  We introduce the STAR-MELT Python package that we developed to facilitate the
analysis of time-resolved emission line spectroscopy of young stellar objects.
STAR-MELT automatically extracts, identifies and fits emission lines. We
summarise our analysis methods that utilises the time domain of high-resolution
stellar spectra to investigate variability in the line profiles and
corresponding emitting regions. This allows us to probe the innermost disc and
accretion structures of YSOs. Local temperatures and densities can be
determined using Boltzmann statistics, the Saha equation, and the Sobolev large
velocity gradient approximation. STAR-MELT allows for new results to be
obtained from archival data, as well as facilitating timely analysis of new
data as it is obtained. We present the results of applying STAR-MELT to three
YSOs, using spectra from UVES, XSHOOTER, FEROS, HARPS, and ESPaDOnS. We
demonstrate what can be achieved for data with disparate time sampling, for
stars with different inclinations and variability types. For EX Lupi, we
confirm the presence of a localised and stable stellar-surface hot spot
associated with the footprint of the accretion column. For GQ Lupi A, we find
that the maximum infall rate from an accretion column is correlated with lines
produced in the lowest temperatures. For CVSO109 we investigate the rapid
temporal variability of a redshifted emission wing, indicative of rotating and
infalling material in the inner disc. Our results show that STAR-MELT is a
useful tool for such analysis, as well as other applications for emission
lines.
