Lithium Dip Found in Unexpectedly Young Stars ⚡ экспресс
Using high-resolution spectra (GALAH DR4, R ~ 28,000) for 211 members of the Serpens star cluster (age 35±5 million years), a lithium dip was found in the effective temperature range of 6200–6800 K with an amplitude of ΔA(Li) ≈ 0.40 dex. This challenges the established view that Li dips only appear in clusters older than 150 million years, shortening the timescale by at least 100 million years. Within the dip region, a significant correlation emerged between rotation speed and lithium depletion: fast rotators (v sin i > 25 km/s) show stronger depletion than slow rotators (v sin i < 25 km/s). This suggests enhanced rotational shear at the boundary between the convective and radiative zones, which intensifies turbulent mixing and accelerates lithium destruction. It was also shown that the lower temperature boundary of the lithium plateau for young open clusters can reach 5500 K. The results call for a revision of standard models of transport and burning of light elements in intermediate-mass stars.
By breaking down the light of the 'Serpens' cluster with spectroscopy (a method that splits light into its component colors), astronomers found that stars start losing lithium as early as 35 million years — four times sooner than thought. This changes our understanding of how sun-like stars mature.
The cause is rotation. A star works like a giant blender: rapid rotation mixes the material, dragging lightweight lithium into the hot interior where it burns up. The faster it spins, the harder it 'mixes' and the sooner the lithium disappears.
The most unexpected twist: this lithium is primordial, born in the Big Bang. Its early disappearance means that stars destroy cosmic 'fossil' elements faster, and we'll have to rethink how galaxies accumulate light elements.
🎯 Lithium is one of the three elements born in the Big Bang, along with hydrogen and helium. Its abundance in the Universe serves as a crucial test of cosmological theories.
🎬 Sci-fi writers often portray stellar cycles as slow processes, but here lithium destruction is accelerated by rotation, like a cosmic blender with a 'turbo' button.