Phase-folded heliocentric radial velocity curve of the donor star in YY Dra , obtained by cross-correlating our individual spectra of the target with the M2 V template spectrum Gl 797 B. The top panel shows the measured radial velocities along with the best circular (solid line) and elliptical (dashed line) fits. The middle panel displays the residuals from the circular fit, while the bottom panel represents those from the elliptical fit. The orbital cycle is shown twice for the sake of clarity. We excluded the 2020 February radial velocities from the fitting process. Data points from this epoch at phases 0.17 − 0.21 and 0.37 − 0.41 clearly exhibit different behaviour.