  X-ray surveys are well suited to detect, identify and study young stars based
on their high levels of magnetic activity and thus X-ray brightness. The
eROSITA instrument onboard the Spectrum-Roentgen-Gamma (SRG) satellite will
perform an X-ray all-sky survey that surpasses existing data by a sensitivity
increase of more than an order of magnitude. The 4 yr survey is expected to
detect more than half a million stars and stellar systems in X-rays.
