Results 31 to 40 of about 547 (181)

The formation of molecules in diffuse interstellar clouds

The Astrophysical Journal, 1977
A chemical system involving carbon and hydrogen is used to obtain steady-state abundances of a number of molecules over a wide range of densities. The calculated CH abundance agrees well with the astronomical observations. For reasonable values of the rate coefficients, the present system of reactions cannot explain, simultaneously, the measured ...
G. F. Mitchell, P. J. Kuntz, J. L. Ginsburg   +2 more
openaire   +1 more source

Shaken or Stirred: The Diffuse Interstellar Medium with Exceptionally High SiO Abundance

The Astrophysical Journal, 2023
Interstellar shocks, a key element of stellar feedback processes, shape the structure of the interstellar medium (ISM) and are essential for the chemistry, thermodynamics, and kinematics of interstellar gas.
Daniel R. Rybarczyk, Snežana Stanimirović, Antoine Gusdorf   +2 more
doaj   +1 more source

Molecules in diffuse interstellar clouds [PDF]

, 1988
The existence of diatomic molecules in the diffuse interstellar gas has been known since the late thirties and from that time numerous observations have been made, at visible and ultraviolet wavelengths, of interstellar molecular absorption lines in the spectra of bright stars.
openaire   +1 more source

The CS molecule in diffuse interstellar clouds

The Astrophysical Journal, 1989
The CS J = 2-1 emission line at 98 GHz has been searched for in 10 diffuse molecular clouds. CS column densities are derived by performing statistical equilibrium calculations for the rotational population distribution which includes collisional excitation by electrons as well as by neutral species.
Drdla, K., Knapp, G.R., Dishoeck, E.F. van   +2 more
openaire   +3 more sources

NaH and LiH in diffuse interstellar clouds

The Astrophysical Journal, 1978
It has been suggested that NaH may be detectable in diffuse interstellar clouds. We discuss the photodissociation process of NaH and calculate the rate of destruction by the interstellar radiation field. In the unshielded field, the mean lifetime is about 10 years. There appears to be no efficient gas-phase mechanism for the production of NaH. If it is
K. Kirby, A. Dalgarno
openaire   +1 more source

On the detection of rubidium in diffuse interstellar clouds

The Astrophysical Journal, 1985
A search for absorption from neutral rubidium at 7800 A was conducted. No evidence for absorption to a 3 sigma limit of less than 1.5 mA was seen in the diffuse interstellar gas toward the stars omicron Persei, zeta Persei, and zeta Ophiuchi. Present results do not confirm the detection by Jura and Smith (1981) toward zeta Oph.
S. R. Federman, C. Sneden, W. V. Schempp, W. H. Smith   +3 more
openaire   +1 more source

On the Stability of Interstellar Neutral Hydrogen Clouds at Large Z-heights

The Astrophysical Journal
Galactic neutral hydrogen (H i ) data drawn from several large-scale surveys have been used to study 32 small clouds found between Galactic longitudes 70° and 140° and latitudes −20° and −45°.
G. L. Verschuur
doaj   +1 more source

A search for interstellar H2O(+) in diffuse clouds

The Astrophysical Journal, 1984
Searches for H2O(+) toward HD 187982, Zeta Oph, O micron Per, and Zeta Per have yielded significant upper limits for H2O(+) when compared with existing models for similar lines of sight. Using available oscillator strength data, the column density for HD 187982, for example, cannot exceed 3 x 10 to the 12th per sq cm H2O(+) molecules.
Wm. H. Smith, W. V. Schempp, S. R. Federman   +2 more
openaire   +1 more source

Evaluating maturity of organic matter in hydrated C1 and CM‐like clasts and a dehydrated clast within a polymict eucrite and a howardite

Meteoritics &Planetary Science, EarlyView.
Abstract Volatile‐rich xenolithic clasts in different types of brecciated meteorites represent unique pristine solar system material. This study investigates the maturity and thermal history of organic matter using Raman spectroscopy and aqueous alteration effects using infrared spectroscopy in the matrix of 15 volatile‐rich clasts (C1 and CM‐like ...
Swarna Prava Das, Alessandro Maturilli, Aurélie Van den Neucker, Markus Patzek, Dipak Kumar Panda, Gopal K. Pradhan, Guneshwar Thangjam, Surya Snata Rout   +7 more
wiley   +1 more source

Raman analysis of organic refractory materials after energetic processing: Evidence for amorphous carbon on TNOs and comets

Meteoritics &Planetary Science, EarlyView.
Abstract Amorphous carbon (αC) is found in various extraterrestrial particles, including those thought to originate from the outer Solar System. αC can form through two main processes involving C‐rich materials: exposure to energetic charged particles and thermal processing.
M. Germanà, A. Vyjidak, G. A. Baratta, B. M. Giuliano, R. G. Urso, C. Scirè, D. Fulvio, T. Grassi, P. Jusko, P. Caselli, M. E. Palumbo   +10 more
wiley   +1 more source