About HD 187321
HD 187321 is an uncommon star. It sits in the constellation Sge, shines at apparent magnitude 7.09 and has spectral type G5II-III.
Its spectrum reads G5II-III — a G-type star: the very same spectral class as our own Sun.
Uncommon star 23 EP
HD 187321
RA 297.1818° · Dec 18.8670° · star
Score breakdown
· 3 badgesUncommon 34 pts → Rare
- Bright giant +12
- Sun-like G-type star +8
- Star +3
Total score 23
11 more points to reach Rare.
Badges
- Star · +3
- Sun-like G-type star · +8
- Bright giant · +12
Trivia
What it actually is
- Spectral class. Its spectrum reads G5II-III — a G-type star: the very same spectral class as our own 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 7.1 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagitta.
- 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.
Its true colour
- Its true colour. Measured through blue and visual filters it comes out orange (B−V 0.9) — cooler than the Sun, and the kind of star that burns steadily for tens of billions of years.
- 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 5120 K, against the Sun's 5778 K.
Properties
- absmag
- -12.91
- bv
- 0.856
- constellation
- Sge
- luminosity
- 12705741.0521
- mag
- 7.09
- name
- HD 187321
- spect
- G5II-III
How to see it
Look for HD 187321 in the constellation Sge. At apparent magnitude 7.09, it is an easy target for binoculars.
Like any astronomical target, HD 187321 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 187321 is an uncommon star
HD 187321 scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, Sun-like G-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.