← Back to dex
Rare variable star 44 EP

HR 1209

RA 58.8462° · Dec 31.0458° · star

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

Computing the sky for your location…

Score breakdown

· 5 badges
44 pts · Rare
Rare 50 pts → Epic
  • Blazing O-type star +26
  • Distant (over 1,000 light-years) +6
  • Variable star +5
  • Gently variable +4
  • A named variable star +3
Total score 44

6 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • Blazing O-type star · +26
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads O9.5pe — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.
  • 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 6.8 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Perseus.
  • 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 November — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

  • Aboard Voyager 1. ≈ 24.5 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-1.364
bv
0.081
constellation
Per
dist ly
1393.829
luminosity
305.9145
mag
6.79
name
HR 1209
spect
O9.5pe
var amplitude
0.07
var designation
X
var max
6.743
var min
6.813

About HR 1209

HR 1209 is a rare variable star. It lies about 1,393.8 light-years from Earth, sits in the constellation Per, shines at apparent magnitude 6.79 and has spectral type O9.5pe.

Its spectrum reads O9.5pe — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.

How to see it

Look for HR 1209 in the constellation Per. At apparent magnitude 6.79, it is an easy target for binoculars.

Like any astronomical target, HR 1209 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 HR 1209 is a rare variable star

HR 1209 scores 44 points on Spacedle's rarity scale, which places it in the rare tier. Another 6 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Distant (over 1,000 light-years), Blazing O-type 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.