Trans-Neptunian Objects as Natural Probes to the Unknown Solar System
... dynamically and chemically evolved protoplanetary disk composed of billions of planetesimals, the building blocks from which the planets formed during the early solar system. Consequently, the study of the physical and dynamical properties of TNOs can reveal important clues about the properties of t ...
... dynamically and chemically evolved protoplanetary disk composed of billions of planetesimals, the building blocks from which the planets formed during the early solar system. Consequently, the study of the physical and dynamical properties of TNOs can reveal important clues about the properties of t ...
The Evolution of Long-Period Comets
... The observed distribution of long-period (> 200 yr) comet orbits has proved dicult to reconcile with theory. Among the discrepancies is the \fading problem": the fraction of comets in the observed sample which are presumed to have made more than one perihelion passage since leaving the Oort cloud i ...
... The observed distribution of long-period (> 200 yr) comet orbits has proved dicult to reconcile with theory. Among the discrepancies is the \fading problem": the fraction of comets in the observed sample which are presumed to have made more than one perihelion passage since leaving the Oort cloud i ...
Oort Cloud Formation and Dynamics
... of the comet’s 1/a value when it is passing through the planetary region; the comet’s original 1/a before it entered the planetary region (as determined by orbital integration); and the comet’s future 1/a after it passes outside the planetary region. A comet with E > 0 is bound to the Sun, i.e., it ...
... of the comet’s 1/a value when it is passing through the planetary region; the comet’s original 1/a before it entered the planetary region (as determined by orbital integration); and the comet’s future 1/a after it passes outside the planetary region. A comet with E > 0 is bound to the Sun, i.e., it ...
The Destruction of an Oort Cloud in a rich stellar cluster
... preceding the formation of the Sun. This model implies a Solar birth environment rich in stars. Several thousand stars were estimated to have been born before the Sun, thus providing the source for 26 Al and 60 Fe traced in chondritic meteorites. The dynamical fate of the Sun was not addressed, but ...
... preceding the formation of the Sun. This model implies a Solar birth environment rich in stars. Several thousand stars were estimated to have been born before the Sun, thus providing the source for 26 Al and 60 Fe traced in chondritic meteorites. The dynamical fate of the Sun was not addressed, but ...
Astrophysics of Dust in Cold Clouds
... A wide variety of galactic objects, including planetary nebulae, HII regions, photodissociation fronts, and reflection nebulae, have strong infrared emission in the 3-13 µm region. Most of the radiated power emerges in 5 broad infrared bands, at 3.3, 6.2, 7.7, 8.6, and 11.3 µm. In Figure 6 we show t ...
... A wide variety of galactic objects, including planetary nebulae, HII regions, photodissociation fronts, and reflection nebulae, have strong infrared emission in the 3-13 µm region. Most of the radiated power emerges in 5 broad infrared bands, at 3.3, 6.2, 7.7, 8.6, and 11.3 µm. In Figure 6 we show t ...
Photospheric processes and magnetic flux tubes
... Pizzo (1990) used a “body-fitted” nonorthogonal coordinate system to map the physical domain into a unit square computational domain. A multigrid elliptic solver is used at each iteration stage for solving Ampère’s equation. Fiedler & Cally (1991) use a similar mesh in which contours of constant Ψ ...
... Pizzo (1990) used a “body-fitted” nonorthogonal coordinate system to map the physical domain into a unit square computational domain. A multigrid elliptic solver is used at each iteration stage for solving Ampère’s equation. Fiedler & Cally (1991) use a similar mesh in which contours of constant Ψ ...
Cosmic Rays
... Propagation Model Goal: One model should explain all ratios, as well as antiproton- and positronrates and diffuse gamma-flux (0) Unknown details about our galaxy (exact ISM distribution, B-field, …) and CR-sources do automatically cancel if looking only at ratios !!! Graz, 29.Nov.2007 ...
... Propagation Model Goal: One model should explain all ratios, as well as antiproton- and positronrates and diffuse gamma-flux (0) Unknown details about our galaxy (exact ISM distribution, B-field, …) and CR-sources do automatically cancel if looking only at ratios !!! Graz, 29.Nov.2007 ...
a PDF file - National Optical Astronomy Observatory
... Cover Photo: Comet Hyakutake is seen rising over the hills near Faraway Ranch in Southern Arizona’s Chiricahua National Monument. The photo was taken about 8:30 pm on the night of 24/25 March, 1996, the comet’s night of closest approach to earth. The bright stars near the top of the image are in the ...
... Cover Photo: Comet Hyakutake is seen rising over the hills near Faraway Ranch in Southern Arizona’s Chiricahua National Monument. The photo was taken about 8:30 pm on the night of 24/25 March, 1996, the comet’s night of closest approach to earth. The bright stars near the top of the image are in the ...
