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Uncommon star 27 EP

40Tau Lib

RA 234.6641° · Dec -29.7778° · star

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Score breakdown

· 6 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Blue-white star +5
  • Star +3
  • On the zodiac +3
  • Main-sequence star +2
Total score 27

7 more points to reach Rare.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads B2.5V — 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.

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 3.7 you can see it with your own eyes from a dark site, over in Libra.
  • 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 May — 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. ≈ 6.4 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-1.595
bv
-0.177
constellation
Lib
dist ly
366.8795
luminosity
378.4426
mag
3.66
name
40Tau Lib
spect
B2.5V

About 40Tau Lib

40Tau Lib is an uncommon star. It lies about 366.9 light-years from Earth, sits in the constellation Lib, shines at apparent magnitude 3.66 and has spectral type B2.5V.

Its spectrum reads B2.5V — 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 40Tau Lib in the constellation Lib. At apparent magnitude 3.66, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 40Tau Lib 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 40Tau Lib is an uncommon star

40Tau Lib 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 6 science badges — Star, Naked-eye visible, On the zodiac, Hot blue B-type star, Main-sequence star 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.