scholarly journals A self-consistent weak friction model for the tidal evolution of circumbinary planets

2019 ◽  
Vol 627 ◽  
pp. A109 ◽  
Author(s):  
F. A. Zoppetti ◽  
C. Beaugé ◽  
A. M. Leiva ◽  
H. Folonier
Keyword(s):  
Body Problem ◽  
Semimajor Axis ◽  
Orbital Evolution ◽  
Friction Model ◽  
The Other ◽  
Tidal Evolution ◽  
Other Hand ◽  
Self Consistent ◽  
The Masses ◽  
Circumbinary Planets

We present a self-consistent model for the tidal evolution of circumbinary planets that is easily extensible to any other three-body problem. Based on the weak-friction model, we derive expressions of the resulting forces and torques considering complete tidal interactions between all the bodies of the system. Although the tidal deformation suffered by each extended mass must take into account the combined gravitational effects of the other two bodies, the only tidal forces that have a net effect on the dynamic are those that are applied on the same body that exerts the deformation, as long as no mean-motion resonance exists between the masses. As a working example, we applied the model to the Kepler-38 binary system. The evolution of the spin equations shows that the planet reaches a stationary solution much faster than the stars, and the equilibrium spin frequency is sub-synchronous. The binary components, on the other hand, evolve on a longer timescale, reaching a super-synchronous solution very close to that derived for the two-body problem. The orbital evolution is more complex. After reaching spin stationarity, the eccentricity was damped in all bodies and for all the parameters analysed here. A similar effect is noted for the binary separation. The semimajor axis of the planet, on the other hand, may migrate inwards or outwards, depending on the masses and orbital parameters. In some cases the secular evolution of the system may also exhibit an alignment of the pericenters, requiring the inclusion of additional terms in the tidal model. Finally, we derived analytical expressions for the variational equations of the orbital evolution and spin rates based on low-order elliptical expansions in the semimajor axis ratioαand the eccentricities. These are found to reduce to the well-known two-body case whenα→ 0 or when one of the masses is taken as equal to zero. This model allows us to find a closed and simple analytical expression for the stationary spin rates of all the bodies, as well as predicting the direction and magnitude of the orbital migration.

scholarly journals Tidal evolution of circumbinary systems with arbitrary eccentricities: applications for Kepler systems

2020 ◽  
Vol 634 ◽  
pp. A12
Author(s):  
F. A. Zoppetti ◽  
A. M. Leiva ◽  
C. Beaugé
Keyword(s):  
Time Lag ◽  
Semimajor Axis ◽  
Tidal Flow ◽  
Orbital Evolution ◽  
Axis Ratio ◽  
Tidal Evolution ◽  
Tidal Interactions ◽  
Orbital Instability ◽  
Outward Migration ◽  
Circumbinary Planets

We present an extended version of the Constant Time Lag analytical approach for the tidal evolution of circumbinary planets introduced in our previous work. The model is self-consistent, in the sense that all tidal interactions between pairs are computed, regardless of their size. We derive analytical expressions for the variational equations governing the spin and orbital evolution, which are expressed as high-order elliptical expansions in the semimajor axis ratio but retain closed form in terms of the binary and planetary eccentricities. These are found to reproduce the results of the numerical simulations with arbitrary eccentricities very well, as well as reducing to our previous results in the low-eccentric case. Our model is then applied to the well-characterised Kepler circumbinary systems by analysing the tidal timescales and unveiling the tidal flow around each different system. In all cases we find that the spins reach stationary values much faster than the characteristic timescale of the orbital evolution, indicating that all Kepler circumbinary planets are expected to be in a sub-synchronous state. On the other hand, all systems are located in a tidal flow leading to outward migration; thus the proximity of the planets to the orbital instability limit may have been even greater in the past. Additionally, Kepler systems may have suffered a significant tidally induced eccentricity damping, which may be related to their proximity to the capture eccentricity. To help understand the predictions of our model, we also offer a simple geometrical interpretation of our results.

