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Rare star 35 EP

HIP 11807

RA 38.0698° · Dec 61.5542° · star

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Score breakdown

· 4 badges
35 pts · Rare
Rare 50 pts → Epic
  • Blazing O-type star +26
  • Never sets (northern circumpolar) +4
  • Star +3
  • Main-sequence star +2
Total score 35

15 more points to reach Epic.

Badges

  • Star · +3
  • Never sets (northern circumpolar) · +4
  • Blazing O-type star · +26
  • Main-sequence star · +2

Trivia

Hard to believe

  • True brightness. It pours out about 648.6 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 O9V — 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 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 10.3 you'll want a small backyard telescope, 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 0.5) — 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.

Properties

absmag
-9.7
bv
0.536
constellation
Cas
luminosity
660693.448
mag
10.3
name
HIP 11807
spect
O9V

About HIP 11807

HIP 11807 is a rare star. It sits in the constellation Cas, shines at apparent magnitude 10.3 and has spectral type O9V.

Its spectrum reads O9V — 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 HIP 11807 in the constellation Cas. At apparent magnitude 10.3, a small backyard telescope will bring it into view.

Like any astronomical target, HIP 11807 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 HIP 11807 is a rare star

HIP 11807 scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 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 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.