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Accuracy levels of metres per second require the fundamental concept of radial velocity for stars and other distant objects to be examined, both as a physical velocity, and as measured by spectroscopic and astrometric techniques. Aiming at definitions that are unambiguous at accuracy levels of 1 m/s, we analyse different concepts of radial velocity and their interrelations. We distinguish between the geometrically defined kinematic radial velocity and astrometric radial velocity on one hand, and the spectroscopically defined barycentric radial-velocity measure on the other. The last two concepts are defined by recent resolutions adopted by the International Astronomical Union (IAU), the motives and consequences of which are explained in this paper.
I present photometric and radial velocity data for Galactic Cepheids, most of them being in the southern hemisphere. There are 1250 Geneva 7-color photometric measurements for 62 Cepheids, the average uncertainty per measurement is better than 0.01 m
The MINiature Exoplanet Radial Velocity Array (MINERVA) is a dedicated observatory of four 0.7m robotic telescopes fiber-fed to a KiwiSpec spectrograph. The MINERVA mission is to discover super-Earths in the habitable zones of nearby stars. This can
This paper presents the specification, design, and development of the Radial Velocity Spectrometer (RVS) on the European Space Agencys Gaia mission. Starting with the rationale for the full six dimensions of phase space in the dynamical modelling of
Planetary rotation rates and obliquities provide information regarding the history of planet formation, but have not yet been measured for evolved extrasolar planets. Here we investigate the theoretical and observational perspective of the Rossiter-M
We have measured the radial velocities of five 51 Peg-type stars and one star with constant velocity. Our measurements, on 20 AA centered at 3947 AA, were conventional using Th/Ar comparison spectra taken every 20 or 40 minutes between the stellar ex