Note the difference in brightness between the close binary pair and Proxima.
| The Sun And Its Nearest Neighbors |
Sun | Alpha Centauri A |
Alpha Centauri B |
Proxima |
| Color | Yellow | Yellow | Orange | Red |
| Spectral type | G2 | G2 | K1 | M5 |
| Temperature | 5800 K | 5800 K | 5300 K | 2700 K |
| Mass | 1.00 | 1.09 | 0.90 | 0.1 |
| Radius | 1.00 | 1.2 | 0.8 | 0.2 |
| Brightness | 1.00 | 1.54 | 0.44 | 0.00006 |
| Distance (light-years) |
0.00 | 4.35 | 4.35 | 4.22 |
| Age (billion years) |
4.6 | 5 - 6 | 5 - 6 | ~1? |
Note that Proxima is not thought to have planets which could harbor life. There are several reasons for this. Some are speculation; others are solid fact. Perhaps the most compelling reason is that it IS a red dwarf. To keep a planet warm enough for liquid water, it would have to orbit Proxima so closely (4 to 9 million miles distant) that it would become tidally locked with one side always facing Proxima. Even if there WERE a narrow habitable zone, there is still a problem with the star. Flares on a red dwarf are just as big as on our own sun. They are proportionately much greater in magnitude in relation to the size of red dwarfs. So a close-in planet could also suffer occasional toastings in all kinds of radiation. All in all, Proxima is not a good place to look for life.
