The Orbital Eccentricity of Small Planet Systems

ABSTRACT Supermassive black holes (SMBHs) are found in most galactic nuclei. A significant fraction of these nuclei also contains a nuclear stellar cluster (NSC) surrounding the SMBH. In this paper, we consider the idea that the NSC forms first, from the merger of several stellar clusters that may contain intermediate-mass black holes (IMBHs). These IMBHs can subsequently grow in the NSC and form an SMBH. We carry out N-body simulations of the simultaneous merger of three stellar clusters to form an NSC, and investigate the outcome of simulated runs containing zero, one, two, and three IMBHs. We find that IMBHs can efficiently sink to the centre of the merged cluster. If multiple merging clusters contain an IMBH, we find that an IMBH binary is likely to form and subsequently merge by gravitational wave emission. We show that these mergers are catalyzed by dynamical interactions with surrounding stars, which systematically harden the binary and increase its orbital eccentricity. The seed SMBH will be ejected from the NSC by the recoil kick produced when two IMBHs merge, if their mass ratio q ≳ 0.15. If the seed is ejected then no SMBH will form in the NSC. This is a natural pathway to explain those galactic nuclei that contain an NSC but apparently lack an SMBH, such as M33. However, if an IMBH is retained then it can seed the growth of an SMBH through gas accretion and tidal disruption of stars.

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Remote and local drivers of Pleistocene South Asian summer monsoon precipitation: A test for future predictions

Science Advances ◽

10.1126/sciadv.abg3848 ◽

2021 ◽

Vol 7 (23) ◽

pp. eabg3848

Author(s):

Steven C. Clemens ◽

Masanobu Yamamoto ◽

Kaustubh Thirumalai ◽

Liviu Giosan ◽

Julie N. Richey ◽

...

Keyword(s):

Carbon Dioxide ◽

South Asian ◽

Summer Monsoon ◽

Large Scale ◽

Asian Summer Monsoon ◽

Precipitation Amount ◽

Monsoon Precipitation ◽

Orbital Eccentricity ◽

South Asian Summer Monsoon ◽

Asian Summer

South Asian precipitation amount and extreme variability are predicted to increase due to thermodynamic effects of increased 21st-century greenhouse gases, accompanied by an increased supply of moisture from the southern hemisphere Indian Ocean. We reconstructed South Asian summer monsoon precipitation and runoff into the Bay of Bengal to assess the extent to which these factors also operated in the Pleistocene, a time of large-scale natural changes in carbon dioxide and ice volume. South Asian precipitation and runoff are strongly coherent with, and lag, atmospheric carbon dioxide changes at Earth’s orbital eccentricity, obliquity, and precession bands and are closely tied to cross-equatorial wind strength at the precession band. We find that the projected monsoon response to ongoing, rapid high-latitude ice melt and rising carbon dioxide levels is fully consistent with dynamics of the past 0.9 million years.

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Astronomically paced marine biological evolution during the Late Paleozoic icehouse-to-greenhouse transition

10.5194/egusphere-egu21-13809 ◽

2021 ◽

Author(s):

Qiang Fang ◽

Huaichun Wu ◽

Shuzhong Shen ◽

Junxuan Fan ◽

Linda Hinnov ◽

...

Keyword(s):

Amplitude Modulation ◽

Biological Evolution ◽

Late Paleozoic ◽

Marine Biodiversity ◽

Orbital Eccentricity ◽

Constant Input ◽

Biological Responses ◽

Carbon Burial ◽

Organic Carbon Burial ◽

Marine Diversity

<p>Late Paleozoic deglaciation is the Earth&#8217;s first icehouse-to-greenhouse transition in a vegetated world, but the climatic and biological responses to this transition have not yet been fully addressed. We conducted cyclostratigraphic analysis on the magnetic susceptibility from a deep marine carbonate succession in South China, to reconstruct the astrochronology of the late Early Permian, and to decipher evolutionary responses to astronomically forced climate changes in a marine diversity time series. Our results indicates that the minima of ~1.8 m.y. short orbital eccentricity amplitude modulation cycles led to seasonally stable precipitation patterns and a constant input of nutrients, which spurred marine biodiversity during this deglaciation. Synchronizing global biotic and abiotic records reveals that peaks of marine biodiversity occurred during nodes of ~1.3 m.y. obliquity amplitude modulation cycles, when ice sheet expansion triggered enhanced precipitation and organic carbon burial during icehouse conditions (290&#8722;285.1 Ma). Starting at 285.1 Ma, the insolation-biodiversity relationship began to change, paced by glacial termination and tropical aridification. With the transition to greenhouse conditions (~279.1&#8722;272 Ma), obliquity nodes became associated instead with terrestrial aridity and marine anoxia, and suppression of marine speciation. Our results bring into focus a pattern of shifting dynamics involving Earth&#8217;s astronomical parameters, climate change and marine biodiversity for icehouse and greenhouse worlds in the late Paleozoic Era.</p>

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Orbital Eccentricity and Unbalanced Magnetic Pull in Salient Pole Synchronous Machines

2018 XIII International Conference on Electrical Machines (ICEM) ◽

10.1109/icelmach.2018.8507067 ◽

2018 ◽

Author(s):

J. Johnny Rocha E ◽

Paulo V.V. Da Silva ◽

Edson C. Bortoni

Keyword(s):

Synchronous Machines ◽

Orbital Eccentricity ◽

Unbalanced Magnetic Pull ◽

Salient Pole

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On planar oscillations of a body with a variable mass distribution in an elliptic orbit

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406211404327 ◽

2011 ◽

Vol 225 (10) ◽

pp. 2288-2295 ◽

Cited By ~ 6

Author(s):

