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Common variable star 18 EP

HD 130437

RA 222.7094° · Dec -60.2862° · star

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Score breakdown

· 4 badges
18 pts · Common
Common 22 pts → Uncommon
  • Hot blue B-type star +6
  • Variable star +5
  • Gently variable +4
  • A named variable star +3
Total score 18

4 more points to reach Uncommon.

Badges

  • Variable star · +5
  • Hot blue B-type star · +6
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 990.8 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 Be — 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.
  • It changes. This star does not hold still: its brightness rises and falls on a rhythm of hours, days or years, either pulsing in size or being eclipsed by a companion.

Find it in the sky

  • How to spot it. At magnitude 9.8 you'll want a small backyard telescope, over in Circinus.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • 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 (B−V 0.6) — almost exactly the Sun's own shade — a stellar twin in colour, if not in size.
  • 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
-10.16
bv
0.611
constellation
Cir
luminosity
1009252.8861
mag
9.84
name
HD 130437
spect
Be
var amplitude
0.15
var designation
CQ
var max
9.771
var min
9.921

Nearby objects

About HD 130437

HD 130437 is a common variable star. It sits in the constellation Cir, shines at apparent magnitude 9.84 and has spectral type Be.

Its spectrum reads Be — 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 130437 in the constellation Cir. At apparent magnitude 9.84, a small backyard telescope will bring it into view.

Like any astronomical target, HD 130437 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 130437 is a common variable star

HD 130437 scores 18 points on Spacedle's rarity scale, which places it in the common tier. Another 4 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, Hot blue B-type star, Gently variable and A named variable 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.