  Astrometric studies and orbital modeling of planetary moons have contributed
significantly to advancing our understanding of their orbital dynamics. These
studies require precise positions measured over extended periods. In this
paper, we present the results of the 2021 Brazilian Jovian mutual phenomena
campaign. The data correspond to eight events between Galilean satellites, in
addition to a rare eclipse of Thebe, an inner satellite, totaling nine events.
A geometric model along with the DE440/JUP365 ephemerides was used to reproduce
the events and simulate the light curves. A Monte Carlo method and chi-squared
statistics were used to fit the simulated light curves to the observations. The
reflectance model adopted for our simulations was the complete version of the
Oren-Nayer model. The average uncertainty of the relative positions of the
Galilean satellites was 5 mas (15 km) and for the inner Thebe satellite 32 mas
(96 km). The seven mutual events (nine independent observations) here analyzed
represent and addition of 17% events (10% light curves) with respect to the
PHEMU21 international campaign. Furthermore, our result of Thebe eclipse is
only the second measurement published to date. Our results contribute to the
ephemeris database, being fundamental to improving satellite orbits and thus
minimizing their uncertainties.
