About HD 186438
HD 186438 is an uncommon star. It sits in the constellation Cyg, shines at apparent magnitude 7.92 and has spectral type F3Ib.
Its spectrum reads F3Ib — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Uncommon star 24 EP
HD 186438
RA 295.7205° · Dec 37.6782° · star
Score breakdown
· 3 badgesUncommon 34 pts → Rare
- Supergiant +18
- Star +3
- Yellow-white F-type star +3
Total score 24
10 more points to reach Rare.
Badges
- Star · +3
- Yellow-white F-type star · +3
- Supergiant · +18
Trivia
What it actually is
- Spectral class. Its spectrum reads F3Ib — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
- Where it is in life. It is a supergiant, hundreds of times wider than the Sun.
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 Cygnus.
- 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 yellow-white (B−V 0.5) — 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 6260 K, against the Sun's 5778 K.
Properties
- absmag
- -12.08
- bv
- 0.53
- constellation
- Cyg
- luminosity
- 5915616.3418
- mag
- 7.92
- name
- HD 186438
- spect
- F3Ib
How to see it
Look for HD 186438 in the constellation Cyg. At apparent magnitude 7.92, it is an easy target for binoculars.
Like any astronomical target, HD 186438 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 186438 is an uncommon star
HD 186438 scores 24 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 10 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, Yellow-white F-type star and Supergiant — 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.