Lithium in Giants
نویسندگان
چکیده
منابع مشابه
Lithium-rich Giants in Globular Clusters
Although red giants deplete lithium on their surfaces, some giants are Li-rich. Intermediate-mass asymptotic giant branch (AGB) stars can generate Li through the Cameron–Fowler conveyor, but the existence of Li-rich, low-mass red giant branch (RGB) stars is puzzling. Globular clusters are the best sites to examine this phenomenon because it is straightforward to determine membership in the clus...
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The application to main-sequence stars of the rotation-induced mixing theory in the presence of μ-gradients leads to partial mixing in the lithium destruction region, not visible in the atmosphere. The induced lithium depletion becomes visible in the sub-giant phase as soon as the convective zone deepens enough. This may explain why the observed “ lithium dilution ” is smoother and the final di...
متن کاملLithium-ri h giants in the Sagittarius dSph Tidal Streams
The nature and origin of Lithium rich giant stars is still matter of debate. In the contest of our spectroscopic survey of giants in the tidal streams of the Sagittarius dwarf spheroidal (dSph) galaxy, we present the serendipitous discovery of 2 super Li-rich stars (A(Li)>3.54.0). Besides D461 in Draco, these are the only Li-rich stars known in a Local Group dSph galaxy. The high Li abundance a...
متن کاملLithium and magnetic fields in giants . HD 232 862 : a magnetic and lithium - rich giant star . ⋆
Aims. We report the detection of an unusually high lithium content in HD 232 862, a field giant classified as a G8II star, and hosting a magnetic field. Methods. With the spectropolarimeters ESPaDOnS at CFHT and NARVAL at TBL, we have collected high resolution and high signal-to-noise spectra of three giants : HD 232 862, KU Peg and HD 21 018. From spectral synthesis we have inferred stellar pa...
متن کاملThe Nature of the lithium rich giants Mixing episodes on the RGB and early-AGB
We present a critical analysis of the nature of the socalled Li-rich RGB stars. For a majority of the stars, we have used Hipparcos parallaxes to determine masses and evolutionary states by comparing their position on the Hertzsprung-Russell diagram with theoretical evolutionary tracks. Among the twenty Li-rich giants whose location on the HR diagram we were able to determine precisely, five ap...
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ژورنال
عنوان ژورنال: Highlights of Astronomy
سال: 1995
ISSN: 1539-2996
DOI: 10.1017/s1539299600011692