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Uncommon variable star 28 EP

HD 163649

RA 269.6800° · Dec -33.3260° · star

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Score breakdown

· 7 badges
28 pts · Uncommon
Uncommon 34 pts → Rare
  • Toward the galactic centre +8
  • Variable star +5
  • Gently variable +4
  • On the zodiac +3
  • Yellow-white F-type star +3
  • A named variable star +3
  • Main-sequence star +2
Total score 28

6 more points to reach Rare.

Badges

  • Variable star · +5
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • Yellow-white F-type star · +3
  • Main-sequence star · +2
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads F3V — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
  • Where it is in life. It is on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.
  • 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 9.2 you'll want a small backyard telescope, over in Sagittarius.
  • 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 June — that's when to go looking.

Could we get there?

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

Properties

absmag
3.9
bv
0.45
constellation
Sgr
dist ly
377.9329
luminosity
2.3988
mag
9.22
name
HD 163649
spect
F3V
var amplitude
0.08
var designation
V1721
var max
9.186
var min
9.266

About HD 163649

HD 163649 is an uncommon variable star. It lies about 377.9 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 9.22 and has spectral type F3V.

Its spectrum reads F3V — an F-type star — a little hotter, whiter and shorter-lived than the Sun.

How to see it

Look for HD 163649 in the constellation Sgr. At apparent magnitude 9.22, a small backyard telescope will bring it into view.

Like any astronomical target, HD 163649 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 163649 is an uncommon variable star

HD 163649 scores 28 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 6 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Toward the galactic centre, On the zodiac, Yellow-white F-type star, Main-sequence 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.