The impact of stellar rotations and binaries on the shape of upper main sequence near turn off in open cluster NGC\,6067

Fuente: arXiv
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Main Authors: Maurya, Jayanand, Zhang, Yu, Kamann, Sebastian, Niu, Hubiao, Frémat, Yves, Lang, Kaixiang, Joshi, Y. C., Samal, M. R., De Cat, Peter, Esamdin, Ali
Format: Preprint
Published: 2025
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author Maurya, Jayanand
Zhang, Yu
Kamann, Sebastian
Niu, Hubiao
Frémat, Yves
Lang, Kaixiang
Joshi, Y. C.
Samal, M. R.
De Cat, Peter
Esamdin, Ali
author_facet Maurya, Jayanand
Zhang, Yu
Kamann, Sebastian
Niu, Hubiao
Frémat, Yves
Lang, Kaixiang
Joshi, Y. C.
Samal, M. R.
De Cat, Peter
Esamdin, Ali
contents We present the analysis of the extended Main Sequence Turn-Off (eMSTO) in the open cluster NGC\,6067. We derive the projected rotational velocity, \textit{v}sin\textit{i}, of the stars belonging to the eMSTO region of the main sequence (MS) utilizing \textit{Gaia}-ESO spectra. Our results reveal a positive correlation between \textit{v}sin\textit{i} and the color of eMSTO stars, where fast-rotating stars predominantly occupy the red part of the MS while slow-rotating ones prefer a bluer side of the MS. The gravity-darkening effect might be a reason for this correlation. We find that most of the close binaries present in the eMSTO population would be slow-rotating due to the tidal-locking phenomenon. We identify four double-lined spectroscopic binaries (SB2) featuring slow-rotating companions, further supporting this tidal-locking hypothesis. However, the spatial distribution and the cumulative radial distribution indicate a higher concentration of red eMSTO stars in the cluster's central region than their bluer counterparts. This suggests that tidal locking is less likely to be the cause of the observed spread in rotation rates among eMSTO stars. Instead, we propose that star-disk interactions during the pre-main-sequence phase might have played a crucial role in spreading the rotation rates of stars, leading to the eMSTO phenomenon in NGC\,6067.
format Preprint
id arxiv_https___arxiv_org_abs_2507_14433
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The impact of stellar rotations and binaries on the shape of upper main sequence near turn off in open cluster NGC\,6067
Maurya, Jayanand
Zhang, Yu
Kamann, Sebastian
Niu, Hubiao
Frémat, Yves
Lang, Kaixiang
Joshi, Y. C.
Samal, M. R.
De Cat, Peter
Esamdin, Ali
Solar and Stellar Astrophysics
Astrophysics of Galaxies
We present the analysis of the extended Main Sequence Turn-Off (eMSTO) in the open cluster NGC\,6067. We derive the projected rotational velocity, \textit{v}sin\textit{i}, of the stars belonging to the eMSTO region of the main sequence (MS) utilizing \textit{Gaia}-ESO spectra. Our results reveal a positive correlation between \textit{v}sin\textit{i} and the color of eMSTO stars, where fast-rotating stars predominantly occupy the red part of the MS while slow-rotating ones prefer a bluer side of the MS. The gravity-darkening effect might be a reason for this correlation. We find that most of the close binaries present in the eMSTO population would be slow-rotating due to the tidal-locking phenomenon. We identify four double-lined spectroscopic binaries (SB2) featuring slow-rotating companions, further supporting this tidal-locking hypothesis. However, the spatial distribution and the cumulative radial distribution indicate a higher concentration of red eMSTO stars in the cluster's central region than their bluer counterparts. This suggests that tidal locking is less likely to be the cause of the observed spread in rotation rates among eMSTO stars. Instead, we propose that star-disk interactions during the pre-main-sequence phase might have played a crucial role in spreading the rotation rates of stars, leading to the eMSTO phenomenon in NGC\,6067.
title The impact of stellar rotations and binaries on the shape of upper main sequence near turn off in open cluster NGC\,6067
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2507.14433