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Common star 17 EP

HD 23990

RA 57.4437° · Dec 9.4075° · star

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Score breakdown

· 4 badges
17 pts · Common
Common 22 pts → Uncommon
  • Hot blue B-type star +6
  • Blue-white star +5
  • Star +3
  • On the zodiac +3
Total score 17

5 more points to reach Uncommon.

Badges

  • Star · +3
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Blue-white star · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9 — 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.

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 6.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Taurus.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around November — 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. ≈ 7.1 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 631.1 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

absmag
1.304
bv
-0.026
constellation
Tau
dist ly
404.1585
luminosity
26.206
mag
6.77
name
HD 23990
spect
B9

About HD 23990

HD 23990 is a common star. It lies about 404.2 light-years from Earth, sits in the constellation Tau, shines at apparent magnitude 6.77 and has spectral type B9.

Its spectrum reads B9 — 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 23990 in the constellation Tau. At apparent magnitude 6.77, it is an easy target for binoculars.

Like any astronomical target, HD 23990 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 23990 is a common star

HD 23990 scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 4 science badges — Star, On the zodiac, Hot blue B-type 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.