Deriving photospheric parameters and elemental abundances for a sample of stars showing the FIP effect

Seli, B. and Kriskovics, L. and Vida, K. (2019) Deriving photospheric parameters and elemental abundances for a sample of stars showing the FIP effect. CONTRIBUTIONS OF THE ASTRONOMICAL OBSERVATORY SKALNATE PLESO, 49 (2). pp. 287-292. ISSN 1335-1842

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Abstract

One puzzling question in solar physics is the difference between elemental abundances in the photosphere and the corona. Elements with low first ionization potential (FIP) can be overabundant in the corona compared to the photosphere under certain circumstances. The same phenomenon has been observed on a handful of stars, while a few of them show the inverse effect. But not all the stars in the original sample had precise photospheric abundances derived from optical spectra, so for some the solar values were adopted. In this work we make homogeneous abundance measurements from optical spectroscopy. We collected spectra of 16 stars showing the FIP effect with the 1-m RCC telescope of Konkoly Observatory, with resolution of λ / Δ λ ˜ 21 000. We determine the fundamental astrophysical parameters (Teff, log g, [M/H], ξmic, v sin i) and individual elemental abundances with the SME spectral synthesis code using MARCS2012 model atmosphere and spectral line parameters from the Vienna Atomic Line Database (VALD).

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