Search Publications
Gnevyshev Peaks and Gaps for Coronal Mass Ejections of Different Widths Originating in Different Solar Position Angles
Kane, R. P.
The sunspot number series at the peak of sunspot activity often has two or three peaks (Gnevyshev peaks; Gnevyshev, Solar Phys.1, 107, 1967; Solar Phys.51, 175, 1977). The sunspot group number (SGN) data were examined for 1997 - 2003 (part of cycle 23) and compared with data for coronal mass ejection (CME) events. It was noticed that they exhibite…
Resolving Spacecraft Earth-Flyby Anomalies with Measured Light Speed Anisotropy
Cahill, Reginald T.
Doppler shift observations of spacecraft, such as Galileo, NEAR, Cassini, Rosetta and MESSENGER in earth flybys, have all revealed unexplained speed `anomalies' - that the doppler-shift determined speeds are inconsistent with expected speeds. Here it is shown that these speed anomalies are not real and are actually the result of using an incorrect…
Tailward propagation of Pi2 waves in the Earth's magnetotail lobe
Balogh, A.; Nakamura, R.; Baumjohann, W. +3 more
Pi2 waves are an intergral part of the substorm process and have been observed on the ground and in space. Using the special ability of Cluster to determine the propagation direction of signals measured in the magnetometer data, it is found that in the lobes of the Earth's magnetotail, for the cases in this study, the Pi2 waves are travelling tail…
Unveiling the nature of RXJ0002+6246 with XMM-Newton
Caraveo, P. A.; Tiengo, A.; de Luca, A. +3 more
The X-ray source RXJ0002+6246 was discovered close to the supernova remnant CTB1 in a ROSAT observation performed in 1992. The source phenomenology (soft spectrum, apparent lack of counterparts, possible pulsations at 242 ms, hints for surrounding diffuse emission) led to interpret it as an isolated neutron star in a new supernova remnant. We have…
Huygens probe entry dynamic model and accelerometer data analysis
Colombatti, Giacomo; Aboudan, Alessio; Ferri, Francesca +1 more
During the first phase of Huygens arrival into Titan's atmosphere the probe is subjected to gravitational and aerodynamic forces in aerodynamic hypersonic regime. Atmospheric drag exerts a strong deceleration on the capsule measured by Huygens atmospheric structure instrument (HASI) servo accelerometer. A 6 DOF (Degree of Freedom) model of the Huy…
XMM-Newton Observations of NGC 4051: Temporal Flux and Spectral Variability during Transition to the Faintest Phase in NGC 4051
Tsuruta, Sachiko; Liebmann, Andrew C.; Kunieda, Hideyo +2 more
We report on the results from temporal and spectral analyses of NGC 4051 observed with XMM-Newton. The X-ray variabilities in the higher-flux states are well explained by the combination of a variable, direct power law and a temporally stable, absorbed component. In low-flux states, however, spectral variations are mainly due to flux changes of th…
The Venus ground-based image Active Archive: A database of amateur observations of Venus in ultraviolet and infrared light
Barentsen, Geert; Koschny, Detlef
The Venus ground-based image Active Archive is an online database designed to collect ground-based images of Venus in such a way that they are optimally useful for science. The Archive was built to support ESA's Venus Amateur Observing Project, which utilizes the capabilities of advanced amateur astronomers to collect filtered images of Venus in u…
Development of thermal sensors and drilling systems for lunar and planetary regoliths
Kaufmann, E.; Kargl, G.; Gao, Yang +2 more
We consider some novel concepts for thermal properties experiments aboard lunar landers or rovers, that may lead to an improved understanding of both the structure of the lunar near surface layers and the lunar thermal history. The new instruments could be developed using the experience and heritage from recently developed systems, like the Rosett…
A Model for the Chromosphere/Wind of 31 Cygni and Its Implications for Single Stars
Eaton, Joel A.
I develop a detailed empirical model for the chromosphere and wind of 31 Cyg based on a previously published analysis of International Ultraviolet Explorer spectra from the 1993 eclipse and on the thermodynamics of how the wind must be driven. I then use this model to interpret observations of single supergiant stars and to assess the evidence tha…
First High Solar Phase Angle Observations of Rhea Using Cassini VIMS: Upper Limits on Water Vapor and Geologic Activity
Brown, R. H.; Buratti, B. J.; Nicholson, P. D. +5 more
Using radiances acquired with Cassini's Visual and Infrared Mapping Spectrometer (VIMS), we construct high solar phase angle curves for Saturn's second largest moon, Rhea. Ground-based studies of Rhea and Saturnian icy satellites are focussing on low phase angles; to our knowledge, these are the first solar phase curve data for Rhea on phase angle…