Results 121 to 130 of about 823,770 (310)

Abundances in Diffuse Interstellar Clouds [PDF]

Highlights of Astronomy, 1980
Interstellar clouds are concentrations of cold (T ≲ 100 K) neutral gas (cf. Spitzer 1978) which are immersed within an intercloud medium. It is worthwhile to distinguish between diffuse clouds (roughly those with E[B-V] ≳ 0.5) and dark clouds (those with E[B-V] ≳ 0.5). This distinction is useful in the sense that diffuse clouds are relatively warm (T ∼
openaire   +1 more source

The cycling of carbon into and out of dust

, 2014
Observational evidence seems to indicate that the depletion of interstellar carbon into dust shows rather wide variations and that carbon undergoes rather rapid recycling in the interstellar medium (ISM).
Bocchio, Marco, Fanciullo, Lapo, Guillet, Vincent, Jones, Anthony, Jones, Anthony P., Köhler, Melanie, Micelotta, Elisabetta, Verstraete, Laurent, Ysard, Nathalie   +8 more
core   +2 more sources

The Hermean Helium Exosphere—Continuous and Sporadic Helium Release Processes

Journal of Geophysical Research: Planets, Volume 130, Issue 4, April 2025.
Abstract Since its detection by Mariner 10, helium has been a key focus in studies of Mercury's exosphere. Recently, Weichbold et al. (2025), https://doi.org/10.1029/2024je008679 provided the first in situ helium measurements, inferring density from Ion Cyclotron Wave (ICW) events observed by the MESSENGER spacecraft.
J. Hener, P. Wurz, F. Weichbold, H. Lammer, D. Schmid, A. Vorburger   +5 more
wiley   +1 more source

The Spectral Energy Distribution of Self-gravitating Interstellar Clouds I. Spheres

, 2007
We derive the spectral energy distribution (SED) of dusty, isothermal, self gravitating, stable and spherical clouds externally heated by the ambient interstellar radiation field.
Bernard J. P., Bernard J. P., Bonnor W. B., Boulanger F., Chlewicki G., Ebert R., Gail H.-P., Jörg Fischera, Laureijs R. J., Lehtinen K., Lehtinen K., Lehtinen K., Lemke D., Mathis J. S., Mattila K., Michael A. Dopita, Ossenkopf V., Padoan P.   +17 more
core   +1 more source

Recent developments and applications of selected ion flow tube mass spectrometry (SIFT‐MS)

Mass Spectrometry Reviews, Volume 44, Issue 2, Page 101-134, March/April 2025.
Abstract Selected ion flow tube mass spectrometry (SIFT‐MS) is now recognized as the most versatile analytical technique for the identification and quantification of trace gases down to the parts‐per‐trillion by volume, pptv, range. This statement is supported by the wide reach of its applications, from real‐time analysis, obviating sample collection ...
David Smith, Patrik Španěl, Nicholas Demarais, Vaughan S. Langford, Murray J. McEwan   +4 more
wiley   +1 more source

Magnetic Braking of Interstellar Clouds [PDF]

Symposium - International Astronomical Union, 1990
We summarize the results of 3-D MHD calculations for a rotating and self-gravitating interstellar cloud. The angle between the axis of rotation and the magnetic field direction varies between π/2 and 0, the corresponding braking time-scales differ by roughly a factor of 3.
openaire   +2 more sources

High-Resolution Images of Diffuse Neutral Clouds in the Milky Way. I. Observations, Imaging, and Basic Cloud Properties

, 2015
A set of diffuse interstellar clouds in the inner Galaxy within a few hundred pc of the Galactic plane has been observed at an angular resolution of ~1 arcmin combining data from the NRAO Green Bank Telescope and the Very Large Array.
Dickey, John M., Lockman, Felix J., Pidopryhora, Yurii, Rupen, Michael P.   +3 more
core   +2 more sources

Abundances of Chemical Elements in Open Star Clusters as Indicators of their Nature

Open Astronomy, 2015
Applying a compilled catalog, we find that the relative abundances of α-elements in open clusters and in field stars of the thin disk of the Galaxy show different dependencies on metallicity, age and parameters of their Galactic orbits.
Marsakov V. A., Gozha M. L., Koval’ V. V., Shpigel’ L. V.   +3 more
doaj   +1 more source

Copernicus observations of C I and CO in diffuse interstellar clouds [PDF]

Copernicus was used to observe absorption lines of C I in its ground state and excited fine structure levels and CO toward 29 stars. We use the C I data to infer densities and pressures within the observed clouds, and because our results are of higher ...
Jenkins, E. B., Jura, M., Loewenstein, M.   +2 more
core   +1 more source

Evidence for Spatially Distinct Galactic Dust Populations

The Astrophysical Journal
We present an implementation of a Bayesian mixture model using Hamiltonian Monte Carlo techniques to search for the spatial separation of Galactic dust populations. Utilizing intensity measurements from the Planck High Frequency Instrument, we apply this
Corwin Shiu, Steven J. Benton, Jeffrey P. Filippini, Aurélien A. Fraisse, William C. Jones, Johanna M. Nagy, Ivan L. Padilla, Juan D. Soler   +7 more
doaj   +1 more source