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Rare variable star 37 EP

Alpheratz

RA 2.0969° · Dec 29.0904° · star

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Score breakdown

· 7 badges
37 pts · Rare
Rare 50 pts → Epic
  • Naked-eye visible +8
  • Has a proper name +8
  • Hot blue B-type star +6
  • Variable star +5
  • Blue-white star +5
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 37

13 more points to reach Epic.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Has a proper name · +8
  • Hot blue B-type star · +6
  • Blue-white star · +5
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9p — 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.
  • 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.

Sense of scale

  • In perspective. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 2.1 you can see it with your own eyes from a dark site, over in Andromeda.
  • 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 September — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 1.7 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-0.297
bv
-0.038
constellation
And
dist ly
97.0125
luminosity
114.4986
mag
2.07
name
Alpheratz
named
yes
spect
B9p
var amplitude
0.02
var designation
Alp
var max
2.063
var min
2.083

About Alpheratz

Alpheratz is a rare variable star. It lies about 97 light-years from Earth, sits in the constellation And, shines at apparent magnitude 2.07 and has spectral type B9p.

Its spectrum reads B9p — 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 Alpheratz in the constellation And. At apparent magnitude 2.07, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, Alpheratz 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 Alpheratz is a rare variable star

Alpheratz scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Naked-eye visible, Has a proper name, Hot blue B-type star, Blue-white star, Barely variable (under 0.05 mag) 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.