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Common star 21 EP

HR 3960

RA 150.5004° · Dec -60.4209° · star

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Score breakdown

· 4 badges
21 pts · Common
Common 22 pts → Uncommon
  • Naked-eye visible +8
  • White A-type star +5
  • Subgiant (leaving the main sequence) +5
  • Star +3
Total score 21

1 more point to reach Uncommon.

Badges

  • Star · +3
  • Naked-eye visible · +8
  • White A-type star · +5
  • Subgiant (leaving the main sequence) · +5

Trivia

What it actually is

  • Spectral class. Its spectrum reads A9IV — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.
  • 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.

Find it in the sky

  • How to spot it. At magnitude 5.9 you can see it with your own eyes from a dark site, over in Carina.
  • 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 February — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out brilliant white (B−V 0.3) — hotter and whiter than the Sun, the colour of Sirius or Vega.
  • Why no green stars. No star ever looks green: a surface hot enough to peak in green also floods out plenty of red and blue, and your eye blends the mixture back to white.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 7710 K, against the Sun's 5778 K.

Properties

absmag
-14.07
bv
0.263
constellation
Car
luminosity
36982817.978
mag
5.93
name
HR 3960
spect
A9IV

About HR 3960

HR 3960 is a common star. It sits in the constellation Car, shines at apparent magnitude 5.93 and has spectral type A9IV.

Its spectrum reads A9IV — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.

How to see it

Look for HR 3960 in the constellation Car. At apparent magnitude 5.93, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, HR 3960 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 3960 is a common star

HR 3960 scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.

That score comes from 4 science badges — Star, Naked-eye visible, White A-type star and Subgiant (leaving the main sequence) — 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.