Why are dwarf stars not considered a good place to look for life?

Preliminary resultsfrom a dedicated research program have shown that planetsaround red dwarfs could be habitable if they can maintain a magnetic fieldfor a few billion years. ... To understand the environment around these common stars, the"Living with a Red Dwarf" program was started three years ago.

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.