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How Prometheus creates structure in Saturn's F ring
Porco, Carolyn C.; Burns, Joseph A.; Murray, Carl D. +4 more
Images of Saturn's narrow and contorted F ring returned by the Cassini spacecraft have revealed phenomena not previously detected in any planetary ring system. The perturbing effect of the inner shepherding satellite, Prometheus, seems to introduce channels through the F ring and a `streamer'-a line of particles that link the ring to the satellite…
XMM-Newton Observation of an X-Ray Trail between the Spiral Galaxy NGC 6872 and the Central Elliptical Galaxy NGC 6876 in the Pavo Group
Jones, Christine; Forman, William R.; Nulsen, Paul +2 more
We present XMM-Newton observations of a trail of enhanced X-ray emission extending along the full 8.7 arcmin ×4' region between the large spiral galaxy NGC 6872 and the dominant elliptical galaxy NGC 6876 in the Pavo group, the first known X-ray trail associated with a spiral galaxy in a poor galaxy group and, with a projected length of…
An XMM-Newton Observation of the Drifting Pulsar B0943+10
Pavlov, George G.; Zhang, Bing; Sanwal, Divas
Radio pulsar subpulse drifting has been interpreted as rotation of subbeams (sparks) of pair plasma produced by intermittent breakdowns of an inner vacuum gap above the pulsar polar cap. This model also predicts strong thermal X-ray emission from the polar cap caused by inflowing particles created in spark discharges. We have observed the best-stu…
Flares observed with XMM-Newton and the VLA
Audard, M.; Güdel, M.; Smith, K.
We present lightcurves obtained in X-ray by the XMM-Newton EPIC cameras and simultaneous radio lightcurves obtained with the VLA for five active M-type flare stars. A number of flare events were observed, and by comparing radio with X-ray data, we consider various possible flare mechanisms. In cases where there seems to be a clear correlation betw…
Propagation of the October/November 2003 CMEs through the heliosphere
Liu, Y.; Wang, C.; Richardson, J. D. +1 more
The solar storms of late October, early November 2003 generated many ICMEs. The Wind, ACE, Ulysses, Cassini, Voyager 2, and Voyager 1 spacecraft are distributed throughout the heliosphere and observe the effects of these ICMEs. We investigate whether these ICMEs form a global merged interaction region. WIND, ACE, and IMP 8 data are combined to pro…
Space Telescope Imaging Spectrograph Ultraviolet Spectra of Large Magellanic Cloud Planetary Nebulae: A Study of Carbon Abundances and Stellar Evolution
Gilmore, Diane; Shaw, Richard A.; Stanghellini, Letizia
We acquired spectra of 24 LMC planetary nebulae (PNs) in the 1150-3000 Å range in order to determine carbon and other ionic abundances. The sample more than doubles the number of LMC PNs with high-quality UV spectra in this wavelength range and whose optical images are available in the Hubble Space Telescope archive. The Space Telescope Imaging Sp…
Absolute magnitudes for late-type dwarf stars for Sloan photometry
Bilir, S.; Karaali, S.; Tunçel, S.
We present a new formula for absolute magnitude determination for late-type dwarf stars as a function of (g-r) and (r-i) for Sloan photometry. The absolute magnitudes estimated by this approach are brighter than those estimated by colour-magnitude diagrams, and they reduce the luminosity function rather close to the luminosity function of Hipparco…
Rapid Dissipation of Primordial Gas from the AU Microscopii Debris Disk
Weinberger, Alycia J.; Redfield, Seth; Roberge, Aki +1 more
The disk around AU Microscopii, an M1 star in the β Pictoris moving group, is extraordinarily well suited for comparison with the β Pic debris disk (type A5 V). We use far-UV absorption spectroscopy of AU Mic to probe its edge-on disk for small amounts of H2, the primary constituent of gas giant planets. Our conservative upper limit on …
Interior channels in Martian valleys: Constraints on fluvial erosion by measurements of the Mars Express High Resolution Stereo Camera
Jaumann, R.; Scholten, F.; Matz, K. -D. +12 more
In High Resolution Stereo Camera (HRSC) images of the Mars Express Mission a 130 km long interior channel is identified within a 400 km long valley network system located in the Lybia Montes. Ages of the valley floor and the surroundings as derived from crater counts define a period of ~350 Myrs during which the valley might have been formed. Base…
Physical conditions in Photo-Dissociation Regions around Planetary Nebulae
Tielens, A. G. G. M.; Bernard-Salas, J.
We present observations of the infrared fine-structure lines of [Si II] (34.8 µm), [O I] (63.2 and 145.5 µm) and [C II] (157.7 µm) obtained with the ISO SWS and LWS spectrographs of nine Planetary Nebulae (PNe). These lines originate in the Photo-Dissociation Regions (PDRs) associated with the nebulae and provide useful informati…