They may exist around suns that are considered red dwarfs. Life in them could be strange, such as plants with black leaves in order to gather sunlight for photosynthesis.
http://www.theverge.com/2014/2/13/5405788/exoplanet-search-for-habitable-planets http://www.theverge.com/2014/2/13/5405788/exoplanet-search-for-habitable-planets
