scholarly journals The Interpretation of Space Observations of Stars and Interstellar Matter

1971 ◽  
Vol 2 ◽  
pp. 466-475
Author(s):  
Donald C. Morton
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
Optical Depth ◽  
Atomic Physics ◽  
Atomic Hydrogen ◽  
Atomic Data ◽  
Interstellar Matter ◽  
Hydrogen Density ◽  
Near Future ◽  
Space Observations

This report will review space observations of stars and the interstellar medium and what we can expect to learn from instruments planned for the near future. Older observations are described in more detail by Underhill and Morton (1967), and Houziaux and Butler (1970). The interpretation of these measurements depends heavily on the results of theoretical and experimental atomic physics. Therefore the last section will describe some of the areas where new atomic data are essential for our understanding of space observations.Rockets or satellites are necessary to detect all wavelengths between 0.1 and 3000 Å except for two bands from 2000 to 2200 Å and from 2700 to 3000 Å accessible at balloon altitudes. However, for most sources outside the solar system the bound-free absorption of atomic hydrogen will obliterate all wavelengths between 100 and 912 Å. For example, unit optical depth at 304 Å occurs at 12 parsecs even if the interstellar hydrogen density is as low as 0.1 atom cm-3.

scholarly journals The FUSE Mission: Atomic Data Needs in the 900–1200 Å Spectral Region

2002 ◽  
Vol 12 ◽  
pp. 79-81
Author(s):  
Kenneth R. Sembach
Keyword(s):  
High Resolution ◽  
Solar System ◽  
Interstellar Medium ◽  
Absorption Line ◽  
Ground State ◽  
Spectral Region ◽  
Theoretical Calculations ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Far Ultraviolet

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.

scholarly journals The Physics of the Interstellar Matter

1974 ◽  
Vol 3 ◽  
pp. 37-49 ◽  
Author(s):  
G. B. Field
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
The United States ◽  
Astronomical Observatory ◽  
Solid Particles ◽  
Heavy Elements ◽  
Interstellar Space ◽  
Interstellar Matter ◽  
Hydrogen Molecules ◽  
Long Time

Some of the most striking recent discoveries about interstellar matter involve molecules. It has been known for a long time that there are atoms and ions in space - mainly hydrogen and helium, of course - but also heavier elements like sodium and calcium. In addition, there are solid particles of dust, about 10-5cm across, which must be composed of heavier elements, as hydrogen and helium cannot condense under interstellar conditions.In 1972, the Orbiting Astronomical Observatory-3, which employs an 80-cm telescope at wavelengths between 1000Å and 3000Å, was launched in the United States and put into operation. In the ensuing year, it has demonstrated that much of the interstellar medium is composed of hydrogen molecules. This result, based upon the observation of Lyman-band absorption in the spectrum of early-type stars, had been anticipated by a rocket observation of H2 by Carruthers in 1970.The same OAO-3 instrument observed resonance lines of many cosmically abundant elements, and found that these elements often appear to be less abundant in interstellar space than in the solar system, relative to hydrogen. As young stars born recently from the interstellar medium do not show this effect, the heavy elements must in fact be present in some other form. Here I will argue that the heavy elements are largely locked up in the form of the dust and, further, that dust is critical for the formation of the molecules in interstellar space.It is appropriate that the Orbiting Astronomical Observatory-3 which made these discoveries has been named in honor of Copernicus, the Polish astronomer we honor here on the 500th anniversary of his birth. Just as his discoveries were revolutionary for the understanding of the solar system, those made using the Observatory named in his honor have been revolutionary for the understanding of the Galaxy.

scholarly journals 7. Carbon Isotope Ratio in Comets and Interstellar Matter

1977 ◽  
Vol 39 ◽  
pp. 499-503 ◽  
Author(s):  
V. Vanysek
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Molecular Clouds ◽  
Carbon Isotope Ratio ◽  
Stellar Atmospheres ◽  
Interstellar Matter ◽  
Interstellar Molecular Clouds

The 12C/13C isotope ratio in the interstellar medium and in stellar atmospheres is discussed and compared to the value found in the solar system and especially in comets. The cometary value (≥ 100) tends to be slightly above the terrestrial value (89) and is definitively higher than that for interstellar molecular clouds (about 30 to 50). This result implies that comets are not of interstellar origin.

scholarly journals The Intrinsic Properties of the Local Interstellar Medium

1997 ◽  
Vol 166 ◽  
pp. 29-32 ◽  
Author(s):  
Olivia Puyoo ◽  
Lotfi Ben Jaffel
Keyword(s):  
Solar System ◽  
Interstellar Medium ◽  
Interstellar Cloud ◽  
Actual State ◽  
The Sun ◽  
Local Interstellar Medium ◽  
Intrinsic Properties ◽  
Hydrogen Density ◽  
Self Consistent ◽  
Local Cloud

