Most of the stars introduced on this page are 'Red Dwarfs'. Actually they represent the most common type of stars. About 73% of all stars in the Milky Way galaxy are dim red dwarfs, featuring less than half the solar surface temperature and low luminosity, but in turn high stellar activity, such as flares and hazardous radiation that can hit red dwarf planets hard potentially prohibiting formation of known lifeforms.

Given its minute energy emission, the habitable zone (HBZ, an imaginary ring where temperatures support liquid water) of a red dwarf is situated near the star, as are planets orbiting inside this zone. The gravitational pull of the star can tidally lock a nearby planet which then faces one hemisphere to the star while the other is enshrouded in darkness - like the Earth moon - the axial rotation period equals the orbital period.

Some densely populated systems, such as TRAPPIST-1, have several planets orbiting in close proximity in that an observer on a planet could see other planets larger than our moon in the sky. Also, the planet may have one or multiple moons themselves. In any case a truly impressive spectacle with fast changes.

Likelihood of life low because:

• Low stellar energy flux
• Tidal lock, tidal heating
• Narrow habitable zone
• Stellar variations, flares, stellar 'wind' of charged particles

On the other hand, if conditions are favorable:

• A red dwarf is aged, known for longevity while some are rather inactive.
• The lower the mass of a red dwarf the longer it will 'live', potentially trillions of years.
• A planet mass big enough to hold an atmosphere capable of heat transfer.
• A low orbit eccentricity for stable meteorological conditions.
• Planets at the outer edge of the HBZ can retain water.
• Planet may have a solid core and a magnetic field shield.
• Lots of known lifeforms on Earth developed and are living under brutal conditions.