搜索结果: 1-15 共查到“知识库 天文学 Over Time”相关记录60条 . 查询时间(0.296 秒)
Collisional evolution and reddening of asteroid surfaces–I. The problem of conflicting time-scales and the role of size-dependent effects
meteorites meteors meteoroids–minor planets asteroids: general
2015/12/25
Space weathering is the generic term used for processes that modify the optical properties of surfaces of atmosphereless rocky bodies under exposure to the space environment. The general agreement abo...
Lynden-Bell & Kalnajs (1972) presented a useful formula for computing the long-range torque between spiral arms and the disk at large. The derivation uses second-order perturbation theory and assumes ...
The Assembly of Galaxies Over Cosmic Time
cosmology: observations galaxies: evolution galaxies: formation galaxies: high-redshift galaxies: stellar content galaxies: structure
2014/12/9
To Understand how galaxies were assembled across the cosmic time remains one of the most outstanding questions in astronomy. The core of this question is how today's Hubble Sequence, namely the differ...
Time dependent embedding of spherically symmetric Rindler spacetime
anisotropic cosmic fluid MS energy curved Rindler ric heat flux
2012/2/21
An anisotropic cosmic fluid with radial heat flux which sources a time dependent Rindler geometry is investigated. Even though its energy density $\rho$ is positive, the radial and transversal pressur...
Graphic solution of R-W metric for the case of positive curvature and cosmic entire space and time
R-W metric hypersphere cosmology large scale structure of the universe space and time absolutism relativism
2011/9/26
The vivid image of R-W metric for the case of hypersphere is given; The hypersphere is proposed as the only model for the physical universe; The cosmic radius R(t) may be defined as a cosmic broad tim...
Orbital effects of the time-dependent component of the Pioneer anomaly
Orbital effects time-dependent component Pioneer anomaly
2011/10/17
We work out the impact that the recently determined time-dependent component of the Pioneer Anomaly (PA), interpreted as an additional exotic acceleration of gravitational origin with respect to the w...
An algorithm is proposed for constructing a group (ensemble) pulsar time based on the application of optimal Wiener filters. This algorithm makes it possible to separate the contributions of variation...
Modified gravity approach based on a preferred time foliation
Modified gravity approach based preferred foliation
2011/10/14
We propose, in a heuristic way, a relativistic modified gravity model as an alternative to particle dark matter at galactic scales. The model is based on a postulated preferred time foliation describe...
Time-Frequency Analysis of Superorbital Modulation of X-ray Binary SMC X-1 by Hilbert-Huang Transform
Time-Frequency Analysis Superorbital Modulation X-ray Binary SMC X-1 Hilbert-Huang Transform
2011/10/21
The high-mass X-ray binary (HMXB) SMC X-1 exhibits a superorbital modulation with a dramatically varying period ranging between ~40 d and ~60 d. This research studies the time-frequency properties of ...
Lookback time and Chandra constrains on cosmological parameters
Cosmological parameters WMAP measurements lookback time dark energy Monte Carlo Markov Chains
2011/10/19
In this paper we combine the WMAP7 with lookback time and Chandra gas fraction data to constrain the main cosmological parameters and the equation of state for the dark energy. We find that the lookba...
A Bayesian Surrogate Model for Rapid Time Series Analysis and Application to Exoplanet Observations
statistics: Bayesian model comparison model selection periodogram numerical methods
2011/10/14
We present a Bayesian surrogate model for the analysis of periodic or quasi-periodic time series data. We describe a computationally efficient implementation that enables Bayesian model comparison. We...
Estimates of Densities and Filling Factors from a Cooling Time Analysis of Solar Microflares Observed with RHESSI
Estimates Densities Filling Factors Solar Microflares
2011/10/12
We use more than 4,500 microflares from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) microflare data set (Christe et al., 2008, Ap. J., 677, 1385) to estimate electron densities a...
Dynamical Opacity-Sampling Models of Mira Variables. II: Time-Dependent Atmospheric Structure and Observable Properties of 4 M-Type Model Series
stars: AGB and post-AGB, stars: atmospheres, stars: variables: other, stars: mass loss
2011/10/11
We present 4 model series of the CODEX dynamical opacity-sampling models of Mira variables with solar abundances, designed to have parameters similar to $o$ Cet, R Leo and R Cas. We demonstrate that t...
Constraining GRB Emission Physics with Extensive Early-Time, Multiband Follow-up
Constraining Emission Physics Extensive Early-Time Multiband Follow-up
2011/10/10
Understanding the origin and diversity of emission processes responsible for Gamma-ray Bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the p...
Real-time, fast radio transient searches with GPU de-dispersion
Real-time fast radio transient searches de-dispersion
2011/10/8
The identification, and subsequent discovery, of fast radio transients through blind-search surveys requires a large amount of processing power, in worst cases scaling as $\mathcal{O}(N^3)$. For this ...