About HD 107447
HD 107447 is a rare variable star. It sits in the constellation Cru, shines at apparent magnitude 6.56 and has spectral type G2Ib.
Its spectrum reads G2Ib — a G-type star: the very same spectral class as our own Sun.
Rare variable star 46 EP
HD 107447
RA 185.3381° · Dec -62.2816° · star
Score breakdown
· 6 badgesRare 50 pts → Epic
- Supergiant +18
- Under the Southern Cross +8
- Sun-like G-type star +8
- Variable star +5
- Gently variable +4
- A named variable star +3
Total score 46
4 more points to reach Epic.
Badges
- Variable star · +5
- Under the Southern Cross · +8
- Sun-like G-type star · +8
- Supergiant · +18
- Gently variable · +4
- A named variable star · +3
Trivia
What it actually is
- Spectral class. Its spectrum reads G2Ib — a G-type star: the very same spectral class as our own Sun.
- Where it is in life. It is a supergiant, hundreds of times wider than the Sun.
- 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 6.6 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Crux.
- 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
- -13.44
- bv
- 0.79
- constellation
- Cru
- luminosity
- 20701413.4879
- mag
- 6.56
- name
- HD 107447
- spect
- G2Ib
- var amplitude
- 0.43
- var designation
- T
- var max
- 6.413
- var min
- 6.843
Nearby objects
How to see it
Look for HD 107447 in the constellation Cru. At apparent magnitude 6.56, it is an easy target for binoculars.
Like any astronomical target, HD 107447 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 107447 is a rare variable star
HD 107447 scores 46 points on Spacedle's rarity scale, which places it in the rare tier. Another 4 points would lift it into a rarer tier.
That score comes from 6 science badges — Variable star, Under the Southern Cross, Sun-like G-type star, Supergiant, Gently 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.