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Rare variable star 37 EP

HR 6802

RA 272.9923° · Dec -28.9015° · star

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Score breakdown

· 8 badges
37 pts · Rare
Rare 50 pts → Epic
  • Toward the galactic centre +8
  • Hot blue B-type star +6
  • Variable star +5
  • Subgiant (leaving the main sequence) +5
  • Blue-white star +5
  • On the zodiac +3
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 37

13 more points to reach Epic.

Badges

  • Variable star · +5
  • Toward the galactic centre · +8
  • On the zodiac · +3
  • Hot blue B-type star · +6
  • Subgiant (leaving the main sequence) · +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 B9IVspe... — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
  • 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 6.5 it is just past naked-eye reach — ordinary binoculars will pull it in, 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
0.995
bv
-0.016
constellation
Sgr
dist ly
413.3789
luminosity
34.8337
mag
6.51
name
HR 6802
spect
B9IVspe...
var amplitude
0.03
var designation
V4045
var max
6.493
var min
6.523

About HR 6802

HR 6802 is a rare variable star. It lies about 413.4 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 6.51 and has spectral type B9IVspe....

Its spectrum reads B9IVspe... — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.

How to see it

Look for HR 6802 in the constellation Sgr. At apparent magnitude 6.51, it is an easy target for binoculars.

Like any astronomical target, HR 6802 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 6802 is a rare variable star

HR 6802 scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Toward the galactic centre, On the zodiac, Hot blue B-type star, Subgiant (leaving the main sequence), 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.