Uncommon variable star 30 EP

HD 54104

RA 106.8362° · Dec -9.5832° · star

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Score breakdown

· 5 badges

30 pts · Uncommon

Uncommon 34 pts → Rare

Bright giant +12
Hot blue B-type star +6
Variable star +5
Gently variable +4
A named variable star +3

Total score 30

4 more points to reach Rare.

Badges

Variable star · +5
Hot blue B-type star · +6
Bright giant · +12
Gently variable · +4
A named variable star · +3

Trivia

Hard to believe

True brightness. It pours out about 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 B3II-III — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
Where it is in life. It is a bright giant, well on its way to the largest stars there are.
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 8.3 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Monoceros.
Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
Best time of year. It stands highest in the middle of the night around January — that's when to go looking.

Its true colour

Its true colour. Measured through blue and visual filters it comes out brilliant white (B−V 0.2) — hotter and whiter than the Sun, the colour of Sirius or Vega.

Properties

absmag: -11.67
bv: 0.151
constellation: Mon
luminosity: 4055085.3545
mag: 8.33
name: HD 54104
spect: B3II-III
var amplitude: 0.14
var designation: V930
var max: 8.255
var min: 8.395

Nearby objects

About HD 54104

HD 54104 is an uncommon variable star. It sits in the constellation Mon, shines at apparent magnitude 8.33 and has spectral type B3II-III.

Its spectrum reads B3II-III — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for HD 54104 in the constellation Mon. At apparent magnitude 8.33, it is an easy target for binoculars.

Like any astronomical target, HD 54104 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 54104 is an uncommon variable star

HD 54104 scores 30 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 4 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Hot blue B-type star, Bright giant, 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.