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Rare star 34 EP

HIP 77994

RA 238.9150° · Dec -54.6435° · star

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Score breakdown

· 3 badges
34 pts · Rare
Rare 50 pts → Epic
  • Blazing O-type star +26
  • Subgiant (leaving the main sequence) +5
  • Star +3
Total score 34

16 more points to reach Epic.

Badges

  • Star · +3
  • Blazing O-type star · +26
  • Subgiant (leaving the main sequence) · +5

Trivia

Hard to believe

  • True brightness. It pours out about 591.6 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 O9.5IV — 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 subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.

Find it in the sky

  • How to spot it. At magnitude 10.4 you'll want a small backyard telescope, over in Norma.
  • 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 May — 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 0.6) — 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
-9.6
bv
0.55
constellation
Nor
luminosity
602559.5861
mag
10.4
name
HIP 77994
spect
O9.5IV

About HIP 77994

HIP 77994 is a rare star. It sits in the constellation Nor, shines at apparent magnitude 10.4 and has spectral type O9.5IV.

Its spectrum reads O9.5IV — 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 77994 in the constellation Nor. At apparent magnitude 10.4, a small backyard telescope will bring it into view.

Like any astronomical target, HIP 77994 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 77994 is a rare star

HIP 77994 scores 34 points on Spacedle's rarity scale, which places it in the rare tier. Another 16 points would lift it into a rarer tier.

That score comes from 3 science badges — Star, Blazing O-type star and Subgiant (leaving the main sequence) — 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.