A1 Journal article – refereed
Spectroscopic study of solar twins and analogues




List of Authors: Juliet Datson, Chris Flynn, Laura Portinari
Publisher: EDP SCIENCES S A
Publication year: 2015
Journal: Astronomy and Astrophysics
Journal name in source: ASTRONOMY & ASTROPHYSICS
Journal acronym: ASTRON ASTROPHYS
Volume number: 574
Number of pages: 12
ISSN: 0004-6361

Abstract


Context. Many large stellar surveys have been and are still being carried out, providing huge amounts of data, for which stellar physical

parameters will be derived. Solar twins and analogues provide a means to test the calibration of these stellar catalogues because

the Sun is the best-studied star and provides precise fundamental parameters. Solar twins should be centred on the solar values.



Aims. This spectroscopic study of solar analogues selected from the Geneva-Copenhagen Survey (GCS) at a resolution of 48 000 provides

effective temperatures and metallicities for these stars. We test whether our spectroscopic parameters, as well as the previous

photometric calibrations, are properly centred on the Sun. In addition, we search for more solar twins in our sample.



Methods. The methods used in this work are based on literature methods for solar twin searches and on methods we developed in

previous work to distinguish the metallicity-temperature degeneracies in the differential comparison of spectra of solar analogues

versus a reference solar reflection spectrum.



Results. We derive spectroscopic parameters for 148 solar analogues (about 70 are new entries to the literature) and verify with

a-posteriori differential tests that our values are well-centred on the solar values. We use our dataset to assess the two alternative

calibrations of the GCS parameters; our methods favour the latest revision. We show that the choice of spectral line list or the choice

of asteroid or time of observation does not affect the results. We also identify seven solar twins in our sample, three of which are

published here for the first time.



Conclusions. Our methods provide an independent means to differentially test the calibration of stellar catalogues around the values

of a well-known benchmark star, which makes our work interesting for calibration tests of upcoming Galactic surveys.



Last updated on 2019-21-08 at 21:41