Search

The metallicity measures the fraction of the star that is made of elements heavier than helium. It is intimately related to the stellar structure and composition and thus plays an important role in a broad range of astrophysical cases, from stellar populations to planet formation. This chapter aims to review the recent observational efforts to measure the metallicity of M dwarfs and to screen few astrophysical cases which have benefited from quantitative metallicity analysis. [ABSTRACT FROM PUBLISHER]

Extrasolar planet searches blossomed and prospered under the auspices of the radial velocity method. However, efficient as it is, it can misinterpret a periodic signal created by stellar phenomena as being originated from a planet. The most common of these is the presence of a cold spot, frequent in active stars. Here we review the representative cases of HD166435, GJ 674 and TWHya and the different methods used to pinpoint the spots' presence. We finish by underlining the importance of infrared measurements, as done in the TWHya campaign, as a way of reducing the effect of spots on radial velocity measurements to a negligible level. [ABSTRACT FROM AUTHOR]