Doyle, AP and Smalley, B and Faedi, F and Pollacco, D and Gómez Maqueo Chew, Y (2017) The Homogeneous Study of Transiting Systems (HoSTS) – II. The influence of the line list on stellar parameters. Monthly Notices of the Royal Astronomical Society, 469 (4). 4850 -4862. ISSN 1365-2966

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Abstract

The use of high-resolution, high signal-to-noise stellar spectra is essential in order to determine the most accurate and precise stellar atmospheric parameters via spectroscopy. This is particularly important for determining the fundamental parameters of exoplanets, which directly depend on the stellar properties. However, different techniques can be implemented when analysing these spectra which will influence the results. These include performing an abundance analysis relative to the solar values in order to negate uncertainties in atomic data, and fixing the surface gravity (log g) to an external value such as those from asteroseismology. The choice of lines used will also influence the results. In this paper, we investigate differential analysis and fixing log g for a set of FGK stars that already have accurate fundamental parameters known from external methods. We find that a differential line list gives slightly more accurate parameters compared to a laboratory line list; however, the laboratory line list still gives robust parameters. We also find that fixing the log g does not improve the spectroscopic parameters. We investigate the effects of line selection on the stellar parameters and find that the choice of lines used can have a significant effect on the parameters. In particular, removal of certain low excitation potential lines can change the Teff by up to 50 K. For future HoSTS papers we will use the differential line list with a solar microturbulence value of 1 km s−1, and we will not fix the log g to an external value.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: stars, abundances, fundamental parameters
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculty of Natural Sciences > School of Physical and Geographical Sciences
Depositing User: Symplectic
Date Deposited: 31 Aug 2017 09:07
Last Modified: 06 Nov 2017 11:42
URI: http://eprints.keele.ac.uk/id/eprint/3962

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