Common variable star 20 EP

HD 100277

RA 172.9529° · Dec -60.6934° · star

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Score breakdown

· 5 badges

20 pts · Common

Common 22 pts → Uncommon

Hot blue B-type star +6
Variable star +5
Gently variable +4
A named variable star +3
Main-sequence star +2

Total score 20

2 more points to reach Uncommon.

Badges

Variable star · +5
Hot blue B-type star · +6
Main-sequence star · +2
Gently variable · +4
A named variable star · +3

Trivia

What it actually is

Spectral class. Its spectrum reads B9.5V — 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 on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.
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 7.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Centaurus.
Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
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 brilliant white (B−V 0) — hotter and whiter than the Sun, the colour of Sirius or Vega.
Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

Properties

absmag: -12.13
bv: 0.043
constellation: Cen
luminosity: 6194410.7508
mag: 7.87
name: HD 100277
spect: B9.5V
var amplitude: 0.08
var designation: V1089
var max: 7.844
var min: 7.924

Nearby objects

About HD 100277

HD 100277 is a common variable star. It sits in the constellation Cen, shines at apparent magnitude 7.87 and has spectral type B9.5V.

Its spectrum reads B9.5V — 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 100277 in the constellation Cen. At apparent magnitude 7.87, it is an easy target for binoculars.

Like any astronomical target, HD 100277 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 100277 is a common variable star

HD 100277 scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

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