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Rare variable star 48 EP

HR 4830

RA 190.7095° · Dec -63.0586° · star

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Score breakdown

· 8 badges
48 pts · Rare
Rare 50 pts → Epic
  • Intrinsically luminous (Mv < −2) +10
  • Naked-eye visible +8
  • Under the Southern Cross +8
  • Distant (over 1,000 light-years) +6
  • Hot blue B-type star +6
  • Variable star +5
  • A named variable star +3
  • Barely variable (under 0.05 mag) +2
Total score 48

2 more points to reach Epic.

Badges

  • Variable star · +5
  • Distant (over 1,000 light-years) · +6
  • Naked-eye visible · +8
  • Under the Southern Cross · +8
  • Hot blue B-type star · +6
  • 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 B2pe — 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.
  • 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 5.3 you can see it with your own eyes from a dark site, over in Crux.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around April — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

  • Aboard Voyager 1. ≈ 21.4 million years at Voyager 1's speed (17 km/s).

Properties

absmag
-2.589
bv
0.195
constellation
Cru
dist ly
1216.9999
luminosity
945.366
mag
5.27
name
HR 4830
spect
B2pe
var amplitude
0.05
var designation
BZ
var max
5.253
var min
5.303

About HR 4830

HR 4830 is a rare variable star. It lies about 1,217 light-years from Earth, sits in the constellation Cru, shines at apparent magnitude 5.27 and has spectral type B2pe.

Its spectrum reads B2pe — 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 4830 in the constellation Cru. At apparent magnitude 5.27, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 4830 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 4830 is a rare variable star

HR 4830 scores 48 points on Spacedle's rarity scale, which places it in the rare tier. Another 2 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, Under the Southern Cross, Hot blue B-type star, 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.