Estimation of Precision of Determining the Yarkovsky Effect Parameter Based on Real and Model Observations of Asteroids

2022 ◽  
Author(s):  
T. Yu. Galushina ◽  
O. N. Letner ◽  
O. M. Syusina
Keyword(s):  
Yarkovsky Effect ◽  
Effect Parameter

Estimation of precision of determination of the Yarkovsky effect parameter based on real and model asteroid observations

2021 ◽  
pp. 170-174
Author(s):  
T.Yu. Galushina ◽  
◽  
O.N. Letner ◽  
O.M. Syusina ◽  
◽  
...  
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Observation Interval ◽  
Mean Square ◽  
Yarkovsky Effect ◽  
Effect Parameter ◽  
Large Observation

The paper presents the results of assessment definition precision of the Yarkovsky effect parameter A 2 for asteroids with small perihelion distances, known on epoch January 2021. It is shown that the observation interval has a significant effect on the precision of A 2. As the interval increases, the root mean square error of the parameter decreases. For asteroids (3200) Phaethon and (137924) 2000 BD19 with a large observation interval, an experiment was carried out to reduce the number of real observations. A decrease of the interval and number of observations leads to a loss in the precision of the parameter being determined. Modeling observations based on real ones with an increase in their precision showed that the root mean square error of the A 2 parameter decreases in proportion to the increase in the observation precision. The increase of interval due to model observations confirmed the conclusion about the inverse dependence of the A 2 uncertainty from number and interval of observations.

scholarly journals Influence of the sample of observations on the determination of the Yarkovsky effect parameter

2021 ◽  
Author(s):  
O. M. Syusina ◽  
◽  
T. Yu. Galushina ◽  
Keyword(s):  
Yarkovsky Effect ◽  
Effect Parameter

The paper presents investigation of influence the sample of observations on the determination of the Yarkovsky effect parameter for some asteroids with small perihelion distances. It is shown that when excluding observations that do not exceed the precision of ”3 sigma”, the value of this effect changes within the obtained precision.

The determination of the Yarkovsky effect parameter for the asteroids with small perihelion distances

2021 ◽  
pp. 151-156
Author(s):  
O.M. Syusina ◽  
◽  
T.Yu. Galushina ◽  
Keyword(s):  
Yarkovsky Effect ◽  
Effect Parameter

Presents the results of determining the parameter of the Yarkovsky effect for all asteroids with small perihelion distances known for January 2021. The comparison of the obtained values is carried out with the results obtained earlier, based on a different approach and with the results presented on the NASA website. On the example of a number of objects, influence of observations of different accuracy influence on the obtained value of the parameter of the Yarkovsky effect was investigated.

The Model for Calculation the Hall Effect Parameter

2004 ◽  
Vol 9 (2) ◽  
pp. 129-138
Author(s):  
J. Kleiza ◽  
V. Kleiza
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Mapping Method ◽  
Sample Thickness ◽  
System Of Nonlinear Equations ◽  
Specific Resistivity ◽  
Conformal Mapping Method ◽  
Effect Parameter ◽  
The Magnetic Field

A method for calculating the values of specific resistivity ρ as well as the product µHB of the Hall mobility and magnetic induction on a conductive sample of an arbitrary geometric configuration with two arbitrary fitted current electrodes of nonzero length and has been proposed an grounded. During the experiment, under the constant value U of voltage and in the absence of the magnetic field effect (B = 0) on the sample, the current intensities I(0), IE(0) are measured as well as the mentioned parameters under the effect of magnetic fields B1, B2 (B1 ≠ B2), i.e.: IE(β(i)), I(β(i)), i = 1, 2. It has been proved that under the constant difference of potentials U and sample thickness d, the parameters I(0), IE(0) and IE(β(i)), I(β(i)), i = 1, 2 uniquely determines the values of the product µHB and specific resistivity ρ of the sample. Basing on the conformal mapping method and Hall’s tensor properties, a relation (a system of nonlinear equations) between the above mentioned quantities has been found.

Inference for treatment effect parameters in potentially misspecified high-dimensional models

Biometrika ◽  
2020 ◽  
Author(s):  
Oliver Dukes ◽  
Stijn Vansteelandt
Keyword(s):  
Sample Size ◽  
Confidence Intervals ◽  
Treatment Effect ◽  
Observational Studies ◽  
Treatment Effects ◽  
Treatment Selection ◽  
High Dimensional ◽  
Selection Mechanism ◽  
Dimensional Models ◽  
Effect Parameter

Summary Eliminating the effect of confounding in observational studies typically involves fitting a model for an outcome adjusted for covariates. When, as often, these covariates are high-dimensional, this necessitates the use of sparse estimators, such as the lasso, or other regularization approaches. Naïve use of such estimators yields confidence intervals for the conditional treatment effect parameter that are not uniformly valid. Moreover, as the number of covariates grows with the sample size, correctly specifying a model for the outcome is nontrivial. In this article we deal with both of these concerns simultaneously, obtaining confidence intervals for conditional treatment effects that are uniformly valid, regardless of whether the outcome model is correct. This is done by incorporating an additional model for the treatment selection mechanism. When both models are correctly specified, we can weaken the standard conditions on model sparsity. Our procedure extends to multivariate treatment effect parameters and complex longitudinal settings.

The Yarkovsky effect as a heat engine

Icarus ◽  
2004 ◽  
Vol 170 (1) ◽  
pp. 229-233 ◽  
Author(s):  
Ralph D. Lorenz ◽  
Joseph N. Spitale
Keyword(s):  
Heat Engine ◽  
Yarkovsky Effect

scholarly journals Impact hazard monitoring: theory and implementation

2015 ◽  
Vol 10 (S318) ◽  
pp. 221-230
Author(s):  
D. Farnocchia
Keyword(s):  
Hazard Assessment ◽  
Yarkovsky Effect ◽  
Monte Carlo Algorithms ◽  
Impact Monitoring ◽  
Successful Technique ◽  
Low Probability ◽  
Computationally Intensive ◽  
Orbit Estimation ◽  
Near Earth Asteroids ◽  
The Impact

AbstractWe review the most standard impact monitoring techniques. Linear methods are the fastest approach but their applicability regime is limited because of the chaotic dynamics of near-Earth asteroids. Among nonlinear methods, Monte Carlo algorithms are the most reliable ones but also most computationally intensive and so unpractical for routine impact monitoring. In the last 15 years, the Line of Variations method has been the most successful technique thanks to its computational efficiency and capability of detecting low probability events deep in the nonlinear regime. We also present some more recent techniques developed to deal with the new challenges arising in the impact hazard assessment problem. In particular, we describe keyhole maps as a tool to go beyond strongly scattering encounters and how to account for nongravitational perturbations, especially the Yarkovsky effect, when their contribution is the main source of prediction uncertainty. Finally, we discuss systematic ranging to deal with the short-term hazard assessment problem for newly discovered asteroids, when only a short observed arc is available thus leading to severe degeneracies in the orbit estimation process.

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