scholarly journals Crystalline Silicates in Space

2002 ◽  
Vol 12 ◽  
pp. 48-51 ◽  
Author(s):  
L.B.F.M. Waters ◽  
F.J. Molster
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
Formation Mechanism ◽  
Apparent Lack ◽  
Evolved Stars ◽  
Circumstellar Shells

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.

scholarly journals 1.16. 4.5 to 11.7 microns spectrophotometric observations of the Galactic bulge by the MIRS/IRTS

1998 ◽  
Vol 184 ◽  
pp. 47-47
Author(s):  
Kin-Wing Chan ◽  
T. L. Roellig ◽  
T. Onaka ◽  
I. Yamamura ◽  
T. Tanabé
Keyword(s):  
Interstellar Medium ◽  
Mass Loss Rate ◽  
Life Time ◽  
High Mass ◽  
Galactic Latitude ◽  
Galactic Bulge ◽  
Stellar Content ◽  
Mid Infrared ◽  
Evolved Stars ◽  
Infrared Background

Using the Mid-Infrared (MIRS) on board the Infrared Telescope in Space (IRTS) we obtained the 4.5 to 11.7 μm spectra of the stellar populations and diffuse interstellar medium in the Galactic bulge (l ≈ 8.7°, b ≈ 2.9, 4.0, 4.7, and 5.7°). Below galactic latitute of 4.0° the mid-infrared background spectra in the bulge are similar to the spectrum of M and K giants. The UIR bands (6.2, 7.7, 8.6, and 11.3 μm) are also detected in these regions and they are likely arising from the diffuse interstellar medium in the bulge. Above galactic latitude of 4.0°, the mid-infrared background spectra are similar to the spectrum of those evolved stars with high mass-loss rate detected by IRAS. One likely interpretation is that this background emission arises predominantly from these stars with very low luminosities that have not been detected by IRAS. The main-sequence life time for such low luminosity evolved stars is at least 10 Gyr, even in the metal poor cases. If these low luminosity evolved stars are metal-rich then the age would be much older. Thus, the existence of a large number (~ 75) of such low luminosity evolved stars in a small region (8′ × 8′) in the bulge would have significant impact on our understanding of the stellar content and the age of the Galactic bulge.

scholarly journals Deuterium in the Solar System

1992 ◽  
Vol 9 ◽  
pp. 341-345
Author(s):  
T. Owen
Keyword(s):  
Water Vapor ◽  
Solar System ◽  
Interstellar Medium ◽  
Condensed Matter ◽  
Hydrogen Gas ◽  
Giant Planets ◽  
Outer Solar System ◽  
History Of

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.

scholarly journals Deuterium in the Solar System

1992 ◽  
Vol 150 ◽  
pp. 97-101 ◽  
Author(s):  
T. Owen
Keyword(s):  
Water Vapor ◽  
Solar System ◽  
Interstellar Medium ◽  
Condensed Matter ◽  
Hydrogen Gas ◽  
Giant Planets ◽  
Outer Solar System ◽  
History Of

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.

scholarly journals Water origin and its role in the Earth’s evolution

2020 ◽  
pp. 115-129
Author(s):  
Ю.Д. КУЗЬМИН ◽  
В.Г. САХНО
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
Water Content ◽  
Great Part ◽  
Terrestrial Planet ◽  
Geochemical Processes ◽  
The Earth ◽  
Water Origin ◽  
Hot Surface

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.

scholarly journals Problems of modelization of circumstellar matter out of equilibrium

1994 ◽  
Vol 162 ◽  
pp. 431-433
Author(s):  
J-P. J. Lafon ◽  
E. Huguet
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Interstellar Medium ◽  
Circumstellar Matter ◽  
Solid Particles ◽  
Heavy Elements ◽  
Circumstellar Envelopes ◽  
Interstellar Gas ◽  
The Core ◽  
Evolved Stars

Circumstellar envelopes of young and evolved stars are responsible for many important phenomena concerning the exchange of matter, angular momentum, energy and maybe magnetic field between the core structure of stars and the interstellar medium. In particular, it is through them that matter enriched in heavy elements flows from evolved stars towards the interstellar gas, submitted to complex ordinary chemistry or photochemistry and condensation into solid particles.

scholarly journals The ionization of galaxies by their planetary nebulae

2011 ◽  
Vol 7 (S283) ◽  
pp. 239-242 ◽  
Author(s):  
Grażyna Stasińska
Keyword(s):  
Interstellar Medium ◽  
Emission Line ◽  
Stellar Evolution ◽  
White Dwarf ◽  
Planetary Nebulae ◽  
Extragalactic Astronomy ◽  
Evolved Stars ◽  
Low Mass

AbstractRecent studies have shown that nuclei of planetary nebulae and their remnants (dubbed HOLMES for “hot low-mass evolved stars”) can easily explain two long-standing problems of extragalactic astronomy: the observed emission-line spectra of ellipticals and LINER-like galaxies and the ionization and heating of the diffuse interstellar medium in spirals. They are summarized in this contribution. It is emphasized that the computation of grids of stellar evolution models until the white dwarf stage is essential not only for the study of planetary nebulae but also for the study of the ionization of galaxies.

First detection of 7Li/6Li-ratio in the interstellar medium beyond the solar-system, and its impact on primordial 7Li

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