scholarly journals On the road to consistent Type Ia supernova explosion models

2006 ◽  
Vol 2 (14) ◽  
pp. 308-309
Author(s):  
Friedrich K. Röpke

AbstractKeeping up with ever more detailed observations, Type Ia supernova (SN Ia) explosion models have seen a brisk development over the past years. The aim is to construct a self-consistent picture of the physical processes in order to gain the predictive power necessary to answer questions arising from the application of SNe Ia as cosmological distance indicators. We review recent developments in modeling these objects focusing on three-dimensional simulations.

2012 ◽  
Vol 548 ◽  
pp. A2 ◽  
Author(s):  
Z. W. Liu ◽  
R. Pakmor ◽  
F. K. Röpke ◽  
P. Edelmann ◽  
B. Wang ◽  
...  

2012 ◽  
Vol 8 (S289) ◽  
pp. 329-329
Author(s):  
Paul Ricker ◽  
Kuo-Chuan Pan ◽  
Ronald Taam

AbstractPopulation synthesis modeling of Type Ia supernova (SN Ia) progenitors suggests that multiple binary evolution channels may give rise to SNe Ia. Independently of the ignition mechanism, the type of progenitor system involved affects the circumstellar environment into which the explosion propagates, as well as the amount of solid angle blocked by the companion (for single-degenerate models). Using three-dimensional adaptive-mesh simulations of SNe Ia in binary systems, we discuss the effects of the progenitor system on the observable characteristics of SNe Ia and the impact of these effects on systematic errors in the use of SNe Ia as cosmic distance indicators.


2013 ◽  
Vol 387 ◽  
pp. 159-163
Author(s):  
Yi Chern Hsieh ◽  
Minh Hai Doan ◽  
Chen Tai Chang

We present the analyses of dynamics behaviors on a stroller wheel by three dimensional finite element method. The vibration of the wheel system causes by two different type barriers on the road as an experiment design to mimic the real road conditions. In addition to experiment analysis, we use two different packages to numerically simulate the wheel system dynamics activities. Some of the simulation results have good agreement with the experimental data in this research. Other interesting data will be measured and analyzed by us for future study and we will investigate them by using adaptive finite element method for increasing the precision of the computation results.


Science ◽  
2020 ◽  
Vol 367 (6476) ◽  
pp. 415-418 ◽  
Author(s):  
Anders Jerkstrand ◽  
Keiichi Maeda ◽  
Koji S. Kawabata

Superluminous supernovae radiate up to 100 times more energy than normal supernovae. The origin of this energy and the nature of the stellar progenitors of these transients are poorly understood. We identify neutral iron lines in the spectrum of one such supernova, SN 2006gy, and show that they require a large mass of iron (≳0.3 solar masses) expanding at 1500 kilometers per second. By modeling a standard type Ia supernova hitting a shell of circumstellar material, we produce a light curve and late-time iron-dominated spectrum that match the observations of SN 2006gy. In such a scenario, common envelope evolution of a progenitor binary system can synchronize envelope ejection and supernova explosion and may explain these bright transients.


JETP Letters ◽  
2016 ◽  
Vol 103 (7) ◽  
pp. 431-434 ◽  
Author(s):  
I. V. Panov ◽  
I. Y. Korneev ◽  
S. I. Blinnikov ◽  
F. Röpke

1990 ◽  
Vol 84 (3) ◽  
pp. 436-443
Author(s):  
Y. Yamada ◽  
T. Nakamura ◽  
K.-i. Oohara

Author(s):  
Xiaoyu Zhang ◽  
Aihua Li

Intelligent vehicles face considerable challenges in the complex traffic environment since they need to deal with various constraints and elements. This dissertation puts forward a novel trajectory planning framework for intelligent vehicles to generate safe and optimal driving trajectories. First, we design a spatiotemporal occupancy framework to deal with all kinds of elements in the complex driving environment based on the Frenét frame. This framework unifies various constraints on the road in the three-dimensional spatiotemporal representation and clearly describes the collision-free configuration space. Then we use the convex approximation method to construct a time-varying convex feasible region based on the above accurate temporal and spatial description. We formulate the trajectory planning problem as a standard quadratic programming formulation with collision-free and dynamics constraints. Finally, we apply the iterative convex optimization algorithm to solve the quadratic programming problem in the time-varying convex feasible region. Moreover, we design several typical experimental scenarios and have verified that the proposed method has good effectiveness and real-time.


2012 ◽  
Vol 8 (S289) ◽  
pp. 328-328
Author(s):  
Brad Tucker ◽  
Brian P. Schmidt ◽  
Peter Garnavich

AbstractPast investigations have shown a connection between the properties of Type Ia supernovae (SNe Ia) and their host galaxies. We refine these studies using ultraviolet through mid-infrared observations of both nearby and distant SN Ia hosts. We present new results showing that the properties of SNe Ia, both intrinsic and with respect to their use as distance indicators, appear to depend on a combination of metallicity, stellar age, and star-formation rate of the host. We suggest that the stellar population age and location of the supernova progenitor all can play a roll in using SNe Ia as precision distance indicators, and advocate that a multiwavelength approach is one way to disentangle the different influences, resulting in an improvement of 8% in distance measurements.


Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-23
Author(s):  
Gang Li ◽  
Huansheng Song ◽  
Zheng Liao

Real-time and accurate detection of parking and dropping events on the road is important for the avoidance of traffic accidents. The existing algorithms for detection require accurate modeling of the background, and most of them use the characteristics of two-dimensional images such as area to distinguish the type of the target. However, these algorithms significantly depend on the background and are lack of accuracy on the type of distinction. Therefore, this paper proposes an algorithm for detecting parking and dropping objects that uses real three-dimensional information to distinguish the type of target. Firstly, an abnormal region is initially defined based on status change, when there is an object that did not exist before in the traffic scene. Secondly, the preliminary determination of the abnormal area is bidirectionally tracked to determine the area of parking and dropping objects, and the eight-neighbor seed filling algorithm is used to segment the parking and the dropping object area. Finally, a three-view recognition method based on inverse projection is proposed to distinguish the parking and dropping objects. The method is based on the matching of the three-dimensional structure of the vehicle body. In addition, the three-dimensional wireframe of the vehicle extracted by the back-projection can be used to match the structural model of the vehicle, and the vehicle model can be further identified. The 3D wireframe of the established vehicle is efficient and can meet the needs of real-time applications. And, based on experimental data collected in tunnels, highways, urban expressways, and rural roads, the proposed algorithm is verified. The results show that the algorithm can effectively detect the parking and dropping objects within different environment, with low miss and false detection rate.


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