Stochasting modeling of planetary ring systems

International Astronomical Union Colloquium ◽

10.1017/s025292110010154x ◽

1984 ◽

Vol 75 ◽

pp. 461-469 ◽

Cited By ~ 1

Author(s):

Robert W. Hart

Keyword(s):

Maximum Entropy ◽

Ring System ◽

The Sun ◽

Ultimate State ◽

Interparticle Interactions ◽

Ring Systems ◽

First Order ◽

Planetary Ring ◽

Insight Into

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

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Scattered light may reveal the existence of ringed exoplanets

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slaa080 ◽

2020 ◽

Vol 496 (1) ◽

pp. L85-L90

Author(s):

Mario Sucerquia ◽

Jaime A Alvarado-Montes ◽

Jorge I Zuluaga ◽

Matías Montesinos ◽

Amelia Bayo

Keyword(s):

Light Curve ◽

Scattered Light ◽

Ring System ◽

Physical Parameters ◽

Summer Solstice ◽

Order Model ◽

Vast Number ◽

Ring Systems ◽

First Order

ABSTRACT Rings around giant exoplanets (hereafter ‘exorings’) are still a missing planetary phenomenon among the vast number of discovered planets. Despite the fact that there exist a large number of methods for identifying and characterizing these exorings, none of them has been successful to date. Most of those efforts focus on the photometric signatures produced by rings around transiting exoplanets; thus, little interest has been intended for the detectable signatures that non-transiting ringed planets might cause owing to the excess of scattered starlight from both their atmosphere and the considerably large surface of their (hypothetical) ring system. This extra scattering produced by exorings would occur at an orbital location defined here as ‘the summer solstice’ of a stellar light curve. In this letter, we develop a first-order model to estimate the photometric signatures of non-transiting exorings, and predict their detectability by using present and future facilities. We also show how, besides the discovery itself, our model can be used to constrain orbital and physical parameters of planet–ring systems.

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20. Positions and Motions of Minor Planets, Comets and Satellites

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00004570 ◽

1982 ◽

Vol 18 (1) ◽

pp. 195-210

Author(s):

E Roemer

Keyword(s):

Working Group ◽

Ring System ◽

Minor Planets ◽

The Sun ◽

Ring Plane ◽

Ring Systems ◽

The Earth ◽

Uranian Ring

An avalanche of discoveries pertaining to the satellite and ring systems of Jupiter and Saturn followed from the encounters of Pioneer 11 with Saturn, of Voyagers 1 and 2 with both Jupiter and Saturn, and from the passage of the Earth through the Saturn ring plane, all of which occurred during the triennium. The first comet discovery from a spacecraft also occurred during the same interval, a coronagraph experiment on the satellite P78-1 apparently catching a Kreutz sungrazer in the last hours before it impacted the Sun on 1979 August 30. Several successfully observed occultations of stars by the Uranian ring system, by minor planets, and possibly by satellites of Neptune and Pluto testify to efforts inspired by the Commission’s Working Group on Prediction of Occultations.

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Galileo Unbound

10.1093/oso/9780198805847.001.0001 ◽

2018 ◽

Cited By ~ 1

Author(s):

David D. Nolte

Keyword(s):

Free Fall ◽

The Sun ◽

Quantum Field ◽

Many Worlds ◽

Quantum Particles ◽

Light Rays ◽

History Of ◽

And Control ◽

The Universe ◽

Insight Into

Galileo Unbound: A Path Across Life, The Universe and Everything traces the journey that brought us from Galileo’s law of free fall to today’s geneticists measuring evolutionary drift, entangled quantum particles moving among many worlds, and our lives as trajectories traversing a health space with thousands of dimensions. Remarkably, common themes persist that predict the evolution of species as readily as the orbits of planets or the collapse of stars into black holes. This book tells the history of spaces of expanding dimension and increasing abstraction and how they continue today to give new insight into the physics of complex systems. Galileo published the first modern law of motion, the Law of Fall, that was ideal and simple, laying the foundation upon which Newton built the first theory of dynamics. Early in the twentieth century, geometry became the cause of motion rather than the result when Einstein envisioned the fabric of space-time warped by mass and energy, forcing light rays to bend past the Sun. Possibly more radical was Feynman’s dilemma of quantum particles taking all paths at once—setting the stage for the modern fields of quantum field theory and quantum computing. Yet as concepts of motion have evolved, one thing has remained constant, the need to track ever more complex changes and to capture their essence, to find patterns in the chaos as we try to predict and control our world.

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Exploring Flaring Behaviour on Low Mass Stars, Solar-type Stars and the Sun

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319009980 ◽

2019 ◽

Vol 15 (S354) ◽

pp. 384-391

Author(s):

L. Doyle ◽

G. Ramsay ◽

J. G. Doyle ◽

P. F. Wyper ◽

E. Scullion ◽

...

