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Uncommon variable star 23 EP

HD 131949

RA 223.8899° · Dec 35.4559° · star

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Score breakdown

· 5 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Deep red star +8
  • Variable star +5
  • Gently variable +4
  • Orange K-type star +3
  • A named variable star +3
Total score 23

11 more points to reach Rare.

Badges

  • Variable star · +5
  • Orange K-type star · +3
  • Deep red star · +8
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 3.5 million 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 K — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions 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 8.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Boötes.
  • 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 May — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out deep orange-red (B−V 1.6) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3700 K, against the Sun's 5778 K.

Properties

absmag
-11.53
bv
1.564
constellation
Boo
luminosity
3564511.3343
mag
8.47
name
HD 131949
spect
K
var amplitude
0.1
var designation
ES
var max
8.417
var min
8.517

About HD 131949

HD 131949 is an uncommon variable star. It sits in the constellation Boo, shines at apparent magnitude 8.47 and has spectral type K.

Its spectrum reads K — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.

How to see it

Look for HD 131949 in the constellation Boo. At apparent magnitude 8.47, it is an easy target for binoculars.

Like any astronomical target, HD 131949 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 131949 is an uncommon variable star

HD 131949 scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Orange K-type star, Deep red 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.