  We developed a tool that measures equivalent widths of various lines in low
resolution optical spectra, and it was applied to stellar spectra obtained as
part of SDSS-V and LAMOST programs. These lines, such as Li I which directly
indicates stellar youth, or optical H I and Ca II which in emission indicate
activity associated with stellar youth, are commonly seen in YSOs. We observe
several notable differences in the properties of these lines between YSOs and
the field stars. Using these data, we devise a set of criteria through which it
is possible to confirm the youth of stars that have been observed by the ABYSS
program, as well as to identify likely young stars that have serendipitously
been observed by other programs. We examine the decrement of H lines seen in
emission in CTTSs, and estimate the properties of the accretion stream that is
responsible for the production of these lines. Finally, we examine the
evolution of Li I as a function of age, and characterize the scatter in its
abundance that appears to be intrinsic in young M dwarfs.

Solar and Stellar Astrophysics