About HD 203155
HD 203155 is a trash star. It sits in the constellation Cyg, shines at apparent magnitude 6.99 and has spectral type F5.
Its spectrum reads F5 — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Trash star 6 EP
HD 203155
RA 319.8326° · Dec 38.8066° · star
Score breakdown
· 2 badgesTrash 15 pts → Common
- Star +3
- Yellow-white F-type star +3
Total score 6
9 more points to reach Common.
Badges
- Star · +3
- Yellow-white F-type star · +3
Trivia
What it actually is
- Spectral class. Its spectrum reads F5 — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Find it in the sky
- How to spot it. At magnitude 7 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 August — 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 6330 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
- -13.01
- bv
- 0.514
- constellation
- Cyg
- luminosity
- 13931568.0295
- mag
- 6.99
- name
- HD 203155
- spect
- F5
How to see it
Look for HD 203155 in the constellation Cyg. At apparent magnitude 6.99, it is an easy target for binoculars.
Like any astronomical target, HD 203155 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 203155 is a trash star
HD 203155 scores 6 points on Spacedle's rarity scale, which places it in the trash tier. Another 9 points would lift it into a rarer tier.
That score comes from 2 science badges — Star and Yellow-white F-type 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.