Characterisation of the Gaia Red Clump

L. Ruiz-Dern (Observatoire de Paris-Meudon, France)*

The Red Clump is a compact group of stars located in the giant branch which are burning helium in their core. They are known to have an absolute magnitude that fairly weakly depends on their age and metallicity, a peculiarity which makes them good distance indicators. Gaia will provide high precision astrometry, photometry and spectroscopy for a billion stars, allowing a very accurate characterisation of the properties of the Red Clump and a new calibration of this standard candle.
We are currently developping our method to calibrate the Red Clump on the Hipparcos catalogue, adding photometry from the Mermilliod and 2MASS catalogues, to cover wavelengths from the ultraviolet to the near-infrared. The calibration is being done by using the Padova isochrones and taking into account the extinction, the metallicity and the age factors. With the first release of the Gaia catalogue we will be able to give the Gaia G band calibration of the Red Clump.

Topic revision: r1 - 2014-11-28 - SusanaBascon
 
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