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Rare variable star 37 EP

HD 109983

RA 189.7146° · Dec 13.8038° · star

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Score breakdown

· 6 badges
37 pts · Rare
Rare 50 pts → Epic
  • Strongly variable +10
  • Deep red star +8
  • Red dwarf +6
  • Variable star +5
  • Cool red M-type star +5
  • A named variable star +3
Total score 37

13 more points to reach Epic.

Badges

  • Variable star · +5
  • Cool red M-type star · +5
  • Deep red star · +8
  • Red dwarf · +6
  • Strongly variable · +10
  • A named variable star · +3

Trivia

Hard to believe

  • True brightness. It pours out about 2.7 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 M... — 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 Coma Berenices.
  • 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 March — 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 3670 K, against the Sun's 5778 K.

Properties

absmag
-11.23
bv
1.585
constellation
Com
luminosity
2703958.3641
mag
8.77
name
HD 109983
spect
M...
var amplitude
0.75
var designation
KM
var max
8.276
var min
9.026

About HD 109983

HD 109983 is a rare variable star. It sits in the constellation Com, shines at apparent magnitude 8.77 and has spectral type M....

Its spectrum reads M... — 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 109983 in the constellation Com. At apparent magnitude 8.77, it is an easy target for binoculars.

Like any astronomical target, HD 109983 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 109983 is a rare variable star

HD 109983 scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

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