Thule Scientific

Topanga, CA, United States

Thule Scientific

Topanga, CA, United States

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Bernstein L.S.,Spectral Sciences, Inc. | Shroll R.M.,Spectral Sciences, Inc. | Lynch D.K.,Thule Scientific | Clark F.O.,Wopeco Research
Astrophysical Journal | Year: 2017

We analyze the spectrum of the 11.2 μm unidentified infrared band (UIR) from NGC 7027 and identify a small fullerene (C24) as a plausible carrier. The blurring effects of lifetime and vibrational anharmonicity broadening obscure the narrower, intrinsic spectral profiles of the UIR band carriers. We use a spectral deconvolution algorithm to remove the blurring, in order to retrieve the intrinsic profile of the UIR band. The shape of the intrinsic profile - a sharp blue peak and an extended red tail - suggests that the UIR band originates from a molecular vibration-rotation band with a blue band head. The fractional area of the band-head feature indicates a spheroidal molecule, implying a nonpolar molecule and precluding rotational emission. Its rotational temperature should be well approximated by that measured for nonpolar molecular hydrogen, ∼825 K for NGC 7027. Using this temperature, and the inferred spherical symmetry, we perform a spectral fit to the intrinsic profile, which results in a rotational constant implying C24 as the carrier. We show that the spectroscopic parameters derived for NGC 7027 are consistent with the 11.2 μm UIR bands observed for other objects. We present density functional theory (DFT) calculations for the frequencies and infrared intensities of C24. The DFT results are used to predict a spectral energy distribution (SED) originating from absorption of a 5 eV photon, and characterized by an effective vibrational temperature of 930 K. The C24 SED is consistent with the entire UIR spectrum and is the dominant contributor to the 11.2 and 12.7 μm bands. © 2017. The American Astronomical Society. All rights reserved.


Harker D.E.,University of California at San Diego | Woodward C.E.,University of Minnesota | Kelley M.S.,University of Maryland University College | Sitko M.L.,Space Science Institute | And 3 more authors.
Astronomical Journal | Year: 2011

We present mid-infrared spectra and images from the Gemini-N (+ Michelle) observations of fragments SW3-[B] and SW3-[C] of the ecliptic (Jupiter family) comet 73P/Schwassmann-Wachmann 3 pre-perihelion. We observed fragment B soon after an outburst event (between 2006 April 16-26 UT) and detected crystalline silicates. The mineralogy of both fragments was dominated by amorphous carbon and amorphous pyroxene. The grain size distribution (assuming aHanner-modified power law) for fragment SW3-[B] has a peak grain radius of ap ∼ 0.5μm, and for fragment SW3-[C], ap ∼ 0.3μm; both values are larger than the peak grain radius of the size distribution for the dust ejected from ecliptic comet 9P/Tempel 1 during the Deep Impact event (a p = 0.2μm). The silicateto- carbon ratio and the silicate crystalline mass fraction for the submicron to micron-sized portion of the grain size distribution on the nucleus of fragment SW3-[B] were 1.341 -0.253+0.250 and 0.335+0.089 -0.112, respectively, while on the nucleus of fragment SW3-[C] they were 0.671 -0.076+0.076 and 0.257-0.043+0.039, respectively. The similarity in mineralogy and grain properties between the two fragments implies that 73P/Schwassmann-Wachmann 3 is homogeneous in composition. The slight differences in grain size distribution and silicate-to-carbon ratio between the two fragments likely arise because SW3-[B] was actively fragmenting throughout its passage while the activity in SW3-[C] was primarily driven by jets. The lack of diverse mineralogy in the fragments SW3-[B] and SW3-[C] of 73P/ Schwassmann-Wachmann 3 along with the relatively larger peak in the coma grain size distribution suggests that the parent body of this comet may have formed in a region of the solar nebulawith different environmental properties than the natal sites where comet C/1995 O1 (Hale-Bopp) and 9P/Tempel 1 nuclei aggregated. © 2011 The American Astronomical Society. All rights reserved.


