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Rare variable star 49 EP

HD 236979

RA 39.6059° · Dec 57.0462° · star

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Score breakdown

· 6 badges
49 pts · Rare
Rare 50 pts → Epic
  • Supergiant +18
  • Strongly variable +10
  • Deep red star +8
  • Variable star +5
  • Cool red M-type star +5
  • A named variable star +3
Total score 49

1 more point to reach Epic.

Badges

  • Variable star · +5
  • Cool red M-type star · +5
  • Supergiant · +18
  • Deep red star · +8
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M1Iab:var — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • Where it is in life. It is a supergiant. Drop it where the Sun is and its surface would engulf the inner planets.
  • 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 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Perseus.
  • 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 October — 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 1.5) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3790 K, against the Sun's 5778 K.

Properties

absmag
-12.01
bv
1.5
constellation
Per
luminosity
5546257.1296
mag
7.99
name
HD 236979
spect
M1Iab:var
var amplitude
0.8
var designation
YZ
var max
7.7
var min
8.5

About HD 236979

HD 236979 is a rare variable star. It sits in the constellation Per, shines at apparent magnitude 7.99 and has spectral type M1Iab:var.

Its spectrum reads M1Iab:var — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

How to see it

Look for HD 236979 in the constellation Per. At apparent magnitude 7.99, it is an easy target for binoculars.

Like any astronomical target, HD 236979 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 236979 is a rare variable star

HD 236979 scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Cool red M-type star, Supergiant, Deep red star, Strongly 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.