Doppler confirmation of TESS planet candidate TOI-1408.01: updated analysis and fitting

Based on the Doppler observations from the FFOREST spectrograph of the 6-meter telescope (BTA) and on the photometric observations from the TESS spacecraft, we provide an updated analysis for TOI-1408, an F-type main sequence star, located 140 pc away, that hosts exoplanet TOI-1408.01. We confirm the qualitative conclusions from our initial paper: (1) a grazing transit geometry such that the planet obscures its host star by only a portion of the visible disc,(2) unreliably fitted planet radius, (3) which nonetheless has a lower bound constraint of $\sim\!1~R_{\rm Jup}$, (4) unexpectedly large planet mass of $\simeq\!1.7~M_{\rm Jup}$, and (5) significant evidence in favor of a moderately eccentric orbit with $e\simeq0.27$. This solution may suggest that the planet is likely to experience a high tidal eccentricity migration at the stage of intense orbital rounding or may indicate the possible presence of other unseen companions in the system, yet to be detected.