Mergers prompted by dynamical resonances in compact, multiple-star
  systems: a stellar-reduction case for the massive triple TIC 470710327
  Eisner et al. (2022) reported the discovery of TIC 470710327, a massive
compact hierarchical triple star system. TIC 470710327 is comprised of a
compact (1.10 d) circular eclipsing binary, with total mass $\approx 10.9-13.2\
\rm{M_{\odot}}$, and a more massive ($\approx 14-17\ \rm{M_{\odot}}$) eccentric
non-eclipsing tertiary in a $52.04$ d orbit. Here we present a progenitor
scenario for TIC 470710327 in which '2+2' quadruple dynamics result in
Zeipel-Lidov-Kozai (ZLK) resonances that lead to a contact phase of the more
massive binary. In this scenario, the two binary systems should form in a very
similar manner, and dynamics trigger the merger of the more massive binary
either during late phases of star formation or several Myr after the zero-age
main sequence (ZAMS), when the stars begin to expand. Any evidence that the
tertiary is a highly-magnetised ($\sim 1-10$ kG), slowly-rotating blue
main-sequence star would hint towards a quadruple origin. Finally, our scenario
suggests that the population of inclined, compact multiple-stellar systems is
reduced into co-planar systems, via mergers, late during star formation or
early in the main sequence. The elucidation of the origin of TIC 470710327 is
crucial in our understanding of multiple massive-star formation and evolution.
