Classification of the 100-500pc WDs

Finally, precise effective temperature values were derived for each object using La Plata evolutionary models. We have successfully classified a total of 65310 white into DAs and non-DAs with an accuracy of 94%. An unbiased subsample of nearly 34000 objects was built, from which we computed a precise spectral distribution spanning an effective temperature range from 5,500 to 40,000 K, while accounting for potential selection effects.

Some characteristic features of the spectral evolution, such as the deficit of helium-rich stars at Teff~35000-40000K and in the range 22000<Teff<25000K, as well as a gradual increase from 18000K to Teff~7000K, where the non-DA stars percentage reaches its maximum of 41%, followed by a decrease for cooler temperatures, are statistically significant. These findings will provide precise constraints for the proposed models of spectral evolution.