We used the Giant Metrewave Radio Telescope (GMRT, India) to observe Saturn in the metric domain â at 0.49 m (610 MHz), 1.28 m (235 MHz), and 2.0 m (150 MHz) -with the aim of constraining the deep atmospheric ammonia and water vapor concentrations around 10-20 kbar. We have obtained a clean detection at 610 MHz, with a disk brightness temperature Tb= 216 ± 32 K, and no significant emission outside of the disk, thus confirming model predictions about the weakness of synchrotron radiation by magnetospheric electrons (Lorenzato et al. 2012, Lorenzato et al. 2012). A marginal detection was obtained at 235 MHz, with Tb= 404 ± 249 K, while an upper limit of 1210 K was set at 150 MHz. Unfortunately, some of the GMRT measurements were affected by strong ionospheric scintillation or radio frequency interferences (RFI). Although the reduction of the LOFAR measurements is much more complex, results are expected in the near future and they will complement nicely with those obtained with the GMRT. We will discuss the constraints resulting from these observations on Saturn's deep atmospheric composition.
SF2A-2015: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics
- Pub Date:
- December 2015
- Saturn; acceleration of electrons; atmosphere; numerical simulations; radio observations