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Rare variable star 35 EP

HD 236180

RA 354.1310° · Dec 51.1270° · star

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Score breakdown

· 7 badges
35 pts · Rare
Rare 50 pts → Epic
  • Deep red star +8
  • Red dwarf +6
  • Variable star +5
  • Cool red M-type star +5
  • Never sets (northern circumpolar) +4
  • Gently variable +4
  • A named variable star +3
Total score 35

15 more points to reach Epic.

Badges

  • Variable star · +5
  • Never sets (northern circumpolar) · +4
  • Cool red M-type star · +5
  • Deep red star · +8
  • Red dwarf · +6
  • Gently variable · +4
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 2.6 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 M2 — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • 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 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cassiopeia.
  • 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 September — 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 1.8) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3370 K, against the Sun's 5778 K.

Properties

absmag
-11.19
bv
1.818
constellation
Cas
luminosity
2606153.55
mag
8.81
name
HD 236180
spect
M2
var amplitude
0.1
var designation
V815
var max
8.755
var min
8.855

About HD 236180

HD 236180 is a rare variable star. It sits in the constellation Cas, shines at apparent magnitude 8.81 and has spectral type M2.

Its spectrum reads M2 — 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 236180 in the constellation Cas. At apparent magnitude 8.81, it is an easy target for binoculars.

Like any astronomical target, HD 236180 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 236180 is a rare variable star

HD 236180 scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Never sets (northern circumpolar), Cool red M-type star, Deep red star, Red dwarf, 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.