Lectura de tesi: "Stellar Activity in Exoplanet Hosts"

  • Autor/Doctorand: Enrique Herrero Casas
  • Dia: 6 d'octubre de 2013
  • Hora: 16:00
  • Lloc: Sala de Graus Eduard Fontseré
  • Tribunal:​
    • President: Dr. Antonio Francesco Lanza
    • Secretari: Dra. María Rosa Zapatero Osorio  
    • Vocal: Dr.  Christophe Lovis
    • Suplents: Dr. Benjamín Montesinos Comino, Dr. Carlos Allende Prieto, Dr. Jorge Torra Roca
  • Directors/Tutors: Dr. Ignasi Ribas Canudas i Dra.    Carme Jordi Nebot
  • Resum: 

    Most of the efforts on the search and characterization of Earth-like exoplanets are currently focused on low mass stars. Some important properties related to the structure and processes in this type of stars are still unknown, so a careful characterization is essential as one of the next steps in exoplanet sciences.

    The characterization of stellar activity in low mass stars was carried out through several techniques that allowed us both to model and to simulate the relationships between the observational data and the stellar properties. Several empirical relations for low mass stars allow to find correlations between certain activity indicators and the rotation period. These have permitted us to estimate stellar inclinations and resulted on a catalog with an optimized selection of targets for exoplanet transit searches.


    Spot modelling techniques allowed us to obtain physical information about stellar activity, specially studying the Kepler photometry of LHS 6343 A. In order to characterize activity effects on exoplanet observations, we designed a methodology to simulate the photosphere of an active rotating star through the integration of small surface elements. This allows to characterize the signal produced by activity and further study its relationship with the stellar properties, as well as the possible effects produced on exoplanet measurements. The methodology allowed us to present several strategies in order to correct or reduce the effects of spots on the photometry of exoplanet transits.

    The results from this work conclude that it is essential to correctly model the stellar activity signals for exoplanetary sciences, and we provide some tools and strategies to characterize and reduce such effects and extract astrophysical information.


Dijous, 25 Setembre, 2014