About HD 21022
HD 21022 is a trash star. It sits in the constellation For, shines at apparent magnitude 9.2 and has spectral type G6/G8V:w.
Its spectrum reads G6/G8V:w — a G-type star: the very same spectral class as our own Sun.
Trash star 13 EP
HD 21022
RA 50.5900° · Dec -32.9944° · star
Score breakdown
· 3 badgesTrash 15 pts → Common
- Sun-like G-type star +8
- Star +3
- Main-sequence star +2
Total score 13
2 more points to reach Common.
Badges
- Star · +3
- Sun-like G-type star · +8
- Main-sequence star · +2
Trivia
Hard to believe
- True brightness. It pours out about 1.8 million times as much light as the Sun. It only looks ordinary because it is so far away.
What it actually is
- Spectral class. Its spectrum reads G6/G8V:w — a G-type star: the very same spectral class as our own Sun.
Find it in the sky
- How to spot it. At magnitude 9.2 you'll want a small backyard telescope, over in Fornax.
- 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 November — 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 4870 K, against the Sun's 5778 K.
Properties
- absmag
- -10.8
- bv
- 0.949
- constellation
- For
- luminosity
- 1819700.8586
- mag
- 9.2
- name
- HD 21022
- spect
- G6/G8V:w
How to see it
Look for HD 21022 in the constellation For. At apparent magnitude 9.2, a small backyard telescope will bring it into view.
Like any astronomical target, HD 21022 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 21022 is a trash star
HD 21022 scores 13 points on Spacedle's rarity scale, which places it in the trash tier. Another 2 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, Sun-like G-type star and Main-sequence 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.