Neutron stars in scalar–tensor gravity with quartic order scalar potential

In this work we investigate the effects of a non-minimally coupled quartic order scalar model on static neutron stars, with non-minimal coupling in Jordan frame being form f(?)=1+??2. Particularly derive Einstein Tolman–Oppenheimer–Volkoff equations, and by numerically integrating them for both interior exterior star, using double shooting python 3 based numerical code, extract masses radii stars evaluated finally frame, along several other related physical quantities interest. With regard to equation state use piecewise polytropic central part Skyrme-Lyon (SLy), Akmal–Pandharipande–Ravenhall (APR) or Wiringa–Fiks–Fabrocini (WFF1) equations state. The resulting M–R graphs are compatible observational bounds imposed GW170817 event which require radius M?1.6M? star be larger than R=10.68?0.04+15km corresponding maximum mass R=9.6?0.03+0.14km. Moreover, WFF1 EoS, was excluded context general relativity, provides realistic results event.