AbstractWe propose a new method to constrain the actual state of the interstellar cloud that surrounds the solar system. Using Voyager UVS Lyman-α sky maps and the powerful principle of invariance, we derive the H distribution all along the spacecraft path. Provided current models of the heliopause interface between the solar and the interstellar winds, we extrapolate this distribution to farther distances from the Sun and infer in a self consistent way key parameters of the local cloud. Our findings are a high interstellar hydrogen density of ~ 0.24 cm−3 and a weak ionization .

scholarly journals Interstellar and interplanetary solids in the laboratory

2015 ◽  
Vol 11 (A29B) ◽  
pp. 416-419 ◽  
Author(s):  
Emmanuel Dartois ◽  
Ivan Alata ◽  
Cécile Engrand ◽  
Rosario Brunetto ◽  
Jean Duprat ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Environmental Parameters ◽  
Interstellar Matter ◽  
Additional Information ◽  
Set Constraints ◽  
Physico Chemical ◽  
Space Environments ◽  
Chemical Conditions ◽  
Extraterrestrial Material ◽  
Shed Light

AbstractThe composition of interstellar matter is driven by environmental parameters and results from extreme interstellar medium physico-chemical conditions. Astrochemists must rely on remote observations to monitor and analyze the interstellar solids composition. They bring additional information from the study of analogues produced in the laboratory, placed in simulated space environments. Planetologists and cosmochemists access and spectroscopically examine collected extraterrestrial material in the laboratory. Diffuse interstellar medium and molecular clouds observations set constraints on the composition of organic solids that can then be compared with collected extraterrestrial materials analyses, to shed light on their possible links.

Atomic hydrogen density measurements in an ion source plasma using a VUV absorption spectrometer

1988 ◽  
Vol 59 (8) ◽  
pp. 1479-1481 ◽  
Author(s):  
G. C. Stutzin ◽  
A. T. Young ◽  
A. S. Schlachter ◽  
J. W. Stearns ◽  
K. N. Leung ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Ion Source ◽  
Density Measurements ◽  
Hydrogen Density ◽  
Absorption Spectrometer

Atmospheric dynamics of tidally synchronized extrasolar planets

2008 ◽  
Vol 366 (1884) ◽  
pp. 4477-4488 ◽  
Author(s):  
James Y.-K Cho
Keyword(s):  
Temperature Distribution ◽  
Solar System ◽  
Flow Pattern ◽  
Extrasolar Planets ◽  
Atmospheric Dynamics ◽  
Reliable Interpretation ◽  
Near Future ◽  
Theoretical Issues

Tidally synchronized planets present a new opportunity for enriching our understanding of atmospheric dynamics on planets. Subject to an unusual forcing arrangement (steady irradiation on the same side of the planet throughout its orbit), the dynamics on these planets may be unlike that on any of the Solar System planets. Characterizing the flow pattern and temperature distribution on the extrasolar planets is necessary for reliable interpretation of data currently being collected, as well as for guiding future observations. In this paper, several fundamental concepts from atmospheric dynamics, likely to be central for characterization, are discussed. Theoretical issues that need to be addressed in the near future are also highlighted.

scholarly journals Visions of Human Futures in Space and SETI

2017 ◽  
Author(s):  
Jason T. Wright ◽  
Michael P. Oman-Reagan
Keyword(s):  
Solar System ◽  
Science Fiction ◽  
Dark Matter Particle ◽  
Short Term ◽  
National Science ◽  
The Galaxy ◽  
Near Future ◽  
Far Future ◽  
Made In

We discuss how visions for the futures of humanity in space and SETI are intertwined, and are shaped by prior work in the fields and by science fiction. This appears in the language used in the fields, and in the sometimes implicit assumptions made in discussions of them. We give examples from articulations of the so-called Fermi Paradox, discussions of the settlement of the Solar System (in the near future) and the Galaxy (in the far future), and METI. We argue that science fiction, especially the campy variety, is a significant contributor to the ‘giggle factor’ that hinders serious discussion and funding for SETI and Solar System settlement projects. We argue that humanity's long-term future in space will be shaped by our short-term visions for who goes there and how. Because of the way they entered the fields, we recommend avoiding the term ‘colony’ and its cognates when discussing the settlement of space, as well as other terms with similar pedigrees. We offer examples of science fiction and other writing that broaden and challenge our visions of human futures in space and SETI. In an appendix, we use an analogy with the well-funded and relatively uncontroversial searches for the dark matter particle to argue that SETI's lack of funding in the national science portfolio is primarily a problem of perception, not inherent merit.Also on arXiv: https://arxiv.org/abs/1708.05318Please cite this version:Wright, Jason T., and Michael P. Oman-Reagan. “Visions of Human Futures in Space and SETI.” International Journal of Astrobiology, 2017, 1–12. doi:10.1017/S1473550417000222.

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