Resolved Gaia Triples
  A sample of 392 low-mass hierarchical triple stellar systems within 100 pc
resolved by Gaia as distinct sources is defined. Owing to the uniform
selection, the sample is ideally suited to study unbiased statistics of wide
triples. The median projected separations in their inner and outer pairs are
151 and 2569 au, respectively, the median separation ratio is close to 15. Some
triples appear in non-hierarchical configurations, and many are just above the
dynamical stability limit. Internal motions in these systems are known with
sufficient accuracy to determine the orbital motion sense of the outer and
inner pairs and to reconstruct the eccentricity distributions. The mean inner
and outer eccentricities are 0.66+-0.02 and 0.54+-0.02, respectively; the less
eccentric outer orbits are explained by dynamical stability. The motion sense
of the inner and outer pairs is almost uncorrelated, implying a mean mutual
inclination of 83.1+-4.5deg. The median mass of the most massive component is
0.71 Msun, the median system mass is 1.53 Msun. In a 0.69 fraction of the
sample the primary belongs to the inner binary, while in the remaining systems
it is the tertiary. A 0.21 fraction of the inner subsystems are twins with mass
ratios >0.95. The median outer mass ratio is 0.41; it decreases mildly with
increasing outer separation. Presumably, these wide hierarchies were formed by
collapse and fragmentation of isolated cores in low-density environments and
represent a small fraction of initial systems that avoided dynamical decay.
Wide pre-main sequence multiples in Taurus could be their progenitors.
