A census of the near-by Pisces-Eridanus stellar stream -- Commonalities
  with and disparities from the Pleiades
  Within a 400~pc sphere around the Sun, we search for members of the
Pisces-Eridanus (Psc-Eri) stellar stream in the Gaia Data Release 2 (DR2) data
set. We compare basic astrophysical characteristics of the stream with those of
the Pleiades. We used a modified convergent-point method to identify stars with
2D - velocities consistent with the space velocity of the Psc-Eri stream and
the Pleiades, respectively. We found 1387 members of the Psc-Eri stream in a G
magnitude range from 5.1 mag to 19.3 mag at distances between 80 and 380 pc
from the Sun. The stream has a nearly cylindrical shape with length and
thickness of about 700 pc and 100 pc, respectively. The total stellar mass
contained in the stream is about 770 M_Sun, and the members are gravitationally
unbound. For the stream we found an age of about 135 Myr. In many astrophysical
properties Psc-Eri is comparable to the open cluster M45 (the Pleiades): in its
age, its luminosity function (LF), its Present-day mass Function (PDMF) as well
as in its total mass. Nonetheless, the two stellar ensembles are completely
unlike in their physical appearance. We cautiously give two possible
explanations for this disagreement: (i) the star-formation efficiency in their
parental molecular clouds was higher for the Pleiades than for Psc-Eri or/and
(ii) the Pleiades had a higher primordial mass segregation immediately after
the expulsion of the molecular gas of the parental cloud.
