Hubble Space Telescope far-ultraviolet imaging of the jet in 3C 273: a common emission component from optical to X-rays*

Ganymede&#8217;s tenuous atmosphere is produced by charged particle sputtering and sublimation of its icy surface. Previous far-ultraviolet observations of the OI1356 &#197; and OI1304 &#197; oxygen emissions were used to derive sputtered molecular oxygen, O2, as an atmospheric constituent. We present a new analysis of high-sensitivity spectra and spectral images of Ganymede&#8217;s oxygen emissions acquired by the COS and STIS instruments on the Hubble Space Telescope. The COS eclipse observations constrain atomic oxygen, O, to be at least two orders of magnitude less abundant than O2. We then show that dissociative excitation of water&#160;vapor, H2O, is found to increase the OI1304 &#197; emissions relative to the OI1356 &#197; emissions around the sub-solar point, where H2O is more abundant than O2. Away from the sub-solar region, the emissions are more than two times brighter at OI1356 &#197; than at OI1304 &#197;, and O2 prevails as found in previous analyses. A ~6-fold higher H2O/O2 mixing ratio on the warmer trailing hemisphere compared to the colder leading hemisphere, a spatial concentration at the sub-solar region, and the ratio-estimated H2O densities identify icy surface sublimation as a local dayside atmospheric source. Our analysis provides the first evidence for a sublimated atmosphere on an icy moon in the outer solar system.

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Insights into the Damage Mechanism of Teflon® FEP from the Hubble Space Telescope

High Performance Polymers ◽

10.1088/0954-0083/12/1/307 ◽

2000 ◽

Vol 12 (1) ◽

pp. 83-104 ◽

Cited By ~ 32

Author(s):

Kim K de Groh ◽

James R Gaier ◽

Rachelle L Hall ◽

Matthew P Espe ◽

Daveen R Cato ◽

...

Keyword(s):

Thermal Cycling ◽

Hubble Space Telescope ◽

Thermal Exposure ◽

Thermal Control ◽

Damage Mechanism ◽

Chain Scission ◽

Space Environment ◽

X Rays ◽

Scanning Calorimetry ◽

Space Telescope

Metallized Teflon® FEP (fluorinated ethylene propylene) thermal control material on the Hubble Space Telescope (HST) has been found to be degrading in the space environment. Teflon® FEP thermal control blankets (space-facing FEP) retrieved during the first servicing mission (SM1) were found to be embrittled on solar-facing surfaces and contained microscopic cracks. During the second servicing mission (SM2) astronauts noticed that the FEP outer layer of the multi-layer insulation (MLI) covering the telescope was cracked in many locations around the telescope. Large cracks were observed on the light shield, forward shell and equipment bays. A tightly curled piece of cracked FEP from the light shield was retrieved during SM2 and was severely embrittled, as witnessed by ground testing. A failure review board was organized to determine the mechanism causing the MLI degradation. Density, x-ray crystallinity and solid-state nuclear magnetic resonance (NMR) analyses of the FEP retrieved during SM1 were inconsistent with results of FEP retrieved during SM2. Because the retrieved SM2 material was curled while in space, it experienced a higher temperature extreme during thermal cycling, estimated at 200°C, than the SM1 material, estimated at 50°C. An investigation on the effects of heating pristine FEP and FEP retrieved from the HST was therefore conducted. Samples of pristine, SM1 and SM2 FEP were heated to 200°C and evaluated for changes in density and morphology. Elevated-temperature exposure was found to have a major impact on the density of the retrieved materials. The characterization of the polymer morphology of the as-received and heated FEP by NMR provided results that were consistent with the density results. Differential scanning calorimetry (DSC) was conducted on pristine, SM1 and SM2 FEP. DSC results provided evidence of chain scission and increased crystallinity in the space exposed FEP, which supported the density and NMR results. Samples exposed to simulated solar flare x-rays, thermal cycling and long-term thermal exposure provided information on the environmental contributions to degradation. These findings have provided insight into the damage mechanisms of FEP in the space environment.

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Far-Ultraviolet Imaging of the Field Star Population in the Large Magellanic Cloud with the [ITAL]Hubble Space Telescope[/ITAL]

The Astronomical Journal ◽

10.1086/300690 ◽

1999 ◽

Vol 117 (1) ◽

pp. 206-224 ◽

Cited By ~ 3

Author(s):

Noah Brosch ◽

Michael Shara ◽

John MacKenty ◽

David Zurek ◽

Brian McLean

Keyword(s):

Hubble Space Telescope ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Space Telescope ◽

Field Star ◽

Far Ultraviolet

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HUBBLE SPACE TELESCOPE DETECTION OF THE DOUBLE PULSAR SYSTEM J0737–3039 IN THE FAR-ULTRAVIOLET

The Astrophysical Journal ◽

10.1088/2041-8205/783/1/l22 ◽

2014 ◽

Vol 783 (1) ◽

pp. L22 ◽

Cited By ~ 4

Author(s):

Martin Durant ◽

Oleg Kargaltsev ◽

George G. Pavlov

Keyword(s):

Hubble Space Telescope ◽

Space Telescope ◽

Far Ultraviolet

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The far-ultraviolet main auroral emission at Jupiter – Part 2: Vertical emission profile

Annales Geophysicae ◽

10.5194/angeo-33-1211-2015 ◽

2015 ◽

Vol 33 (10) ◽

pp. 1211-1219 ◽

Cited By ~ 8

Author(s):

B. Bonfond ◽

J. Gustin ◽

J.-C. Gérard ◽

D. Grodent ◽

A. Radioti ◽

...

Keyword(s):

Hubble Space Telescope ◽

Total Power ◽

Space Telescope ◽

Auroral Emission ◽

Ultraviolet Range ◽

Auroral Emissions ◽

Generation Mechanisms ◽

Far Ultraviolet ◽

Advanced Camera For Surveys ◽

Imaging Spectrograph

Abstract. The aurorae at Jupiter are made up of many different features associated with a variety of generation mechanisms. The main auroral emission, also known as the main oval, is the most prominent of them as it accounts for approximately half of the total power emitted by the aurorae in the ultraviolet range. The energy of the precipitating electrons is a crucial parameter to characterize the processes at play which give rise to these auroral emissions, and the altitude of the emissions directly depends on this energy. Here we make use of far-UV (FUV) images acquired with the Advanced Camera for Surveys on board the Hubble Space Telescope and spectra acquired with the Space Telescope Imaging Spectrograph to measure the vertical profile of the main emissions. The altitude of the brightness peak as seen above the limb is ~ 400 km, which is significantly higher than the 250 km measured in the post-dusk sector by Galileo in the visible domain. However, a detailed analysis of the effect of hydrocarbon absorption, including both simulations and FUV spectral observations, indicates that FUV apparent vertical profiles should be considered with caution, as these observations are not incompatible with an emission peak located at 250 km. The analysis also calls for spectral observations to be carried out with an optimized geometry in order to remove observational ambiguities.

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