A5090591444- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Scientific Research and Discoveries
- History and Developments in Astronomy
- Historical Astronomy and Related Studies
- Statistical Mechanics and Entropy
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Advanced Thermodynamics and Statistical Mechanics
- Historical and Architectural Studies
- Spacecraft Dynamics and Control
- Quantum chaos and dynamical systems
- Nuclear physics research studies
- High-pressure geophysics and materials
- Archaeology and ancient environmental studies
- History of Science and Medicine
- Astrophysical Phenomena and Observations
- Planetary Science and Exploration
- Astronomical Observations and Instrumentation
- Diverse Historical and Scientific Studies
- Material Science and Thermodynamics
Maxwell Institute for Mathematical Sciences
2013-2023
University of Edinburgh
2012-2023
Kyoto University
2009
Purple Mountain Observatory
2001-2007
Izumi City General Hospital
1996
The University of Tokyo
1996
Nippon Shokubai (Japan)
1996
Goddard Space Flight Center
1982
NGC Aerospace (Canada)
1982
University of Cambridge
1973-1977
Numerical experiments have demonstrated something of the importance binaries in N-body systems, and this paper aims to provide a comprehensive theoretical picture their behaviour. It begins by testing possible ‘ equilibrium ’ distributions for against results computational experiments, but is mainly concerned with dynamics encounters between other members system.
In this paper we show the results of a large set N-body simulations modelling evolution globular clusters driven by relaxation, stellar and disc shocking, including effects tidal field Galaxy. We investigate multi-mass models with power-law initial mass function (IMF) starting different masses, concentrations, slopes IMF located at galactocentric distances. to what extent various evolutionary processes alter shape these changes depend on position cluster in The both global local functions...
The gravitational N-body problem is to describe the evolution of an isolated system N point masses interacting only through Newtonian forces. For =2 solution due Newton. =3 there no general analytic solution, but has occupied generations illustrious physicists and mathematicians including Laplace, Lagrange, Gauss Poincaré, inspired modern subjects nonlinear dynamics chaos theory. remains one oldest unsolved problems in physics.
Most of the observed extrasolar planets are found on tight and often eccentric orbits. The high eccentricities not easily explained by planet-formation models, which predict that should be rather circular Here we explore whether fly-bys involving planetary systems with properties similar to those gas giants in Solar system can produce planets. Using numerical simulations, show cause immediate ejection planets, sometimes also lead capture one or more intruder. More common, however, is only...
In this paper a cluster is modelled as smooth potential (due to the stars) plus steady tidal field of Galaxy. model there minimum energy below which stars cannot escape. Above energy, however, time scale on escape varies with orbital parameters star (mainly its energy) in way we attempt quantify, both theoretical arguments and computer simulations. Within limitations show that long enough complicate interpretation full N-body simulations clusters, above may remain bound for about Hubble time.
In this paper, globular star clusters which contain a subsystem of stellar mass black holes (BH) are investigated. This is done by considering two-component models, as these the simplest approximation more realistic multimass systems, where one component represents BH population and other all stars. These systems found to undergo long phase evolution centre system dominated dense subsystem. After segregation has driven most into compact subsystem, be influenced cluster in it contained. The...
The evolution of globular clusters due to 2-body relaxation results in an outward flow energy and at some stage all need a central source sustain their evolution. Henon provided the insight that we do not know details production order understand relaxation-driven cluster, least outside core. He two self-similar solutions for based on view cluster as whole determines amount is produced core: steady expansion isolated clusters, homologous contraction evaporating tidal field. We combine these...
Based on recent findings of a formation mechanism substructure in tidal tails by Kuepper, Macleod & Heggie (2008) we investigate more comprehensive set N-body models star clusters orbits about Milky-Way-like potential. We find that the predicted epicyclic overdensities arise any tail no matter which orbit cluster follows as long lives enough for to build up. The distance along from centre depends circular only mass and strength field, therefore decreases monotonically with time, while...
We describe a major upgrade of Monte Carlo code that has previously been used for many studies dense star clusters. outline the steps needed in order to calibrate results new against N-body simulations large-N systems, up N = 200 000. The version (called MOCCA), addition features old version, incorporates direct Fewbody integrator three- and four-body interactions, treatment escape process based on work by Fukushige & Heggie. Now stars fulfil criterion are not removed immediately, but can...
We review what has been learned recently using N -body simulations about the evolution of globular clusters. While star clusters have become more realistic, and now include single binary stars, prospect reaching large enough is still a distant one. Nevertheless restricted kinds brought valuable progress for certain problems current observational interest, including origin structure tidal tails In addition, such forced us to rethink some basic aspects stellar dynamics, including, in...
We study the dynamical evolution of idealized stellar systems by averaging results from many N-body simulations, each having modest numbers stars. For isolated with stars uniform mass, we discuss aspects up to point core collapse: relaxation and its N-dependence, density profile, development velocity dispersion anisotropy, rate escape.
We examine the longitudinal distribution of stars escaping from a cluster along tidal tails. Using both theory and simulations, we show that, even in case star circular galactic orbit, when tide is steady, exhibits maxima at distance many radii cluster.
Based on our recent work tidal tails of star clusters we investigate a few 104 M⊙ by means velocity dispersion profiles and surface density profiles. We use comprehensive set N-body computations various orbits within realistic field to study the evolution these with time, ongoing cluster dissolution. From find that population potential escapers, i.e. energetically unbound stars inside Jacobi radius, dominates at radii above about 50 per cent radius. Beyond 70 radius nearly all are unbound....
At least 10%–15% of nearby Sunlike stars have known Jupiter-mass planets. In contrast, very few planets are found in mature open and globular clusters such as the Hyades 47 Tuc. We explore here possibility that this dichotomy is due to postformation disruption planetary systems associated with stellar encounters long-lived clusters. One supporting piece evidence for scenario discovery freely floating low-mass objects star forming regions. use two independent numerical approaches, a hybrid...
We investigate the epicyclic motion of stars escaping from star clusters. Using streaklines, we visualise path and show how leads to over- underdensities in tidal tails clusters moving on circular eccentric orbits about a galaxy. Additionally, effect cluster mass tails, by showing that their structure is better matched when perturbing included. By adjusting streaklines results N-body computations can accurately quickly reproduce all observed substructure, especially streaky features often...
Most globular clusters have half-mass radii of a few pc with no apparent correlation their masses. This is different from elliptical galaxies, for which the Faber-Jackson relation suggests strong positive between mass and radius. Objects that are somewhat in low-mass such as ultra-compact dwarf mass-radius consistent extension bright ellipticals. Here we show at an age 10 Gyr break ~10^6 Msun established because objects below this mass, i.e. clusters, undergone expansion driven by stellar...
We derive analytical expressions for the change in orbital eccentricity of a binary following distant encounter with third star on hyperbolic or parabolic orbit. To establish accuracy these expressions, we present detailed comparisons results direct numerical integrations equations motion three bodies. treat particular care difficult case zero initial eccentricity. In this case, show that $\delta e$ induced by declines general as power-law, e\propto (a/\rp)^{5/2}$, where $a$ is semi-major...
view Abstract Citations (112) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the Exponential Instability of N-Body Systems Goodman, Jeremy ; Heggie, Douglas C. Hut, Piet We reconsider old problem growth numerical errors in N-body integrations. analyze effects successive encounters and show that these tend to magnify on a time scale which is comparable with crossing time. This conclusion based an approximate treatment can be analyzed three...