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Common star 21 EP

HD 170368

RA 277.6489° · Dec -36.4066° · star

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Score breakdown

· 5 badges
21 pts · Common
Common 22 pts → Uncommon
  • Toward the galactic centre +8
  • White A-type star +5
  • Star +3
  • On the zodiac +3
  • Main-sequence star +2
Total score 21

1 more point to reach Uncommon.

Badges

  • Star · +3
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • White A-type star · +5
  • Main-sequence star · +2

Trivia

Hard to believe

  • True brightness. It pours out about 2 million times as much light as the Sun. It only looks ordinary because it is so far away.

What it actually is

  • Spectral class. Its spectrum reads A7V+... — 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 on the main sequence, quietly fusing hydrogen in its core exactly as the Sun does.

Find it in the sky

  • How to spot it. At magnitude 9.1 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.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out brilliant white (B−V 0.3) — hotter and whiter than the Sun, the colour of Sirius or Vega.
  • Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

Properties

absmag
-10.91
bv
0.261
constellation
Sgr
luminosity
2013724.2499
mag
9.09
name
HD 170368
spect
A7V+...

About HD 170368

HD 170368 is a common star. It sits in the constellation Sgr, shines at apparent magnitude 9.09 and has spectral type A7V+....

Its spectrum reads A7V+... — 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 170368 in the constellation Sgr. At apparent magnitude 9.09, a small backyard telescope will bring it into view.

Like any astronomical target, HD 170368 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 170368 is a common star

HD 170368 scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.

That score comes from 5 science badges — Star, Toward the galactic centre, On the zodiac, White A-type star and Main-sequence 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.