Dynamical information along with survey data on metallicity and in some cases
age have been used recently by some authors to search for candidates of stars
that were born in the cluster where the Sun formed. We have acquired high
resolution, high signal-to-noise ratio spectra for 30 of these objects to
determine, using detailed elemental abundance analysis, if they could be true
solar siblings. Only two of the candidates are found to have solar chemical
composition. Updated modeling of the stars' past orbits in a realistic Galactic
potential reveals that one of them, HD162826, satisfies both chemical and
dynamical conditions for being a sibling of the Sun. Measurements of
rare-element abundances for this star further confirm its solar composition,
with the only possible exception of Sm. Analysis of long-term high-precision
radial velocity data rules out the presence of hot Jupiters and confirms that
this star is not in a binary system. We find that chemical tagging does not
necessarily benefit from studying as many elements as possible, but instead
from identifying and carefully measuring the abundances of those elements which
show large star-to-star scatter at a given metallicity. Future searches
employing data products from ongoing massive astrometric and spectroscopic
surveys can be optimized by acknowledging this fact.Comment: ApJ, in press. Tables 2 and 4 are available in full in the "Other
formats: source" downloa