Lynch D.K.,Thule Scientific | Dearborn D.S.P.,Lawrence Livermore National Laboratory | Lock J.A.,Cleveland State University
Applied Optics | Year: 2011

We present new observations of glitter and glints using short and long time exposure photographs and high frame rate videos. Using the sun and moon as light sources to illuminate the ocean and laboratory water basins, we found that (1) most glitter takes place on capillary waves rather than on gravity waves, (2) certain aspects of glitter morphology depend on the presence or absence of thin clouds between the light source and the water, and (3) bent glitter paths are caused by asymmetric wave slope distributions We present computer simulations that are able to reproduce the observations and make predictions about the brightness, polarization, and morphology of glitter and glints.We demonstrate that the optical catastrophe represented by creation and annihilation of a glint can be understood using both ray optics and diffraction theory. © 2011 Optical Society of America.


Bernstein L.S.,Spectral Sciences, Inc. | Clark F.O.,Wopeco Research | Cline J.A.,Spectral Sciences, Inc. | Lynch D.K.,Thule Scientific
Astrophysical Journal | Year: 2015

We argue that the observed spectroscopic and statistical properties of the diffuse interstellar band (DIB) carriers are those that are needed to produce the anomalous microwave emission (AME). We explore this idea using a carrier-impartial model for AME based on the observed DIB statistical properties. We show that an observed distribution of profile widths for narrow DIBs can be mapped into an AME spectrum. The mapping model is applied to width distributions observed for HD 204827 and HD 183143, selected because their spectroscopic and statistical properties bracket those for most other sight lines. The predicted AME spectra for these sight lines agree well with the range of spectral shapes, and peak frequencies, ∼23-31 GHz, typically observed for AME. We use the AME spectral profiles to derive a strong constraint between the average carrier size and its rotational temperature. The constraint is applied to a variety of postulated molecular carrier classes, including polycyclic aromatic hydrocarbons, fulleranes, hydrocarbon chains, and amorphous hydrocarbon clusters. The constraint favors small, cold carriers with average sizes of ∼8-15 carbon atoms, and average rotational temperatures of ∼3-10 K, depending on carrier type. We suggest new observations, analyses, and modeling efforts to help resolve the ambiguities with regard to carrier size and class, and to further clarify the DIB-AME relationship. © 2015. The American Astronomical Society. All rights reserved..


Lynch D.K.,U.S. Geological Survey | Hudnut K.W.,U.S. Geological Survey | Adams P.M.,Thule Scientific
Geomorphology | Year: 2013

New field observations, aerial surveys, LiDAR measurements and laboratory studies of mud samples (2006 to 2012) are reported of several formerly submerged fumarole complexes that are presently undergoing surface exposure as the Salton Sea level drops. Some remain submerged as of this writing (2012). The fumarole fields range in area from 1000 to ~50,000m2. They consist of hundreds of warm to boiling hot gryphons (mud volcanoes), salses (mud pots), and countless active gas vents. Unusually-shaped mud volcanoes in the form of vertical tubes with central vents were observed in many places. Since exposure began in ~2007, the surface morphology has changed dramatically, with a trend toward more and growing gryphons, larger mud pots and the development of sulfur vents. Chemical analysis of mud from several gryphons revealed the presence of the ammoniated sulfate minerals boussingaultite and lecontite among other more common sulfates. With other geothermal features, the fumaroles define a well-defined lineament marking the trace of a probable fault. A model for the development of gryphon morphology is presented. © 2013 Elsevier B.V.


