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Rare variable star 36 EP

HD 183143

RA 291.8607° · Dec 18.2959° · star

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Score breakdown

· 5 badges
36 pts · Rare
Rare 50 pts → Epic
  • Supergiant +18
  • Hot blue B-type star +6
  • Variable star +5
  • Gently variable +4
  • A named variable star +3
Total score 36

14 more points to reach Epic.

Badges

  • Variable star · +5
  • Hot blue B-type star · +6
  • Supergiant · +18
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B7Ia — 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.
  • Where it is in life. It is a luminous supergiant — among the largest and rarest stars in the galaxy.
  • 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 6.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagitta.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out orange (B−V 1) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 4720 K, against the Sun's 5778 K.

Properties

absmag
-13.16
bv
1.009
constellation
Sge
luminosity
15995580.2861
mag
6.84
name
HD 183143
spect
B7Ia
var amplitude
0.15
var designation
HT
var max
6.778
var min
6.928

About HD 183143

HD 183143 is a rare variable star. It sits in the constellation Sge, shines at apparent magnitude 6.84 and has spectral type B7Ia.

Its spectrum reads B7Ia — 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 183143 in the constellation Sge. At apparent magnitude 6.84, it is an easy target for binoculars.

Like any astronomical target, HD 183143 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 183143 is a rare variable star

HD 183143 scores 36 points on Spacedle's rarity scale, which places it in the rare tier. Another 14 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Hot blue B-type star, Supergiant, 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.