The main sequence from F to K stars of the solar neighbourhood in SDSS colours

TL;DR

This paper examines the main sequence of F to K stars in the solar neighborhood using SDSS colors, comparing filter transformations and theoretical models to understand stellar populations.

Contribution

It evaluates different filter transformations and compares observed and theoretical main sequences in SDSS colors for F to K stars.

Findings

Good agreement with star cluster fiducials in g',r',i' colors

Systematic differences in filter transformations affect main sequence location

Theoretical isochrones show discrepancies, especially in (r-i) color

Abstract

For an understanding of Galactic stellar populations in the SDSS filter system well defined stellar samples are needed. The nearby stars provide a complete stellar sample representative for the thin disc population. We compare the filter transformations of different authors applied to the main sequence stars from F to K dwarfs to SDSS filter system and discuss the properties of the main sequence. The location of the mean main sequence in colour-magnitude diagrams is very sensitive to systematic differences in the filter transformation. A comparison with fiducial sequences of star clusters observed in g',r',i' show good agreement. Theoretical isochrones from Padua and from Dartmouth have still some problems especially in (r-i)-colour.