# Summary of K2 Program GO11126

Title: The age of moderately metal-poor stars in Bulge Globular Clusters  Campaign 11

PI: Valentini, Marica (Kepler Guest Observer Office)
CoIs: Ortolani, Sergio; Chiappini, Cristina; Miglio, Andrea; Anders, Friedrich; Montalban, Josefina; Bica, Eduardo Luiz Damiani; Barbuy, Beatriz; Cantelli, Elvis

MOTIVATION: Most of the current observational efforts in finding the chemical imprints left by the first stars have focused on the most metal-poor stars found in the MW halo. However, studies based on the chemical and kinematic properties of stars in the different MW components have shown that not only the halo, but also the bulge and thick disk are potential hosts of the oldest stars in our Galaxy. 
By studying the heavy element content of few stars in the oldest MW GC NGC6522, located in the Galactic Bulge, Chiappini et al. (2001) and Barbuy et al. (2014) suggested that Bulge stars at moderately low metallicites are as old as the oldest halo stars, which are 100 times more metal poor ([Fe/H] = -3). Obviously, no age measurements are available for any of the red giants studied in these works. As the correspondence between age and metallicity is strongly dependent on the star formation history of the particular studied component, it is crucial to confirm that moderately metal poor Bulge stars are very old and hence born from an interstellar medium essentially enriched by the first stellar generations of massive stars. This confirmation can be performed by measuring with high precision the ages and abundances of red giants in moderately metal poor Bulge Globular Clusters. Two metal-poor Bulge Globular Clusters are present in the K2 C11 field: Pal 6 and NGC 6355. As only asteroseismic measurements will be able to provide precise ages for these distant red giants, this is an opportunity not to be missed by K2. The feasibility and the impact of the use of asteroseismology coupled with spectroscopy have been confirmed by recent works in the field of Galactic Archaeology (i.e. Chiappini et al. 2015).

RELEVANCE: The derivation of precise and accurate abundances and ages for red giants in Bulge Globular Clusters is hampered by the lack of the knowledge about extinction and ages for red giants (difficulties in determining atmospheric parameters plus degeneracies in the HR diagram the RG locus). A dedicated program combining asteroseismology with K2 and spectroscopy will avoid such limitations, providing an ambitious and new dataset where to look for the imprints of first stars. This will be the only opportunity to confirm/discard the old ages of Red Giant Bulge stars in Globular Clusters of moderate metallicities ([Fe/H] ~ -1). With this project we open a new window into the study of the fossil records of the first stellar generations.

AIM: Here we aim at observing a rather small sample (5-10 targets per cluster) of Red Giants in NGC 6355 and Pal 6 during  C11. Most of the stars already have secured spectroscopic follow-up by our group. The light curves, obtained from this campaign, will lead us to obtain fundamental seismic information. With this data we aim to a) confirm that Bulge stars of moderately low metallicities are very old objects, as old as the oldest halo stars observed ; and b) analyse the chemical pattern of the oldest objects in order to establish if there are imprints left by the first stellar generations. A parallel pilot project will be carried for field stars, which have already APOGEE spectra.

METHODOLOGY: The K2 data will be used to determine the radius and the mass of each stars using asteroseismology. This information will be complemented by already secured ground-based spectroscopy (individual bulge globular cluster studies of Barbuy and collaborators). It will be therefore possible to determine precise distances (and hence reddening) and precise model-dependent ages for each target.  Finally, the inferred ages together with key abundance indicators, will be combined in order to identify possible imprints of the first stellar generations left in the oldest stars in the Galactic Bulge.

# Targets requested by this program that have been observed (93)
EPIC ID, RA (J2000) [deg], Dec (J2000) [deg], magnitude, Investigation IDs
200127414, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127415, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127416, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127417, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127418, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127419, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127420, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127421, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127422, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127423, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127424, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127425, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127426, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127427, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127428, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127429, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127430, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127431, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127432, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127433, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127434, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127435, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127436, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127437, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127438, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127439, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127440, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127441, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127442, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127443, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127444, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127445, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127446, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127447, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127448, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127449, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127450, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127451, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127452, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127453, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127454, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127455, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127456, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127457, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127458, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127459, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127460, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127461, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127462, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127463, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127464, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127465, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127466, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127467, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127468, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127469, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127470, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127471, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127472, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127473, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127474, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127475, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127476, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127477, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127478, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127479, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127480, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127481, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127482, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127483, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127484, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127485, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127486, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127487, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127488, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127489, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127490, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127491, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127492, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127493, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127494, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127495, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127496, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127497, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127498, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127499, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127500, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
200127501, , , , GO11049_LC|GO11111_LC|GO11126_LC|CLUSTER_TILE
251249151, , , , GO11126_LC
251249152, , , , GO11126_LC
251249172, , , , GO11126_LC
251249175, , , , GO11126_LC
251249178, , , , GO11126_LC