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The OCCASO Open Clusters Revisited with Gaia Data

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The OCCASO Open Clusters Revisited with Gaia Data The OCCASO open clusters revisited with Gaia data Carme Jordi 1; Ricardo Carrera 2; Lola Balaguer-Núñez 1 ; Laia Casamiquela 3; Juan Carbajo-Hijarrubia 1; Mercè Romero-Gómez 1; Sergio Blanco-Cuaresma 4; Elena Pancino 5 1Universitat de Barcelona (ICCUB-IEEC); 2INAF-Osservatorio Astronomico di Padova; 3Laboratoire d'Astrophysique de Bordeaux; 4Harvard-Smithsonian Center for Astropysics; 5INAF-Osservatorio Astronomico di Arcetri Motivation I. INTRODUCTION II. OBSERVATIONS III. RESULTS OF THE SURVEY In order to take advantage of the potential Observations are distributed in three Observations and data reduction completed Galactic Open Clusters (OCs) are Observations are distributed in three of Open Clusters (OCs) to investigate the instruments in La Palma and Calar Alto for 18 OCs. 4 additional open clusters have crucial to investigate the instruments in La Palma and Calar Alto Galactic disc, large and homogeneous sam- observatories: completed observations, and their data formation and evolution of the observatories: ples are needed: • HERMES@Mercator(1.2m) R∼85000 reduction is in progress. Galactic disc. However, complete • HERMES@Mercator (1.2m) R∼85000 • Radial velocities + proper motions • FIES@NOT(2.5m) R∼67000 information is available for only • FIES@NOT (2.5m) R∼67000 • Ages • CAFE@CAHA(2.2m) R∼60000 Radial velocities and spatial velocities ∼ 5% of the 2100 OC in the Milky • CAFE@CAHA (2.2m) R∼60000 • Detailed chemical abundances analysis published in Casamiquela et al Way listed in the literature. Granted large program with NOT&Mercator : 5 nights/semester in each telescope until (2016, MNRAS 458, 3150). The Gaia-ESO Survey (GES) is aiming to Therefore, OCs are main targets summer 2015. Regular programs since then. complement the high precision astrometry Stellar parameters and [Fe/H] abundances in space missions (Gaia, Kepler), from Gaia, with radial velocities and published in Casamiquela et al (2017, and in large ground-based The observational strategy involves: detailed chemical abundances. MNRAS 470, 4363). spectroscopic surveys . However, • OCsFutureolder observations than 0.4 Gyrwill be done with these ground-based surveys are • ≥6future RedClump WEAVE stars instrumentin each at cluster WHT The OCCASO Survey is developed in parallel Typical uncertainties of the survey: mainly sampling the Southern • SignalMEGARA to noise instrument ratio SNR ≥at70 GTC to GES and replicating GES-UVES (high • Radial velocities: 0.5 – 0.9 km/s hemisphere OCs (Gaia-ESO • resolution) observational strategy and Large range age, Rgc, Z. • T : 57 K survey, GALAH), or do not have eff analysis, in order to make them homo- • log g: 0.2 dex an specific program for geneous . In this way one can analyze Telescope NOT Mercator 2.2mCAHA • [Fe/H]: 0.03 homogeneously sample OCs together the results from the Northern and Awarded 25 25 15 (APOGEE). Southern OCs for scientific purposes. Observed 20 20 13 Analysis of NGC6705 in Casamiquela et al Time lost 30% 17% 50% (2018, A&A 610, 66) We aim to complement these surveys obtaining detailed abundances for more than 20 chemical species in around 30 IV. Cluster members Selected and Revised with Gaia northern OCs. The pre-Gaia proper motions of the OCs in the literature have large uncertainties, much larger than the precision of the radial velocities from OCCASO. This prevents accurate kinematical analysis. The advent of Gaia Data Release 2 (Gaia Collaboration, Brown et al 2018, A&A in press) has allowed a redetermination of the membership and of the mean proper motions and parallaxes for all known clusters (Cantat-Gaudin et al, 2018, A&A in press arXiv:1805.08726). Using these data, we have revisited the membership of our RCs observed stars and obtained mean Clusters selection parameters for all our OOCASO OCs. The plots below show the case of NGC7789 as an example. Our survey includes 25 OCs at different galactocentric distances, height above the plane and with different ages. Up to now, we have completed the observations of the following 18 OCs: Rgc Cluster Age (Gyr) Observed (kpc) Stars NGC 752 8,8 1,6 7 NGC 2099 9,9 0,4 7 NGC 7789 Proper motions Parallax vs pmDEC Color-magnitude diagram NGC 2682 9,2 4,2 6 IC 4756 8,1 0,8 6 NGC 6633 7,7 0,6 4 V. CLUSTER POSITIONS AND VELOCITIES VI. ORBIT CALCULATION NGC 6705 6,9 0,2 7 Gaia DR2 mean parallaxes and proper motions and OCCASO radial The orbits of the OCs have been calculated using a gravitational NGC 6791 8,0 7,9 6 velocities have been combined obtain 3D spatial velocities and potential of the Galaxy with two spirals arms and no central bar NGC 6819 8,2 2,9 6 peculiar velocities with respect to the RSR. The results significantly (Pichardo et al 2003, ApJ 582, 230). The assumed mass of the arms differ from our previous calculations due to the significant NGC 6991 8,5 1,3 6 is 5% of the mass disc. The arms have a pitch angle of 12 deg and a differences with proper motions in Kharchenko et al (2013, A&A pattern speed of 30 km/s/kpc. NGC 7762 8,9 2,0 6 558, 53) and Dias et al (2014, A&A 564, 79). NGC 7789 9,5 1,6 7 NGC 188 King 1 9,1 4,0 4 NGC 2420 NGC 2099 NGC 559 10,0 2,0 1 NGC 6705 NGC 1817 10,5 0,4 5 Berkeley 11,2 1,0 6 17 NGC 2420 10,7 2,9 7 NGC 6939 8,8 1,3 7 NGC 7142 9,8 4,1 4 Left: Spatial distribution and velocity (red squares and arrows) with Left: Projection of the orbits onto the galactic plane for 4 OCs as respect to the spiral arms and the high-mass star forming regions examples. All orbits have very small eccentricities. Right : The vertical CONTACT studied in Reid et al (2014, in grey). Right : The vertical component as component for the same OCs. Old clusters reach larger heights above a function of galactocentric distance and age. the plane than young OCs, as expected. Carme Jordi Universitat de Barcelona, ICCUB-IEEC e-mail: [email protected].
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