NOAO >   Observing Info >   Approved Programs >   2009A-0062

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Proposal Information for 2009A-0062


PI: Konstanze Zwintz, University Vienna, zwintz@astro.univie.ac.at
Address: Institute of Astronomy, Turkenschanzstrasse 17, Vienna, Vienna A-1180, Austria

CoI: Torsten Bohm, Observatoire Midi-Pyrenees, France
CoI: Thomas Kallinger, University Vienna, Austria
CoI: Werner W. Weiss, University Vienna, Austria

Title: Watching stellar evolution in `real time': the case of HR 5999

Abstract: Due to their different evolutionary stages, pre- and post-main sequence stars of same effective temperature, luminosity and mass have different inner density profiles. The properties of stellar pulsations are sensitive to these differences and provide unique means to put constraints on the evolutionary stages of (pulsating) stars. A single pulsation period of ~4.99 h was discovered in 1995 in the pre-main sequence star HR 5999, but it is very likely that additional pulsation frequencies at lower amplitudes exist and can be revealed with longer time-series providing higher accuracy. The proposed observations will provide a longer time coverage, higher frequency resolution and improved sensitivity to discover additional frequencies at lower amplitudes. We will use the denser pulsation frequency spectrum of HR 5999 for a detailed asteroseismic analysis and the identification of the observed pulsation modes. Finally, we plan to investigate the evolutionary change of the star's known pulsation period to constrain the speed of stellar evolution at such young ages. First measurements revealed evolutionary period changes in a pre-main sequence star that are more than a factor 40 faster than expected from theory. In combination with the already existing period determinations from the years 1984 and 1995, the proposed photometric time-series of HR 5999 for 2009 will enable us to investigate this discrepancy.


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NOAO >   Observing Info >   Approved Programs >   2009A-0062

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