About HD 57321
HD 57321 is a common star. It sits in the constellation Mon, shines at apparent magnitude 7.15 and has spectral type F2II.
Its spectrum reads F2II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Common star 18 EP
HD 57321
RA 110.0784° · Dec -8.5498° · star
Score breakdown
· 3 badgesCommon 22 pts → Uncommon
- Bright giant +12
- Star +3
- Yellow-white F-type star +3
Total score 18
4 more points to reach Uncommon.
Badges
- Star · +3
- Yellow-white F-type star · +3
- Bright giant · +12
Trivia
What it actually is
- Spectral class. Its spectrum reads F2II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
- Where it is in life. It is a bright giant, well on its way to the largest stars there are.
Find it in the sky
- How to spot it. At magnitude 7.2 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Monoceros.
- Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
- 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 yellow-white (B−V 0.4) — a shade brighter and crisper than our own Sun.
- 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 6830 K, against the Sun's 5778 K.
Properties
- absmag
- -12.85
- bv
- 0.41
- constellation
- Mon
- luminosity
- 12022644.3462
- mag
- 7.15
- name
- HD 57321
- spect
- F2II
How to see it
Look for HD 57321 in the constellation Mon. At apparent magnitude 7.15, it is an easy target for binoculars.
Like any astronomical target, HD 57321 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 57321 is a common star
HD 57321 scores 18 points on Spacedle's rarity scale, which places it in the common tier. Another 4 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, Yellow-white F-type star and Bright giant — 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.