Browsing by Author "Guilera, O. M."

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Hybrid stars with sequential phase transitions: the emergence of the g2 mode
    (2021) Rodriguez, M. C.; Ranea-Sandoval, Ignacio F.; Mariani, M.; Orsaria, M. G.; Malfatti, G.; Guilera, O. M.
    Neutron stars are the densest objects in the Universe, with M similar to 1.4M(circle dot) and R similar to 12 km, and the equation of state associated to their internal composition is still unknown. The extreme conditions to which matter is subjected inside neutron stars could lead to a phase transition in their inner cores, giving rise to a hybrid compact object. The observation of 2M(circle dot) binary pulsars (PSR J1614-2230, PSR J0343+0432 and PSR J0740+6620) strongly constraints theoretical models of the equation of state. Moreover, the detection of gravitational waves emitted during the binary neutron star merger, GW170817, and its electromagnetic counterpart, GRB170817A, impose additional constraints on the tidal deformability. In this work, we investigate hybrid stars with sequential phase transitions hadron-quark-quark in their cores.We assume that both phase transitions are sharp and analyse the rapid and slow phase conversion scenarios. For the outer core, we use modern hadronic equations of state. For the inner core we employ the constant speed of sound parametrization for quark matter. We analyze more than 3000 hybrid equations of state, taking into account the recent observational constraints from neutron stars. The effects of hadron-quark-quark phase transitions on the normal oscillation modes f and g, are studied under the Cowling relativistic approximation. Our results show that, in the slow conversion regime, a second quark-quark phase transition gives rise to a new g(2) mode. We discuss the observational implications of our results associated to the gravitational waves detection and the possibility of detecting hints of sequential phase transitions and the associated g(2) mode.
  • No Thumbnail Available
    Item
    Planetesimal fragmentation and giant planet formation II. Dependencies with planetesimal relative velocities and compositions
    (2019) San Sebastian, I. L.; Guilera, O. M.; Parisi, M. G.
    Context. Most planet formation models that incorporate planetesimal fragmentation consider a catastrophic impact energy threshold for basalts at a constant velocity of 3 km s(-1) throughout the process of the formation of the planets. However, as planets grow, the relative velocities of the surrounding planetesimals increase from velocities of the order of meters per second to a few kilometers per second. In addition, beyond the ice line where giant planets are formed, planetesimals are expected to be composed roughly of 50% ices.
  • Thumbnail Image
    Item
    Thermal torque effects on the migration of growing low-mass planets
    (2019) Guilera, O. M.; Cuello, N.; Montesinos, M.; Bertolami, M. M. M.; Ronco, M. P.; Cuadra Stipetich, Jorge Rodrigo; Masset, F. S.