Oral title: Spin-Orbit Alignment of Planetary Systems (SOAPS): The Case of 57 Kepler Planets and Planet Candidat

Oral abstract: Planets are expected to form and evolve in the protoplanetary disk in which they are born, preserving 
coplanar orbits and spin-orbit alignment. However, observationally it is common to find exoplanets in a wide range of 
orbital inclinations. The obliquity is the physical property that can probe the history of formation and evolution of planetary 
systems describing their current orbital configuration. In this work, we carried out a study of exoplanetary architectures 
based on obliquity measurements in the line of sight for 31 stars observed by Kepler encompassing the following 
atmospheric properties: Teff from 4700 to 6500 K, [Fe/H] from -0.5 to 0.3 dex, log g from 3.7 to 4.6 cms^-2. These stars 
harbor a total of 57 transiting planets and planet candidates, with orbital periods ranging from 0.8 to 300 days, and 
planetary radii ranging from 0.3 to 13 Rearth, as measured from their Kepler transit light curves. Historically, studies of 
orbital alignment/misalignment have been mainly focused on systems with hot Jupiters. However, taking into account 
planetary populations as those in our sample, is decisive to have full outlook of planetary formation and evolution. We 
measured the obliquity in the line of sight through the implementation of an MCMC algorithm to find the most probable 
stellar tilt. To do so, we measured vsini employing Subaru HDS spectra (R~160 000), and combining with robust stellar 
rotational periods and stellar radii from the literature. As a result, we find a qualitative tight dependence between planetary 
multiplicity and coplanarity, and high alignment of the orbits. We did not find evidence that candidate stellar companions 
modify the observed distribution of the obliquity in the line of sight. Our results do not support that alignment occurs 
preferably around relative cool stars through tidal interactions over hotter stars. Finally we explore the possible 
evolutionary pathways for the planetary systems in our sample to constrain mechanisms and scenarios that could 
explain the observed obliquities of our sample.