← Back to dex
Uncommon variable star 31 EP

17 Aur

RA 79.5787° · Dec 33.7673° · star

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

Computing the sky for your location…

Score breakdown

· 6 badges
31 pts · Uncommon
Uncommon 34 pts → Rare
  • Strongly variable +10
  • Hot blue B-type star +6
  • Variable star +5
  • Blue-white star +5
  • A named variable star +3
  • Main-sequence star +2
Total score 31

3 more points to reach Rare.

Badges

  • Variable star · +5
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • Blue-white star · +5
  • Strongly variable · +10
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B9.5V — 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.
  • 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 6.2 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.

Properties

absmag
0.716
bv
-0.043
constellation
Aur
dist ly
398.2368
luminosity
45.0402
mag
6.15
name
17 Aur
spect
B9.5V
var amplitude
0.57
var designation
AR
var max
6.14
var min
6.71

About 17 Aur

17 Aur is an uncommon variable star. It lies about 398.2 light-years from Earth, sits in the constellation Aur, shines at apparent magnitude 6.15 and has spectral type B9.5V.

Its spectrum reads B9.5V — 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 17 Aur in the constellation Aur. At apparent magnitude 6.15, it is an easy target for binoculars.

Like any astronomical target, 17 Aur 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 17 Aur is an uncommon variable star

17 Aur scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.

That score comes from 6 science badges — Variable star, Hot blue B-type star, Main-sequence star, Blue-white 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.