scholarly journals The origin and evolution of interstellar organics

2008 ◽  
Vol 4 (S251) ◽  
pp. 35-44 ◽  
Author(s):  
Jean E. Chiar ◽  
Yvonne J. Pendleton
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Laboratory Experiments ◽  
Ir Detector ◽  
Space Telescope ◽  
Origin And Evolution ◽  
Past Work ◽  
Dust Composition ◽  
Absorption Features ◽  
Dust Absorption

AbstractOver the last decade, we have made great strides in better understanding dust composition and evolution in dense clouds and the diffuse interstellar medium (ISM). Thanks to improvements in IR detector sensitivity on ground-based telescopes and the Spitzer Space Telescope mission, we are no longer limited to a handful of bright background stars in order to study dust composition in quiescent dense clouds and the diffuse ISM. More thorough sampling of lines of sight in these regions has highlighted the dichotomy of the nature and composition of dust in these environments. In addition, successes in recreating interstellar processes and dust-analogs in the laboratory have helped us to understand the differences in dust absorption features we observe in the ISM. In this article, we focus on the organic components of interstellar dust, reviewing past work and highlighting the most recent observations and laboratory experiments.

scholarly journals Comets as a Reflection of Interstellar Medium Chemistry

1994 ◽  
Vol 160 ◽  
pp. 327-342 ◽  
Author(s):  
J. Mayo Greenberg ◽  
Osama M. Shalabiea
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Theoretical Modelling ◽  
Gas Evolution ◽  
Mantle Material ◽  
Complex Molecules ◽  
Morphological Criteria ◽  
Dust Composition

A brief summary of the observed infrared and other properties of interstellar dust is given. Chemical, physical and morphological criteria are discussed concerning the degree to which there are constraints relating comets to interstellar dust chemistry representative of the presolar nebula. Results of theoretical modelling of dust and gas evolution in dense clouds are used to compare with observed dust composition. Sources of the distribution of simple as well as complex molecules in the coma are related to what is presently known about the volatile ices in interstellar dust and to processes leading to evaporation of organic “refractory” grain mantle material represented by laboratory residues produced by photoprocessing of ices. The criterion of preservation of interstellar volatiles in comets leads to the further criterion that the ice in comets is amorphous. Criteria for relating interstellar dust volatiles to asteroids are discussed.

Interstellar Dust Absorption Features in the Infrared Spectrum of HH 100-IR: Searching for the Nitrogen Component of the Ices

1996 ◽  
Vol 458 ◽  
pp. 363 ◽  
Author(s):  
D. C. B. Whittet ◽  
R. G. Smith ◽  
A. J. Adamson ◽  
D. K. Aitken ◽  
J. E. Chiar ◽  
...  
Keyword(s):  
Infrared Spectrum ◽  
Interstellar Dust ◽  
Absorption Features ◽  
Dust Absorption

PRONAOS observations of the interstellar medium: New insights on interstellar Dust

2002 ◽  
Vol 4 ◽  
pp. 9-9
Author(s):  
I. Ristorcelli ◽  
B. Stepnik ◽  
X. Dupac ◽  
A. Abergel ◽  
J. P. Bernard ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust

scholarly journals DIBs, Interstellar Dust, and Extinction

2013 ◽  
Vol 9 (S297) ◽  
pp. 147-152 ◽  
Author(s):  
G. C. Clayton
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Dust Grains ◽  
Weak Correlation ◽  
Interstellar Clouds ◽  
The Galaxy ◽  
The Relationship

AbstractThe relationship between DIBs and dust is still unknown. The correlation between reddening and DIB strength means that the DIBs are mixed in with the dust and gas in interstellar clouds. The DIBs are relatively stronger in the diffuse interstellar medium than in dense clouds. There is only a weak correlation between the DIBs and the UV extinction parameters including the 2175 Å bump strength and the far-UV rise. In addition, the bump dust grains are sometimes polarized, while the DIBs are not. However, observations of DIBs in the SMC show that when the 2175 Å bump is weak or missing so are the DIBs. Two of the four sightlines that deviate strongly from the CCM UV extinction in the Galaxy show weak DIBs.

scholarly journals Asymmetric mass-loss from the white dwarf WD 0253+209 : Secret revealed

BIBECHANA ◽  
2012 ◽  
Vol 8 ◽  
pp. 1-7
Author(s):  
Binil Aryal
Keyword(s):  
Interstellar Medium ◽  
Mass Loss ◽  
Flux Density ◽  
White Dwarf ◽  
Total Mass ◽  
Interstellar Dust ◽  
Mass Loss Rate ◽  
Infrared Image ◽  
Asymptotic Giant Branch ◽  
Color Temperature

Dust structures around the white dwarf WD 0253+209 is studied in 100 and 60 micron infrared image. These images are received from Infrared Astronomical Satellite Survey (IRAS Survey). The post Asymptotic Giant Branch (AGB) emission of the white dwarf's precursors' wind and the ambient interstellar matter is studied. The distribution of the relative flux density is studied and analyzed in the context of the dust color temperature, mass loading trend and the amount of total mass deposited due the interaction in the interstellar medium. The twisted curved emission structure at 100 micron in the region of interest is probably due to the interaction between the ambient interstellar medium and the He-flashes of the parent planetary nebula of the central white dwarf WD 0253+209. The total mass of the filamentary arc is found to be ~ 5 solar masses, as predicted. The mass loss rate of the post AGB star goes up to 10-5 solar masses per year. It is concluded that the first He-flash occurred at least ~2500 years ago.Keywords: white dwarf; interstellar medium; flux density; interstellar dust; mass of the gasDOI: http://dx.doi.org/10.3126/bibechana.v8i0.4806BIBECHANA 8 (2012) 1-7

scholarly journals Polyaromatic disordered carbon grains as carriers of the UV bump: Far-UV to mid-IR spectroscopy of laboratory analogs

