scholarly journals Mass Loss from Contact Binary Systems and their Dynamical Evolution

1980 ◽  
Vol 88 ◽  
pp. 511-515
Author(s):  
Kyoji Nariai

When there is mass loss from a binary system, the lost mass carries energy and angular momentum out of the system. Therefore, the remaining system must adjust its orbital parameters to the changing values of the total kinematic energy E and the total angular momentum N as the total mass M decreases. The parameters concerned here are : the fractional mass μ, the semi-major axis a, and the eccentricity e.

Author(s):  
Gloria Guilluy ◽  
Alessandro Sozzetti ◽  
Paolo Giacobbe ◽  
Aldo S. Bonomo ◽  
Giuseppina Micela

AbstractSince the first discovery of an extra-solar planet around a main-sequence star, in 1995, the number of detected exoplanets has increased enormously. Over the past two decades, observational instruments (both onboard and on ground-based facilities) have revealed an astonishing diversity in planetary physical features (i. e. mass and radius), and orbital parameters (e.g. period, semi-major axis, inclination). Exoplanetary atmospheres provide direct clues to understand the origin of these differences through their observable spectral imprints. In the near future, upcoming ground and space-based telescopes will shift the focus of exoplanetary science from an era of “species discovery” to one of “atmospheric characterization”. In this context, the Atmospheric Remote-sensing Infrared Exoplanet Large (Ariel) survey, will play a key role. As it is designed to observe and characterize a large and diverse sample of exoplanets, Ariel will provide constraints on a wide gamut of atmospheric properties allowing us to extract much more information than has been possible so far (e.g. insights into the planetary formation and evolution processes). The low resolution spectra obtained with Ariel will probe layers different from those observed by ground-based high resolution spectroscopy, therefore the synergy between these two techniques offers a unique opportunity to understanding the physics of planetary atmospheres. In this paper, we set the basis for building up a framework to effectively utilise, at near-infrared wavelengths, high-resolution datasets (analyzed via the cross-correlation technique) with spectral retrieval analyses based on Ariel low-resolution spectroscopy. We show preliminary results, using a benchmark object, namely HD 209458 b, addressing the possibility of providing improved constraints on the temperature structure and molecular/atomic abundances.


Author(s):  
Luis Acedo

In this paper, we revisit a modified version of the classical Whitehead's theory of gravity in which all possible bilinear forms are considered to define the corresponding metric. Although, this is a linear theory that fails to give accurate results for the most sophisticated predictions of general relativity, such as gravity waves, it can still provide a convenient framework to analyze some new phenomena in the Solar System. In particular, recent development in the accurate tracking of spacecraft and the ephemerides of planetary positions have revealed certain anomalies in relation with our standard paradigm for celestial mechanics. Among them the so-called flyby anomaly and the anomalous increase of the astronomical unit play a prominent role. In the first case the total energy of the spacecraft changes during the flyby and a secular variation of the semi-major axis of the planetary orbits is found in the second anomaly. For this to happen it seems that a net energy and angular momentum transfer is taken place among the orbiting and the central body. We evaluate the total transfer per revolution for a planet orbiting the Sun in order to predict the astronomical unit anomaly in the context of Whitehead's theory. This could lead to a more deeply founded hypothesis for an extended gravity model.


1977 ◽  
Vol 42 ◽  
pp. 365-370
Author(s):  
Józef Smak

The mass loss from cataclysmic binaries seems an important and worth studying phenomenon for a number of reasons. It is probably enough to mention only two of them:(a) Whenever we can directly observe the ejected material, determine its amount and the rate of mass loss, as well as its chemical composition (this being the case of the expanding envelopes of novae), we are getting a good insight into the basic physical mechanisms responsible for the observed phenomena.(b) The mass loss (together with the mass transfer) and the loss of the orbital angular momentum are related directly to the dynamical evolution of a binary system and - indirectly - to the evolution of its components.


Author(s):  
J. Salmon ◽  
R. M Canup

Impacts that leave the Earth–Moon system with a large excess in angular momentum have recently been advocated as a means of generating a protolunar disc with a composition that is nearly identical to that of the Earth's mantle. We here investigate the accretion of the Moon from discs generated by such ‘non-canonical’ impacts, which are typically more compact than discs produced by canonical impacts and have a higher fraction of their mass initially located inside the Roche limit. Our model predicts a similar overall accretional history for both canonical and non-canonical discs, with the Moon forming in three consecutive steps over hundreds of years. However, we find that, to yield a lunar-mass Moon, the more compact non-canonical discs must initially be more massive than implied by prior estimates, and only a few of the discs produced by impact simulations to date appear to meet this condition. Non-canonical impacts require that capture of the Moon into the evection resonance with the Sun reduced the Earth–Moon angular momentum by a factor of 2 or more. We find that the Moon's semi-major axis at the end of its accretion is approximately 7 R ⊕ , which is comparable to the location of the evection resonance for a post-impact Earth with a 2.5 h rotation period in the absence of a disc. Thus, the dynamics of the Moon's assembly may directly affect its ability to be captured into the resonance.


