What happened before?

We seek to find the precursors of Herbig Ae/Be stars in solar vicinity within 500 pc from Sun. do this by creating an optically selected sample intermediate mass T-Tauri (IMTT stars) here defined as masses $1.5 M_{\odot}\leq M_* \leq 5 M_{\odot}$ and spectral type between F K3, literature. use literature optical photometry (0.4-1.25$\mu$m) distances determined Gaia DR2 parallax measurements together with Kurucz stellar model spectra place a HR-diagram. With Siess evolutionary tracks we identify derive ages. Spitzer classify disks around into Meeus Group I II based on their [F$_{30}$/F$_{13.5}$] index. also examine 10$\mu$m silicate dust grain emission Polycyclic Aromatic Hydrocarbons (PAH). From build qualitative picture compare available spatially resolved images at infrared sub-millimeter wavelengths confirm our classification. 49 excess. The identified are similar older disk geometries population. Spatially infra-red sub-mm suggest gaps spirals present younger stars. Comparing timescale evolution towards main sequence current models protoplanetary similarity points that disconnected, they represent two different paths.