star system
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2022 ◽  
Vol 924 (2) ◽  
pp. 66
Author(s):  
Mitchell E. Yenawine ◽  
William F. Welsh ◽  
Jerome A. Orosz ◽  
Allyson Bieryla ◽  
William D. Cochran ◽  
...  

Abstract We explore the fascinating eclipses and dynamics of the compact hierarchical triple-star system KOI-126 (KIC 5897826). This system is composed of a pair of M-dwarf stars (KOI-126 B and C) in a 1.74 day orbit that revolve around an F star (KOI-126 A) every 34 days. Complex eclipse shapes are created as the M stars transit the F star, due to two effects: (1) the duration of the eclipse is a significant fraction of the M-star orbital period, so the prograde or retrograde motion of the M stars in their orbit lead to unusually short or long duration eclipses; (2) due to 3-body dynamics, the M-star orbit precesses with an astonishingly quick timescale of 1.74 yr for the periastron (apsidal) precession, and 2.73 yr for the inclination and nodal angle precession. Using the full Kepler data set, supplemented with ground-based photometry, plus 29 radial velocity measurements that span 6 yr, our photodynamical modeling yields masses of M A = 1.2713 ± 0.0047 M ⊙ (0.37%), M B = 0.23529 ± 0.00062 M ⊙ (0.26%), and M C = 0.20739 ± 0.00055 M ⊙ (0.27%) and radii of R A = 1.9984 ± 0.0027 R ⊙ (0.14%), R B = 0.25504 ± 0.00076 R ⊙ (0.3%), and R C = 0.23196 ± 0.00069 R ⊙ (0.3%). We also estimate the apsidal motion constant of the M dwarfs, a parameter that characterizes the internal mass distribution. Although it is not particularly precise, we measure a mean apsidal motion constant, k 2 ¯ , of 0.046 − 0.028 + 0.046 , which is approximately 2σ lower than the theoretical model prediction of 0.150. We explore possible causes for this discrepancy.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saeed Haddadi ◽  
Mehrdad Ghominejad ◽  
Ahmad Akhound ◽  
Mohammad Reza Pourkarimi

AbstractThe uncertainty principle is known as a foundational element of quantum theory, providing a striking lower bound to quantify our prediction for the measured result of two incompatible observables. In this work, we study the thermal evolution of the entropic uncertainty bound in the presence of quantum memory for an inhomogeneous four-qubit spin-star system that is in the thermal regime. Intriguingly, our results show that the entropic uncertainty bound can be controlled and suppressed by adjusting the inhomogeneity parameter of the system.


