← Back to dex
Common variable star 15 EP

HD 209458

RA 330.7949° · Dec 18.8843° · star

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

Computing the sky for your location…

Score breakdown

· 4 badges
15 pts · Common
Common 22 pts → Uncommon
  • Variable star +5
  • Gently variable +4
  • Yellow-white F-type star +3
  • A named variable star +3
Total score 15

7 more points to reach Uncommon.

Badges

  • Variable star · +5
  • Yellow-white F-type star · +3
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads F8 — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • 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 7.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Pegasus.
  • 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 August — 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. ≈ 2.8 million years at Voyager 1's speed (17 km/s).

Properties

absmag
4.171
bv
0.594
constellation
Peg
dist ly
161.864
luminosity
1.869
mag
7.65
name
HD 209458
spect
F8
var amplitude
0.05
var designation
V376
var max
7.629
var min
7.679

About HD 209458

HD 209458 is a common variable star. It lies about 161.9 light-years from Earth, sits in the constellation Peg, shines at apparent magnitude 7.65 and has spectral type F8.

Its spectrum reads F8 — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for HD 209458 in the constellation Peg. At apparent magnitude 7.65, it is an easy target for binoculars.

Like any astronomical target, HD 209458 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 209458 is a common variable star

HD 209458 scores 15 points on Spacedle's rarity scale, which places it in the common tier. Another 7 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, Yellow-white F-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.