On the ages and evolution of exoplanetary systems

  • Suheil Harjani

Student thesis: Master of Science by Research


Exoplanetary science is a growing field in astrophysics, however the ages of planet hosts and the future evolution of systems are not well understood. This thesis looks at better constraining the ages of hot ($T_{\rm eff} > 6000$\,K), intermediate-mass (1.1 to 1.6\,M$_\odot$) host stars using stellar evolution models. The ages of 35 hosts are found to be between 0.4 and 4.4\,Gyr, which broadly agrees with the ages given in existing literature. The orbital evolution of 55 planetary systems is simulated, with regards to the competing effects of stellar mass loss and tidal interactions with the host. It is found that the planets are migrating outwards in all but the one case of HAT-P-32b. The changes in period would, however, be unobservable, with $dP/dt \sim 10^{-7}$\,s\,yr$^{-1}$ in most cases. It is expected that all the planets investigated will at some point be engulfed by the host star. Those on the shortest orbits ($a < 0.07$\,AU) are engulfed on the sub-giant branch, while planets with wider orbits are engulfed closer to the RGB tip. The angular momentum transferred to the convective envelope, in both cases, does not provide sufficient spin-up for this to be detected in engulfed systems.
Date of Award1 Aug 2019
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorBattye (Supervisor) & Iain Mcdonald (Supervisor)

Cite this