Ross 248

DISTANCE 10.306 light years

MASS 0.136

LUMINOSITY 0.0018

RADIUS 0.16

SURFACE TEMPERATURE 3,142 K

Ross 248, also known as HH Andromedae or Gliese 905, is a small star located in the northern constellation of Andromeda. With an age of 20 billion years, this red dwarf 'flare-type' star (spectral type M6V) is considered old in terms of the average lifespan of a typical main-sequence star. The flare up nature of this star varies its luminosity in a cyclic fashion that occurs every 4.2 years or thereabouts. Again not an ideal location for alien life to establish on an unseen rocky planet.

A planet may be orbiting Ross 248 of unspecified mass but this has not yet been confirmed as of 2023.

About the only piece of worthy information to note is how Voyager 2 will pass within 1.7 light years of this red dwarf in approximately 40,000 years. And, in terms of the distance to our Sun, this red dwarf will be closer to us than Alpha Centauri within the next 80,000 years. Of course, by then we will have electromagnetic vehicles to venture out to this star, and we may even decide to pick up Voyager 2 and bring it back to Earth just to reduce the clutter in space with yet more of our space junk (and so avoid yet another potential collision for those star-faring pilots and passengers of Earth who want to visit this solar system).

Epsilon Eridani

DISTANCE 10.502 light years

MASS 0.82

LUMINOSITY 0.30

RADIUS 0.74

SURFACE TEMPERATURE 5,183 K

AGE 950 million years

Epsilon Eridani is a star in the southern constellation of Eridanus visible to the naked eye in Earth's night sky. This main sequence star has an orange surface (spectral type K2), meaning it is slightly cooler than our Sun. It has three-quarters the Sun's mass, giving out one-third the light. However, it seems the age of this star is quite young, at roughly under a billion years. It also means the star is producing a higher level of magnetic activity than our Sun and as a result is whipping out a particularly strong stellar wind of about 30 times higher than the stellar wind generated by our Sun.

In the 1980s, satellites equipped with infra-red detectors have found dust around Epsilon Eridani in support of a planetary system of diameter seven times the Earth's distance from the Sun. In more recent times, more powerful infra-red satellites has now put the debris of dust much further out to as much as 100 astronomical units. And where there is a dust, there are likely to be planets. In fact, the indirect method of detecting planets by 'wobbles' in a star's motion has successfully revealed a dark companion. At first it was thought to be a brown dwarf in the 1980s due to its suggested size of between six and ten times that of Jupiter and orbiting the star every 26 years at a distance from the star of approximately 1,200 million kilometres. Canadian astronomers Bruce Campbell, Gordon Walker and Stephenson Yang from the observatory at Mauna Kea, Hawaii, made the first announcement of this dark companion in the 1980s after a period of 6 years of careful observation of the star. As of 2000, NASA scientists can now confirm this dark companion is a large gaseous planet (named Epsilon Eridani b) with a mass of 0.66 that of Jupiter, and its correct orbital period is 7.3 years at roughly 3.53 astronomical units from the parent star. If these figures are correct, then it would suggest that this planet is much closer to the star than our own Jupiter, which is about 5.2 astronomical units from the Sun. However, there appears to be much more gaseous planets orbiting Epsilon Eridani than our own and is lying invisibly in the gap found in the debris disc between 20 and 70 astronomical units. At the moment, scientists are unable to detect all the gaseous planets (let alone rocky ones lying in the inner orbits, which are expected to be among this large solar system), probably because their numbers and spread around the solar system is making the task of detecting each and every one of them much more difficult through the 'wobble' technique.

Is there an inner rocky planet capable of supporting native alien life? Perhaps. However, the youthful age of this star would suggest that any life on a rocky planet in the right habitable zone may be only starting off as tiny microbes at this stage, or perhaps the chemistry on an unseen Earth-like planet hasn't quite sparked the right moment for life to appear at the present time. The primitive nature of any alien life in this star system seems to be confirmed by the fact that in 1995, a microwave survey of the sky, called Project Phoenix, had searched for signals from extraterrestrialsof selected star systems of which Epsilon Eridani was one of its targets, but no signals were found. Perhaps we will need to wait for another 3.5 billion years before we can get a reply?

Lacaille 9352

DISTANCE 10.724 light years

MASS 0.486

LUMINOSITY 0.0367

RADIUS 0.46

SURFACE TEMPERATURE 3,727 K

More red dwarfs than you can poke a stick at, this one is no exception. A small cool red dwarf of spectral type M0.5V and a type of main sequence star. This one is located in the southern constellation of Piscis Austrinus.

About the only notable feature of this solar system is the existence of two super-Earth planets (discovered in June 2020). There is the potential for a third planet but this has yet to be confirmed as of 2023. If it is a planet, this one is likely to be in the habitable zone, but again its size will decide how likely life can develop on its surface. Given that the red dwarf is fairly stable and emitting constant radiation of the safer frequency range, it would not be too surprising if primitive life forms could emerge on some unseen rocky world.

Ross 128

DISTANCE 11.07 light years

MASS 0.168

LUMINOSITY 0.00362

RADIUS 0.197

SURFACE TEMPERATURE 3,264 K

AGE 9.45 billion years

Ross 128 is a red dwarf star located in the zodiac constellation Virgo. The age of this red dwarf is the same as our Sun. But its dim orange-red colour (spectral type M4 V) may not be emitting sufficient light for primitive plants to evolve on some hidden planet. About the only good thing going for it and for alien life is the stability of its nuclear fusion process and its constant emission of light, mostly in the infra-red band.

Infra-red detectors have found dust around this star. On closer inspection, it would appear that this red dwarf may be harbouring at least one Earth-sized planet, known as Ross 128b. This one is a little more interesting in the sense that the planet is located in the star’s inner habitable zone. Technically-advanced alien life may be slim, but primitive alien life could be in abundance. Again all this depends on whether alien life can adapt to the infra-red light from its parent star. Worthy of an exploration once humans get cracking on developing an electromagnetic vehicle to take them to the stars.

Luyten 789-6

DISTANCE 11.1 light years

MASS A: 0.1187 B: 0.1145 C: 0.0930

LUMINOSITY A: 0.0001 B: ? C: 0.0001

RADIUS A: 0.1 B: 0.1 C: 0.1

SURFACE TEMPERATURE A: 2,827 K B: 2,650 K C: ?

Also named Gliese 866, EZ Aquarii, and LHS 68, Luyten 789-6 is located in the constellation Aquarius. This one is a little more interesting in the sense that it is a triple star system, and has an age of 20 billion years making this star system quite old. Whilst its age might be favourable to alien life, their spectral type of M5 V would suggest a very poor candidate for finding life native to this star system. In fact, due to the high rotation rate of the main star (Luyten 789-6 A), it sends out flares every now and then. The other two red dwarfs, however, appear more stable. They orbit each other at a distance of 0.8 astronomical units making one complete orbit in 3.8 days, and then revolves around the main red dwarf lasting 823 days to complete one orbit. These two red dwarfs lying so close to each other would allow a planet in the habitable zone to orbit them with great stability, but so far no planet has been detected.

The distance of separation for the two inner binary stars would allow for a rocky planet to exist in the habitable zone, but so far scientists are out of luck in finding such a planet, or any other planet for that matter further out from this star system.

Other than that piece of interesting news, this triple star system will make it closest approach to our Solar System in approximately 32,300 years at a distance of 8.2 light-years from the Sun.