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Uncommon variable star 23 EP

20Chi Ser

RA 235.4476° · Dec 12.8475° · star

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Score breakdown

· 5 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Variable star +5
  • White A-type star +5
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 23

11 more points to reach Rare.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • White A-type star · +5
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads A0p Sr — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
  • 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 5.3 you can see it with your own eyes from a dark site, over in Serpens.
  • 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 May — 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. ≈ 3.9 million years at Voyager 1's speed (17 km/s).

Properties

absmag
1.197
bv
0.033
constellation
Ser
dist ly
219.7815
luminosity
28.9201
mag
5.34
name
20Chi Ser
spect
A0p Sr
var amplitude
0.04
var designation
Chi
var max
5.33
var min
5.37

About 20Chi Ser

20Chi Ser is an uncommon variable star. It lies about 219.8 light-years from Earth, sits in the constellation Ser, shines at apparent magnitude 5.34 and has spectral type A0p Sr.

Its spectrum reads A0p Sr — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for 20Chi Ser in the constellation Ser. At apparent magnitude 5.34, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 20Chi Ser 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 20Chi Ser is an uncommon variable star

20Chi Ser scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, Naked-eye visible, White A-type star, Barely variable (under 0.05 mag) 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.