Emergence of a lithium dip in ~35 Myr "Snake" Open Clusters
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2026
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| author | Zhang, Yun-Yi Tian, Hai-Jun Shi, Jian-Rong Xie, Cheng-Cheng Yang, Xiang-Ming |
| author_facet | Zhang, Yun-Yi Tian, Hai-Jun Shi, Jian-Rong Xie, Cheng-Cheng Yang, Xiang-Ming |
| contents | We report the discovery of a lithium dip (Li-dip) in the stellar "Snake" (age = $35 \pm 5$ Myr), challenging the classical view that Li-dips emerge only at ages $\gtrsim 150$ Myr. Using high-resolution spectra from GALAH DR4 ($R \sim 28,000$) for 211 member stars, we identify a clear depletion feature in a $T_{\mathrm{eff}}$ range of 6200--6800 K with a depth of $ΔA(\mathrm{Li}) \approx 0.40$ dex. Our analysis reveals two key advances: the Li-dip appears $\gtrsim 100$ Myr earlier than the previous observations, and within the dip temperature range, a significant correlation is found between rotational velocity and lithium depletion. Specifically, fast rotators ($v \sin i > 25$ km s$^{-1}$) exhibit stronger lithium depletion than slow rotators ($v \sin i < 25$ km s$^{-1}$). This trend suggests that faster rotators develop stronger rotational shear at the convective-radiative boundary, which enhances turbulent mixing and accelerates lithium destruction. It is also found that the lower temperature edge of the lithium plateau can reach as low as 5500 K for the young open clusters. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2602_07367 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Emergence of a lithium dip in ~35 Myr "Snake" Open Clusters Zhang, Yun-Yi Tian, Hai-Jun Shi, Jian-Rong Xie, Cheng-Cheng Yang, Xiang-Ming Solar and Stellar Astrophysics Astrophysics of Galaxies Chemical Physics We report the discovery of a lithium dip (Li-dip) in the stellar "Snake" (age = $35 \pm 5$ Myr), challenging the classical view that Li-dips emerge only at ages $\gtrsim 150$ Myr. Using high-resolution spectra from GALAH DR4 ($R \sim 28,000$) for 211 member stars, we identify a clear depletion feature in a $T_{\mathrm{eff}}$ range of 6200--6800 K with a depth of $ΔA(\mathrm{Li}) \approx 0.40$ dex. Our analysis reveals two key advances: the Li-dip appears $\gtrsim 100$ Myr earlier than the previous observations, and within the dip temperature range, a significant correlation is found between rotational velocity and lithium depletion. Specifically, fast rotators ($v \sin i > 25$ km s$^{-1}$) exhibit stronger lithium depletion than slow rotators ($v \sin i < 25$ km s$^{-1}$). This trend suggests that faster rotators develop stronger rotational shear at the convective-radiative boundary, which enhances turbulent mixing and accelerates lithium destruction. It is also found that the lower temperature edge of the lithium plateau can reach as low as 5500 K for the young open clusters. |
| title | Emergence of a lithium dip in ~35 Myr "Snake" Open Clusters |
| topic | Solar and Stellar Astrophysics Astrophysics of Galaxies Chemical Physics |
| url | https://arxiv.org/abs/2602.07367 |