# University of Hertfordshire

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

Research output: Contribution to journalArticle

### Documents

• 904650

Accepted author manuscript, 246 KB, PDF document

Original language English 542-552 Monthly Notices of the Royal Astronomical Society 422 1 15 Mar 2012 https://doi.org/10.1111/j.1365-2966.2012.20629.x Published - 2012

### Abstract

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.

### Notes

11 pages, 7 tables, 5 figs, to appear in MNRAS

ID: 697539