منابع مشابه
Helioseismological Implications of Recent Solar Abundance Determinations
We show that standard solar models are in good agreement with the helioseismologically determined sound speed and density as a function of solar radius, the depth of the convective zone, and the surface helium abundance, as long as those models do not incorporate the most recent heavy element abundance determinations. However, sophisticated new analyses of the solar atmosphere infer lower abund...
متن کاملStellar Absolute Magnitudes via the Statistical Parallax Method
I review statistical parallax absolute magnitude determinations which employ data from the Hipparcos satellite for RR Lyrae and Cepheid variables, and for several other stellar classes. Five groups have studied the RR Lyrae stars, and the results are reassuringly consistent: MV (RR) = 0.77 ± 0.13 mag at [Fe/H] = –1.6 dex. Extensive Monte Carlo simulations showed that systematic errors are small...
متن کاملRelativistic stellar aberration for the Space Interferometry Mission: parallax analysis
This paper is a continuation of our previous analysis (i.e. Turyshev 2002a, 2002b) of the relativistic stellar aberration requirements for the Space Interferometry Mission (SIM). Here we have considered a problem of how the expected astrometric accuracy of parallax determination will constrain the accuracy of the spacecraft navigation. We show that effect of the spacecraft’s navigational errors...
متن کاملStellar Abundances: Recent and Foreseeable Trends
The determination of chemical abundances from stellar spectra is considered a mature field of astrophysics. Digital spectra of stars are recorded and processed with standard techniques, much like samples in the biological sciences. Nevertheless, uncertainties typically exceed 20%, and are dominated by systematic errors. The first part of this paper addresses what is being done to reduce measure...
متن کاملPrimitive Parallax and Parallax Primitives
This paper describes an implementation of parallax depth perception designed to be a contributing unit to a distributed perceptual intelligence. The work was done in the context of the Cog project, a large-scale eeort to develop human or at least infant intelligence from the bottom up. Our implementation uses fast-approximation \good enough" region mapping and relevant motion detection over mul...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Science
سال: 1884
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.ns-3.62.456