2017 ◽  
Vol 607 ◽  
pp. A73 ◽  
Author(s):  
L. Gavilan ◽  
K. C. Le ◽  
T. Pino ◽  
I. Alata ◽  
A. Giuliani ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Vacuum Ultraviolet ◽  
Interstellar Extinction ◽  
Electronic Transitions ◽  
Mid Infrared ◽  
Pressure Experiment ◽  
Circumstellar Extinction ◽  
Integrated Intensities ◽  
Far Ultraviolet

Context. A multiwavelength study of laboratory carbons with varying degrees of hydrogenation and sp2 hybridization is required to characterize the structure of the carbonaceous carriers of interstellar and circumstellar extinction. Aims. We study the spectral properties of carbonaceous dust analogs from the far-ultraviolet to the mid-infrared and correlate features in both spectral ranges to the aromatic/aliphatic degree. Methods. Analogs to carbonaceous interstellar dust encountered in various phases of the interstellar medium have been prepared in the laboratory. These are amorphous hydrogenated carbons (a-C:H), analogs to the diffuse interstellar medium component, and soot particles, analogs to the polyaromatic component. Thin films (d < 100 nm) have been measured in transmission in the vacuum-ultraviolet (VUV; 120–210 nm) within the atmospheric pressure experiment (APEX) chamber of the DISCO beam line at the SOLEIL synchrotron radiation facility. Spectra of these films were further measured through the UV-Vis (210 nm–1 μm) and in the mid-infrared (3–15 μm). Results. Tauc optical gaps, Eg, are derived from the visible spectra. The major spectral features are fitted through the VUV to the mid-infrared to obtain positions, full-widths at half maximum (FWHM), and integrated intensities. These are plotted against the position of the π-π∗ electronic transitions peak. Unidentified or overlapping features in the UV are identified by correlations with complementary infrared data. A correlation between the optical gap and position of the π-π∗ electronic transitions peak is found. The latter is also correlated to the position of the sp3 carbon defect band at ~8 μm, the aromatic C=C stretching mode position at ~6 μm, and the H/C ratio. Conclusions. Ultraviolet and infrared spectroscopy of structurally diverse carbon samples are used to constrain the nanostructural properties of carbon carriers of both circumstellar and interstellar extinction, such as the associated coherent lengths and the size of polyaromatic units. Our study suggests that carriers of the interstellar UV bump should exhibit infrared bands akin to the A/B classes of the aromatic infrared bands, while the circumstellar bump carriers should exhibit bands corresponding to the B/C classes.

scholarly journals X-ray extinction from interstellar dust

2019 ◽  
Vol 629 ◽  
pp. A78 ◽  
Author(s):  
E. Costantini ◽  
S. T. Zeegers ◽  
D. Rogantini ◽  
C. P. de Vries ◽  
A. G. G. M. Tielens ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Interstellar Dust ◽  
Simulated Data ◽  
X Ray ◽  
Cosmic Abundance ◽  
Grain Size Distributions ◽  
Edge Features ◽  
Different Grain Size ◽  
Near Future

Aims. We present a study on the prospects of observing carbon, sulfur, and other lower abundance elements (namely Al, Ca, Ti, and Ni) present in the interstellar medium using future X-ray instruments. We focus in particular on the detection and characterization of interstellar dust along the lines of sight. Methods. We compared the simulated data with different sets of dust aggregates, either obtained from past literature or measured by us using the SOLEIL-LUCIA synchrotron beamline. Extinction by interstellar grains induces modulations of a given photolelectric edge, which can be in principle traced back to the chemistry of the absorbing grains. We simulated data of instruments with characteristics of resolution and sensitivity of the current Athena, XRISM, and Arcus concepts. Results. In the relatively near future, the depletion and abundances of the elements under study will be determined with confidence. In the case of carbon and sulfur, the characterization of the chemistry of the absorbing dust will be also determined, depending on the dominant compound. For aluminum and calcium, despite the large depletion in the interstellar medium and the prominent dust absorption, in many cases the edge feature may not be changing significantly with the change of chemistry in the Al- or Ca-bearing compounds. The exinction signature of large grains may be detected and modeled, allowing a test on different grain size distributions for these elements. The low cosmic abundance of Ti and Ni will not allow us a detailed study of the edge features.

scholarly journals The Interstellar Dust Emission Seen by ISO

1998 ◽  
Vol 11 (2) ◽  
pp. 1142-1144 ◽  
Author(s):  
J.L. Puget
Keyword(s):  
Interstellar Medium ◽  
Small Molecules ◽  
Interstellar Dust ◽  
Solid Phase ◽  
Dust Emission ◽  
Atom Clusters ◽  
Interstellar Grains ◽  
Small Atom

Among the important contributions of ISO to the physics of the interstellar medium, this paper concentrates only on the emission from the solid phase (the interstellar grains) and the small atom clusters which are the bridge between the grains and the small molecules with less than about 10 atoms.

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