Context. Many efforts are currently made to detect Earth-like planets around low-mass stars in almost every extra-solar planet search. M dwarfs are considered ideal targets for Doppler radial velocity searches because their low masses and luminosities make low-mass planets orbiting in these stars' habitable zones more easily detectable than those

Context: Aims: This work presents the results obtained by CoRoT on HD 50844, the only δ Sct star observed in the CoRoT initial run (57.6 d). The aim of these CoRoT observations was to investigate and characterize for the first time the pulsational behaviour of a δ Sct star, when observed at a level of precision and with a much better duty cycle

Context: We present an analysis of the observations of HD 51106 and HD 50747 by the satellite CoRoT, obtained during its initial run, and of the spectroscopic preparatory observations. Aims: We complete an analysis of the light curve, extract the main frequencies observed, and discuss some preliminary interpretations about the stars. Methods: We

The Hectochelle is an optical band, fiber-fed, multiobject echelle spectrograph deployed at the MMT Observatory on Mount Hopkins, Arizona. The optical fibers that feed the Hectochelle are positioned by the Hectospec robot positioner on the MMT f/5 focal surface, and the Hectochelle shares an optical fiber feed system with the Hectospec, a moderate

We argue that heights of formation (HOFs) should not be assigned to spectral lines since a single line my sample very different layers of the atmosphere, depending on the physical parameter of interest and the technique employed to determine it. HOFs should be assigned to specific measurements. General expressions to compute these HOFs for

Wave propagation through sunspots involves conversion between waves of acoustic and magnetic character. In addition, the thermal structure of sunspots is very different than that of the quiet Sun. As a consequence, the interpretation of local helioseismic measurements of sunspots has long been a challenge. With the aim of understanding these