Epic star 51 EP

HD 10125

RA 25.2198° · Dec 64.1731° · star

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Score breakdown

· 4 badges

51 pts · Epic

Epic 78 pts → Anomaly

Blazing O-type star +26
Supergiant +18
Never sets (northern circumpolar) +4
Star +3

Total score 51

27 more points to reach Anomaly.

Badges

Star · +3
Never sets (northern circumpolar) · +4
Blazing O-type star · +26
Supergiant · +18

Trivia

Hard to believe

True brightness. It pours out about 4.2 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 O9.5Ib — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.
Where it is in life. It is a supergiant, hundreds of times wider than the Sun.

Find it in the sky

How to spot it. At magnitude 8.3 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cassiopeia.
Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
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 yellow-white (B−V 0.3) — 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.

Properties

absmag: -11.74
bv: 0.306
constellation: Cas
luminosity: 4325138.3104
mag: 8.26
name: HD 10125
spect: O9.5Ib

Nearby objects

About HD 10125

HD 10125 is an epic star. It sits in the constellation Cas, shines at apparent magnitude 8.26 and has spectral type O9.5Ib.

Its spectrum reads O9.5Ib — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.

How to see it

Look for HD 10125 in the constellation Cas. At apparent magnitude 8.26, it is an easy target for binoculars.

Like any astronomical target, HD 10125 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 10125 is an epic star

HD 10125 scores 51 points on Spacedle's rarity scale, which places it in the epic tier. Another 27 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, Never sets (northern circumpolar), Blazing O-type star and Supergiant — 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.