Quest for the lost siblings of the Sun

Abstract

Aims. The aim of this paper is to find lost siblings of the Sun by analyzing high resolution spectra. Finding solar siblings will enable us to constrain the parameters of the parental cluster and the birth place of the Sun in the Galaxy. Methods. The solar siblings can be identified by accurate measurements of metallicity, stellar age and elemental abundances for solar neighbourhood stars. The solar siblings candidates were kinematically selected based on their proper motions, parallaxes and colours. Stellar parameters were determined through a purely spectroscopic approach and partly physical method, respectively. Comparing synthetic with observed spectra, elemental abundances were computed based on the stellar parameters obtained using a partly physical method. A chemical tagging technique was used to identify the solar siblings.Results. We present stellar parameters, stellar ages, and detailed elemental abundances for Na, Mg, Al, Si, Ca, Ti, Cr, Fe, and Ni for 32 solar sibling candidates. Our abundances analysis shows that four stars are chemically homogenous together with the Sun. Technique of chemical tagging gives us a high probability that they might be from the same open cluster. Only one candidate -HIP 40317 -which has solar metallicity and age could be a solar sibling. We performed simulations of the Sun's birth cluster in analytical Galactic model and found that most of the radial velocities of the solar siblings lie in the range −10 ≤ V r ≤ 10 km s −1 , which is smaller than the radial velocity of HIP 40317 (V r = 34.2 km s −1 ), under different Galactic parameters and different initial conditions of the Sun's birth cluster. The sibling status for HIP 40317 is not directly supported by our dynamical analysis.

GaiaFGK benchmark stars: abundances ofαand iron-peak elements

“…The cool giant β Ara again has a value of the abundance of Cr from Luck (1979) that is much higher than our value. We provide [Cr/H] for the two very cool giants ψ Phe and α Cet, and no comparison is available in the literature.…”

“…The agreement for the remaining stars with the literature is also very good, except for β Ara, which we again compare with the abundances of Luck (1979), having the same behavior as the remaining elements, that is, our abundances are lower than those of Luck (1979) because of a systematic difference in the stellar parameters. We were able to provide abundances for the cool giants ψ Phe and α Cet, which have no Co abundance reported in the literature to our knowledge.…”

“…We preferred to be conservative and have fewer abundance determinations, but ensured that our values are accurate. It still remains a challenge to derive abundances for these elements and stars; we were unable find a value reported in the literature, either, except [Mn/H] for β Ara of 0.36 by Luck (1979).…”

“…Recent works on main-sequence stars performed differential analyses of chemical abundances with respect to the Sun (e.g. Meléndez et al 2012;Bensby et al 2014;Liu et al 2015;Battistini & Bensby 2015), which allows a very precise analysis of relative differences in Galactic stellar populations. We note that the dispersion of Mn is systematically higher than that of the other elements.…”

GALAH survey: chemically tagging the thick disk

“…Even a few rare outliers will be enormously valuable for tracking stellar migration over cosmic time. The specific example of the Solar Family is discussed elsewhere (Bland-Hawthorn et al 2010a) and the first searches have already started (Liu et al 2015). The simulated numbers above depend on the details of the initial cluster mass function of the disrupted objects and its mass range.…”