Sirius
| DISTANCE 8.58 light years |
| MASS A : 2.06 B : 1.02 |
| LUMINOSITY A: 24 B: 0.0080 |
| RADIUS A: 1.71 solar radii B: 0.0084 solar radii |
| TEMPERATURE A: 9,940 K B: 25,000 K |
Sirius, also known as Alpha Canis Majoris, is the brightest star in the night sky. This young, 300-million-year-old binary system has an orbital period of 50.09 years, with an average distance between the two stars of about 3 billion kilometres but varies over time due to their elliptical orbit. Sirius A, a pure white coloured star (spectral type A0 or A1), has a radius of approximately one million kilometres, and Sirius B is a small white dwarf of radius close to 5,000 kilometres (spectral type DA2).
This small white companion is an ageing star which has used up its main sources of energy and now shines feebly as it loses heat to its outer layers. It is believed among astronomers that the small white dwarf was once the more massive of the two. Any native life developing on an unseen planet in this system would be very primitive indeed.
Luyten 726-8
| DISTANCE 8.73 light years |
| MASS A : 0.1225 B : 0.1195 |
| LUMINOSITY A: 0.00147 B: 0.00125 |
| RADIUS A: 0.165 B: 0.159 |
| SURFACE TEMPERATURE A: 2,784 K B: 2,728 K |
Luyten 726-8, also known as Gliese 65, is a binary star system located in the constellation Cetus. The stars are separated by an average distance of 1.65 billion kilometres (but varies from 2.1 to 8.8 astronomical units) and take approximately 26.5 years to orbit each other. As for the type of stars we have lurking in this part of the cosmic neighborhood. Luyten 726-8 A or BL Ceti (spectral type M5.5V) is of the 'flare-up' variety. Luyten 726-8 A or UV Ceti (spectral type M6 V) also displays flare activity, and is slightly dimmer. Not an ideal solar system to find technically-advanced aliens.
Willem Jacob Luyten discovered the system in 1948 while compiling a catalog of stars with high proper motion. He noted its exceptionally high proper motion of 3.37 arc seconds annually and cataloged it as Luyten 726-8.
Two dark companions, possibly planets, seem to orbit one or both of these stars although the period of orbit for each has not been determined as of 2023.
Ross 154
| DISTANCE 9.67 light years |
| MASS 0.17 |
| LUMINOSITY 0.0038 |
| RADIUS 0.24 |
| SURFACE TEMPERATURE 3,293 K |
| AGE 800 million years old |
Ross 154, also known as V1216 Sgr, is a star located in the southern zodiac constellation of Sagittarius. This is another uninteresting red dwarf 'flare-type' star (spectral type M3.5V), probably younger than our Sun. It is emitting harmful, sporadic bursts of radiation every two days or so; and its dim red colour may not be of a suitable wavelength to support primitive photosynthesizing microorganisms, assuming life were in fact trying to emerge on some unseen rocky terrestrial world in this part of the stellar neighbourhood. Just to add to the difficulties of any alien life in this solar system, the star is said to be emitting stronger the usual x-rays. Unless the alien life can live in a cave or underground and/or have a thick shell to withstand the extra radiation, this is one place you will most likely not find any intelligent and technically-advanced civilisation.
American astronomer Frank Elmore Ross catalogued this star in 1925 and gave it the name we see today.