  Exoplanets have been observed around stars at all stages of stellar
evolution, in many cases orbiting in configurations that will eventually lead
to the planets being engulfed or consumed by their host stars, such as Hot
Jupiters or ultra-short period planets. Furthermore, objects such as polluted
white dwarfs provide strong evidence that the consumption of planets by stars
is a common phenomenon. This consumption causes several significant changes in
the stellar properties, such as changes to the stellar spin, luminosity,
chemical composition, or mass loss processes. Here, we explore this wide
variety of effects for a comprehensive range of stellar and planetary masses
and stages of stellar evolution, from the main sequence over red giants to the
white dwarfs. We determine that planet consumption can cause transient
luminosity features that last on the order of centuries to millennia, and that
the post-consumption stellar spins can often reach break-up speeds.
Furthermore, stellar moss loss can be caused by this spin-up, as well as
through surface grazing interactions, leading to to the formation of unusual
planetary nebula shapes or collimated stellar gas ejections. Our results
highlight several observable stellar features by which the presence or previous
existence of a planet around a given star can be deduced. This will provide
future observational campaigns with the tools to better constrain exoplanet
demographics, as well as planetary formation and evolution histories.
