  The Jovian magnetic field, being the strongest and largest planetary one in
the solar system, could offer us new insights into possible microscopic scale
new physics, such as a non-zero mass of the Standard Model (SM) photon or a
light dark photon kinetically mixing with the SM photon. We employ the immense
data set from the latest Juno mission, which provides us unprecedented
information about the magnetic field of the gas giant, together with a more
rigorous statistical approach compared to the literature, to set strong
constraints on the dark photon mass and kinetic mixing parameter, as well as
the SM photon mass. The constraint on the dark photon parameters is independent
of whether dark photon is (part of) dark matter or not, and serves as the most
stringent one in a certain regime of the parameter space.