Observations of the Magnetic Fields Inside and Outside the
... From time to time, energetic jets of particles are emitted by the Sun and are channeled by the Earth's magnetic field toward the two poles of the Earth, where they encounter at high speed the gas particles in the atmosphere. The ensuing collisions energize the local gas particles; these auroral part ...
... From time to time, energetic jets of particles are emitted by the Sun and are channeled by the Earth's magnetic field toward the two poles of the Earth, where they encounter at high speed the gas particles in the atmosphere. The ensuing collisions energize the local gas particles; these auroral part ...
Studies of dark matter in and around stars
... There is by now compelling evidence that most of the matter in the Universe is in the form of dark matter, a form of matter quite different from the matter we experience in every day life. The gravitational effects of this dark matter have been observed in many different ways but its true nature is ...
... There is by now compelling evidence that most of the matter in the Universe is in the form of dark matter, a form of matter quite different from the matter we experience in every day life. The gravitational effects of this dark matter have been observed in many different ways but its true nature is ...
PSRD: Chondrules: Important, but Possibly Unfathomable
... Chondrules might have broader cosmic significance beyond helping us understand formation of our Solar System. Astronomers have identified other solar systems that contain Earth-like planetary bodies. Did chondrule formation play a role in the formation of those far-off planets? Or could we observe t ...
... Chondrules might have broader cosmic significance beyond helping us understand formation of our Solar System. Astronomers have identified other solar systems that contain Earth-like planetary bodies. Did chondrule formation play a role in the formation of those far-off planets? Or could we observe t ...
PDF file
... phenomena which appear on the solar surface. Moreover, we discuss the magnetic reconnection model which can explain these active phenomena, at least morphologically. In Chapter 2 we report a detailed examination of the fine structures inside flare ribbons and the temporal evolution of such structure ...
... phenomena which appear on the solar surface. Moreover, we discuss the magnetic reconnection model which can explain these active phenomena, at least morphologically. In Chapter 2 we report a detailed examination of the fine structures inside flare ribbons and the temporal evolution of such structure ...
IRC −10414: a bow-shock-producing red supergiant star
... Most runaway OB stars, like the majority of massive stars residing in their parent clusters, go through the red supergiant (RSG) phase during their lifetimes. Nonetheless, although many dozens of massive runaways were found to be associated with bow shocks, only two RSG bow-shock-producing stars, Be ...
... Most runaway OB stars, like the majority of massive stars residing in their parent clusters, go through the red supergiant (RSG) phase during their lifetimes. Nonetheless, although many dozens of massive runaways were found to be associated with bow shocks, only two RSG bow-shock-producing stars, Be ...
Professor Comet: April, 2017
... nuclei up to 60 km across in size. Tidal gravitation forces from neighboring stars and density variations within region to region within the milky way galaxy plane would force these objects to orbits closer to the Sun! ...
... nuclei up to 60 km across in size. Tidal gravitation forces from neighboring stars and density variations within region to region within the milky way galaxy plane would force these objects to orbits closer to the Sun! ...
The Diffuse Interstellar Bands in History and in the UV
... (Snow et al. 1977; Seab & Snow 1985). These searches were confined to stars no fainter than about fourth magnitude (Copernicus) to seventh magnitude (International Ultraviolet Explorer). The COS can observe reddened stars to tenth magnitude with EB−V values of up to 1.5 magnitudes. Hence the COS has ...
... (Snow et al. 1977; Seab & Snow 1985). These searches were confined to stars no fainter than about fourth magnitude (Copernicus) to seventh magnitude (International Ultraviolet Explorer). The COS can observe reddened stars to tenth magnitude with EB−V values of up to 1.5 magnitudes. Hence the COS has ...
IV Interstellar Dust
... been able to produce grains in the laboratory, much less reproduce the conditions they would experience in interstellar space, although great progress is being made along these lines. Materials are known to change their properties under conditions of radiation bombardment (especially energetic parti ...
... been able to produce grains in the laboratory, much less reproduce the conditions they would experience in interstellar space, although great progress is being made along these lines. Materials are known to change their properties under conditions of radiation bombardment (especially energetic parti ...
Critique of Modern Oort Comet Theory
... Once an orbit is made more elliptical, it becomes likely for it to cross the orbits of the planets. Thus, some kind of gravitational interaction with a planet would also be more likely. This is believed to lead to comet orbits being altered into very long eccentric orbits that would put their farthe ...
... Once an orbit is made more elliptical, it becomes likely for it to cross the orbits of the planets. Thus, some kind of gravitational interaction with a planet would also be more likely. This is believed to lead to comet orbits being altered into very long eccentric orbits that would put their farthe ...