A Burov ◽

I Kosenko

Keyword(s):

Mass Distribution ◽

Large Scale ◽

Variable Mass ◽

Relative Equilibria ◽

The Body ◽

Global Dynamics ◽

Central Field ◽

Attitude Dynamics ◽

Orbital Eccentricity ◽

Space Elevators

Planar motion of an orbiting body having a variable mass distribution in a central field of gravity is under analysis. Within the so-called ‘satellite approximation’ planar attitude dynamics is reduced to the 3/2-degrees of freedom description by one ODE of second order. The law of the mass distribution variations implying an existence of the special relative equilibria, such that the body is oriented pointing to the attracting centre by the same axis for any value of the orbit eccentricity is indicated. For particular example of an orbiting dumb-bell equipped by a massive cabin, wandering between the ends of the dumb-bell. For this example stability of the equilibria such that the dumb-bell ‘points to’ the attracting centre by one of its ends is studied. The chaoticity of global dynamics is investigated. Two important examples of a vibrating dumb-bell and of a dumb-bell equipped by a cabin wandering between its endpoints are considered. The dynamics of space objects, including moving elements, has been investigated by many authors. These studies usually have been connected with the necessity to estimate the influence of relative motions of moving parts, for example, crew motions [ 1 , 2 ], circulation of liquids [ 3 ], etc. on the attitude dynamics of a spacecraft. The development of projects of large-scale space systems with mobile elements, in particular, of satellite systems with tethered elements and space elevators, has posed problems related to their dynamics. Various aspects of the role of mass distribution even for the simplest orbiting systems, like dumb-bell systems are known since the publications [ 4 – 7 ], etc. The possibility of the sudden loss of stability because of the mass redistribution has been pointed out in reference [ 8 ] (see also references [ 9 – 13 ]). The considered system belongs to the mentioned class of systems and represents by itself one of the simplest systems allowing both analytical and numerical treatment, without supplementary simplifying assumptions such as smallness of the orbital eccentricity. Another set of applied problems is related to orientation keeping of the system for deployment and retrieval of tethered subsatellites as well as for relative cabin motions of space elevators. In particular, the problem of the stabilization/destabilization possibility for the given state of motion due to rapid oscillations of the cabin exists. This could be the subject of another additional investigation.

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The Relation between Spin and Orbital Periods in HMXBs

Symposium - International Astronomical Union ◽

10.1017/s0074180900194422 ◽

2003 ◽

Vol 214 ◽

pp. 215-217

Author(s):

Q. Z. Liu ◽

X. D. Li ◽

D. M. Wei

Keyword(s):

Magnetic Fields ◽

Orbital Period ◽

Critical Line ◽

High Mass ◽

Orbital Eccentricity ◽

X Ray ◽

Spin Period ◽

Orbital Periods ◽

X Ray Binaries

The relation between the spin period (Ps) and the orbital period (Po) in high-mass X-ray binaries (HMXBs) is investigated. In order for Be/X-ray binaries to locate above the critical line of observable X-ray emission due to accretion, it is necessary for an intermediate orbital eccentricity to be introduced. We suggest that some peculiar systems in the Po − Ps diagram are caused by their peculiar magnetic fields.

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Age and driving mechanisms of the Eocene–Oligocene transition from astronomical tuning of a lacustrine record (Rennes Basin, France)

Climate of the Past ◽

10.5194/cp-17-2343-2021 ◽

2021 ◽

Vol 17 (6) ◽

pp. 2343-2360

Author(s):

Slah Boulila ◽

Guillaume Dupont-Nivet ◽

Bruno Galbrun ◽

Hugues Bauer ◽

Jean-Jacques Châteauneuf

Keyword(s):

Hydrological Cycle ◽

Sedimentary Facies ◽

Late Eocene ◽

Depositional Environments ◽

Orbital Eccentricity ◽

Pass Filter ◽

Low Pass Filter ◽

Climate Conditions ◽

Driving Mechanisms ◽

Natural Gamma

Abstract. The Eocene–Oligocene Transition (EOT) marks the onset of the Antarctic glaciation and the switch from greenhouse to icehouse climates. However, the driving mechanisms and the precise timing of the EOT remain controversial mostly due to the lack of well-dated stratigraphic records, especially in continental environments. Here we present a cyclo-magnetostratigraphic and sedimentological study of a ∼ 7.6 Myr long lacustrine record spanning the late Eocene to the earliest Oligocene, from a drill core in the Rennes Basin (France). Cyclostratigraphic analysis of natural gamma radiation (NGR) log data yields duration estimates of Chrons C12r through C16n.1n, providing additional constraints on the Eocene timescale. Correlations between the orbital eccentricity curve and the 405 kyr tuned NGR time series indicate that 33.71 and 34.10 Ma are the most likely proposed ages of the EO boundary. Additionally, the 405 kyr tuning calibrates the most pronounced NGR cyclicity to a period of ∼1 Myr, matching the g1–g5 eccentricity term, supporting its significant expression in continental depositional environments, and hypothesizing that the paleolake level may have behaved as a low-pass filter for orbital forcing. Two prominent changes in the sedimentary facies were detected across the EOT, which are temporally equivalent to the two main climatic steps, EOT-1 and Oi-1. We suggest that these two facies changes reflect the two major Antarctic cooling/glacial phases via the hydrological cycle, as significant shifts to drier and cooler climate conditions. Finally, the interval spanning the EOT precursor glacial event through EOT-1 is remarkably dominated by obliquity. This suggests preconditioning of the major Antarctic glaciation, either from obliquity directly affecting the formation/(in)stability of the incipient Antarctic Ice Sheet (AIS), or through obliquity modulation of the North Atlantic Deep Water production.

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