Study of Lithium Rich Giants with the GALAH Spectroscopic Survey. (arXiv:1901.03832v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Deepak/0/1/0/all/0/1">Deepak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Reddy_B/0/1/0/all/0/1">Bacham Eswar Reddy</a>

In this article, we speculate on the possible mechanisms for Li enhancement
origin in RGB stars based on a large data set of around 340,299 stars collected
from the GALAH survey combined with the Gaia astrometry. Data has 51,982 low
mass (M$leq$ 2M$_{odot}$) RGB stars with reliable atmospheric parameters. The
data set shows a well populated RGB with well-defined luminosity bump and red
clump with significant number of stars at each of these two key phases. We
found 335 new Li-rich RGB stars with Li abundance, A(Li) $geq$ 1.80 $pm$ 0.14
dex, of which 20 are super Li-rich with A(Li) $geq$ 3.20~dex. Most of them
appear to be in the red clump region which, when combined with stellar
evolutionary timescales on RGB, indicates that the Li enhancement origin may
lie at RGB tip during He-flash rather than by external source of merging of
sub-stellar objects or during luminosity bump evolution. Kinematic properties
of sample stars suggest that Li-rich giants are relatively more prevalent among
giants of thin disk compared to thick disk and halo.

In this article, we speculate on the possible mechanisms for Li enhancement
origin in RGB stars based on a large data set of around 340,299 stars collected
from the GALAH survey combined with the Gaia astrometry. Data has 51,982 low
mass (M$leq$ 2M$_{odot}$) RGB stars with reliable atmospheric parameters. The
data set shows a well populated RGB with well-defined luminosity bump and red
clump with significant number of stars at each of these two key phases. We
found 335 new Li-rich RGB stars with Li abundance, A(Li) $geq$ 1.80 $pm$ 0.14
dex, of which 20 are super Li-rich with A(Li) $geq$ 3.20~dex. Most of them
appear to be in the red clump region which, when combined with stellar
evolutionary timescales on RGB, indicates that the Li enhancement origin may
lie at RGB tip during He-flash rather than by external source of merging of
sub-stellar objects or during luminosity bump evolution. Kinematic properties
of sample stars suggest that Li-rich giants are relatively more prevalent among
giants of thin disk compared to thick disk and halo.

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