| 1. |
- Coustenis, A., et al.
(författare)
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TandEM : Titan and Enceladus mission
- 2009
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:3, s. 893-946
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Tidskriftsartikel (refereegranskat)abstract
- TandEM was proposed as an L-class (large) mission in response to ESA's Cosmic Vision 2015-2025 Call, and accepted for further studies, with the goal of exploring Titan and Enceladus. The mission concept is to perform in situ investigations of two worlds tied together by location and properties, whose remarkable natures have been partly revealed by the ongoing Cassini-Huygens mission. These bodies still hold mysteries requiring a complete exploration using a variety of vehicles and instruments. TandEM is an ambitious mission because its targets are two of the most exciting and challenging bodies in the Solar System. It is designed to build on but exceed the scientific and technological accomplishments of the Cassini-Huygens mission, exploring Titan and Enceladus in ways that are not currently possible (full close-up and in situ coverage over long periods of time). In the current mission architecture, TandEM proposes to deliver two medium-sized spacecraft to the Saturnian system. One spacecraft would be an orbiter with a large host of instruments which would perform several Enceladus flybys and deliver penetrators to its surface before going into a dedicated orbit around Titan alone, while the other spacecraft would carry the Titan in situ investigation components, i.e. a hot-air balloon (MontgolfiSre) and possibly several landing probes to be delivered through the atmosphere.
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| 2. |
- Gordon, I.E., et al.
(författare)
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The HITRAN2020 molecular spectroscopic database
- 2022
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier. - 0022-4073 .- 1879-1352. ; 277
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Tidskriftsartikel (refereegranskat)abstract
- The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years). All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules. The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition.
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| 3. |
- Herique, A., et al.
(författare)
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Direct observations of asteroid interior and regolith structure : Science measurement requirements
- 2018
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Ingår i: Advances in Space Research. - : Elsevier BV. - 0273-1177 .- 1879-1948. ; 62:8, s. 2141-2162
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Tidskriftsartikel (refereegranskat)abstract
- Our knowledge of the internal structure of asteroids is, so far, indirect - relying entirely on inferences from remote sensing observations of the surface, and theoretical modeling of formation and evolution. What are the bulk properties of the regolith and deep interior? And what are the physical processes that shape asteroid internal structures? Is the composition and size distribution observed on the surface representative of the bulk? These questions are crucial to understand small bodies' history from accretion in the early Solar System to the present, and direct measurements are needed to answer these questions for the benefit of science as well as for planetary defense or exploration. Radar is one of the main instruments capable of sounding asteroids to characterize internal structure from sub-meter to global scale. In this paper, we review the science case for direct observation of the deep internal structure and regolith of a rocky asteroid of kilometer size or smaller. We establish the requirements and model dielectric properties of asteroids to outline a possible instrument suite, and highlight the capabilities of radar instrumentation to achieve these observations. We then review the expected science return including secondary objectives contributing to the determination of the gravitational field, the shape model, and the dynamical state. This work is largely inherited from MarcoPolo-R and AIDA/AIM studies.
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| 4. |
- Cabrit, B, et al.
(författare)
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Comparison between EISCAT UHF and VHF backscattering cross section
- 1996
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. ; 101:A2, s. 2369-2376
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We present a comparison between the backscattering cross sections at 224 and 933 MHz measured with European Incoherent Scatter (EISCAT) radars during the passage of a discrete are. It shows a difference of 2 orders of magnitude which cannot simply be expl
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| 5. |
- Isham, B, et al.
(författare)
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Aspect angle dependence of HF enhanced incoherent backscatter
- 1999
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Ingår i: ACTIVE EXPERIMENTS IN SPACE PLASMAS. - : PERGAMON PRESS LTD. - 0273-1177. ; 24:8, s. 1003-1006
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Tidskriftsartikel (refereegranskat)abstract
- An HF ionospheric interaction experiment was performed in November and December of 1997 using the EISCAT HF transmitter and 931 and 224 MHz incoherent scatter radars, all co-located near Tromso, Norway. During this experiment the pointing of the UHF radar
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| 6. |
- Isham, B., Hagfors, T., Mishin, E., Rietveld, M.T., LaHoz, C., Kofman, W., Leyser, T.B.