1982 ◽  
Vol 69 ◽  
pp. 187-189
Author(s):  
F. Mardirossian ◽  
G. Giuricin

AbstractWe have examined the observational data of 102 Algols in order to clarify the implications on their evolutionary scenario of various assumptions concerning mass and angular momentum loss during mass transfer. We have found that case B mass exchange is strongly favoured for Algols of relatively low total mass (~ M < 7 Mʘ), while case A predominates, though not so widely as expected in Algols of higher total mass.


2011 ◽  
Vol 312-315 ◽  
pp. 27-32
Author(s):  
R. Leticia Corral Bustamante ◽  
Aarón Raúl Rodríguez-Corral ◽  
T.J Amador-Parra ◽  
E.A. Vázquez-Tapia

Cosmic censorship!: black hole wrapped up by its entropy and hidden by its event horizon. In this paper, we postulate a metric to solve the Einstein equations of general relativity, which predicts the thermodynamic behavior of a gigantic mass that collapses to a black hole; taking into account the third law of thermodynamics that states that neither physical process can produce a naked singularity. However, under certain conditions, the model allows to evident violation to the cosmic censorship, exposing the hole nakedness. During the collapse of the hole, quantum effects appear: the area decrease and radiation produced has a high entropy, so that increases total entropy and expose the presence of the hole, while the appearance of the event horizon hide the singularity of the exterior gazes. It is verified that in certain circumstances, the model predicts that the hole mass is bigger than its angular momentum; and in all circumstances, this predicts an hole with enormous superficial graveness that satisfy a relationship of the three parameters that describe the hole (mass, charge and angular momentum); factors all indicative that the singularity is not naked. Then, there are no apparent horizons in accord with cosmic censorship conjecture. Even though the surface gravity of the hole prevents destroying its horizon wrapping singularity, there exists evidence of this singularity by the results of the spin-mass relationship and the escape velocity obtained. The lost information and the slow rate of rotation of the semi-major axis of the mass (dragging space and time around itself as it rotates), agree with Einstein's prediction, show the transport of energy through heat and mass transfer, which were measured by entropy of the hole by means of coordinated semi-spherical that include the different types of intrinsic energy to the process of radiation of the hole event horizon.


2007 ◽  
Vol 3 (S249) ◽  
pp. 419-424
Author(s):  
Ji-Wei Xie ◽  
Ji-Lin Zhou

AbstractWe numerically investigate the conditions for planetesimal accretion in the circumprimary disk under the perturbing presence of a companion star, with focus on the γ Cephei system. Gas drag is included with a dissipating time scale of 105years. We show at the beginning(within 103∼ 104years), gas drag damps the ΔVbetween planetesimals of same sizes and increases ΔVbetween planetesimals of different sizes. However, after increasing to high values(300∼800m/s), we find the ΔVbetween bodies of different sizes decrease to very low values (below 10m/s) in a few 105yrs(depending on the gas-dissipating time scaleTdamp, radial sizeRpand semi-major axisapof planetesimals). Hence, the high ΔVis somewhat short-lived, and runaway accretion can be turned on later. We conclude that the conditions for planetary formation in binary systems (even close binary systems) are much better than what we expected before.


2014 ◽  
Vol 9 (S310) ◽  
pp. 168-169
Author(s):  
Eduard D. Kuznetsov ◽  
Stanislav O. Kudryavtsev

AbstractBoth analytical and numerical results are used to study high-order resonance regions in the vicinity of Molnya-type orbits. Based on data of numerical simulations, long-term orbital evolution are studied for objects in highly elliptical orbits depending on their area-to-mass ratio. The Poynting–Robertson effect causes a secular decrease in the semi-major axis of a spherically symmetrical satellite. Under the Poynting–Robertson effect, objects pass through the regions of high-order resonances. The Poynting–Robertson effect and secular perturbations of the semi-major axis lead to the formation of weak stochastic trajectories.


2020 ◽  
Vol 24 (1) ◽  
pp. 56-60
Author(s):  
Mohamed R. Amin

AbstractThe focus of this paper is the design of a self-maintenance orbit using two natural forces against each other. The effect of perturbations due to Earth's oblateness up to the third order on both the semi-major axis and eccentricity for a low Earth orbit satellite together with the perturbation due to air drag on the same orbital parameters were used, in order to create self-maintenance orbits. Numerical results were simulated for a low earth orbit satellite, which substantiates the applicability of the results.


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