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Centro de Astrofísica da Universidade do Porto

The impact of stellar companions within the fiber in the radial velocities calculations

D. Cunha, P. Figueira, N. C. Santos, C. Lovis, G. Boué

Abstract.
Since the discovery by Mayor & Queloz in 1995 of the first planet orbiting another star than the Sun, the search for a planet similar to the Earth has become a priority. With the announced arrival of high precision instruments such as the ESPRESSO, we aim at achieving RV precisions better than 10 cm/s, opening the door for the detection of an Earth-mass exoplanet. For such high precision we expect that several systematic will become the limiting factor instead of the photon noise. The characterization of possible sources of noise becomes thus urgent. One possible noise source occurs with the presence of a stellar companion within the fiber. If two stars are within the fiber, the fiber will scramble the target and the stellar companion spectra, and the resulting spectra will contain the spectra of both stars. We present a study in which we characterize the impact on the radial velocity of the target induced by a stellar companion within the fiber. For this work we are using use HARPS data and transposing the result to the forthcoming ESPRESSO spectrograph. The results of the simulations will be presented and we will access the limitations induced for the detection of other Earths using present and future precise radial velocities.

17th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun
Barcelona, Spain
June 2012

Type: Poster

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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