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Search for an exosphere around 51 Pegasi B with ISO
Rauer, H.; Schneider, J.; Bockelée-Morvan, D. +2 more
The detection of absorption features in spectra of 51 Peg obtained during transit of its planet would provide a first clue on the physical nature of the planet. We have searched for signatures of an exosphere of the planet orbiting 51 Peg in the wavelength range from 2.39 µm to 3.5 µm and from 4.55 µm to 4.74 µm using SWS o…
Knots in the Outer Shells of the Planetary Nebulae IC 2553 and NGC 5882
Corradi, Romano L. M.; Gonçalves, Denise R.; Villaver, Eva +2 more
We present images and high-resolution spectra of the planetary nebulae IC 2553 and NGC 5882. Spatiokinematic modeling of the nebulae shows that they are composed of a markedly elongated inner shell and of a less aspherical outer shell expanding at a considerably higher velocity than the inner one. Embedded in the outer shells of both nebulae are f…
On the Ongoing Multiple Blowout in NGC 604
Maíz-Apellániz, Jesús; Tenorio-Tagle, Guillermo; Muñoz-Tuñón, Casiana +2 more
Several facts regarding the structure of NGC 604 are examined here. The three main cavities produced by the mechanical energy from massive stars, which in NGC 604 are spread over a volume of 106 pc3, are shown here to be undergoing blowout into the halo of M33. High-resolution long-slit spectroscopy is used to track the impac…
Adaptive optics near-infrared imaging of NGC 2992 - unveiling core structures related to radio figure-of-8 loops
Alonso-Herrero, Almudena; Morris, Simon L.; Chapman, Scott C. +1 more
We present near-infrared adaptive optics, Very Large Array (VLA) radio and Hubble Space Telescope (HST) optical imaging of the nearby Seyfert galaxy NGC 2992. Spiral structure and an extension to the west are traced down to the core region at the limiting resolution of our near-infrared images. A faint, diffuse loop of near-infrared and radio emis…
The Physical Conditions in a Polar Coronal Hole and Nearby Regions from Norikura and SOHO Observations
Ichimoto, K.; Singh, Jagdev; Raju, K. P. +1 more
The distribution of emission-line intensities, Doppler velocities, and line widths in a polar coronal hole and nearby regions are obtained from the spectroscopic observations carried out on 1998 November 3 at the Norikura Solar Observatory, Japan. The coronal red line [Fe X] λ6374 that is prominent at coronal hole temperatures is used for the stud…
The Structure of Wolf-Rayet Winds. II. Observations of Ionization Stratification in the WN Subtype
Morris, P.; Herald, J. E.; Schulte-Ladbeck, R. E. +1 more
Motivated by the question of the importance of ionization stratification in solving the ``momentum problem'' of Wolf-Rayet stellar winds, we have chosen a sample of 14 WN stars for a systematic study. We performed measurements of the emission line widths on ultraviolet, optical, and infrared spectra to obtain data spanning a large range of ionizat…
Gamma-Ray Burst Arrival-Time Localizations: Simultaneous Observations by Ulysses, Pioneer Venus Orbiter, SIGMA, WATCH, and PHEBUS
Cline, T.; Hurley, K.; Sunyaev, R. +15 more
Between the launch of the Ulysses spacecraft in 1990 October and the entry of Pioneer Venus Orbiter (PVO) into the atmosphere of Venus in 1992 October, concurrent coverage by Ulysses, PVO, the WATCH experiments aboard the Granat and Eureca spacecraft, and the SIGMA and PHEBUS experiments aboard the Granat spacecraft was obtained for numerous gamma…
The 90-day oscillations of Jupiter's Great Red Spot revisited
Sánchez-Lavega, A.; Colas, F.; Lecacheux, J. +3 more
We have analyzed a large set of ground-based CCD images covering the period from 1993 to early 1999, to address the current status and behavior of the 90-day longitudinal oscillations of the Jovian Great Red Spot (GRS). The good temporal sampling of these data have been complemented with a small set of high resolution Hubble Space Telescope images…
Multispectral Observations of Jupiter's Aurora
Walker, R. J.; Trafton, L. M.; Clarke, J. T. +10 more
Remote sensing of Jupiter's aurora from x-ray to radio wavelengths has revealed much about the nature of the jovian aurora and about the impact of ionosphere-magnetosphere coupling on the upper atmosphere of Jupiter. As indicated by the combination of x-ray and ultraviolet observations, both energetic heavy ions and electrons energized in the oute…
Ultraviolet Spectroscopy of Polar Coronal Jets
Raymond, J. C.; Dobrzycka, D.; Cranmer, S. R.
We have observed a total of five UVCS/SOHO polar jets that correlate with the Extreme-Ultraviolet Imaging Telescope (EIT) and Large Angle Spectrometric Coronagraph (LASCO) jet events. We analyzed spectroscopic observations of these jets and found that they typically undergo two phases: at the first phase the O VI lines show a brief intensity enhan…