2021 ◽  
Author(s):  
Otília Beatriz Fiori Arantes

Os dois ensaios que compõem este e-book, “Ruinas do Futuro” e “A era das formas urbanas extremas”, foram redigidos a rigor em continuidade. O primeiro, uma reflexão introdutória ao livro Chai-na — estudo de caso da China como máquina acelerada de crescimento urbano, alavancado pela Olímpiada de 2008. O segundo, uma conferência no ENANPARQ de 2012, tira consequências do que foi esboçado na segunda parte daquele livro, acerca das hiper- ou trans- urbanizações nas grandes cidades (ou aglomerações) asiáticas e africanas, e identifica o contraponto obsceno representado pela proliferação do que Mike Davis e Daniel Monk chamaram de paraísos fora da lei. Ambos estudos se completam para fornecer um panorama não só dos contrastes monstruosos que definem o mundo contemporâneo, mas o cenário original do que viria ser chamado de “urbanismo militar” (tempo de cidades sitiadas, escaneadas, de populações-alvo rastreadas, vigiadas, preventivamente contidas e abordadas segundo perfis de risco). Abrindo o volume, Otília Arantes, para analisar a China e sua fantasia megalômana de um futuro que se quer infinito, foi buscar no passado as aspirações  coletivas, de realização ou superação, que animaram a história da moderna sociedade capitalista, os dreamworlds que embalaram os devaneios de prosperidade das populações a leste e oeste da divisão entre os dois grandes blocos da guerra fria. Quando despertaram desse sonho utópico de produção e consumo de massa, tais populações se depararam com a dureza da dura realidade: de um lado, a gigantesca expansão do “planeta favela” fechando a fronteira urbana, de outro, o recobrimento de suas contradições pelas “folies” do Star System arquitetônico. A evocação de Benjamin, neste primeiro ensaio, está diretamente vinculada à constatação do fenômeno que, no geral, acompanha estes grandes acontecimentos de massa: o sonho coletivo de bem aventurança, felicidade e poder. Desde o século XIX, esta colonização dos sonhos foi um dado que  Benjamin, por mais que apostasse num despertar para a revolução, não ignorava. Hoje, segundo a Autora, a crença de que a remodelagem do mundo pela industrialização-urbanização levaria as massas ao paraíso teria ruído. Duas formas de “mundo de sonho”, comparadas no momento mesmo de um falso despertar, como mostram os dois ensaios, o segundo, tendo como principal referência cidades do chamado terceiro mundo.   Palavras-chave:  China, Dreamworld, Hiperespacialidade, Hiperurbanização, Lagos, Luna Park, Mike Davis, Moscou, Mundos de Sonhos, New York delirante, Paraísos do Mal, Paris, capital do século XIX, Perestroika, Planeta Favela, Rem Kolhaas, Rockfeller Center, Ruinas do futuro, Sonho americano, Star system da arquitetura, Steven Graham, Susan Buck-Morse, Susan Sontag, Skyscraper, Transurbanização, Urbanismo militar, Walter Benjamin


Plaridel ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 31-54
Author(s):  
Cherish Aileen Brillon

This paper looks at the actresses who portrayed Darna and how they are presented as spectacles in the entertainment articles that promote the film and television adaptations. This frame of inquiry comes from the notion that the visual aesthetics of Darna in komiks is largely informed by the superhero genre’s dependence on spectacle as shown in the superhero’s feats of greatness and in her actions and movements which are all larger than life and extraordinary. If this is the case for Darna in print, then how about the actresses tasked with performing her in the movies and television series? How are their bodies being turned into a spectacle in promotional materials in order to conform to the needs of the capital (entertainment industry)? In using the spectacle of the body as framework, the paper also draws on the star system and the role of producers of text in the creation of Darna as we know her today. The aim is to reveal how female bodies were made part of the construction of Darna’s image outside of its fictional universe which results in a discourse that highlights the body of the celebrities rather than Darna’s continuing relevance as a Filipino icon. This sets aside her representational power to embody the struggle and demand of Filipinos for justice and a better life as audience’s attention is diverted towards how these actresses prepared their bodies to perform Darna.


2021 ◽  
Vol 917 (2) ◽  
pp. 93
Author(s):  
Veselin B. Kostov ◽  
Brian P. Powell ◽  
Guillermo Torres ◽  
Tamás Borkovits ◽  
Saul A. Rappaport ◽  
...  

2021 ◽  
Author(s):  
Guangnan Zhu ◽  
Kuan Lu ◽  
Qingjie Cao ◽  
Panfeng Huang ◽  
Kangyu Zhang

Abstract In this paper, an n-star general dynamic model of tethered satellite system with closed-loop configuration is provided. An analytical method for periodic solution stability of the general dynamic model is proposed based on Floquet theory, which proved that the periodic solution stability of the system depends on the maximum modulus for the eigenvalue of a matrix related to the Jacobian matrix. The periodic solution stability of a 3-star system with equilateral triangle as the initial configuration is analyzed as an example based upon the analytical method. The critical stable spin angular velocity of the 3-star system is analyzed when the system spins clockwise, and its numerical simulation is carried out to verify the results. The results show that the analytical method of periodic solution stability can solve the critical stable spin angular velocity accurately of the tethered satellite system, and the 3-star system can guarantee stable spin when the spin angular velocity is about 2.1 times of its revolution angular velocity, otherwise the disturbed system will not be able to re-converge to the initial configuration in finite time.


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