Orbital evolution of the Carina dwarf galaxy and self-consistent determination of star formation history^⋆

¹ Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Germany
e-mail: spasetto@ari.uni-heidelberg.de
² Max-Planck-Institut für Astronomie, Heidelberg, Germany
³ Department of Astronomy, University of Padova, Italy
⁴ National Astronomical Observatories of China (NAOC), Chinese Academy of Sciences (CAS), Datun Lu 20A, Chaoyang District, Beijing 100012, PR China
⁵ Main Astronomical Observatory (MAO), National Academy of Sciences of Ukraine (NASU), Akademika Zabolotnoho 27, 03680 Kyiv, Ukraine

Received: 7 October 2009
Accepted: 8 September 2010

Abstract

We present a new study of the evolution of the Carina dwarf galaxy that includes a simultaneous derivation of its orbit and star formation history. The structure of the galaxy is constrained through orbital parameters derived from the observed distance, proper motions, radial velocity, and star formation history. The different orbits admitted by the large proper motion errors are investigated in relation to the tidal force exerted by an external potential representing the Milky Way. Our analysis is performed with the aid of fully consistent N-body simulations that are able to follow the dynamics and the stellar evolution of the dwarf system in order to determine the star formation history of Carina self-consistently. We also find a star formation history characterized by several bursts, partially matching the observational expectation. We find also compatible results between dynamical projected quantities and the observational constraints. The possibility of a past interaction between Carina and the Magellanic Clouds is also separately considered and deemed unlikely.