Rare variable star 43 EP

HR 4800

RA 189.0978° · Dec 59.4869° · star

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Score breakdown

· 6 badges

43 pts · Rare

Rare 50 pts → Epic

Dramatic variable (over 2 magnitudes) +20
Giant star +6
Variable star +5
Cool red M-type star +5
Never sets (northern circumpolar) +4
A named variable star +3

Total score 43

7 more points to reach Epic.

Badges

Variable star · +5
Never sets (northern circumpolar) · +4
Cool red M-type star · +5
Giant star · +6
Dramatic variable (over 2 magnitudes) · +20
A named variable star · +3

Trivia

Hard to believe

True brightness. It pours out about 2.5 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 M4IIIe-M7e — 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 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Ursa Major.
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 orange (B−V 1.2) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.

Properties

absmag: -11.17
bv: 1.21
constellation: UMa
luminosity: 2558585.8869
mag: 8.83
name: HR 4800
spect: M4IIIe-M7e
var amplitude: 4.63
var designation: T
var max: 7.147
var min: 11.777

Nearby objects

About HR 4800

HR 4800 is a rare variable star. It sits in the constellation UMa, shines at apparent magnitude 8.83 and has spectral type M4IIIe-M7e.

Its spectrum reads M4IIIe-M7e — 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 HR 4800 in the constellation UMa. At apparent magnitude 8.83, it is an easy target for binoculars.

Like any astronomical target, HR 4800 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 HR 4800 is a rare variable star

HR 4800 scores 43 points on Spacedle's rarity scale, which places it in the rare tier. Another 7 points 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, Dramatic variable (over 2 magnitudes) 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.