Recent Progress in Laboratory Astrophysics Achieved with NASA Ames’ COSmIC Facility

AbstractWe describe the characteristics and the capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to generate, process and analyze interstellar, circumstellar and planetary analogs in the laboratory. COSmIC stands for ’Cosmic Simulation Chamber’ and is dedicated to the study of neutral and ionized molecules and nanoparticles under the low temperature and high vacuum conditions that are required to simulate various space environments such as diffuse interstellar clouds, circumstellar outflows and planetary atmospheres. Recent results obtained using COSmIC will be highlighted. In particular, the progress that has been achieved in the domain of the diffuse interstellar bands (DIBs) and in monitoring, in the laboratory, the formation of circumstellar dust grains and planetary atmosphere aerosols from their gas-phase molecular precursors. Plans for future laboratory experiments on interstellar and planetary molecules and grains will also be addressed, as well as the implications of the studies underway for astronomical observations and past and future space mission data analysis.

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Laboratory Astrophysics with COSmIC: Interstellar and Planetary Applications

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317005099 ◽

2015 ◽

Vol 11 (A29A) ◽

Author(s):

Farid Salama ◽

Cesar S. Contreras ◽

Ella Sciamma-O'Brien ◽

Salma Bejaoui

Keyword(s):

Laboratory Astrophysics ◽

Laboratory Facility ◽

Generate Process

AbstractWe discuss the capabilities of the laboratory facility, COSmIC, that was developed to generate, process and analyze interstellar, circumstellar and planetary analogs in the laboratory

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C2 and Diffuse Interstellar Bands

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313015718 ◽

2013 ◽

Vol 9 (S297) ◽

pp. 121-124 ◽

Cited By ~ 2

Author(s):

M. Kaźmierczak ◽

M. Schmidt ◽

T. Weselak ◽

G. Galazutdinov ◽

J. Krełowski

Keyword(s):

Interstellar Clouds ◽

Physical Conditions ◽

Diffuse Interstellar Bands ◽

Carbon Molecules ◽

Long Chain

AbstractC2, the simplest multicarbon molecule is a useful astronomical tool, because the analysis of its lines allows to determine the physical conditions in interstellar clouds. C2 abundances give information about the chemistry of interstellar clouds, especially on the pathway to the formation of long-chain carbon molecules, which may be connected with carriers of diffuse interstellar bands (Douglas 1977, Thorburn et al. 2003). Here we summarize all relations between C2 and diffuse interstellar bands (DIBs).

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An elastic model of Phobos’ libration

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037446 ◽

2020 ◽

Vol 636 ◽

pp. A27

Author(s):

Yongzhang Yang ◽

Jianguo Yan ◽

Xi Guo ◽

Qingbao He ◽

Jean-Pierre Barriot

Keyword(s):

Numerical Model ◽

Gravity Field ◽

Numerical Integration ◽

Elastic Properties ◽

Rotational Motion ◽

Space Mission ◽

Elastic Model ◽

Shape Model ◽

Future Space ◽

Least Squares Fit

Context. Study the rotation of a celestial body is an efficient way to infer its interior structure, and then may give information of its origin and evolution. In this study, based on the latest shape model of Phobos from Mars Express (MEX) mission, the polyhedron approximation approach was used to simulate the gravity field of Phobos. Then, the gravity information was combined with the newest geophysical parameters such as GM and k2 to construct the numerical model of Phobos’ rotation. And with an appropriate angles transformation, we got the librational series respect to Martian mean equator of date. Aims. The purpose of this paper is to develop a numerical model of Phobos’ rotational motion that includes the elastic properties of Phobos. The frequencies analysis of the librational angles calculated from the numerical integration results emphasize the relationship between geophysical properties and dynamics of Phobos. This work will also be useful for a future space mission dedicated to Phobos. Methods. Based on the latest shape model of Phobos from MEX mission, we firstly modeled the gravity field of Phobos, then the gravity coefficients were combined with some of the newest geophysical parameters to simulate the rotational motion of Phobos. To investigate how the elastic properties of Phobos affect its librational motion, we adopted various k2 into our numerical integration. Then the analysis was performed by iterating a frequency analysis and linear least-squares fit of Phobos’ physical librations. From this analysis, we identified the influence of k2 on the largest librational amplitude and its phase. Results. We showed the first ten periods of the librational angles and found that they agree well with the previous numerical results which Phobos was treated as a perfectly rigid body. We also found that the maximum amplitudes of the three parameters of libration are also close to the results from a rigid model, which is mainly due to the inclination of Phobos and moments of inertia. The other amplitudes are slightly different, since the physics contained in our model is different to that of a previous study, specifically, the different low-degree gravity coefficients and ephemeris. The libration in longitude τ has the same quadratic term with previous numerical study, which is consistent with the secular acceleration of Phobos falling onto Mars. We investigated the influence of the tidal Love number k2 on Phobos’ rotation and found a detectable amplitude changes (0.0005°) expected in the future space mission on τ, which provided a potential possibility to constrain the k2 of Phobos by observing its rotation. We also studied the influence of Phobos’ orbit accuracy on its libration and suggested a simultaneous integration of orbit and rotation in future work.

