About HD 81222
HD 81222 is an uncommon variable star. It sits in the constellation Vel, shines at apparent magnitude 7.57 and has spectral type F8II.
Its spectrum reads F8II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Uncommon variable star 33 EP
HD 81222
RA 140.5674° · Dec -55.9603° · star
Score breakdown
· 5 badgesUncommon 34 pts → Rare
- Bright giant +12
- Strongly variable +10
- Variable star +5
- Yellow-white F-type star +3
- A named variable star +3
Total score 33
1 more point to reach Rare.
Badges
- Variable star · +5
- Yellow-white F-type star · +3
- Bright giant · +12
- Strongly variable · +10
- A named variable star · +3
Trivia
What it actually is
- Spectral class. Its spectrum reads F8II — 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.
- It changes. This star does not hold still: its brightness rises and falls on a rhythm of hours, days or years, either pulsing in size or being eclipsed by a companion.
Find it in the sky
- How to spot it. At magnitude 7.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Vela.
- 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 February — that's when to go looking.
Its true colour
- Its true colour. Measured through blue and visual filters it comes out yellow (B−V 0.8) — almost exactly the Sun's own shade — a stellar twin in colour, if not in size.
- 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.
Properties
- absmag
- -12.43
- bv
- 0.752
- constellation
- Vel
- luminosity
- 8165823.7136
- mag
- 7.57
- name
- HD 81222
- spect
- F8II
- var amplitude
- 0.67
- var designation
- V
- var max
- 7.181
- var min
- 7.851
How to see it
Look for HD 81222 in the constellation Vel. At apparent magnitude 7.57, it is an easy target for binoculars.
Like any astronomical target, HD 81222 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 81222 is an uncommon variable star
HD 81222 scores 33 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 1 point would lift it into a rarer tier.
That score comes from 5 science badges — Variable star, Yellow-white F-type star, Bright giant, Strongly variable and A named variable 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.