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Rare star 44 EP

HD 151515

RA 252.4510° · Dec -42.0017° · star

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Score breakdown

· 4 badges
44 pts · Rare
Rare 50 pts → Epic
  • Blazing O-type star +26
  • Bright giant +12
  • Star +3
  • On the zodiac +3
Total score 44

6 more points to reach Epic.

Badges

  • Star · +3
  • On the zodiac · +3
  • Blazing O-type star · +26
  • Bright giant · +12

Trivia

What it actually is

  • Spectral class. Its spectrum reads O7II... — 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 bright giant, well on its way to the largest stars there are.

Find it in the sky

  • How to spot it. At magnitude 7.2 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Scorpius.
  • 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 June — 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.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 8810 K, against the Sun's 5778 K.

Properties

absmag
-12.84
bv
0.123
constellation
Sco
luminosity
11912420.0803
mag
7.16
name
HD 151515
spect
O7II...

About HD 151515

HD 151515 is a rare star. It sits in the constellation Sco, shines at apparent magnitude 7.16 and has spectral type O7II....

Its spectrum reads O7II... — 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 151515 in the constellation Sco. At apparent magnitude 7.16, it is an easy target for binoculars.

Like any astronomical target, HD 151515 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 151515 is a rare star

HD 151515 scores 44 points on Spacedle's rarity scale, which places it in the rare tier. Another 6 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, On the zodiac, Blazing O-type star and Bright giant — 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.