Last Successful Campaigns of the OCCASO Project


The Open Clusters Chemical Abundances from Spanish Observatories project (OCCASO, 2013-2015)  has just finished successfully the second run of observations at the Mercator Telescope using the HERMES Fibre-fed echelle spectrograph in high resolution mode (R∼85000). Two more runs were observed with the NOT telescope and the high-resolution FIbre-fed Echelle Spectrograph (FIES) last April and September. Up to now we have been able to measure 45 stars in 9 clusters.

Our project in collaboration with the IAC, OABo (Italy) and OCA (France) aims to determine homogeneous abundances for more than 20 chemical species for red clump stars in a sample of 25 Northern open clusters older than 0.5 Gyr. These objects cover wide ranges of ages, metallicities, heights above the plane, and Galactocentric distances. The sample includes the oldest, the most metal-rich and a few anticentre Open Clusters which cannot be observed by Gaia-ESO survey (GES).

We have been awarded 5 nights per semester (2013 – 2015) and telescope (FIES/NOT and HERMES/Mercator). These data will allow us to properly analyse the existence of trends in the Galactic disk. For the sake of homogeneity, we will replicate the GES observational strategy and data analysis.