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Common variable star 20 EP

HD 16723

RA 40.1107° · Dec -14.4491° · star

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Score breakdown

· 5 badges
20 pts · Common
Common 22 pts → Uncommon
  • Variable star +5
  • White A-type star +5
  • Subgiant (leaving the main sequence) +5
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 20

2 more points to reach Uncommon.

Badges

  • Variable star · +5
  • White A-type star · +5
  • Subgiant (leaving the main sequence) · +5
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads A7IV — 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.
  • Where it is in life. It is a subgiant, caught in the act of leaving the main sequence as the hydrogen in its core runs out.
  • 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 6.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cetus.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around October — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

absmag
0.451
bv
0.261
constellation
Cet
dist ly
582.4213
luminosity
57.491
mag
6.71
name
HD 16723
spect
A7IV
var amplitude
0.04
var designation
BS
var max
6.683
var min
6.723

About HD 16723

HD 16723 is a common variable star. It lies about 582.4 light-years from Earth, sits in the constellation Cet, shines at apparent magnitude 6.71 and has spectral type A7IV.

Its spectrum reads A7IV — 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 HD 16723 in the constellation Cet. At apparent magnitude 6.71, it is an easy target for binoculars.

Like any astronomical target, HD 16723 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 16723 is a common variable star

HD 16723 scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

That score comes from 5 science badges — Variable star, White A-type star, Subgiant (leaving the main sequence), 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.