Bernstein L.S.,Spectral Sciences, Inc. | Clark F.O.,Spectral Sciences, Inc. | Lynch D.K.,Thule Scientific
Astrophysical Journal | Year: 2013

We suggest that the diffuse interstellar bands (DIBs) arise from absorption lines of electronic transitions in molecular clusters primarily composed of a single molecule, atom, or ion ("seed"), embedded in a single-layer shell of H2 molecules. Less abundant variants of the cluster, including two seed molecules and/or a two-layer shell of H2 molecules, may also occur. The lines are broadened, blended, and wavelength-shifted by interactions between the seed and surrounding H 2 shell. We refer to these clusters as contaminated H2 clusters (CHCs). We show that CHC spectroscopy matches the diversity of observed DIB spectral profiles and provides good fits to several DIB profiles based on a rotational temperature of 10 K. CHCs arise from ∼centimeter-sized, dirty H2 ice balls, called contaminated H2 ice macro-particles (CHIMPs), formed in cold, dense, giant molecular clouds (GMCs), and later released into the interstellar medium (ISM) upon GMC disruption. Attractive interactions, arising from Van der Waals and ion-induced dipole potentials, between the seeds and H2 molecules enable CHIMPs to attain centimeter-sized dimensions. When an ultraviolet (UV) photon is absorbed in the outer layer of a CHIMP, it heats the icy matrix and expels CHCs into the ISM. While CHCs are quickly destroyed by absorbing UV photons, they are replenished by the slowly eroding CHIMPs. Since CHCs require UV photons for their release, they are most abundant at, but not limited to, the edges of UV-opaque molecular clouds, consistent with the observed, preferred location of DIBs. An inherent property of CHCs, which can be characterized as nanometer size, spinning, dipolar dust grains, is that they emit in the radio-frequency region. We also show that the CHCs offer a natural explanation for the anomalous microwave emission feature in the ∼10-100 GHz spectral region. © 2013. The American Astronomical Society. All rights reserved.


Lynch D.K.,Thule Scientific
Applied Optics | Year: 2015

New observations and analyses are presented of the opposition effect on mud cracks (mud polygons) on desert playas. The enhanced brightness of the surface near the antisolar point has been previously and correctly ascribed to two sources: shadow-hiding and coherent backscatter. The observations reported here suggest that a third optical mechanism influences the OE: some parts of the mud polygon are more strongly illuminated than others, depending on the angle of incidence of sunlight. This causes the areas facing the observer and the sun to be brighter than the rest of the polygon field. This mechanism, called "dilution," also should occur in all OEs. © 2014 Optical Society of America.


Lynch D.K.,Thule Scientific
Applied Optics | Year: 2015

The angular diameter of Snell's window as a function of maximumwave slope is calculated. For flat water the diameter is 97° and increases up to about 122° when the wave slope is about 16°. Steeper waves break and disrupt the smooth surface used in the analysis. Breaking waves produce a window almost 180° wide. The brightness of the dark area around Snell's window is heavily influenced by turbidity and upwelling radiation, especially in shallow water. © 2014 Optical Society of America.


Lynch D.K.,Thule Scientific
Applied Optics | Year: 2015

We investigate the brightness distribution in and around outdoor shadows (for a variety of sky conditions) using modeling and field measurements. The dominant factor influencing the brightness of a shadow is the solid angle subtended by the object blocking the Sun. Occulters at the zenith that subtend a small solid angle cast shadows that are bright and possess a nearly uniform brightness across their extent. Shadows from large occulters are much darker and their brightness varies considerably, being darkest at their centers. For nonzenith occulters, the proximal (nearest the Sun) side of the shadow is darker than the distal side and the shadow will be darkest beneath the center of the occulter. Occulters (e.g., tree or cloud) influence the brightness of sunlit portions near the shadow because they block part of the sky and reflect light into the shadow. The aureole has a significant influence on the brightness of shadow edges. Semi-analytic formulations for the brightness in shadows are presented, and analytic expressions in wells and tunnels are derived. © 2015 Optical Society of America.


Lynch D.K.,Thule Scientific
Applied Optics | Year: 2015

Scattering by microscopic particles renders virtually all dusty surfaces brighter than dust-free surfaces. Examples of surface brightening are demonstrated in the landscape and laboratory and explained theoretically using Mie theory calculations. The implications for landscape photography and remote sensing are discussed. © 2014 Optical Society of America.

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