Uncommon variable star 33 EP

HD 149683

RA 247.4912° · Dec 72.2803° · star

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Score breakdown

· 6 badges

33 pts · Uncommon

Uncommon 34 pts → Rare

Strongly variable +10
Giant star +6
Variable star +5
Cool red M-type star +5
Never sets (northern circumpolar) +4
A named variable star +3

Total score 33

1 more point to reach Rare.

Badges

Variable star · +5
Never sets (northern circumpolar) · +4
Cool red M-type star · +5
Giant star · +6
Strongly variable · +10
A named variable star · +3

Trivia

Hard to believe

True brightness. It pours out about 1.4 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 M7IIIe — 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 9.5 you'll want a small backyard telescope, over in Ursa Minor.
Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
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 orange (B−V 1.1) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.

Properties

absmag: -10.52
bv: 1.142
constellation: UMi
luminosity: 1406047.5241
mag: 9.48
name: HD 149683
spect: M7IIIe
var amplitude: 1.11
var designation: R
var max: 8.959
var min: 10.069

Nearby objects

About HD 149683

HD 149683 is an uncommon variable star. It sits in the constellation UMi, shines at apparent magnitude 9.48 and has spectral type M7IIIe.

Its spectrum reads M7IIIe — 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 149683 in the constellation UMi. At apparent magnitude 9.48, a small backyard telescope will bring it into view.

Like any astronomical target, HD 149683 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 149683 is an uncommon variable star

HD 149683 scores 33 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 1 point would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Never sets (northern circumpolar), Cool red M-type star, Giant 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.