2MASS J1812-2608

DISTANCE 11.588 light years

MASS A : 0.153

This uninspiring name is given to a newly discovered brown dwarf (spectral class T) with 1.5 per cent of our Sun's solar mass. There are currently no known exoplanets in this star system. The only thing we know about this object is that it has an unusually strong magnetic field.

Groombridge 34

DISTANCE 11.619 light years

MASS A : 0.398 B : 0.16

LUMINOSITY A: 0.02249 B: 0.00085

RADIUS A: 0.385 B: 0.18

AGE A: 3.02 billion years B: 2.754 billion years

SURFACE TEMPERATURE A: 3,603 K B: 3,318 K

Groombridge 34 is a binary star system in the northern constellation of Andromeda. Its was named in 1838 by the British astronomer Stephen Groombridge. Groombridge 34 A is a red dwarf variable 'flare-type' star (spectral type M1) that emits irregular bursts of light, while its companion is an ordinary red dwarf (spectral type M6) although there are indications that it will exhibit random variations in luminosity due to flares. They orbit each other at a distance of approximately 93 astronomical units (AU), with an orbital period of around 1,230 years.

Close study of this binary system has revealed what is probably a planet orbiting Groombridge 34 A called Gliese 15 Ab (also known as Groombridge 34 Ab or GX Andromedae b). At this stage, there is no evidence that it is a rocky planet capable of supporting life.

DX Cancri

DISTANCE 11.83 light years

MASS 0.9

LUMINOSITY 0.09

RADIUS 0.11

AGE 200 million years old

SURFACE TEMPERATURE 2,840 K

DX Cancri (or Gliese 1111) is a red dwarf star in the constellation of Cancer. There is nothing particularly special about this red dwarf (spectral type M6.5V), as it is considered quite typical for stars of this type. However, it does exhibit random and intermittent increases in brightness when it ejects flares into space, making this star system a difficult place for life to establish itself on a nearby planet. Of course, this does not mean that no alien life can exist. Primitive alien creatures could be sheltered in caves, but it is unlikely that life could evolve into a technically-advanced form, as far as we can tell.

Tau Ceti

DISTANCE 11.90 light years

MASS 0.78

LUMINOSITY 0.44

Tau Ceti (spectral type G8) is one of the nearest stars that is sufficiently similar to the Sun (and is visible in the night sky here on Earth) to be regarded as a likely centre for a planetary system and the highest prospects for finding extraterrestrial life. Indeed, this star is so stable with little stellar variability, that it should be able to support highly intelligent and technically-advanced life to evolve on an unseen planet.

Speaking of planets, indirect observations have revealed at least four planets orbiting Tau Ceti, and as many as two of these are in the habitable zone for life to take hold and evolve over billions of years. One of the other planets is large enough to be described as a Jovian planet, similar to our gaseous planet Jupiter. Details of its size relative to our planet Jupiter remain scarce at this stage, until more time has been spent analysing the planet's gravitational pull on the star.

Compared to our Sun, Tau Ceti is metal deficient, but not completely metal-free. It simply means that nearby rocky planets are unlikely to have fewer metals available to develop technology. So what little metals are available are likely to be highly valued by a primitive alien civilisation, much like gold is here on Earth. However, this does not necessarily mean that a technically advanced civilisation could not exist. There are enough metals to help a civilisation develop a spacecraft. In fact, all an alien civilisation would need to do is travel around the solar system to acquire a lot more metals if they so wished. Also, this star system seems to have ten times as much dust in its debris disk as our Solar System. A great resource for any budding civilisation looking to make a mark in its cosmic region.

Gliese 1061

DISTANCE 12.00 light years

MASS 0.113

LUMINOSITY 0.1

Located in the constellation of Horologium, here we have another ordinary red dwarf (spectral type M5). However, what makes this one a little more interesting is the discovery of three exoplanets. They are designated Gliese 1061b, Gliese 1061c, and Gliese 1061d. In the first planet from the star (i.e., Gliese 1061b), astronomers believe that there is a super-Earth exists with a mass of 1.37 times that of the Earth. This inner planet has an orbital radius of 0.021 AU and completes its orbit in 3.2 days. In fact, the next two planets are also described as super-Earth planets. With a mass of 1.74 of our Earth, we know Gliese 1061c orbits the red dwarf in a period of 6.7 days.

The third super-Earth has a mass 1.64 times that of our own Earth. It has an orbital period of 13 days and was discovered in 2020. Gliese 1061d is a potentially habitable exoplanet.

Luyten's Star

DISTANCE 12.36 light years

MASS 0.27

LUMINOSITY 0.0014

Located in the constellation Canis Minor, it is a single red dwarf of about a quarter the Sun's mass with a surface temperature of about 3000 degrees Kelvin (spectral type M5). Early observations in the 1990s gave rise to what was thought to be a huge invisible companion of mass 60 relative to Jupiter looming nearby. If true, this body would take about seven years to complete an orbit around the red dwarf. However, as of 2020, astronomers are happy to announce that Luyten’s Star contains two confirmed rocky planets and two candidate rocky planets, with the possibility of a fifth planet lurking in this system that has yet to be confirmed. What makes this star system interesting is the outermost rocky planet known as GJ 273b. It is described as a super-Earth (i.e., slightly larger than our own) and lies in the habitable zone of its star where liquid water can exist. Because of the high probability of finding alien life on this planet, it has become a favourite destination for some people to send a radio signal containing music from Earth's human inhabitants on one day each year.

Scientists are not expecting to find a technically advanced alien life in this star system (so getting a response to our radio communications will be highly unlikely, so don't hold your breath on this one), but evolving animal and plant life could definitely be on the cards for the fourth rocky planet.

Kapteyn's Star

DISTANCE 12.83 light years

MASS 0.274

LUMINOSITY 0.12

RADIUS 0.3

Discovered by the Dutch astronomer Jacobus Kapteyn in 1898, this seemingly ordinary looking red dwarf (spectral type M1) is 30 per cent the diameter of the Sun, but only 1.2 per cent the luminosity of the Sun. What makes this red dwarf a little distinctive from other similar stars is the way it orbits the Milky Way. It seems to move in the opposite direction to other stars. Its retrograde orbit could suggest that this red dwarf was once part of another smaller galaxy that has merged with our Milky Way a long time ago. Apart from this interesting observation, we know that the star was closest to our Sun at 7.0 light years away about 10,900 years ago. Now the star is moving away.

In 2014, astronomers announced the discovery of two planets orbiting Kapteyn’s Star, known simply as Kapteyn b and Kapteyn c. However, a more thorough 2021 study has refuted the claims.

Lacaille 8760

DISTANCE 12.87 light years

MASS 0.4

LUMINOSITY 0.025

Another ordinary red dwarf (spectral type M0), typical of stars of this type. This one is located in the constellation of Microscopium and one of the brightest main-sequence M-class stars in the Earth's night sky (although you still need a telescope to observe it).

Apart from that, no planets have been detected as of 2023 unless they are quite small and of the rocky variety and, therefore, not able to pull on the star enough for us to detect them.