THE LITHIUM ABUNDANCES OF A LARGE SAMPLE OF RED GIANTS

• Published in: The Astrophysical journal Vol. 785; no. 2; pp. 1 - 12
• Main Authors: Liu, Y J, Tan, K F, Wang, L, Zhao, G, SATO, BUN'EI, Takeda, Y, Li, H N
• Format: Journal Article
• Language: English
• Published: United States 20-04-2014
• Subjects: ABUNDANCE; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CORRECTIONS; CORRELATIONS; DATA ANALYSIS; Expansion; LITHIUM; LTE; MASS; METALLICITY; PLANETS; RED GIANT STARS; Rotation; STARS; VELOCITY
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/785/2/94

The lithium abundances for 378 G/K giants are derived with non-local thermodynamic equilibrium correction considered. Among these are 23 stars that host planetary systems. The lithium abundance is investigated, as a function of metallicity, effective temperature, and rotational velocity, as well as the impact of a giant planet on G/K giants. The results show that the lithium abundance is a function of metallicity and effective temperature. The lithium abundance has no correlation with rotational velocity at v sin i < 10 km s super(-1). Giants with planets present lower lithium abundance and slow rotational velocity (v sin i < 4 km s super(-1)). Our sample includes three Li-rich G/K giants, 36 Li-normal stars, and 339 Li-depleted stars. The fraction of Li-rich stars in this sample agrees with the general rate of less than 1% in the literature, and the stars that show normal amounts of Li are supposed to possess the same abundance at the current interstellar medium. For the Li-depleted giants, Li-deficiency may have already taken place at the main sequence stage for many intermediate mass (1.5-5 M sub([middot in circles])) G/K giants. Finally, we present the lithium abundance and kinematic parameters for an enlarged sample of 565 giants using a compilation of the literature, and confirm that the lithium abundance is a function of metallicity and effective temperature. With the enlarged sample, we investigate the differences between the lithium abundance in thin-/thick-disk giants, which indicate that the lithium abundance in thick-disk giants is more depleted than that in thin-disk giants.