About HD 99683
HD 99683 is an uncommon star. It sits in the constellation Cen, shines at apparent magnitude 8.94 and has spectral type F2Ib/II.
Its spectrum reads F2Ib/II — an F-type star — a little hotter, whiter and shorter-lived than the Sun.
Uncommon star 24 EP
HD 99683
RA 171.8582° · Dec -60.5462° · 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
Hard to believe
- True brightness. It pours out about 2.3 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 F2Ib/II — 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 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Centaurus.
- Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
- Best time of year. It stands highest in the middle of the night around March — 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
- -11.06
- bv
- 0.803
- constellation
- Cen
- luminosity
- 2312064.7902
- mag
- 8.94
- name
- HD 99683
- spect
- F2Ib/II
Nearby objects
How to see it
Look for HD 99683 in the constellation Cen. At apparent magnitude 8.94, it is an easy target for binoculars.
Like any astronomical target, HD 99683 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 99683 is an uncommon star
HD 99683 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.