — 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 12070 K, against the Sun's 5778 K.

Properties

absmag
-11.5
bv
-0.128
constellation
Cnc
luminosity
3467368.5045
mag
8.5
name
HD 75750
spect
B5

About HD 75750

HD 75750 is a common star. It sits in the constellation Cnc, shines at apparent magnitude 8.5 and has spectral type B5.

Its spectrum reads B5 — 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 75750 in the constellation Cnc. At apparent magnitude 8.5, it is an easy target for binoculars.

Like any astronomical target, HD 75750 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 75750 is a common star

HD 75750 scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, On the zodiac, Hot blue B-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.