Uncommon variable star 31 EP

HD 219910

RA 349.9261° · Dec -31.3549° · star

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Score breakdown

· 6 badges

31 pts · Uncommon

Uncommon 34 pts → Rare

Deep red star +8
Giant star +6
Variable star +5
Cool red M-type star +5
Gently variable +4
A named variable star +3

Total score 31

3 more points to reach Rare.

Badges

Variable star · +5
Cool red M-type star · +5
Giant star · +6
Deep red star · +8
Gently variable · +4
A named variable star · +3

Trivia

Hard to believe

True brightness. It pours out about 2.4 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 M0III: — 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 giant. It has already exhausted its core hydrogen and swollen up enormously in response.
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 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sculptor.
Southern sky. It rides the southern half of the sky — an easier target the further south 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 1.6) — one of the coolest surfaces a star can have while still fusing.

Properties

absmag: -11.12
bv: 1.57
constellation: Scl
luminosity: 2443430.5527
mag: 8.88
name: HD 219910
spect: M0III:
var amplitude: 0.15
var designation: BQ
var max: 8.819
var min: 8.969

Nearby objects

About HD 219910

HD 219910 is an uncommon variable star. It sits in the constellation Scl, shines at apparent magnitude 8.88 and has spectral type M0III:.

Its spectrum reads M0III: — 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 219910 in the constellation Scl. At apparent magnitude 8.88, it is an easy target for binoculars.

Like any astronomical target, HD 219910 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 219910 is an uncommon variable star

HD 219910 scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.

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