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Uncommon variable star 23 EP

HR 2722

RA 108.6106° · Dec 24.7111° · star

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Score breakdown

· 6 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Variable star +5
  • White A-type star +5
  • Blue-white star +5
  • On the zodiac +3
  • 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
  • On the zodiac · +3
  • White A-type star · +5
  • Blue-white star · +5
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads A1sp... — 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 6.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Gemini.
  • 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 January — 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. ≈ 9.6 million years at Voyager 1's speed (17 km/s).

Properties

absmag
0.756
bv
-0.002
constellation
Gem
dist ly
547.2415
luminosity
43.411
mag
6.88
name
HR 2722
spect
A1sp...
var amplitude
0.03
var designation
V356
var max
6.867
var min
6.897

About HR 2722

HR 2722 is an uncommon variable star. It lies about 547.2 light-years from Earth, sits in the constellation Gem, shines at apparent magnitude 6.88 and has spectral type A1sp....

Its spectrum reads A1sp... — 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 HR 2722 in the constellation Gem. At apparent magnitude 6.88, it is an easy target for binoculars.

Like any astronomical target, HR 2722 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 2722 is an uncommon variable star

HR 2722 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 6 science badges — Variable star, On the zodiac, White A-type star, Blue-white 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.