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Rare variable star 45 EP

HR 6684

RA 269.0767° · Dec 0.6704° · star

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Score breakdown

· 8 badges
45 pts · Rare
Rare 50 pts → Epic
  • Intrinsically luminous (Mv < −2) +10
  • Naked-eye visible +8
  • Distant (over 1,000 light-years) +6
  • Hot blue B-type star +6
  • Variable star +5
  • Subgiant (leaving the main sequence) +5
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 45

5 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • Naked-eye visible · +8
  • Hot blue B-type star · +6
  • Subgiant (leaving the main sequence) · +5
  • Intrinsically luminous (Mv < −2) · +10
  • Barely variable (under 0.05 mag) · +2
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B2IV-V — 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 5.8 you can see it with your own eyes from a dark site, over in Ophiuchus.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • 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. Impossible with our current technology — and the next millennium of it.

Properties

absmag
-2.279
bv
0.058
constellation
Oph
dist ly
1358.9834
luminosity
710.5588
mag
5.82
name
HR 6684
spect
B2IV-V
var amplitude
0.04
var designation
V2052
var max
5.801
var min
5.841

About HR 6684

HR 6684 is a rare variable star. It lies about 1,359 light-years from Earth, sits in the constellation Oph, shines at apparent magnitude 5.82 and has spectral type B2IV-V.

Its spectrum reads B2IV-V — 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 6684 in the constellation Oph. At apparent magnitude 5.82, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 6684 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 6684 is a rare variable star

HR 6684 scores 45 points on Spacedle's rarity scale, which places it in the rare tier. Another 5 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Distant (over 1,000 light-years), Naked-eye visible, Hot blue B-type star, Subgiant (leaving the main sequence), Intrinsically luminous (Mv < −2), 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.