SIMBAD references

2011ApJ...742L..28C - Astrophys. J., 742, L28 (2011/December-1)

On a new theoretical calibration of the Stromgren hk metallicity index: NGC 6522 as a first test case.

CALAMIDA A., BONO G., CORSI C.E., IANNICOLA G., RIPEPI V., ANTHONY-TWAROG B., TWAROG B., ZOCCALI M., BUONANNO R., CASSISI S., FERRARO I., GRUNDAHL F., PIETRINFERNI A. and PULONE L.

Abstract (from CDS):

We present a new theoretical calibration of the Strömgren metallicity index hk using α-enhanced evolutionary models transformed into the observational plane by using atmosphere models with the same chemical mixture. We apply the new metallicity-index-color (MIC) relations to a sample of 85 field red giants (RGs) and find that the difference between photometric estimates and spectroscopic measurements is on average smaller than 0.1 dex with a dispersion of σ= 0.19 dex. The outcome is the same if we apply the MIC relations to a sample of eight RGs in the bulge globular cluster NGC 6522, but the standard deviation ranges from 0.26 (hk, v - -y) to 0.49 (hk, u - -y). The difference is mainly caused by a difference in photometric accuracy. The new MIC relations based on the Ca - -y color provide metallicities systematically more metal-rich than the spectroscopic ones. We found that the Ca band is affected by Ca abundance and possibly by chromospheric activity.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: evolution

Simbad objects: 15

goto Full paper

goto View the reference in ADS

To bookmark this query, right click on this link: simbad:2011ApJ...742L..28C and select 'bookmark this link' or equivalent in the popup menu


2021.06.16-22:52:58

© Université de Strasbourg/CNRS

    • Contact