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Uncommon variable star 31 EP

HR 3661

RA 138.1272° · Dec -43.6133° · star

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Score breakdown

· 7 badges
31 pts · Uncommon
Uncommon 34 pts → Rare
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Variable star +5
  • Blue-white star +5
  • A named variable star +3
  • Main-sequence star +2
  • Barely variable (under 0.05 mag) +2
Total score 31

3 more points to reach Rare.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • 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 B8V — 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 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 5.6 you can see it with your own eyes from a dark site, over in Vela.
  • 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 February — that's when to go looking.

Could we get there?

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

Properties

absmag
-1.075
bv
-0.107
constellation
Vel
dist ly
692.4755
luminosity
234.4229
mag
5.56
name
HR 3661
spect
B8V
var amplitude
0.04
var designation
KL
var max
5.538
var min
5.578

About HR 3661

HR 3661 is an uncommon variable star. It lies about 692.5 light-years from Earth, sits in the constellation Vel, shines at apparent magnitude 5.56 and has spectral type B8V.

Its spectrum reads B8V — 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 3661 in the constellation Vel. At apparent magnitude 5.56, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 3661 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 3661 is an uncommon variable star

HR 3661 scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.

That score comes from 7 science badges — Variable star, Naked-eye visible, Hot blue B-type star, Main-sequence star, 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.