Common star 15 EP

HD 16653

RA 40.6258° · Dec 58.5726° · star

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Score breakdown

· 4 badges

15 pts · Common

Common 22 pts → Uncommon

Hot blue B-type star +6
Never sets (northern circumpolar) +4
Star +3
Main-sequence star +2

Total score 15

7 more points to reach Uncommon.

Badges

Star · +3
Never sets (northern circumpolar) · +4
Hot blue B-type star · +6
Main-sequence star · +2

Trivia

Hard to believe

True brightness. It pours out about 2.4 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 B9.5V — 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.
Where it is in life. It is on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.

Find it in the sky

How to spot it. At magnitude 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cassiopeia.
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 October — that's when to go looking.

Its true colour

Its true colour. Measured through blue and visual filters it comes out brilliant white (B−V 0.1) — hotter and whiter than the Sun, the colour of Sirius or Vega.
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: -11.11
bv: 0.142
constellation: Cas
luminosity: 2421029.0467
mag: 8.89
name: HD 16653
spect: B9.5V

Nearby objects

About HD 16653

HD 16653 is a common star. It sits in the constellation Cas, shines at apparent magnitude 8.89 and has spectral type B9.5V.

Its spectrum reads B9.5V — 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 16653 in the constellation Cas. At apparent magnitude 8.89, it is an easy target for binoculars.

Like any astronomical target, HD 16653 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 16653 is a common star

HD 16653 scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 7 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, Never sets (northern circumpolar), Hot blue B-type star and Main-sequence 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.