Multiple Populations in Low-mass Globular Clusters: Eridanus
Multiple populations (MPs), characterized by variations in light elemental abundances, have been found in stellar clusters in the Milky Way, Magellanic Clouds, as well as several other dwarf galaxies. Based on a large number of observations, mass has been suggested to be a key parameter affecting th...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/acac22 |
| _version_ | 1797695840082460672 |
|---|---|
| author | Yue Wang Baitian Tang Chengyuan Li Holger Baumgardt Ricardo R. Muñoz José G. Fernández-Trincado Doug Geisler Yuanqing Fang |
| author_facet | Yue Wang Baitian Tang Chengyuan Li Holger Baumgardt Ricardo R. Muñoz José G. Fernández-Trincado Doug Geisler Yuanqing Fang |
| author_sort | Yue Wang |
| collection | DOAJ |
| description | Multiple populations (MPs), characterized by variations in light elemental abundances, have been found in stellar clusters in the Milky Way, Magellanic Clouds, as well as several other dwarf galaxies. Based on a large number of observations, mass has been suggested to be a key parameter affecting the presence and appearance of MPs in stellar clusters. To further investigate the existence of MPs in low-mass clusters and explore the mass threshold for the formation of MPs, we carried out a project studying the composition of the stellar population in several low-mass Galactic globular clusters. Here we present our study on the cluster Eridanus. With blue-UV low-resolution spectra obtained with the OSIRIS/Multi-object spectrograph on the Gran Telescopio Canarias, we computed the spectral indices of CH and CN for a sample of giant stars and derived their carbon and nitrogen abundances using model spectra. A significant dispersion in the initial surface abundance of nitrogen was found in the sample, indicating the existence of MPs in Eridanus. Inspecting the age–initial mass distribution of in situ clusters with MPs, we find a slight trend that initial mass increases with increasing age, and the lowest initial masses of $\mathrm{log}{M}_{\mathrm{initial}}$ ∼ 4.98 and 5.26 are found at the young and old end, respectively, which might provide a rough reference for the mass threshold for clusters to form MPs. However, more observations of clusters with low initial masses are still necessary before any firm conclusion can be drawn. |
| first_indexed | 2024-03-12T03:17:01Z |
| format | Article |
| id | doaj.art-74f9fc437929410997cc89d4265d91b8 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:17:01Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-74f9fc437929410997cc89d4265d91b82023-09-03T14:08:24ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194328610.3847/1538-4357/acac22Multiple Populations in Low-mass Globular Clusters: EridanusYue Wang0https://orcid.org/0000-0002-7531-603XBaitian Tang1https://orcid.org/0000-0002-0066-0346Chengyuan Li2https://orcid.org/0000-0002-3084-5157Holger Baumgardt3https://orcid.org/0000-0002-1959-6946Ricardo R. Muñoz4José G. Fernández-Trincado5Doug Geisler6https://orcid.org/0000-0002-3900-8208Yuanqing Fang7Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People's Republic Of ChinaSchool of Physics and Astronomy, Sun Yat-sen University , Zhuhai 519082, People's Republic Of China ; tangbt@mail.sysu.edu.cn; CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area , Zhuhai, 519082, People's Republic of ChinaSchool of Physics and Astronomy, Sun Yat-sen University , Zhuhai 519082, People's Republic Of China ; tangbt@mail.sysu.edu.cn; CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area , Zhuhai, 519082, People's Republic of ChinaSchool of Mathematics and Physics, The University of Queensland , St Lucia, QLD 4072, AustraliaDepartamento de Astronomia, Universidad de Chile , Camino del Observatorio 1515, Las Condes, Santiago, ChileInstituto de Astronomía, Universidad Católica del Norte , Avenida Angamos 0610, Antofagasta, ChileDepartamento de Astronomia, Casilla 160-C, Universidad de Concepcion , Chile; Instituto de Investigación Multidisciplinario en Ciencia y Tecnología, Universidad de La Serena , Avenida Raúl Bitrán S/N, La Serena, Chile; Departamento de Astronomía, Facultad de Ciencias, Universidad de La Serena , Avenida Juan Cisternas 1200, La Serena, ChileSchool of Physics and Astronomy, Sun Yat-sen University , Zhuhai 519082, People's Republic Of China ; tangbt@mail.sysu.edu.cnMultiple populations (MPs), characterized by variations in light elemental abundances, have been found in stellar clusters in the Milky Way, Magellanic Clouds, as well as several other dwarf galaxies. Based on a large number of observations, mass has been suggested to be a key parameter affecting the presence and appearance of MPs in stellar clusters. To further investigate the existence of MPs in low-mass clusters and explore the mass threshold for the formation of MPs, we carried out a project studying the composition of the stellar population in several low-mass Galactic globular clusters. Here we present our study on the cluster Eridanus. With blue-UV low-resolution spectra obtained with the OSIRIS/Multi-object spectrograph on the Gran Telescopio Canarias, we computed the spectral indices of CH and CN for a sample of giant stars and derived their carbon and nitrogen abundances using model spectra. A significant dispersion in the initial surface abundance of nitrogen was found in the sample, indicating the existence of MPs in Eridanus. Inspecting the age–initial mass distribution of in situ clusters with MPs, we find a slight trend that initial mass increases with increasing age, and the lowest initial masses of $\mathrm{log}{M}_{\mathrm{initial}}$ ∼ 4.98 and 5.26 are found at the young and old end, respectively, which might provide a rough reference for the mass threshold for clusters to form MPs. However, more observations of clusters with low initial masses are still necessary before any firm conclusion can be drawn.https://doi.org/10.3847/1538-4357/acac22Globular star clustersStellar abundances |
| spellingShingle | Yue Wang Baitian Tang Chengyuan Li Holger Baumgardt Ricardo R. Muñoz José G. Fernández-Trincado Doug Geisler Yuanqing Fang Multiple Populations in Low-mass Globular Clusters: Eridanus The Astrophysical Journal Globular star clusters Stellar abundances |
| title | Multiple Populations in Low-mass Globular Clusters: Eridanus |
| title_full | Multiple Populations in Low-mass Globular Clusters: Eridanus |
| title_fullStr | Multiple Populations in Low-mass Globular Clusters: Eridanus |
| title_full_unstemmed | Multiple Populations in Low-mass Globular Clusters: Eridanus |
| title_short | Multiple Populations in Low-mass Globular Clusters: Eridanus |
| title_sort | multiple populations in low mass globular clusters eridanus |
| topic | Globular star clusters Stellar abundances |
| url | https://doi.org/10.3847/1538-4357/acac22 |
| work_keys_str_mv | AT yuewang multiplepopulationsinlowmassglobularclusterseridanus AT baitiantang multiplepopulationsinlowmassglobularclusterseridanus AT chengyuanli multiplepopulationsinlowmassglobularclusterseridanus AT holgerbaumgardt multiplepopulationsinlowmassglobularclusterseridanus AT ricardormunoz multiplepopulationsinlowmassglobularclusterseridanus AT josegfernandeztrincado multiplepopulationsinlowmassglobularclusterseridanus AT douggeisler multiplepopulationsinlowmassglobularclusterseridanus AT yuanqingfang multiplepopulationsinlowmassglobularclusterseridanus |