Plasma Diagnostics and Hydrodynamic Evolution of Solar Flares
... Firstly, I would like to acknowledge the Irish Research Council, the Fulbright Association and NASA’s Living With a Star Targeted Research and Technology Program for funding the research contained in this thesis. I would like to thank my supervisor, Prof. Peter Gallagher for giving me the opportunit ...
... Firstly, I would like to acknowledge the Irish Research Council, the Fulbright Association and NASA’s Living With a Star Targeted Research and Technology Program for funding the research contained in this thesis. I would like to thank my supervisor, Prof. Peter Gallagher for giving me the opportunit ...
- Repository of the Academy`s Library
... (gas plus magnetic) pressure, and with the plasma inertia, caused by the frozen-in condition (perpendicular motions of the plasma lead to the change of the magnetic field geometry, and the other way around). MHD waves have been intensively studied in the Earth’s magnetosphere for several decades. In ...
... (gas plus magnetic) pressure, and with the plasma inertia, caused by the frozen-in condition (perpendicular motions of the plasma lead to the change of the magnetic field geometry, and the other way around). MHD waves have been intensively studied in the Earth’s magnetosphere for several decades. In ...
Venus Worship - the layish website
... they move on to consider their effects and meanings – in other words, prediction of astronomical cycles must have preceded astrological interpretation, and pure astronomy (star and planet positions in relation to each other) still always remained its foundation. Thus, apart from iconographical conn ...
... they move on to consider their effects and meanings – in other words, prediction of astronomical cycles must have preceded astrological interpretation, and pure astronomy (star and planet positions in relation to each other) still always remained its foundation. Thus, apart from iconographical conn ...
- UCL Discovery
... B2 . When the magnetic field is strong, the pressure is large, and when the magnetic field strength changes in space there is a gradient in the magnetic pressure. This gradient results in the magnetic pressure force, which acts in the direction of decreasing magnetic field strength. In order to main ...
... B2 . When the magnetic field is strong, the pressure is large, and when the magnetic field strength changes in space there is a gradient in the magnetic pressure. This gradient results in the magnetic pressure force, which acts in the direction of decreasing magnetic field strength. In order to main ...
astro-ph/9505110 PDF
... Our results are shown in Figures 4 and 5 (Garnett et al. 1994, 1995). We nd that the C/O ratio increases monotonically as a function of O/H, from about 1/4 solar at the lowest metallicities up to solar values. At the same time, C/N also appears to increase with O/H in the irregular galaxies, but th ...
... Our results are shown in Figures 4 and 5 (Garnett et al. 1994, 1995). We nd that the C/O ratio increases monotonically as a function of O/H, from about 1/4 solar at the lowest metallicities up to solar values. At the same time, C/N also appears to increase with O/H in the irregular galaxies, but th ...
Flare Observations
... sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections (CMEs), electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristic ...
... sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections (CMEs), electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristic ...
Solar Flares: Magnetohydrodynamic Processes | SpringerLink
... up to the typical temperature of a flare. However, Cargill and Priest (1982) later pointed out that it is important to consider the slow MHD shocks suggested by Petschek (1964). Forbes and Priest (1984) noted that a fast MHD shock (termination shock) is also formed above the reconnected loop when a ...
... up to the typical temperature of a flare. However, Cargill and Priest (1982) later pointed out that it is important to consider the slow MHD shocks suggested by Petschek (1964). Forbes and Priest (1984) noted that a fast MHD shock (termination shock) is also formed above the reconnected loop when a ...
Heliosphere
The heliosphere is the bubble-like region of space dominated by the Sun, which extends far beyond the orbit of Pluto. Plasma ""blown"" out from the Sun, known as the solar wind, creates and maintains this bubble against the outside pressure of the interstellar medium, the hydrogen and helium gas that permeates the Milky Way Galaxy. The solar wind flows outward from the Sun until encountering the termination shock, where motion slows abruptly. The Voyager spacecraft have actively explored the outer reaches of the heliosphere, passing through the shock and entering the heliosheath, a transitional region which is in turn bounded by the outermost edge of the heliosphere, called the heliopause. The overall shape of the heliosphere is controlled by the interstellar medium, through which it is traveling, as well as the Sun, and does not appear to be perfectly spherical. The limited data available and unexplored nature of these structures have resulted in many theories.On September 12, 2013, NASA announced that Voyager 1 had exited the heliosphere on August 25, 2012, when it measured a sudden increase in plasma density of about forty times. Because the heliopause marks one boundary between the Sun's solar wind and the rest of the galaxy, a spacecraft such as Voyager 1 which has departed the heliosphere can be said to have reached interstellar space.