Prof. Tomaž Zwitter: Large spectroscopic stellar surveys

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   Large spectroscopic stellar surveys

   Prof. Tomaž Zwitter, Faculty of Mathematics and Physics, University of Ljubljana

Our Galaxy is a typical galaxy in the Universe, so its formation and evolution can serve as a general role model. It is also one of the few galaxies where individual stars can be observed. Many of these stars are very old, with low mass stars being able to survive since the times of Galaxy formation. Studies of chemical composition and dynamical properties of stars in the Galaxy is therefore an alternative to cosmological observations of distant galaxies.

Most of the physical parameters of stars can be revealed only with spectroscopic observations. To get a relevant sample a very large number of stars distributed across the whole sky needs to be observed. So large spectroscopic surveys are needed for the task. Results of the RAVE project which is the largest survey so far will be presented, along with the first results of the projects Gaia-ESO, Hermes/GALAH, and Gaia, all of which we are part of. These projects contribute also to our knowledge of stellar evolution, as they discover and measure properties of rare types of objects and of the matter between the stars in an unbiased way.