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Diffuse Interstellar Bands – The Unidentified Part of the Interstellar Absorption Spectrum

Symposium - International Astronomical Union ◽

10.1017/s0074180900125112 ◽

1989 ◽

Vol 135 ◽

pp. 67-86 ◽

Cited By ~ 1

Author(s):

Jacek Krełowski

Keyword(s):

Absorption Spectrum ◽

Line Of Sight ◽

Optical Parameters ◽

Interstellar Matter ◽

Molecular Absorption ◽

Interstellar Clouds ◽

Diffuse Interstellar Bands ◽

Intensity Ratios ◽

Molecular Abundances

The unidentified (since 1921) diffuse interstellar bands (DIBs) are discussed together with their relations to other interstellar absorptions sucn as: continuous extinction, polarization and atomic or molecular absorption lines. It is shown that DIBs do not form the absorption spectrum of one agent, but probably of several (3 or more). DIBs as well as other interstellar absorptions are usually formed in several clouds along a line-of-sight. Thus, they suffer Doppler splitting; the first high resolution profiles free of the latter effect are described. Since single interstellar clouds may differ not only in radial velocities but also in many physical (optical) parameters, the observed interstellar absorptions are ill-defined averages over all clouds situated along any line-of-sight. It is of basic importance to determine not only the single cloud profiles of diffuse bands, but also their relations to other interstellar absorptions in the same clouds. Intensity ratios of DIBs are shown to be sensitive to the shapes of extinction curves, depletion patterns of elements and molecular abundances in the considered clouds. The sensitivity of the DIBs to the variation in polarization is less documented but probably also present. Thus the diffuse lines are presented as the unidentified part of the absorption spectrum of interstellar matter. Their identification depends on the determination of their relations to other interstellar absorptions which must be determined precisely.

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Probing the missing link between the diffuse interstellar bands and the total-to-selective extinction ratio $R_V\,\!-\!$ I. Extinction versus reddening

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2103 ◽

2019 ◽

Vol 489 (1) ◽

pp. 708-713 ◽

Cited By ~ 1

Author(s):

Kaijun Li ◽

Aigen Li ◽

F Y Xiang

Keyword(s):

Extinction Ratio ◽

Interstellar Extinction ◽

Extinction Curve ◽

Interstellar Clouds ◽

Diffuse Interstellar Bands ◽

Hydrogen Column Density ◽

Wide Range ◽

Chemical Conditions ◽

Physical And Chemical ◽

Selective Extinction

ABSTRACT The carriers of the still (mostly) unidentified diffuse interstellar bands (DIBs) have been a long-standing mystery ever since their first discovery exactly 100 yr ago. In recent years, the ubiquitous detection of a large number of DIBs in a wide range of Galactic and extragalactic environments has led to renewed interest in connecting the occurrence and properties of DIBs to the physical and chemical conditions of the interstellar clouds, with particular attention paid to whether the DIB strength is related to the shape of the interstellar extinction curve. To shed light on the nature and origin of the DIB carriers, we investigate the relation between the DIB strength and RV, the total-to-selective extinction ratio, which characterizes how the extinction varies with wavelength (i.e. the shape of the extinction curve). We find that the DIB strength and RV are not related if we represent the strength of a DIB by its reddening-normalized equivalent width (EW), in contrast to the earlier finding of an anticorrelation in which the DIB strength is measured by the extinction-normalized EW. This raises a fundamental question about the appropriate normalization for the DIB EW. We argue that the hydrogen column density is a more appropriate normalization than extinction and reddening.