scholarly journals Demonstration of chromatinic structures in avian tubercle bacilli in the early stages of development

1947 ◽  
Vol 45 (4) ◽  
pp. 413-416 ◽  
Author(s):  
E. M. Brieger ◽  
C. F. Robinow
Keyword(s):  
Hydrochloric Acid ◽  
Early Development ◽  
The Other ◽  
Feulgen Reaction ◽  
Cytological Investigation ◽  
Stages Of Development ◽  
The Third ◽  
Early Stages ◽  
Other Hand ◽  
The Masses

In a cytological investigation of three branching and two non-branching strains grown on Loewenstein medium, it was found that avian tubercle bacilli contain chromatinic material which gives a positive Feulgen reaction and is readily stainable with Giemsa's solution after treatment of the fixed bacteria with hydrochloric acid.Growing filamentous forms of both ‘bacterial’ and ‘mycelial’ strains from 1 to 2 day old cultures contain variable numbers of irregularly spaced, more or less spherical chromatinic bodies which vary in staining in the same bacillus, some being red, others purple. During the third or fourth day the chromatinic material in the bacteria increases very much until most of it is fused into an almost homogeneous deeply stained column. In thenon-branchingstrains the filamentous forms with high chromatin content soon break up into small mono-or binucleate elements, and the same holds true for the ‘straight’ filamentous forms which are also present in cultures of branching strains. The ‘mycelial’ forms, on the other hand, disintegrate at this time (fourth or fifth day of cultivation), and it is uncertain whether they contribute (by partial fragmentation) to the masses of small mono- or binucleate forms which are the predominant element in old cultures of all the strains investigated.The chromatinic structures of avian tubercle bacilli have the same staining properties as those of ordinary non-acid-fast bacteria but differ from them in their behaviour during the early development of the bacilli.

scholarly journals Abu Al Wared Revolution And The Idea Of Awaited Al Sufyanii

2017 ◽  
Vol 13 (2) ◽  
pp. 321
Author(s):  
Mohammad Alesa
Keyword(s):  
The Other ◽  
Military Power ◽  
Islamic History ◽  
Political Determinants ◽  
Other Hand ◽  
Economic Determinant ◽  
Long Time ◽  
The Masses ◽  
The Revolution

The idea of the Redeemer prevailed in most human civilizations, but in different forms. This, however, was coupled with a state of despair and the inability to change the reality. The idea was manifested in Islamic history through religious, tribal, and political determinants. Thus, it was one of the slogans of the Umayyad against the Abbasid authority to denounce their legitimacy in power. The Rebel, Abu Al Wared, used this slogan to establish the foundation of the revolution against the Abbasid power. Nevertheless, they realized its danger and took efforts to eliminate such danger before the spread of the revolution. Savior logo continued to be a way to convince the masses to revolt against authority for a long time, especially in the Abbasid era. In addition, it had a socio-economic determinant against feudal power on one hand and military power on the other hand.

scholarly journals Climate Change in India: A Wakeup Call from Bollywood

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Manvi Sharma ◽  
◽  
Ajay K. Chaubey
Keyword(s):  
Climate Change ◽  
Detailed Analysis ◽  
Environmental Degradation ◽  
Climatic Condition ◽  
Drastic Change ◽  
The Other ◽  
Other Hand ◽  
The Masses ◽  
New Generation ◽  
The Village

