2MASS J1812-2608

DISTANCE 11.588 light years

MASS A : 0.153

This uninspiring name is for a newly discovered brown dwarf (spectral class T) that has 1.5 per cent of our Sun's solar mass. At the moment, there are no known exoplanets in this star system. About the only thing we can say about this object is its unusual 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 located in the northern constellation of Andromeda. Its was named in 1838 by British astronomer Stephen Groombridge. Groombridge 34 A is a red dwarf variable 'flare-type' star (spectral type M1) emitting 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 with a separation distance of approximately 93 astronomical units (AU), and the orbital period is around 1,230 years.

A close study of this binary system has revealed what is likely to be a planet orbiting Groombridge 34 A called Gliese 15 Ab (also known as Groombridge 34 Ab or GX Andromedae b). No indications at this stage 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 located in the Cancer constellation. Nothing particularly special to note about this red dwarf (spectral type M6.5V) as it is considered quite typical of 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 on a nearby planet. Of course, this does not mean no alien life can exist. Primitive alien creatures could be sheltered inside caves, but it is unlikely to allow life to evolve to any 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 sufficiently like 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 of finding extraterrestrial life. Indeed, this star is so stable with little stellar variation that it should permit 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 those planets 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 known as Jupiter. Details remainn scanty at this stage about its size in comparison to our planet Jupiter until more time has been spent to analyse the planet's pull on the star.

Compared to our Sun, Tau Ceti is metal deficient, but not entirely without any metals. It simply means that any rocky planets nearby are unlikely to have less available metals to develop a 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 no technically-advanced civilisation could exist. There are enough metals to help a civilisation to develop a spacecraft. In fact, all it takes is for an alien civilisation to travel around the solar system to acquire a lot more metals if they so choose. Apart from that, this star system seems to hold ten times as much dust in its debris disk compared to our Solar System.

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. It is in the first planet from the star (i.e., Gliese 1061b) in which astronomers believe that a super-Earth exists with a mass of 1.37 times that of the Earth’s. This inner planet has an orbital radius of 0.021 AU and completes it in a period of 3.2 days. Indeed, the next two planets are 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, this is a single red dwarf of about one-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 with respect to Jupiter looming nearby. If this was true, the time for this body to complete one orbit around the red dwarf was about seven years. 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 but yet to be confirmed. What makes this star system interesting is the outermost rocky planet known as GJ 273b. This one is described as a super-Earth (i.e., slightly larger than our own) and lying in its star’s habitable zone where liquid water can exist. Because of the high prospect of finding alien life on this planet, it has become a favourite destination for some people to send annually on one day a radio signal containing music from Earth's human inhabitants.

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), 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) has a diameter of 30 per cent of the Sun's, but its luminosity is just 1.2% that of the Sun. What makes this red dwarf a little distinctive from other similar stars is the way it orbits the Milky Way. It would appear that it moves in the opposite direction to other stars. Its retrograde orbit may 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 that interesting observation, we do know the star had its closest approach to our Sun at 7.0 light years away about 10,900 years ago (or around the end of the last great ice age). Now the star is moving away from us.

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 Microscopium and one of the brightest M-class main-sequence star in Earth's night sky (although you do still need to use 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.