TELESCOPES

Author: ALONSO SOBRINO ROI.
Year: 2005.
University: LA LAGUNA [www.ull.es].
Place of defense: FACULTAD DE FISICA Y MATEMÁTICAS.
Place of preparation: INSTITUTO DE ASTROFISICA DE CANARIAS.

Summary: A transit occurs when an exoplanet that stands between the observer and the star around which they orbit. The decrease in the flow of the star leads lets us know certain orbital parameters and some physical characteristics of the planet that are inaccessible by other techniques. THE diversity of studies and knowledge gained following the detection of transits of HD 209458b led to the use of this technique as a tool for the discovery of exoplanets. In this thesis, we describe the instrument STARE (node located at the Observatorio del Teide of the TrES network, which has two other similar instruments in the observatory Lowell, Arizona, and Mount Palomar, California, both in the USA) devoted to the search using the method of exoplanets transits. This is a small camera Schmidt (10 cm in diameter) that performs differential photometry of stellar large fields (6.1Â º x6.1Â seventh), campaigns for hundreds of hours. We conducted a complete description of the analytical tools used to achieve the required clarifications to detect transits of giant exoplanets (to be overcome details of 1% in thousands of stars), as well as the noise sources that limit this clarification. There are a number of stellar configurations that simulate signals produced by an exoplanet in transit, and require monitoring techniques that allow expose these false alarms. We conducted a detailed study of these techniques, ranging from careful analysis of the light curve of the original, without the need for further comments until precise measurement of the radial velocity of the star, the last step needed to confirm the discovery of an exoplanet . The rapid detection of false alarms in projects such as TrES leads us to propose a protocol of confirmation of an exoplanet, sorted according to the effort required to perform each step. These monitoring techniques are applied to 16 candidates for exoplanets obtained in a campaign observation TrES, in a field in the constellation Lyra. The detailed analysis of the light curves original allow us to discard 15 of the 16 candidates, while the number of follow-up observations made us show the different configurations that cause stellar photometric signals similar to those produced by an exoplanet. Thus, 6 proved stellar binary systems and 7 systems triples (either physically linked, or two stars linked and one located in the line of sight). For two other candidates was not possible to resolve the configuration. The only candidate who surpassed all the evidence required, TrES-1, is the first exoplanet transits by the method of around a relatively bright star. TrES-1 orbit around a star type K0V, with a period of 3.030065 +-0.000008 d, has a mass of 0.76 +-0.05 MJ, a radius of 1.04 ^ (+0.08) - (0.05) RJ, basically an orbit circular, with an inclination of i = 89.5 ^ (+0.5) - (0.3) degrees, and an effective temperature T) (elf = 1060 +-50 K. The star around which orbit has a metallicity [Fe / H_] = 0.00 +-0.09, an elf (T) = 5250 +-75K, a surface gravity of logg = 4.6 + - 0.2, and shows no traces Lithium, while there are indications that another stellar activity. With these parameters, TrES-1 is currently the second best known exoplanet, after HD 209458b. Its magnitude in the infrared proved to be suitable for the use of IRAC bordered by the Spitzer satellite, which allowed the detection of secondary eclipse. This detection of secondary eclipse. This detection was used to estimate the effective temperature of the planet and its eccentricity, and is the first detection of thermal emission from an exoplanet (along with the detection announced simultá 8 neamente 4ca emission at 24 microns thermal HD 209458b by Deming et al. 2005). Finally, we present a preliminary analysis of some observations of the transit of Venus in June 2004 at VTT solar telescope (Vacuum Tower Telescope) Observatorio del Teide, which detect ^ (12) CO_2 and ^ (13) CO_2en mesosphere Venus by the method of transmission spectroscopy. This method has been successfully applied to study the atmosphere of HD 209458b, and allow in the coming years to study various components of the atmospheres exoplanetarias.