Amidst Bollywood’s romanticized landscapes and grandeur settings, depiction of the flora and fauna, roaring rivers and drought prone lands, is difficult to locate. But the new millennium has witnessed some new generation filmmakers, sensitized towards the ecological concerns, thus marking a shift from the illustration of idealised landscapes to the representation of nature’s wrath. Since, cinema in India, has a deep-rooted impact on the masses, these creators employ films as tools to sensitize the population towards the climate change threat which though as perilous as the COVID-19 crisis, is often ignored by a significant amount of population. Dawning upon themselves the responsibility of environmental awakening, Nila Madhab Panda and Abhishek Kapoor highlight in their movies, Kadvi Hawa(2017) and Kedarnath(2018), respectively, the horrors of human callousness, leading to drastic change in Climatic condition in India. Panda’s Kadavi Hawa, dealing with non-repayment of loans followed by suicides, portrays the heart-wrenching imagery of environmental degradation and Climate change that has rendered the Village of Mahua, arid and infertile. Kapoor’s Kedarnath on the other hand, appeals for action through horrifying imagery of the catastrophic floods that disrupted the holy town of Kedarnath, in 2013. Through a detailed analysis of the aforementioned visual portrayals, this article aims to emphasise as to how Films can play an important role in effectively addressing dealing with the issues related to Climate. Further, the rationale of this paper is to underscore the possibility of more such storylines, as a tool towards effective engagement and levitation of conscience.

scholarly journals Membangun Konstruksi Keilmuan Ekonomi Islam

2014 ◽  
Vol 5 (1) ◽  
pp. 175
Author(s):  
Yulizar D. Sanrego Nz
Keyword(s):  
Business Community ◽  
The Other ◽  
Economic Problems ◽  
Other Hand ◽  
Global Study ◽  
Major Attention ◽  
Formed Part ◽  
The Masses ◽  
The Way

<p>Theories of Islamic economics have formed part and parcel of the global study on economy. Practically on the other hand, Islamic economics have shown its competing ability and</p>received in turn a cheerful welcome from the business community as well as from the masses at the global stage. This paper is an attempt to make a contribution in the field of what we may call the scientific construction of Islamic economics. The paper proposes that this science consists of two aspects, namely value and knowledge. With regards to the latter, on which this paper will pay its major attention, the role of methodology is crucial. This paper will therefore touch on this issue and the role of methodology in inventing knowledge and in the analysis of economic datum. Here by methodology we mean particularly fiqh. We contend that fiqh is in itself methodology. It is rich with methodological tools such as the concept of maqashid al-syariah (the purpose of divine law) which may be used not only to analyze economic datum but also to provide a schemata in resolving some economic problems. By speaking of fiqh as a science of economics we hope to pave the way for the possible invention of the science of economics based on fiqh and its philosophy.

Exploring the Location and Linear Stability of the Equilibrium Points in the Equilateral Restricted Four-Body Problem

2020 ◽  
Vol 30 (10) ◽  
pp. 2050155
Author(s):  
Euaggelos E. Zotos
Keyword(s):  
Linear Stability ◽  
Body Problem ◽  
Equilibrium Points ◽  
Libration Points ◽  
The Other ◽  
Classification Method ◽  
Four Body Problem ◽  
The Masses ◽  
Stable Points ◽  
Planar Version

The planar version of the equilateral restricted four-body problem, with three unequal masses, is numerically investigated. By adopting the grid classification method we locate the coordinates, on the plane [Formula: see text], of the points of equilibrium, for all possible values of the masses of the primaries. The linear stability of the libration points is also determined, as a function of the masses. Our analysis indicates that linearly stable points of equilibrium exist only when one of the primaries has a considerably larger mass, with respect to the other two primary bodies, when the triangular configuration of the primaries is also dynamically stable.

scholarly journals Confinement Mechanism in the Field Correlator Method

2009 ◽  
Vol 2009 ◽  
pp. 1-30 ◽  
Author(s):  
Yu. A. Simonov ◽  
V. I. Shevchenko
Keyword(s):  
Critical Temperature ◽  
Green's Function ◽  
Gluon Condensate ◽  
String Tension ◽  
The Other ◽  
Vacuum Fluctuations ◽  
Qcd Vacuum ◽  
Other Hand ◽  
Self Consistent ◽  
Nonperturbative Qcd

Confinement in QCD results from special properties of vacuum fluctuations of gluon fields. There are two numerically different scales, characterizing nonperturbative QCD vacuum dynamics: “small” one, corresponding to gluon condensate, critical temperature etc, which is about 0.1–0.3 GeV, and a “large” one, given by inverse confining string width, glueball and gluelump masses, and so forth, which is about 1.5–2.5 GeV. We discuss the origin of this hierarchy in a picture where confinement is ensured by quadratic colorelectric field correlators of the special type. These correlators, on the other hand, can be calculated via gluelump Green's function, whose dynamics is defined by the correlators themselves. In this way one obtains a self-consistent scheme, where string tension can be expressed in terms ofΛQCD.

scholarly journals Do All Spiral Galaxies Have a Massive Dark Halo?