(författare)
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A search for the location of the HF excitation of enhanced ion acourstic and Langmuir waves with EISCAT and the Tromsø heater
- 1999
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Ingår i: Radiophysics and Quantum Electronics. ; 42:7, s. 607-618
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Isham, B., Rietveld, M.T., Hagfors, T., LaHoz, C., Mishin, E., Kofman, W., Leyser, T.B., van Eyken, A.P
(författare)
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Aspect Angle Dependence of HF Enhanced Incoherent Backscatter
- 1999
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Ingår i: Advances of Space Research. ; 24, s. 10081-10087
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Ligterink, N. F. W., et al.
(författare)
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The ALMA-PILS survey: Detection of CH3NCO toward the low-mass protostar IRAS 16293-2422 and laboratory constraints on its formation
- 2017
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Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966.
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Tidskriftsartikel (refereegranskat)abstract
- Methyl isocyanate (CH3NCO) belongs to a select group of interstellar molecules considered to be relevant precursors in the formation of larger organic compounds, including those with peptide bonds. The molecule has only been detected in a couple of high-mass protostars and potentially on comets. A formation route on icy grains has been postulated for this molecule but experimental evidence is lacking. Here we ex- tend the range of environments where methyl isocyanate is found, and unambiguously identify CH3NCO through the detection of 43 unblended transitions in the ALMA Protostellar Interferometric Line Survey (PILS) of the low mass solar-type protostel- lar binary IRAS 16293-2422. The molecule is detected toward both components of the binary with a ratio HNCO/CH3NCO ∼4–12. The isomers CH3CNO and CH3OCN are not identified, resulting in upper abundance ratios of CH3NCO/CH3CNO > 100 and CH3NCO/CH3OCN > 10. The resulting abundance ratios compare well with those found for related N-containing species toward high-mass protostars. To constrain its formation, a set of cryogenic UHV experiments is performed. VUV irradiation of CH4:HNCO mixtures at 20 K strongly indicate that methyl isocyanate can be formed in the solid-state through CH3 and (H)NCO recombinations. Combined with gas-grain models that include this reaction, the solid-state route is found to be a plausible sce- nario to explain the methyl isocyanate abundances found in IRAS 16293-2422. Key
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| 9. |
- McCarrick, Heather, et al.
(författare)
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The Simons Observatory Microwave SQUID Multiplexing Detector Module Design
- 2021
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 922:1
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Tidskriftsartikel (refereegranskat)abstract
- Advances in cosmic microwave background (CMB) science depend on increasing the number of sensitive detectors observing the sky. New instruments deploy large arrays of superconducting transition-edge sensor (TES) bolometers tiled densely into ever larger focal planes. High multiplexing factors reduce the thermal loading on the cryogenic receivers and simplify their design. We present the design of focal-plane modules with an order of magnitude higher multiplexing factor than has previously been achieved with TES bolometers. We focus on the novel cold readout component, which employs microwave SQUID multiplexing (μmux). Simons Observatory will use 49 modules containing 70,000 bolometers to make exquisitely sensitive measurements of the CMB. We validate the focal-plane module design, presenting measurements of the readout component with and without a prototype detector array of 1728 polarization-sensitive bolometers coupled to feedhorns. The readout component achieves a 95% yield and a 910 multiplexing factor. The median white noise of each readout channel is 65 pA √Hz . This impacts the projected SO mapping speed by <8%, which is less than is assumed in the sensitivity projections. The results validate the full functionality of the module. We discuss the measured performance in the context of SO science requirements, which are exceeded.
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| 10. |
- Oyama, S., Ishii, M., Murayama, Y., Shinagawa, H., Buchert, S., Fujii, R. and Kofman, W.
(författare)
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Generation of atmospheric gravity waves associated with auroral activity in the polar F region
- 2001
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Ingår i: Journal of Geophysical Research. ; 106, s. 18543-
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Tidskriftsartikel (refereegranskat)abstract
- Relations between auroral activities and the generation of neutral-wind oscillations in the polar F region (150-300 km) were investigated using data from the European Incoherent Scatter (EISCAT) radar, the all-sky auroral camera, and the IMAGE (Internatio
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