Improving spectroscopic lithium abundances

Lithium abundances in halo dwarfs

The pioneering observations of Spite & Spite showed lithium abundances in halo dwarfs to be almost uniform, irrespective of metallicity and mass over a range of effective temperatures from ∼5600 K up to the main-sequence turnoff. They inferred that the observed abundance was “hardly altered” from that produced in the hot Big Bang. Subsequent efforts have endeavoured to determine how small or la...

Lithium abundances in exoplanet-host stars : modelling

Aims. Exoplanet-host stars (EHS) are known to present superficial chemical abundances different from those of stars without any detected planet (NEHS). EHS are, on the average, overmetallic compared to the Sun. The observations also show that, for cool stars, lithium is more depleted in EHS than in NEHS. The aim of this paper is to obtain constraints on possible models able to explain this diff...

Internal Rotation, Mixing and Lithium Abundances

Lithium is an excellent tracer of mixing in stars as it is destroyed (by nuclear reactions) at a temperature around ∼ 2.5 × 10 K. The lithium destruction zone is typically located in the radiative region of a star. If the radiative regions are stable, the observed surface value of lithium should remain constant with time. However, comparison of the meteoritic and photospheric Li abundances in t...

Magnetic resonance spectroscopic imaging studies of lithium

Spectroscopic Constants , Abundances , and Opacities of the TiH Molecule

Using previous measurements and quantum chemical calculations to derive the molecular properties of the TiH molecule, we obtain new values for its ro-vibrational constants, thermochemical data, spectral line lists, line strengths, and absorption opacities. Furthermore, we calculate the abundance of TiH in M and L dwarf atmospheres and conclude that it is much higher than previously thought. We ...