We present seven evolutionary tracks for low-mass white dwarfs with helium cores , ranging in mass from 0.179 to 0.414 M _ { \odot } .
We generated the pre-white dwarf models from a 1 M _ { \odot } sequence extending up to the tip of its red-giant branch by applying high mass-loss rates at appropriate positions , and we followed their evolution across the Hertzsprung-Russell diagram and down the cooling path .

We discuss the internal structures and cooling properties of these new models and compare them with those of recently published models for low-mass white dwarfs which are based on simplified initial configurations .
We also demonstrate that our new models seem to remove the apparent discrepancies between the characteristic ages of millisecond pulsars and the cooling ages of their white dwarf companions .