trappist-1 (or 2mass j23062928-0502285) is an ultracool red dwarf star located almost 40 light years away from the sun in the constellation of aquarius. the red dwarf is known for having seven earth-sized rocky planets around it. these planets were discovered between 2016 and 2017, and are likely rocky and some may even have liquid water on them. four of these planets (d, e, f, and g) are in the habitable zone, so they are most likely to have liquid water. three other planets here (b, c, and h) are not in the habitable zone, and are likely not habitable.