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Epic variable star 52 EP

The2Cru

RA 181.0801° · Dec -63.1657° · star

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Score breakdown

· 9 badges
52 pts · Epic
Epic 78 pts → Anomaly
  • Intrinsically luminous (Mv < −2) +10
  • Naked-eye visible +8
  • Under the Southern Cross +8
  • Hot blue B-type star +6
  • Variable star +5
  • Subgiant (leaving the main sequence) +5
  • Blue-white star +5
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 52

26 more points to reach Anomaly.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Under the Southern Cross · +8
  • Hot blue B-type star · +6
  • Subgiant (leaving the main sequence) · +5
  • Blue-white star · +5
  • Intrinsically luminous (Mv < −2) · +10
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B2IV — 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 subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.
  • 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. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 4.7 you can see it with your own eyes from a dark site, over in Crux.
  • 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.

Could we get there?

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

Properties

absmag
-2.37
bv
-0.081
constellation
Cru
dist ly
853.8115
luminosity
772.6806
mag
4.72
name
The2Cru
spect
B2IV
var amplitude
0.02
var designation
The-2
var max
4.707
var min
4.727

About The2Cru

The2Cru is an epic variable star. It lies about 853.8 light-years from Earth, sits in the constellation Cru, shines at apparent magnitude 4.72 and has spectral type B2IV.

Its spectrum reads B2IV — 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 The2Cru in the constellation Cru. At apparent magnitude 4.72, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, The2Cru 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 The2Cru is an epic variable star

The2Cru scores 52 points on Spacedle's rarity scale, which places it in the epic tier. Another 26 points would lift it into a rarer tier.

That score comes from 9 science badges — Variable star, Naked-eye visible, Under the Southern Cross, Hot blue B-type star, Subgiant (leaving the main sequence), Blue-white star, Intrinsically luminous (Mv < −2) and Barely variable (under 0.05 mag) — 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.