On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856
The detection of split main sequences (MSs) associated with young clusters (≲600 Myr) has attracted a lot of attention. A prevailing scenario is that a bimodality of stellar rotation distribution drives the bifurcation of the MS. Nevertheless, the origin of the stellar rotation dichotomy remains unc...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/accae0 |
| _version_ | 1797699692760399872 |
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| author | Li Wang Chengyuan Li Long Wang Chenyu He Chen Wang |
| author_facet | Li Wang Chengyuan Li Long Wang Chenyu He Chen Wang |
| author_sort | Li Wang |
| collection | DOAJ |
| description | The detection of split main sequences (MSs) associated with young clusters (≲600 Myr) has attracted a lot of attention. A prevailing scenario is that a bimodality of stellar rotation distribution drives the bifurcation of the MS. Nevertheless, the origin of the stellar rotation dichotomy remains unclear. Hypotheses involving tidally locked binaries or blue straggler stars (BSSs) have been proposed to explain the observed split MSs. This work examines if the long-term dynamical evolution of star clusters can produce the observed split MSs, through high-performance N -body simulation. For example, the young massive cluster NGC 1856 exhibits an apparent MS bifurcation. Our simulation reports that at the age of NGC 1856, tidally locked binaries are fully mixed with single stars. This is consistent with the observation that there is no significant spatial difference between blue MS and red MS stars. However, we find that only high-mass-ratio binaries can evolve to the tidally locked phase at the age of the NGC 1856. These tidally locked binaries will populate a much redder sequence than the MS of single stars rather than a blue MS, which is inconsistent with the hypothesis. The number of tidally locked binaries cannot account for the observation. Our simulation shows that BSSs produced by binary interactions do populate in the blue periphery as shown in a color–magnitude diagram, and their spatial distribution shows a similar pattern of single stars. However, the number of BSSs does not fit the observation. |
| first_indexed | 2024-03-12T04:11:30Z |
| format | Article |
| id | doaj.art-00d875ec6134494a936532b5472c3241 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:11:30Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-00d875ec6134494a936532b5472c32412023-09-03T10:57:22ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194925310.3847/1538-4357/accae0On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856Li Wang0https://orcid.org/0000-0003-3471-9489Chengyuan Li1https://orcid.org/0000-0002-3084-5157Long Wang2https://orcid.org/0000-0001-8713-0366Chenyu He3https://orcid.org/0000-0001-9131-6956Chen Wang4https://orcid.org/0000-0002-0716-3801School of Physics and Astronomy, Sun Yat-sen University , Daxue Road, Zhuhai, 519082, People's Republic of China ; lichengy5@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 , Daxue Road, Zhuhai, 519082, People's Republic of China ; lichengy5@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 , Daxue Road, Zhuhai, 519082, People's Republic of China ; lichengy5@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 , Daxue Road, Zhuhai, 519082, People's Republic of China ; lichengy5@mail.sysu.edu.cn; CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area , Zhuhai, 519082, People's Republic of ChinaMax Planck Institute for Astrophysics , Garching, GermanyThe detection of split main sequences (MSs) associated with young clusters (≲600 Myr) has attracted a lot of attention. A prevailing scenario is that a bimodality of stellar rotation distribution drives the bifurcation of the MS. Nevertheless, the origin of the stellar rotation dichotomy remains unclear. Hypotheses involving tidally locked binaries or blue straggler stars (BSSs) have been proposed to explain the observed split MSs. This work examines if the long-term dynamical evolution of star clusters can produce the observed split MSs, through high-performance N -body simulation. For example, the young massive cluster NGC 1856 exhibits an apparent MS bifurcation. Our simulation reports that at the age of NGC 1856, tidally locked binaries are fully mixed with single stars. This is consistent with the observation that there is no significant spatial difference between blue MS and red MS stars. However, we find that only high-mass-ratio binaries can evolve to the tidally locked phase at the age of the NGC 1856. These tidally locked binaries will populate a much redder sequence than the MS of single stars rather than a blue MS, which is inconsistent with the hypothesis. The number of tidally locked binaries cannot account for the observation. Our simulation shows that BSSs produced by binary interactions do populate in the blue periphery as shown in a color–magnitude diagram, and their spatial distribution shows a similar pattern of single stars. However, the number of BSSs does not fit the observation.https://doi.org/10.3847/1538-4357/accae0Star clustersClose binary starsBlue straggler starsN-body simulations |
| spellingShingle | Li Wang Chengyuan Li Long Wang Chenyu He Chen Wang On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856 The Astrophysical Journal Star clusters Close binary stars Blue straggler stars N-body simulations |
| title | On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856 |
| title_full | On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856 |
| title_fullStr | On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856 |
| title_full_unstemmed | On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856 |
| title_short | On the Origin of the Split Main Sequences of the Young Massive Cluster NGC 1856 |
| title_sort | on the origin of the split main sequences of the young massive cluster ngc 1856 |
| topic | Star clusters Close binary stars Blue straggler stars N-body simulations |
| url | https://doi.org/10.3847/1538-4357/accae0 |
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