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Coronal activity cycles in 61 Cygni
Schmitt, J. H. M. M.; Robrade, J.; Favata, F. +3 more
Context: .While the existence of stellar analogues of the 11 years solar activity cycle is proven for dozens of stars from optical observations of chromospheric activity, the observation of clearly cyclical coronal activity is still in its infancy.
Aims: .In this paper, long-term X-ray monitoring of the binary 61 Cygni is used to investigate p…
Probing the Dust Responsible for Small Magellanic Cloud Extinction
Gordon, Karl D.; Sofia, Ulysses J.; Clayton, Geoffrey C. +4 more
We explore the abundances and depletion levels of elements important to dust composition in four Small Magellanic Cloud (SMC) sight lines observed with the Hubble Space Telescope. The apparent optical depth method is used to interpret the high-resolution ultraviolet absorption data toward AzV 18, AzV 456, Sk 108, and Sk 155; the latter two sight l…
An Asymmetric Outflow from the Herbig Ae Star HD 163296
Bruhweiler, F. C.; Grady, C. A.; Kimble, R. A. +2 more
We present an observational picture of the HH 409 bipolar outflow including the detection of six previously unreported Herbig-Haro knots from the Herbig Ae star HD 163296. This study combines seven years of data from ground-based Fabry-Pérot and HST coronagraphic imagery, as well as HST long-slit spectral imagery. The redshifted counterjet include…
Mapping of Titan: Results from the first Titan radar passes
Lorenz, R. D.; Soderblom, L. A.; Stiles, B. +33 more
The first two swaths collected by Cassini's Titan Radar Mapper were obtained in October of 2004 (Ta) and February of 2005 (T3). The Ta swath provides evidence for cryovolcanic processes, the possible occurrence of fluvial channels and lakes, and some tectonic activity. The T3 swath has extensive areas of dunes and two large impact craters. We inte…
Solar control of radar wave absorption by the Martian ionosphere
Gurnett, D. A.; Morgan, D. D.; Plaut, J. J. +6 more
The MARSIS active sounder aboard the Mars Express spacecraft, under certain conditions in the Martian ionosphere, fails to detect the planetary surface. We have generated a statistical measure of the surface reflection visibility, which we plot as a time series and compare with both in situ particle data taken at Mars and solar x-ray data taken at…
XMM-Newton observations of the black hole X-ray transient XTE J1650-500 in quiescence
Homan, Jeroen; Miller, Jon M.; Belloni, Tomaso +4 more
We report the result of an XMM-Newton observation of the black hole X-ray transient XTE J1650-500 in quiescence. The source was not detected, and we set upper limits on the 0.5-10 keV luminosity of 0.9-1.0 × 1031 ergs-1 (for a newly derived distance of 2.6 kpc). These limits are in line with the quiescent luminosities of blac…
The Current-Free Electric Double Layer in a Coronal Magnetic Funnel
Marsch, Eckart; Boswell, Roderick W.; Charles, Christine
Current-free double layers (CFDLs) have been recently discovered in a number of laboratory devices, when a low collisional plasma is forced to expand from a high magnetic field source region to a low magnetic field diffusion region. This experimental setup bears a striking resemblance to the natural conditions prevailing in the magnetic funnels of…
Electron Density Modeling of a Streamer Using LASCO Data of 2004 January and February
Thernisien, A. F.; Howard, R. A.
We present a three-dimensional reconstruction of the electron density of a streamer using a newly developed forward modeling technique. The streamer was observed by SOHO LASCO continuously at the end of 2004 January, but for this study we consider two dates, about 7 days apart. On the first day the streamer was seen ``edge-on,'' in which the coron…
Nature of Nuclear Rings in Unbarred Galaxies: NGC 7742 and NGC 7217
Moiseev, A. V.; Sil'chenko, O. K.
We have studied an unbarred Sb galaxy with a nuclear star-forming ring, NGC 7742, by means of two-dimensional spectroscopy, long-slit spectroscopy, and imaging and have compared the results with the properties of another galaxy of this type, NGC 7217, which was studied by us earlier. Both galaxies have many peculiar features in common: each has tw…
The May 13, 2005 Eruption: Observations, Data Analysis and Interpretation
Liu, C.; Yurchyshyn, V.; Abramenko, V. +1 more
In this study, we present detailed description and analysis of the May 13, 2005 eruption, the corresponding coronal mass ejection (CME) and intense geomagnetic storm observed near the Earth on May 15, 2005. This isolated two-ribbon M8.0 flare and the very fast CME occurred in a relatively simple magnetic configuration during a quiet period of sola…