As a result, lower-mass stars experience the first and third dredge-ups in their evolution but not the second. The names of the dredge-ups are set by the evolutionary and structural state of the star in which each occurs, not by the sequence experienced by the star. The result is an increase in the abundance of carbon relative to oxygen, which can create a carbon star. This dredge-up causes helium, carbon and the s-process products to be brought to the surface. The third dredge-up occurs after a star enters the asymptotic giant branch and a flash occurs along a helium burning shell. This second dredge-up results in an increase in the surface abundance of 4He and 14N, whereas the amount of 12C and 16O decreases. (see the review by Garaud 2018) has reopened the debate on the origin of post dredge-up surface abundance variations in red giant branch (RGB) stars. This is a low value but not exceptional if compared to the sample of typical single. The period of the primary’s surface rotation resembles the orbital period within 10 days.The radial rotational gradient between the surface and core in KIC9163796 is found to be 6.9+2.0 1.0. When helium fusion comes to an end at the core, convection mixes the products of the CNO cycle. stage of the rst dredge-up event on the red-giant branch. The second dredge-up occurs in stars with 4–8 solar masses. As a result of the convective mixing, the outer atmosphere will display the spectral signature of hydrogen fusion: the 12C/ 13C and C/ N ratios are lowered, and the surface abundances of lithium and beryllium may be reduced. The first dredge-up occurs when a main-sequence star enters the red-giant branch. As a result, the fusion products are mixed into the outer layers of the stellar atmosphere where they can appear in the spectrum of the star. We performed a detailed analysis of the use of measured in red giant branch stars between the completion of the first dredge up and the red giant branch bump (_ in star clusters with well-established ages and metallicities are required to better test theoretical calibrations of this age indicator.A dredge-up is a period in the evolution of a star where a surface convection zone extends down to the layers where material has undergone nuclear fusion.
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