← Back to dex
Uncommon star 27 EP

Eta2CrA

RA 282.3958° · Dec -43.4341° · star

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 5 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Subgiant (leaving the main sequence) +5
  • Blue-white star +5
  • Star +3
Total score 27

7 more points to reach Rare.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • Hot blue B-type star · +6
  • Subgiant (leaving the main sequence) · +5
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9IV — 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.

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 5.6 you can see it with your own eyes from a dark site, over in Corona Australis.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around July — 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. ≈ 8.5 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-0.247
bv
-0.077
constellation
CrA
dist ly
481.7667
luminosity
109.3453
mag
5.6
name
Eta2CrA
spect
B9IV

About Eta2CrA

Eta2CrA is an uncommon star. It lies about 481.8 light-years from Earth, sits in the constellation CrA, shines at apparent magnitude 5.6 and has spectral type B9IV.

Its spectrum reads B9IV — 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 Eta2CrA in the constellation CrA. At apparent magnitude 5.6, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, Eta2CrA 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 Eta2CrA is an uncommon star

Eta2CrA scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 5 science badges — Star, Naked-eye visible, Hot blue B-type star, Subgiant (leaving the main sequence) and Blue-white 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.