Keyword(s):

High Energy ◽

The Sun ◽

Low Mass Stars ◽

Highly Active ◽

Rotation Phase ◽

Solar Type ◽

Low Mass ◽

Insight Into ◽

Reconnection Model ◽

High Cadence

AbstractWe report on our project to study the activity in both the Sun and low mass stars. Utilising high cadence, Hα observations of a filament eruption made using the CRISP spectropolarimeter mounted on the Swedish Solar Telescope has allowed us to determine 3D velocity maps of the event. To gain insight into the physical mechanism which drives the event we have qualitatively compared our observation to a 3D MHD reconnection model. Solar-type and low mass stars can be highly active producing flares with energies exceeding erg. Using K2 and TESS data we find no correlation between the number of flares and the rotation phase which is surprising. Our solar flare model can be used to aid our understanding of the origin of flares in other stars. By scaling up our solar model to replicate observed stellar flare energies, we investigate the conditions needed for such high energy flares.

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Relational Chase Procedures Interpreted as Resolution with Paramodulation1

Fundamenta Informaticae ◽

10.3233/fi-1991-15203 ◽

1991 ◽

Vol 15 (2) ◽

pp. 123-138

Author(s):

Joachim Biskup ◽

Bernhard Convent

Keyword(s):

Alternative Interpretation ◽

Order Logic ◽

First Order Logic ◽

Inference Problem ◽

First Order ◽

Inference Problems ◽

The One ◽

The Relationship ◽

Theoretical Foundations ◽

Insight Into

In this paper the relationship between dependency theory and first-order logic is explored in order to show how relational chase procedures (i.e., algorithms to decide inference problems for dependencies) can be interpreted as clever implementations of well known refutation procedures of first-order logic with resolution and paramodulation. On the one hand this alternative interpretation provides a deeper insight into the theoretical foundations of chase procedures, whereas on the other hand it makes available an already well established theory with a great amount of known results and techniques to be used for further investigations of the inference problem for dependencies. Our presentation is a detailed and careful elaboration of an idea formerly outlined by Grant and Jacobs which up to now seems to be disregarded by the database community although it definitely deserves more attention.

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Synthesis of Pyrazolofuropyrazine via One-Pot SNAr Reaction and Intramolecular Direct C–H Arylation

Synthesis ◽

10.1055/s-0036-1591885 ◽

2018 ◽

Vol 50 (07) ◽

pp. 1493-1498 ◽

Cited By ~ 3

Author(s):

Shinichiro Fuse ◽

Hiroyuki Nakamura ◽

Megumi Inaba ◽

Shinichi Sato ◽

Manjusha Joshi

Keyword(s):

Drug Discovery ◽

Rapid Development ◽

Ring System ◽

Biologically Active ◽

Drug Candidate ◽

One Pot ◽

Ring Systems ◽

Drug Candidates ◽

Fused Ring ◽

Snar Reaction

Fused-ring systems containing heterocycles are attractive templates for drug discovery. Biologically active 6-5-5+6 fused-ring systems that possess heterocycles are available, but these require a relatively large number of synthetic steps for preparation. Therefore, pyrazolofuropyrazine was designed as a 6-5-5+6 ring system template that incorporates ready accessibility for drug discovery. Pyrazolofuropyrazines were successfully constructed in only a few steps via one-pot SNAr reaction/intramolecular C–H direct arylation. As a drug candidate, pyrazolofuropyrazine has earned a favorable LogP, although significant biological activity has yet to be established; the ready accessibility of pyrazolofuropyrazine template, however, offers an opportunity for the rapid development of promising new drug candidates.

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Closing up onto our sun: solar imaging

EPJ Web of Conferences ◽

10.1051/epjconf/202024007011 ◽

2020 ◽

Vol 240 ◽

pp. 07011

Author(s):

Kushagra Shrivastava ◽

Keith Wen Kai Chia ◽

Kang Jun Wong ◽

Alfred Yong Liang Tan ◽

Hwee Tiang Ning

Keyword(s):

Solar Activity ◽

The Sun ◽

Research Needs ◽

Large Numbers ◽

Wide Range ◽

Future Science ◽

Insight Into ◽

Term Data ◽

Made In

Solar activity research provides insight into the Sun’s past, future (Science Daily, 2018). The solar activity includes observations of large numbers of intense sunspots, flares, and other phenomena; and demands a wide range of techniques and measurements on the observations. This research needs long term data collection before critical analyses can occur, to generate meaningful learning and knowledge. In this project, we will use solar imaging to make observations of solar activity, and take our baby steps to make contributions in citizen science. Observations will be made in 3 wavelengths to gain a more thorough analysis by looking at different perspectives of the Sun, namely H-Alpha, Calcium-K, and white light.

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Dust in Planetary Ring Systems

International Astronomical Union Colloquium ◽

10.1017/s0252921100067105 ◽

1991 ◽

Vol 126 ◽

pp. 349-356

Author(s):

Mark R. Showalter

Keyword(s):

General Class ◽

Large Population ◽

Physical Processes ◽

Ring Systems ◽

Interstellar Grains ◽

Planetary Ring

AbstractEach of the outer gas giants Jupiter, Saturn, Uranus and Neptune is now known to be encircled by a system of rings. Some of these, such as the A, B, and C rings of Saturn and the nine narrow Uranian rings, are rather optically thick and are composed primarily of large bodies (1 cm to 10 m). However, every other system has been found to contain a large population of micron-sized dust. Such rings reveal the effects of a variety of physical processes that are also acting on interplanetary and interstellar grains. When such rings are examined as members of a general class, recurring patterns begin to emerge.

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