  Primordial black holes (PBHs) are hypothetical objects that could have
originated from density fluctuations in a very early phase of our Universe.
Recent observations restrict the masses that such PBHs could have, if they are
to constitute all of dark matter today: $10^{17} \, {\rm g} \leq m \leq 10^{23}
\, {\rm g}$. With such low masses, general relativity predicts that the
corresponding radii for the PBHs would be atomic or subatomic in size. When
captured by a star, such a tiny PBH could exhibit an orbit completely or
partially inside the body of the star, without significantly changing its mass
for quite a long time. Here we examine the possible trajectories of a PBH that
is captured by a Sun-like star. When in motion in the interior of the star, the
amount of stellar mass that effectively interacts with the PBH will be a
function of its distance to the center of the star. As a consequence, a strong
effect on the shape of the orbits emerges, leading to PBH trajectories that
could be open or closed, and exhibiting a rich variety of patterns.
