Context. Future astrometric missions such as SIM PlanetQuest need very stable reference stars. K giants have large luminosities, which place them at large distances and thus the jitter of their photocenters by companions is relatively small. Therefore K giants would be best suited as references. To confirm this observationally a radial velocity survey is performed to quantify the level of intri...

Context. This paper is the second one in a series devoted to the study of properties of binaries involving M giants. Aims. The binary frequency of field M giants is derived and compared with the binary fraction of K giants. Methods. Diagrams of the CORAVEL spectroscopic parameter Sb (measuring the average line-width) vs. radial-velocity standard deviation for our samples are used to define appr...

K and M giants show variability on timescales from years down to days and possibly even hours. I discuss the contribution that can be made with high-precision photometry that will be obtained by the MONS Star Trackers. These include observations of flare-like events on Mira variables, and oscillation spectra for K giants and short-period M giants.

A new calibration of the Strömgren (b−y),m1 diagram in terms of iron abundance of red giants is presented. This calibration is based on a homogeneous sample of giants in the globular clusters ω Centauri, M22, and M55 as well as field giants from the list of AnthonyTwarog & Twarog (1998). Towards high metallicities, the new calibration is connected to a previous calibration by Grebel & Richtler ...

[email protected] Most countries and civilizations have stories about giants in their culture. In Greek and Roman times, Giants were an integral part of history. Ovid documents the story of Giants who once piled mountains up to the stars and were destroyed when Zeus hurled his thunderbolts at them. Homer, in his Odyssey, describes many Giants, often the Cyclops, including ...

The formation of gas giant planets is assumed to be preceded by the emergence of solid cores in the conventional sequential-accretion paradigm. This hypothesis implies that the presence of earth-like planets can be inferred from the detection of gas giants. A similar prediction cannot be made with the gravitational instability (hereafter GI) model which assumes that gas giants (hereafter giants...

The properties of 322 intermediate-mass late-G giants (comprising 10 planet-host stars) selected as the targets of Okayama Planet Search Program, many of which are red-clump giants, were comprehensively investigated by establishing their various stellar parameters (atmospheric parameters including turbulent velocity fields, metallicity, luminosity, mass, age, projected rotational velocity, etc....

Context. This paper is the third one in a series devoted to studying the properties of binaries involving M giants. Aims. We use a new set of orbits to construct the first (e− logP ) diagram of an extensive sample of M giant binaries, to obtain their mass-function distribution, and to derive evolutionary constraints for this class of binaries and related systems. Methods. The orbital properties...