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Common variable star 17 EP

HD 19918

RA 45.1549° · Dec -81.9020° · star

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Score breakdown

· 4 badges
17 pts · Common
Common 22 pts → Uncommon
  • Variable star +5
  • White A-type star +5
  • Gently variable +4
  • A named variable star +3
Total score 17

5 more points to reach Uncommon.

Badges

  • Variable star · +5
  • White A-type star · +5
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads Ap... — 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 9.3 you'll want a small backyard telescope, over in Hydrus.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • 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. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 14.1 million years at Voyager 1's speed (17 km/s).

Properties

absmag
2.398
bv
0.269
constellation
Hyi
dist ly
801.3659
luminosity
9.5675
mag
9.35
name
HD 19918
spect
Ap...
var amplitude
0.06
var designation
BT
var max
9.323
var min
9.383

About HD 19918

HD 19918 is a common variable star. It lies about 801.4 light-years from Earth, sits in the constellation Hyi, shines at apparent magnitude 9.35 and has spectral type Ap....

Its spectrum reads Ap... — 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 19918 in the constellation Hyi. At apparent magnitude 9.35, a small backyard telescope will bring it into view.

Like any astronomical target, HD 19918 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 19918 is a common variable star

HD 19918 scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 4 science badges — Variable star, White A-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.