1999 ◽  
Vol 183 ◽  
pp. 157-157 ◽  
Author(s):  
M. Honma ◽  
Y. Sofue
Keyword(s):  
Dark Matter ◽  
Spiral Galaxies ◽  
The Other ◽  
Dark Halo ◽  
Rotation Curves ◽  
Other Hand ◽  
Flat Rotation Curves ◽  
The Masses ◽  
Scale Length

We have investigated the masses and extents of dark halos of spiral galaxies by two methods. First, we have reanalyzed HI outer rotation curves so far obtained considering the velocity uncertainties. We confirmed that many HI rotation curves indicate the existence of dark matter to some extent. However, we also found that only few rotation curves provide direct evidences for halos extended beyond 10 disk scale length. On the other hand, recent HI observations revealed that several galaxies have declining rotation curves that are approximated by Keplerian in the outermost regions. Considering the velocity uncertainties in the outer rotation curves, we found that these declining rotation curves are not rare compared to flat rotation curves. If these declining rotation curves indeed trace the mass truncation, these results indicate that some dark halos have moderate masses that are comparable or slightly larger than disk masses.

scholarly journals V.—What is a Metamorphic Rock?

1911 ◽  
Vol 8 (8) ◽  
pp. 356-361
Author(s):  
E. H. L. Schwarz
Keyword(s):  
Metamorphic Rock ◽  
The Other ◽  
Boric Oxide ◽  
Other Hand ◽  
First Case ◽  
Ore Bodies ◽  
The Masses ◽  
Open Question

The latest book on metamorphism, Dr. V. Grubenmann's Kristallinen Schiefer, still leaves it an open question what a metamorphic rock is. Generally speaking there is no doubt about the matter; every geologist has a more or less precise idea of what he means by the term, but no one has yet been able to propound a definition which is perfectly satisfactory, and which will enable one to distinguish a metamorphic rock from all other kinds and at the same time convey an expression of the characteristic peculiarities inherent in such a rock. The need of a definition is very necessary. The want of it has led Dr. Grubenmann to include some rocks among the crystalline schists which one ordinarily would not refer to that class, and on the other hand there are some rocks frequently referred to that class which are not included. In the first case, the masses of emery form the twelfth group of Dr. Grubenmann's classification, yet the analysis of the Naxos emery, which reveals traces of boric oxide (1.15 per cent. in one case) would seem to place these lenses among the ore-bodies deposited by pneumatolitic action.

Monte Carlo Simulation of Diffusion with Uniform Sinks and Sources for Vacancies

2005 ◽  
Vol 237-240 ◽  
pp. 1168-1173 ◽  
Author(s):  
Jaroslav Ženíšek ◽  
Jiří Svoboda ◽  
Franz Dieter Fischer
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Monte Carlo Model ◽  
Kirkendall Effect ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Self Consistent

A new concept of generation and annihilation of vacancies at uniform sinks and sources for vacancies is incorporated into the standard Monte Carlo model for vacancy mediated diffusion. This model enables to treat the vacancy wind as well as the deformation of the specimen and the shift of the Kirkendall plane. The Monte Carlo model is used for the testing of the recent phenomenological theories of diffusion by Darken, Manning and Moleko. The agreement with the self-consistent Moleko theory is excellent. On the other hand the agreement with the classical Darken theory used very often for the explanation of the Kirkendall effect is rather poor.

Sign in / Sign up

Export Citation Format

Share Document