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Uncommon star 31 EP

HD 63733

RA 117.4406° · Dec -19.0069° · star

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Score breakdown

· 3 badges
31 pts · Uncommon
Uncommon 34 pts → Rare
  • S-type star (zirconium giant) +20
  • Deep red star +8
  • Star +3
Total score 31

3 more points to reach Rare.

Badges

  • Star · +3
  • S-type star (zirconium giant) · +20
  • Deep red star · +8

Trivia

What it actually is

  • Spectral class. Its spectrum reads S — an S-type giant, its atmosphere laced with zirconium dredged up from the fusion going on below.

Find it in the sky

  • How to spot it. At magnitude 7.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Puppis.
  • 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 January — that's when to go looking.

Its true colour

  • Its true colour. Measured through blue and visual filters it comes out deep orange-red (B−V 1.7) — one of the coolest surfaces a star can have while still fusing.

By the numbers

  • Surface temperature. Its colour puts the surface at roughly 3460 K, against the Sun's 5778 K.

What's in a name

  • Its catalogue. The HD number is from the Henry Draper Catalogue, in which Annie Jump Cannon personally classified the spectra of nearly 400,000 stars — still the largest such feat by one person.

Properties

absmag
-12.1
bv
1.745
constellation
Pup
luminosity
6025595.8607
mag
7.9
name
HD 63733
spect
S

About HD 63733

HD 63733 is an uncommon star. It sits in the constellation Pup, shines at apparent magnitude 7.9 and has spectral type S.

Its spectrum reads S — an S-type giant, its atmosphere laced with zirconium dredged up from the fusion going on below.

How to see it

Look for HD 63733 in the constellation Pup. At apparent magnitude 7.9, it is an easy target for binoculars.

Like any astronomical target, HD 63733 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 HD 63733 is an uncommon star

HD 63733 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 3 science badges — Star, S-type star (zirconium giant) and Deep red 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.