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Uncommon variable star 29 EP

HD 46421

RA 98.9045° · Dec 45.6231° · star

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Score breakdown

· 5 badges
29 pts · Uncommon
Uncommon 34 pts → Rare
  • Strongly variable +10
  • Giant star +6
  • Variable star +5
  • Cool red M-type star +5
  • A named variable star +3
Total score 29

5 more points to reach Rare.

Badges

  • Variable star · +5
  • Cool red M-type star · +5
  • Giant star · +6
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads M4:IIIvar — 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 8.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Auriga.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around December — 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. ≈ 16.1 million years at Voyager 1's speed (17 km/s).

Properties

absmag
0.843
bv
1.371
constellation
Aur
dist ly
913.6021
luminosity
40.0682
mag
8.08
name
HD 46421
spect
M4:IIIvar
var amplitude
0.56
var designation
TU
var max
7.947
var min
8.507

About HD 46421

HD 46421 is an uncommon variable star. It lies about 913.6 light-years from Earth, sits in the constellation Aur, shines at apparent magnitude 8.08 and has spectral type M4:IIIvar.

Its spectrum reads M4:IIIvar — 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 HD 46421 in the constellation Aur. At apparent magnitude 8.08, it is an easy target for binoculars.

Like any astronomical target, HD 46421 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 46421 is an uncommon variable star

HD 46421 scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 5 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Cool red M-type star, Giant star, Strongly 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.