  Ultra-hot Jupiters are gas giants that orbit so close to their host star that
they are tidally locked, causing a permanent hot dayside and a cooler
nightside. Signatures of their nonuniform atmospheres can be observed with
high-resolution transit transmission spectroscopy by resolving time-dependent
velocity shifts as the planet rotates and varying areas of the evening and
morning terminator are probed. These asymmetric shifts were seen for the first
time in iron absorption in WASP-76b. Here, we search for other atoms/ions in
the planet's transmission spectrum and study the asymmetries in their signals.
We detect Li I, Na I, Mg I, Ca II, V I, Cr I, Mn I, Fe I, Ni I, and Sr II, and
tentatively detect H I, K I, and Co I, of which V, Cr, Ni, Sr II, and Co have
not been reported before. We notably do not detect Ti or Al, even though these
species should be readily observable, and hypothesize this could be due to
condensation or cold trapping. We find that the observed signal asymmetries in
the detected species can be explained in different ways. We find a relation
between the expected condensation or ionization temperatures and the strength
of the observed asymmetry, which could indicate rain-out or recombination on
the nightside. However, we also find a dependence on the signal broadening,
which could imply a two-zoned atmospheric model, in which the lower atmosphere
is dominated by a day-to-night wind, while the upper atmosphere is dominated by
a vertical wind or outflow. These observations provide a new level of modeling
constraint and will aid our understanding of atmospheric dynamics in highly
irradiated planets.
