نتایج جستجو برای: radial velocity
تعداد نتایج: 195675 فیلتر نتایج به سال:
We present an updated set of constraints for the progenitor of PSR J0737−3039 and for the natal kicks imparted to pulsar B taking into account both the evolutionary and kinematic history of the double neutron star. For this purpose, we use recently reported scintillation velocity measurements to trace the motion of the system in the Galaxy backwards in time as a function of the unknown orientat...
Strong, sharp, negative seismic discontinuities, velocity decreases with depth, are observed beneath the Pacific seafloor at ∼60 km depth. It has been suggested that these are caused by an increase in radial anisotropy with depth, which occurs in global surface wave models. Here we test this hypothesis in two ways. We evaluate whether an increase in surface wave radial anisotropy with depth is ...
Radial velocity observations of K giants have revealed periodic variations for some of the stars. The periods range from approximately 180 to 1000 or more days with velocity amplitudes ranging from approximately 50 m/s to 500 m/s. Except for Iota Draconis (Frink et al. 2002), all variations are nearly sinusoidal. Companions with zero orbital eccentricity as well as pulsations may cause these ra...
We report the detection of multi-periodic oscillations of the cool evolved star α Hya (HD 81797, K3II-III). Two-hundred and forty-three high-resolution spectra (R = 48 000) of this star have been obtained in March and April 2005 with FEROS at the 2.2 m-MPG/ESO telescope in La Silla Observatory, Chile. We observed oscillations in the stellar radial velocity and the asymmetry of the spectral line...
Context. Astronomical research dealing with accurate radial velocity measurements need reliable astronomical standards to calibrate the spectrographs and to assess possible systematics. Stellar radial velocity standards offer a reference at the level of a few hundred m s−1 and are not adequate for most present needs. Aims. We aim to show that sunlight reflected by asteroids is a fairly accessib...
Motion artefacts in time-of-flight range imaging are treated as a feature to measure. Methods for measuring linear radial velocity from range imaging cameras are developed and tested. With the measurement of velocity, the range to the position of the target object at the start of the data acquisition period is computed, effectively correcting the motion error. A new phase based pseudo-quadratur...
As part of our radial velocity survey of low Galactic latitude structures that surround the Galactic disc, we report the detection of the so called Monoceros Ring in the foreground of the Carina dwarf galaxy at Galactic coordinates (l, b) = (260◦,−22◦) based on VLT/FLAMES observations of the dwarf galaxy. At this location, 20 degrees in longitude greater than previous detections, the Ring has a...
Dynamic compaction is a soil improvement method which has been widely used for the increase of bearing capacity through stress wave propagation during heavy tamping. The cost and time of project implementation can be effectively curtailed by developing a model that can be used in the design of dynamic compaction operations. The numerical models offered so far are mostly one or two-dimensional, ...
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