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Rare variable star 39 EP

16Tau4Eri

RA 49.8792° · Dec -21.7579° · star

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Score breakdown

· 7 badges
39 pts · Rare
Rare 50 pts → Epic
  • Naked-eye visible +8
  • Deep red star +8
  • Giant star +6
  • Variable star +5
  • Cool red M-type star +5
  • Gently variable +4
  • A named variable star +3
Total score 39

11 more points to reach Epic.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Cool red M-type star · +5
  • Giant star · +6
  • Deep red star · +8
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M3/M4III — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.
  • 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 3.7 you can see it with your own eyes from a dark site, over in Eridanus.
  • 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 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. ≈ 5.4 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-1.151
bv
1.614
constellation
Eri
dist ly
304.5341
luminosity
251.4201
mag
3.7
name
16Tau4Eri
spect
M3/M4III
var amplitude
0.07
var designation
Tau-4
var max
3.66
var min
3.73

About 16Tau4Eri

16Tau4Eri is a rare variable star. It lies about 304.5 light-years from Earth, sits in the constellation Eri, shines at apparent magnitude 3.7 and has spectral type M3/M4III.

Its spectrum reads M3/M4III — an M-type red star — and M stars are the silent majority: roughly three of every four stars in the galaxy are one.

How to see it

Look for 16Tau4Eri in the constellation Eri. At apparent magnitude 3.7, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 16Tau4Eri 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 16Tau4Eri is a rare variable star

16Tau4Eri scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Naked-eye visible, Cool red M-type star, Giant star, Deep red star, Gently variable 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.