On the Age Calibration of Open Clusters Using Red Clump Stars
In this study, we extend the dust-independent Hatzidimitriou relation between cluster age and d _B _− _R color difference between the red giant branch (RGB) and red clump to younger cluster ages. We perform membership analysis on 14 galactic open clusters using Gaia DR3 astrometry, then compute the...
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ada1c4 |
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| author | Abigail R. Chriss Guy Worthey |
| author_facet | Abigail R. Chriss Guy Worthey |
| author_sort | Abigail R. Chriss |
| collection | DOAJ |
| description | In this study, we extend the dust-independent Hatzidimitriou relation between cluster age and d _B _− _R color difference between the red giant branch (RGB) and red clump to younger cluster ages. We perform membership analysis on 14 galactic open clusters using Gaia DR3 astrometry, then compute the difference in color of the RGB and red clump d _B _− _R using Gaia photometry. We also compute d _B _− _R for five fields surrounding Small Magellanic Cloud clusters. We find that the trend derived from older clusters does not extrapolate to younger ages and becomes double valued. We confirm that d _B _− _R is independent of metallicity. Current stellar evolutionary isochrones do not quantitatively reproduce the trend and furthermore predict an increased color gap with a decrease in metallicity that is not echoed in the data. Integrated light models based on current isochrones exaggerate the color change over the −0.5 < [Fe/H] < 0 interval at the few-percent level. |
| format | Article |
| id | doaj-art-6dbe81e8b17145f28c05b6a4289924a9 |
| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-6dbe81e8b17145f28c05b6a4289924a92025-01-20T02:20:01ZengIOP PublishingThe Astronomical Journal1538-38812025-01-0116928110.3847/1538-3881/ada1c4On the Age Calibration of Open Clusters Using Red Clump StarsAbigail R. Chriss0https://orcid.org/0009-0003-8929-7110Guy Worthey1https://orcid.org/0000-0003-1388-5525Department of Physics and Astronomy, Bowdoin College , 8800 College Station, Brunswick, ME 04011-8488, USADepartment of Physics and Astronomy, Washington State University , 1245 Webster Hall, Pullman, WA 99164-2814, USAIn this study, we extend the dust-independent Hatzidimitriou relation between cluster age and d _B _− _R color difference between the red giant branch (RGB) and red clump to younger cluster ages. We perform membership analysis on 14 galactic open clusters using Gaia DR3 astrometry, then compute the difference in color of the RGB and red clump d _B _− _R using Gaia photometry. We also compute d _B _− _R for five fields surrounding Small Magellanic Cloud clusters. We find that the trend derived from older clusters does not extrapolate to younger ages and becomes double valued. We confirm that d _B _− _R is independent of metallicity. Current stellar evolutionary isochrones do not quantitatively reproduce the trend and furthermore predict an increased color gap with a decrease in metallicity that is not echoed in the data. Integrated light models based on current isochrones exaggerate the color change over the −0.5 < [Fe/H] < 0 interval at the few-percent level.https://doi.org/10.3847/1538-3881/ada1c4Open star clustersStellar agesRed giant clumpRed giant branchHertzsprung Russell diagram |
| spellingShingle | Abigail R. Chriss Guy Worthey On the Age Calibration of Open Clusters Using Red Clump Stars The Astronomical Journal Open star clusters Stellar ages Red giant clump Red giant branch Hertzsprung Russell diagram |
| title | On the Age Calibration of Open Clusters Using Red Clump Stars |
| title_full | On the Age Calibration of Open Clusters Using Red Clump Stars |
| title_fullStr | On the Age Calibration of Open Clusters Using Red Clump Stars |
| title_full_unstemmed | On the Age Calibration of Open Clusters Using Red Clump Stars |
| title_short | On the Age Calibration of Open Clusters Using Red Clump Stars |
| title_sort | on the age calibration of open clusters using red clump stars |
| topic | Open star clusters Stellar ages Red giant clump Red giant branch Hertzsprung Russell diagram |
| url | https://doi.org/10.3847/1538-3881/ada1c4 |
| work_keys_str_mv | AT abigailrchriss ontheagecalibrationofopenclustersusingredclumpstars AT guyworthey ontheagecalibrationofopenclustersusingredclumpstars |