منابع مشابه
Radial Velocity Variations in K Giants: Planets or Pulsations?
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...
متن کاملRadial Velocity Variability of Field Brown Dwarfs
We present paper six of the NIRSPEC Brown Dwarf Spectroscopic Survey, an analysis of multi-epoch, highresolution (R ∼ 20,000) spectra of 25 field dwarf systems (3 late-type M dwarfs, 16 L dwarfs, and 6 T dwarfs) taken with the NIRSPEC infrared spectrograph at the W. M. Keck Observatory. With a radial velocity (RV) precision of ∼2 km s, we are sensitive to brown dwarf companions in orbits with p...
متن کاملVelocity spectrum imaging using radial k-t SPIRiT
Background Fourier velocity encoding (FVE) [P.R.Moran,MRI (1),1982] assesses the distribution of velocities within a voxel by acquiring a range of velocity encodes (kv) points. The ability to measure intra-voxel phase dispersion, however, comes at the expense of clinically infeasible scan times. We have recently extended [C.Santelli, ESMRMB(345),2011] the auto-calibrating parallel imaging techn...
متن کاملRadial Velocity
The radial velocity technique was utilized to make the first exoplanet discoveries and continues to play a major role in the discovery and characterization of exoplanetary systems. In this chapter we describe how the technique works, and the current precision and limitations. We then review its major successes in the field of exoplanets. With more than 250 planet detections, it is the most prol...
متن کاملI. Stable stars
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...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1991
ISSN: 0252-9211
DOI: 10.1017/s0252921100079987