Effective temperatures, rotational velocities, microturbulent velocities and abundances in the atmospheres of the Sun,. HD1835 and HD10700

Source: arXiv


We describe our procedure to determine effective temperatures, rotational
velocities, microturbulent velocities, and chemical abundances in the
atmospheres of Sun-like stars. We use independent determinations of iron
abundances using the fits to the observed Fe I and Fe II atomic absorption
lines. We choose the best solution from the fits to these spectral features for
the model atmosphere that provides the best confidence in the determined log
N(Fe), Vt, and vsini. First, we compute the abundance of iron for a set of
adopted microturbulent velocities. To determine the most self-consistent
effective temperature and microturbulent velocity in any star's atmosphere, we
used an additional constraint where we minimise the dependence of the derived
abundances of Fe I and Fe II on the excitation potential of the corresponding
lines. We analyse the spectra of the Sun and two well known solar type stars,
HD1835 and HD10700 to determine their abundances, microturbulent velocity and
rotational velocity. For the Sun abundances of elements obtained from the fits
of their absorption features agree well enough (+/- 0.1 dex) with the known
values for the Sun. We determined a rotational velocity of vsini = 1.6 +/- 0.3
km/s for the spectrum of the Sun as a star. For HD1835 the self-consistent
solution for Fe I and Fe II lines log N(Fe)=+0.2 was obtained with a model
atmosphere of 5807/4.47/+0.2 andmicroturbulent velocity Vt = 0.75 km/s, and
leads to vsini = 7.2 $\pm$ 0.5 km/s. For HD10700 the self-consistent solution
log N(Fe) = -4.93 was obtained using a model atmosphere of 5383/4.59/-0.6and
microturbulent velocity Vt = 0.5 km/s. The Fe I and Fe II lines give rise to a
vsini = 2.4 +/- 0.4 km/s. Using the Teff found from the ionisation equilibrium
parameters for all three stars, we found abundances of a number of other
elements: Ti, Ni, Ca, Si, Cr. ... Abriged.

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