Papers by Charles Kaminski
Science, 1996
The saturated hydrocarbons ethane (C2H6) and methane (CH4) along with carbon monoxide (CO) and wa... more The saturated hydrocarbons ethane (C2H6) and methane (CH4) along with carbon monoxide (CO) and water (H2O) were detected in comet C/1996 B2 Hyakutake with the use of high-resolution infrared spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. The inferred production rates of molecular gases from the icy, cometary nucleus (in molecules per second) are 6.4 X 10(26) for C2H6, 1.2 X 10(27) for CH4, 9.8 X 10(27) for CO, and 1.7 X 10(29) for H2O. An abundance of C2H6 comparable to that of CH4 implies that ices in C/1996 B2 Hyakutake did not originate in a thermochemically equilibrated region of the solar nebula. The abundances are consistent with a kinetically controlled production process, but production of C2H6 by gas-phase ion molecule reactions in the natal cloud core is energetically forbidden. The high C2H6/CH4 ratio is consistent with production of C2H6 in icy grain mantles in the natal cloud, either by photolysis of CH4-rich ice or by hydrogen-addition reactions to acetylene condensed from the gas phase.
Icarus, 1998
We report the first multi-filter set of absolutely-calibrated nearinfrared images of Uranus, its ... more We report the first multi-filter set of absolutely-calibrated nearinfrared images of Uranus, its rings, and three major satellites -. Titania, Ariel, and Miranda. Along with imagery utilizing the canonical K filter bandpass (effective wavelength 2.20 pm), absolutely calibrated images of the Uranian system are presented for the first time for three additional filter bandpasses: J (1.27 pm), H (1.62 pm) and in a narrow bandpass (0.1 p m full-width-at-half-maximum) centered at 1.73 p m (hereafter designated H') particularly diagnostic of C-H stretch vibrational absorptions common in hydrocarbons. Multi-filter-derived spectra of the southern ring ansa including the bright apoapse of the dominant E ring show no absorptions due to condensable volatiles, including water, ammonia, and light (high H:C) hydrocarbons. Plausible near-infrared spherical geometric and single-scattering particle albedos consistent with Voyager-derived phase functions range from 0.069 to 0.102 and 0.030 to 0.037, respectively. These are approximately 50% greater than visible values, consistent with the optical properties of charcoal, carbonaceous chondrite material, and the darkside of Iapetus, and consistent with the hypothesis that a primary component of the ring particles is high stoichiometric ratio C:H organics produced by charged-particle and/or photochemical weathering of methane clathrate and/or hydrocarbon ice material originating from nearby moonlets. Additional components consistent with the ring spectrum include silicates such as pyroxene, but not olivine. Analytical modelling of the ring structure indicates &-ring near-infrared opacities of 0.37 f 0.05 and 1.8 f 0 . 3 at apoapsis and periapsis, respectively. Ariel is more than 25% brighter than Miranda and 15% 3 brighter than Titania at all near-infrared wavelengths. Comparisons with UV-visible spectra by Karkoschka (1997, Icarus 125, 348-363) show consistency with the hypothesis that the water-ice surfaces of Titania and Ariel are contaminated with low-reflectance, near-ir-reddened substances similar to the weathered high C:H material postulated for the Uranian ring system. The relatively blue, near-infrared dark surface of Miranda (fulldisk near-infrared albedo of -0.22 at 2.40 phase angle) exhibits the greatest water ice absorption band-depth and the largest H-and K-filter brightness surge measured among the Uranian satellites, consistent with
Icarus, 1988
We report 1981-1984 thermal infrared observations of 10 Io eclipse reappearances and three eclips... more We report 1981-1984 thermal infrared observations of 10 Io eclipse reappearances and three eclipse disappearances. Absolute calibration errors were estimated from measurements of Callisto during nine of the eclipses with the following values: 5% at 8.7, 10.2, 12.5, and 20/zm; and 15% at 30 pm. The longer wavelength (8.7, 10.2, 12.5, 20, and 30 pro) eclipse data were used to determine not only the thermal radiation from the volcanoes, but also to find the best thermophysical parameters by a least-squares fitting procedure. No simple thermophysical model capable of fitting all wavelengths simultaneously was found. We found that adequate fitting of the eclipse cooling and heating curves requires not only vertically inhomogeneous models, but also models that are horizontally inhomogeneous at least in the sense of requiring two different aibedo regimes. The best model required a variation of the thermophysical parameters between the light and dark albedo components. The thermal inertia of the bright component was nearly 10 times that of the dark component and required a vertically inhomogeneous surface. The dark component's surface was, however, homogeneous. It is shown from the improvement in the sum of the squares of the residuals that the differences of parameters between light and dark regions are significant at the 99.9% level. A major result of this paper is the accurate determination of the volcanic heat radiation for the sub-Jupiter hemisphere. We were able to find solutions for the temperature, effective radiating area, and longitude separately for a high-temperature and a low-temperature volcanic source. The longitudes of either of these sources, when the data were sufficient to make significant determinations, lie within a few degrees of the Loki volcano. The area of the low-temperature source is approximately that of the lava lake seen in Voyager photographs. We believe that Loki is the primary source of excess thermal radiation seen in eclipses of Io, but based on Voyager results it, most likely, is not the only source contributing to the eclipse flux. We have performed a careful evaluation of errors and find that the statistical uncertainty of the total volcanic flux from the Loki region can be as low as 3 to 9% when multiple eclipses, including both disappearances and reappearances, are observed. When comparing one year's data with another, the uncertainty associated with the flux calibration is not involved and only the statistical uncertainty is applicable to the comparison. We have studied the variability of the thermal emission of the volcanoes seen on the sub-Jupiter hemisphere and find that a solution based on the data of W. Sinton, A. Tokunaga, E. Becklin, I. Gatley, T. Lee, and C. Lonsdale ( , Science 210, 1015( -1017 and on the data of D. Morrison and C. Telesco (1980, Icarus 44, 226-233) gives a total flux that is considerably more than that which we find for 1981, 1982, 1983, and 1984 or the Voyager results. Our data for the last four enumerated years give little evidence, by themselves, for variability of the total volcanic flux from the sub-Jupiter hemisphere.
