Coloquios y Seminarios
Coloquio "Upstream ion cyclotron waves at Venus: observations from Venus Express "
Magda Delva
Space Research Institute, Austrian Academy of
Sciences, Graz, Austria
Miércoles 30 de mayo 2012, 15:00hs.
Aula del Edificio IAFE
The magnetometer measurements aboard the Venus Express
spacecraft revealed the existence of proton cyclotron waves upstream
of the Venus bow shock. An overview of the detected waves, their
properties and place of occurrence from the first two Venus years of
the mission at solar minimum is presented. The conditions for their
occurrence in terms of the motional solar wind electric field are
studied, as well as the conditions for their generation. Generation is
only possible from freshly ionized local planetary hydrogen, which has
implications for the Venus exosphere.
New analyses for Mars now enable a comparison of the waves at both planets.
New analyses for Mars now enable a comparison of the waves at both planets.
Coloquio "Turbulencia en la magnetosfera terrestre "
Marina Stepanova
Departamento de Física,
Universidad de Santiago de Chile.
Miércoles 23 de mayo 2012, 14:00hs.
Aula del Edificio IAFE
Existen numerosas evidencias experimentales de que la presencia de turbulencia cambia drásticamente las propiedades de los fluidos. La turbulencia en los plasmas espaciales se ha estudiado intensamente durante décadas, especialmente la turbulencia en el viento solar. El estudio de los efectos de la turbulencia en las magnetosferas planetarias es bastante reciente, habiéndose encontrado evidencias de que la misma afecta fuertemente su dinámica.
Se presentan los resultados experimentales sobre el desarrollo de la turbulencia en la capa de plasmas (plasma sheet) en la cola de la magnetosfera, obtenidos utilizando los datos de los satélites Interball-Tail, Cluster, y Themis. Se discute la posibilidad de la existencia de la capa estable turbulenta y las evidencias experimentales que la sostienen. Se muestra que existe una fuerte relación entre el nivel de la turbulencia y la actividad geomagnética.
Coloquio "Recent results in exoplanetology with the SOPHIE spectrograph "
Rodrigo Díaz
Laboratoire d'Astrophysique de Marseille (LAM),
Francia
Miercoles 28 de marzo 2012, 14:00hs.
Aula del Edificio IAFE
SOPHIE is one of the most precise radial-velocity instruments to search for and characterize extrasolar planets. It is a high-resolution spectrograph installed in the 1.93-m telescope at the Observatoire de Haute-Provence, stabilised in pressure and temperature, which results in a highly-stable instrument, needed for exoplanet.
Besides the varied projects of planet search carried out with this instrument, SOPHIE is a key element in the follow-up of planet candidates provided by different photometric transit surveys, as SuperWASP, CoRoT, and more recently, Kepler. Moreover, it is also well-suited to further characterize the detected planets, by means of the Rossiter-McLaughlin effect, for example.
In the first part of the talk I will discuss some of the most important results obtained with SOPHIE, and I will then focus on the upgrade performed on SOPHIE on June 2011, that has increased the instrument's stability by a factor of 6, and has opened the door to the detection of Neptune-mass and Super-Earth planets.
Coloquios y Seminarios de años anteriores