scholarly journals Morphology of solar system scale plasma lenses in the interstellar medium: a test from pulsar scintillation parabolic arcs

2021 ◽  
Vol 508 (1) ◽  
pp. 125-131
Author(s):  
Xun Shi

ABSTRACT Scintillation spectra of some pulsars have suggested the existence of ≲ AU scale density structures in the ionized interstellar medium, whose astrophysical correspondence is still a mystery. The detailed study of Brisken et al. suggested two possible morphologies for these structures: A parallel set of filaments or sheets (the ‘parallel stripes model’), or a filament broken up into denser knots (the ‘threaded beads model’). Here, we propose a straightforward test that can distinguish these two morphologies: Whether the apex of the main parabolic arc created by the scattered images deviates from the origin of the scintillation spectrum or not. In the ‘parallel stripes’ model, the scattered images move along the stripes as the relative position of the pulsar moves. As a result, the pulsar is always co-linear with the scattered images, and thus, the apex of the main parabolic arc stays at the origin of the scintillation spectrum. In the ‘threaded beads’ model, the scattered images remain at almost fixed positions relative to the density structures, and thus, the pulsar is not co-linear with the scattered images at most times, leading to an offset between the apex and the origin. Looking for this possible offset in a large sample of pulsar scintillation spectra, or monitoring the evolution of parabolic arcs will help pin down the morphology of these tiny density structures and constrain their astrophysical origin.

1992 ◽  
Vol 9 ◽  
pp. 341-345
Author(s):  
T. Owen

AbstractValues of D/H measured in the methane on the giant planets and Titan indicate the presence of two distinct reservoirs of deuterium in the outer solar system. The dominant reservoir is in hydrogen gas, the second, multi-component reservoir is found in the hydrogen that is bound in condensed compounds. Both reservoirs appear to have originated in the interstellar medium. In contrast, the values of D/H in water vapor on Mars and Venus (especially) exhibit a large enrichment from the “condensed matter” starting value. Interpretation of this enrichment may illuminate the history of water on these two planets.


1992 ◽  
Vol 150 ◽  
pp. 97-101 ◽  
Author(s):  
T. Owen

Values of D/H measured in the methane on the giant planets and Titan indicate the presence of two distinct reservoirs of deuterium in the outer solar system. The dominant reservoir is in hydrogen gas, the second, multi-component reservoir is found in the hydrogen that is bound in condensed compounds. Both reservoirs appear to have originated in the interstellar medium. In contrast, the values of D/H in water vapor on Mars and Venus (especially) exhibit a large enrichment from the “condensed matter” starting value. Interpretation of this enrichment may illuminate the history of water on these two planets.


2020 ◽  
pp. 115-129
Author(s):  
Ю.Д. КУЗЬМИН ◽  
В.Г. САХНО

По одной из гипотез, вода на Земле имеет метеорное (поверхностное), а не ювенильное (земное) происхождение. Она не может образовываться в конденсированных средах, т.е. в недрах планеты, как считали и считают многие геологи и геофизики. Данный вывод требует других подходов, отличных от устоявшихся взглядов на происхождение воды, эволюцию гидросферы, атмосферы и содержания воды в горных породах на разных геофизических уровнях Земли и других планетах Солнечной системы. Согласно нашей гипотезе, вода на Земле образовалась в результате синтеза водорода и кислорода из космического газопылевого вещества на горячей поверхности твердой планеты с последующим формированием атмосферы, гидросферы Земли и их активным участием в эволюции Земли, во всех геофизических и геохимических процессах. There is one hypothesis that the Earths water is of meteoric rather than endogenous origin. It cannot emerge in condensed environments, namely in the planets interior, as it was believed by many geologists and geophysics. This inference requires other approaches differing from the fixed views on the water origin, evolvement of hydrosphere and atmosphere, water content of rocks in various geophysical layers of the Earth and on other planets of the Solar System. According to our hypothesis, water is a result of synthesis of hydrogen and oxygen from interstellar medium on a hot surface of terrestrial planet followed by the birth of atmosphere and hydrosphere which played a great part in the evolution and all geophysical and geochemical processes of the Earth.


2003 ◽  
Vol 718 ◽  
pp. 659-661 ◽  
Author(s):  
S. Kawanomoto ◽  
K.T. Suzuki ◽  
H. Ando ◽  
T. Kajino

2002 ◽  
Vol 12 ◽  
pp. 48-51 ◽  
Author(s):  
L.B.F.M. Waters ◽  
F.J. Molster

AbstractAn overview is given of the occurrence and properties of crystalline silicates in space. Crystalline silicates are found in circumstellar shells of both young and evolved stars, and are present in Solar System comets. These silicates are Mg-rich and Fe-poor, in contrast to amorphous silicates. We discuss the formation mechanism of crystalline silicates and the apparent lack of these grains in the interstellar medium.


2003 ◽  
Vol 288 (3) ◽  
pp. 369-375 ◽  
Author(s):  
T.W. Hartquist ◽  
S.A.E.G. Falle ◽  
D.A. Williams

1805 ◽  
Vol 95 ◽  
pp. 233-256 ◽  

Our attention has lately been directed again to the construc­tion of the heavens, on which I have already delivered several detached papers. The changes which have taken place in the relative position of double stars, have ascertained motions in many of them, which are probably of the same nature with those that have hitherto been called proper motions. It is well known that many of the principal stars have been found to have changed their situation, and we have lately had a most valuable acquisition in Dr. Maskelyne's Table of proper motions of six and thirty of them. If this Table affords us a proof of the motion of the stars of the first brightness, such as are probably in our immediate neighbourhood, the changes of the position of minute double stars that I have ascertained, many of which can only be seen by the best telescopes, likewise prove that motions are equally carried on in the remotest parts of space which hitherto we have been able to penetrate. The proper motions of the stars have long engaged the attention of astronomers, and in the year 1783, I deduced from them, with a high degree of probability, a motion of the sun and solar system towards λ Herculis. The reasons which were then pointed out for introducing a solar motion, will now be much strengthened by additional considerations; and the above mentioned Table of well ascertained proper motions will also enable us to enter rigorously into the necessary calculations for ascertaining its direction, and discovering its velocity. When these points are established, we shall be prepared to draw some consequences from them that will account for many phenomena which otherwise cannot be explained.


2002 ◽  
Vol 12 ◽  
pp. 79-81
Author(s):  
Kenneth R. Sembach

AbstractThe Far Ultraviolet Spectroscopic Explorer (FUSE) is presently producing high resolution (R ∼ 20,000) absorption-line spectra of astronomical objects ranging from Solar System planets to quasars. The 900-1200 Å spectral region observed by FUSE is exceedingly rich in atomic and molecular transitions arising out of the ground state. It is already clear from early FUSE observations that the atomic data (e.g., oscillator strengths) for some transitions are considerably different than those predicted by theoretical calculations. I briefly describe the most pressing oscillator strength needs in this wavelength range for studies of the interstellar medium.


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