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Rare variable star 43 EP

HR 7739

RA 303.8162° · Dec 25.5920° · star

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Score breakdown

· 8 badges
43 pts · Rare
Rare 50 pts → Epic
  • Intrinsically luminous (Mv < −2) +10
  • Naked-eye visible +8
  • Hot blue B-type star +6
  • Variable star +5
  • Blue-white star +5
  • Gently variable +4
  • A named variable star +3
  • Main-sequence star +2
Total score 43

7 more points to reach Epic.

Badges

  • Variable star · +5
  • Naked-eye visible · +8
  • Hot blue B-type star · +6
  • Main-sequence star · +2
  • Blue-white star · +5
  • Intrinsically luminous (Mv < −2) · +10
  • Gently variable · +4
  • A named variable star · +3

Trivia

What it actually is

  • Spectral class. Its spectrum reads B3V — 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 4.8 you can see it with your own eyes from a dark site, over in Vulpecula.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around July — that's when to go looking.

Could we get there?

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

Properties

absmag
-2.624
bv
-0.181
constellation
Vul
dist ly
991.3557
luminosity
976.3376
mag
4.79
name
HR 7739
spect
B3V
var amplitude
0.07
var designation
QR
var max
4.748
var min
4.818

About HR 7739

HR 7739 is a rare variable star. It lies about 991.4 light-years from Earth, sits in the constellation Vul, shines at apparent magnitude 4.79 and has spectral type B3V.

Its spectrum reads B3V — 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 7739 in the constellation Vul. At apparent magnitude 4.79, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 7739 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 7739 is a rare variable star

HR 7739 scores 43 points on Spacedle's rarity scale, which places it in the rare tier. Another 7 points would lift it into a rarer tier.

That score comes from 8 science badges — Variable star, Naked-eye visible, Hot blue B-type star, Main-sequence star, Blue-white star, Intrinsically luminous (Mv < −2), 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.