Astronomers have determined the chemical composition of the nearest stellar flux known as Pisces-Eridano. A study by scientists from the University of Texas is published at arXiv.org.
Stellar streams are long thin clusters of stars that are elongated in a line and rotating around galaxies, which are created by the tensile action of tidal forces. For astronomers, the observation of these structures can be of great importance – they can be used to test various models of galaxy formation.
Pisces Eridano is a cluster of the southern hemisphere that is 420 light-years away from the Milky Way disk. It is a cylindrical stream of nearly 1,400 identified stars distributed over a distance of about 2,300 light years. Due to its relative proximity and size, the cluster is regarded as a laboratory for studying star formation and testing theories of the chemical and dynamic evolution of stellar systems.
Spectrographic observations using the LAMOST telescope showed that stellar flux has a near-solar metallicity [Fe/H] of about -0.03 with a spread of metallicity of about 0.07. It has abundance dispersions that exceed typical uncertainties for many elements. However, the flow does not show significant content gradients along its main axis, with the exception of the ratio of silicon to iron [Si/Fe].
Based on these data, astronomers calculated the age of the stream – it is about 120 million years.