John T. Trauger

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Small-angle coronagraphy is technically and scientifically appealing because it enables the use of smaller telescopes, allows covering wider wavelength ranges, and potentially increases the yield and completeness of circumstellar environment – exoplanets and disks – detection and characterization campaigns. However, opening up this new parameter space is(More)
Neutral sodium emissions encircling Jupiter exhibit an intricate and variable structure that is well matched by a simple loss process from Io's atmosphere. These observations imply that fast neutral sodium is created locally in the Io plasma torus, both near Io and as much as 8 hours downstream. Sodium-bearing molecules may be present in Io's upper(More)
Io leaves a magnetic footprint on Jupiter's upper atmosphere that appears as a spot of ultraviolet emission that remains fixed underneath Io as Jupiter rotates. The specific physical mechanisms responsible for generating those emissions are not well understood, but in general the spot seems to arise because of an electromagnetic interaction between(More)
Deep V and I CCD images in a central and an outer field of the Local Group dwarf elliptical galaxy NGC 147 have been obtained with the Wide Field and Planetary Camera-2 (WFPC2) on board of the Hubble Space Telescope. The color-magnitude diagram shows a number of interesting features, including a well defined red giant branch (RGB), a red horizontal branch(More)
Io’s sodium clouds result mostly from a combination of two atmospheric escape processes at Io. Neutralization of Na+ and/or NaX+ pickup ions produces the “stream” and the “jet” and results in a rectangular-shaped sodium nebula around Jupiter. Atmospheric sputtering of Na by plasma torus ions produces the “banana cloud” near Io and a diamond-shaped sodium(More)
We present Wide Field Camera 3 images taken with the Hubble Space Telescope within a single field in the southern grand design star-forming galaxy M83. Based on their size, morphology and photometry in continuum-subtracted Hα, [S II ], Hβ, [O III ] and [O II ] filters, we have identified 60 supernova remnant candidates, as well as a handful of young(More)
The protoÈplanetary nebula, CRL 2688, has been imaged through a wideband Ðlter centered at 606 nm (F606W) with the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope. CRL 2688 is the prototypical bipolar reÑection nebula in which a star is surrounded by a dense, Ñattened cocoon of dust seen nearly edge-on and starlight escapes preferentially(More)
The electrodynamic interaction of the dust and gas comae of comet Shoemaker-Levy 9 with the jovian magnetosphere was unique and different from the atmospheric effects. Early theoretical predictions of auroral-type processes on the comet magnetic field line and advanced modeling of the time-varying morphology of these lines allowed dedicated observations(More)
Relative to ground-based telescopes, the James Webb Space Telescope (JWST) will have a substantial sensitivity advantage in the 2.2-5 μm wavelength range where brown dwarfs and hot Jupiters are thought to have significant brightness enhancements. To facilitate high contrast imaging within this band, the Near-Infrared Camera (NIRCAM) will employ a Lyot(More)
The detection and characterization of an Earth-like planet orbiting a nearby star requires a telescope with an extraordinarily large contrast at small angular separations. At visible wavelengths, an Earth-like planet would be 1 x 10(-10) times fainter than the star at angular separations of typically 0.1 arcsecond or less. There are several proposed space(More)