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Performance of Elastomeric Silicones in Ablative and Space Environments

Rubber Chemistry and Technology ◽

10.5254/1.3547133 ◽

1966 ◽

Vol 39 (4) ◽

pp. 1247-1257 ◽

Cited By ~ 4

Author(s):

Clyde L. Whipple ◽

John A. Thorne

Keyword(s):

High Vacuum ◽

Thermal Control ◽

Heat Fluxes ◽

Space Environment ◽

Space Applications ◽

Wide Range ◽

Environmental Extremes ◽

Temperature Ranges ◽

Space Environments ◽

Thermal Control Coatings

Abstract Elastomeric silicones are among the best materials available for many ablative and space applications. In ablative applications, these materials protect launching equipment, safeguard various parts of vehicles and spacecraft during flight, and shield re-entering spacecraft. Generally, elastomeric silicones are used where ablative conditions involve low to moderate heat fluxes and shear forces. Ablative characteristics of materials can vary widely depending on polymer type, fillers, and applications techniques, and no one elastomeric silicone will perform in a wide range of ablative missions. A good knowledge of the ablative characteristics of silicone materials is required to select the best candidates for a given application. In the space environment, silicones are often used for seals, thermal control coatings, potting materials, and other applications because they perform well over wide temperature ranges, and because they are inherently stable to high-vacuum and ultraviolet conditions. Data given in this paper illustrate that silicones show little weight loss or loss of properties on exposure to space environmental extremes. Furthermore, these losses can be made almost negligible by proper conditioning of the finished elastomer.

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Acoustic in-ice positioning in the Enceladus Explorer project

Annals of Glaciology ◽

10.3189/2014aog68a035 ◽

2014 ◽

Vol 55 (68) ◽

pp. 253-259 ◽

Cited By ~ 5

Author(s):

Dmitry Eliseev ◽

Dirk Heinen ◽

Klaus Helbing ◽

Ruth Hoffmann ◽

Uwe Naumann ◽

...

Keyword(s):

Space Mission ◽

Positioning System ◽

Test Scenario ◽

Full System ◽

Ice Surface ◽

Curved Trajectories ◽

Future Space ◽

Glacier Ice ◽

Taylor Glacier ◽

Acoustic Positioning

AbstractThe Enceladus Explorer project is a preparatory study for a future space mission to Saturn’s moon, Enceladus. Its ultimate goal is to probe liquid-water pockets below the ice surface of Enceladus for signatures of life. A probe could be based on the IceMole concept, which melts curved trajectories through the ice. In the Enceladus Explorer project, a specialized IceMole probe for a terrestrial test scenario is in development. The goal of this exploratory study is to probe water from a liquid crevasse close to Blood Falls at Taylor Glacier, Antarctica. To navigate such a probe it is essential to be able to determine its position and monitor its trajectory. Part of the navigation system is the in-ice acoustic positioning system. For this, the head of the IceMole is equipped with acoustic sensors, which receive signals from synchronized acoustic emitters situated at the ice surface. Based on the measured propagation times, the speed of sound in ice and the positions of the emitters at the surface, the position of the IceMole can be determined by trilateration techniques. Here we present the developed acoustic positioning system, which is designed to track the in-ice melting probe up to distances of 100 m in glacier ice. Results from full-system tests in water and a first field test on Morteratschgletscher, Switzerland, are discussed.

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Broadband Cavity Enhanced Absorption Spectroscopy: A New Approach to Search for DIB Carriers

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313015998 ◽

2013 ◽

Vol 9 (S297) ◽

pp. 281-285

Author(s):

A. J. Walsh ◽

D. Zhao ◽

W. Ubachs ◽

H. Linnartz

Keyword(s):

Absorption Spectroscopy ◽

Broad Band ◽

Incoherent Light ◽

New Approach ◽

Interstellar Clouds ◽

Enhanced Absorption ◽

Cavity Enhanced Absorption Spectroscopy ◽

Diffuse Interstellar Bands ◽

Planar Plasma ◽

Set Up

AbstractA new and sensitive set-up to swiftly test proposed carriers of the diffuse interstellar bands (DIBs), over a relatively broad spectral range, is described. The instrument utilizes broad-band cavity enhanced absorption spectroscopy (BBCEAS) and incorporates an optomechanical shutter to modulate light from a continuous incoherent light source. A pulsed supersonically expanding planar plasma expansion is used to mimic conditions in translucent interstellar clouds. Measurements of plasma durations as low as 400 μs are possible. The sensitivity is estimated to be better than 10 ppm/pass, measured with an effective exposure time of only ca. 1 s. The performance and potential of the instrument is demonstrated on spectra of C5H, C6H and C9H3 recorded through expanding hydrocarbon plasma.

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