Icarus, 1989
Observations were made of the disk of Uranus near 5 tan with 2% spectral resolution in June of 19... more Observations were made of the disk of Uranus near 5 tan with 2% spectral resolution in June of 1987. The observed spectrum is very unlike those of Jupiter and Saturn in the same region. It is characterized by an intensity peak at 4.8/zm near 3 x 10 -9 m¢m -2 sr -1 pm -I (equivalent to a brightness temperature near 142 K or a geometric albedo of 7 x 10 -3 ) with steep declines at shorter and longer wavelengths. Models discussed in the context of the data are exploratory in nature. Some component of the radiation must originate near the 140 K atmospheric level; this is true whether the radiation is reflected sunlight or thermal emission. The short-wavelength portion of the spectrum can be fit roughly by a partly reflecting, partly emitting cloud near 8 bar total pressure. The longwavelength portion of the spectrum is not fit well by various mixtures of PH3, CH3D, or distant wings of CH4 bands (although the latter may need to be taken into account). Additional opacity near 4.7 pm, possibly provided by CO or other trace gases is required to improve the fit; higher resolution data are recommended for identifying the source of the opacity. Further observations near 4 pm would also help to assess the role of continuum opacity sources.
Icarus, 2000
818)354-7427 FAX (818)354-0966 bonnie.buratti@jpl .nasa.gov ABSTRACT Photometric observations of ... more 818)354-7427 FAX (818)354-0966 bonnie.buratti@jpl .nasa.gov ABSTRACT Photometric observations of the five medium-sized satellites of Saturn were obtained with the 60-inch telescope at Palomar Mountain Observatory during the Ring Plane Crossing in August 1995. The albedos of these satellites are very high at -0.9 #m, an indication that the fraction of opaque contaminants on their surfaces is very low. The geometric albedos for the leading sides of the satellites are: Enceladus: 1.02; Tethys: 0.90; Dione: 0.72; and Rhea: 0.76. For Mimas, the geometric albedo of the trailing side is 0.72. The amplitudes of the satellites' rotational lightcurves is somewhat less than in the visual portion of the spectrum, ranging from 0.40 for Dione to Tethys. The lightcurve of Enceladus Enceladus and Mimas are brighter on the other three satellites. This result 0.10 for Rhea, to 0.05 for is not sinusoidal. Both trailing side, unlike the suggests that coating by Saturn's E-ring is a major factor in determining the optical properties of all five satellites. 2 1 t .
Icarus, 1999
Multispectral images of Mars, taken at the NASA Infrared Telescope Facility (IRTF) near and at th... more Multispectral images of Mars, taken at the NASA Infrared Telescope Facility (IRTF) near and at the 1995 opposition, are used to identify and track its atmospheric clouds and ground ices. Band depth mapping is used to help distinguish between the composition of volatiles and provide a check for the techniques of principal components analysis (PCA) and linear mixture modeling (LMM). PCA/LMM are used to create maps that track clouds and volatiles, a technique that requires no a priori spectral information in order to create these maps. Band depth maps at 3.33 µm, which have been shown to trace CO 2 frosts, show some transient features which could indicate polar CO 2 clouds at the time of these observations. We show that band depth maps at 2.25 µm are good tracers of H 2 O frosts and that band depth maps at 3.69 µm can distinguish between coarseand fine-grained water frosts. These maps have allowed the detection of fine-grained water frosts in the north polar region and along the morning and evening limb regions. From the PCA technique we find that just two principal components can account for over 99% of the data variance. The first of these is an infrared albedo unit and the second is an ice/thermal unit. Plotting the spectral data cubes in this new vector space, we find that most of the martian disk can be modeled by spectrally mixing three endmember spectra having extreme values of these principal components. The morning and evening regions of Mars are composed of 40-60% of the north polar ice/thermal component endmember, indicating a frost component there consistent with the band depth mapping results. With a combination of these techniques it is possible to not only identify the extensive martian clouds, but to also determine composition. These new results are particularly relevant in light of recent Mars Pathfinder descent temperature profile data that indicated upper atmosphere temperatures below the CO 2 frost condensation point, implying that CO 2 ice clouds may be an important radiative component of the current martian climate.
The Astrophysical Journal Supplement Series, 2014
The Stratospheric Observatory for Infrared Astronomy (SOFIA) has recently concluded a set of engi... more The Stratospheric Observatory for Infrared Astronomy (SOFIA) has recently concluded a set of engineering flights for Observatory performance evaluation. These in-flight opportunities are viewed as a first comprehensive assessment of the Observatory's performance and are used to guide future development activities, as well as to identify additional Observatory upgrades. Pointing stability was evaluated, including the image motion due to rigid-body and flexible-body telescope modes as well as possible aero-optical image motion. We report on recent improvements in pointing stability by using an active mass damper system installed on the telescope. Measurements and characterization of the shear layer and cavity seeing, as well as image quality evaluation as a function of wavelength have also been performed. Additional tests targeted basic Observatory capabilities and requirements, including pointing accuracy, chopper evaluation and imager sensitivity. This paper reports on the data collected during these flights and presents current SOFIA Observatory performance and characterization.
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Papers by Charles Kaminski