Search Publications
Fast Mid-IR Flashes Detected During Small Solar X-Ray Bursts
Kaufmann, Pierre; Marcon, Rogério; Godoy, Rodolfo +6 more
Solar observations in the mid-infrared 8 - 14 µm band continuum were carried out with cadence of 5 frames per second, in December 2007. Rapid small heated sources, with a typical duration of the order of seconds, were found on the bright plage-like areas around sunspots, in association with relatively weak GOES soft X-ray bursts. This work p…
Structures and Intermittency in Small Scales Solar Wind Turbulence
Sahraoui, Fouad; Goldstein, Melvyn
Several observations in space plasmas have reported the presence of coherent structures at different plasma scales. Structure formation is believed to result from nonlinear interactions between the plasma modes, which depend strongly on their phase synchronization. Despite this important role of the phases in turbulence, very limited work has been…
Gnevyshev Peaks in the CME Average Speeds in Cycle 23
Kane, R. P.
Sunspots have a major 11-year cycle, but the three to four years near the maximum may show two or more peaks called Gnevyshev peaks. Earlier, it was reported that in Solar Cycle 23, the double peak in sunspot numbers was reflected in the electromagnetic radiations and coronal mass ejection (CME) frequencies in the solar atmosphere, but with phase …
Reconstruction of nonmonotonic electron density profiles of the Martian topside ionosphere
Wang, X. -D.; Zou, H.; Wang, J. -S. +1 more
One of the problems in reconstructing the real ionosphere from an ionogram is the occurrence of a 'valley,' where electron density decreases with altitude and make a non-monotonic profile. For the case of the Earth ionosphere, the ordinary and extraordinary ray data, accompanied with an empirical model, based on the observations, are necessary to …
Fractal dissipation of small-scale magnetic fluctuations in solar wind turbulence as seen by CLUSTER
Khotyaintsev, Y.; Sahraoui, F.; Chapman, S. +2 more
A robust multiscale analysis of high-frequency magnetic field measurements from the Cluster spacecraft is presented using complimentary measurements from the magnetometer and search-coil instruments; in a stationary interval of fast ambient solar wind. We show a surprising and novel result: that for time-scales smaller than the ion-gyro period the…
Orbits of new Hipparcos binaries: III
Balega, Yu. Yu.; Balega, I. I.; Malogolovets, E. V.
We present apparent orbits and fundamental parameters of three pairs of early M-type dwarfs. The orbital elements are determined from speckle interferometric observations at the 6-m BTA telescope of the Special Astrophysical Observatory. The orbits of two pairs, HIP39402 and HIP 104565 are built for the first time. The orbit of HIP106972 is revise…
Venus Express: The presence of turbulence in the mesosphere of venus is confirmed
Izakov, M. N.
Among the numerous and valuable results obtained from the Venus Express spacecraft, information from several instruments suggests that turbulence is present in the mesosphere. In this paper, the results of these experiments are interpreted with the use of the available data on turbulence in planetary atmospheres. Accounting for turbulence is neces…
A Survey of IUE Spectra of the Active Binary System UX Arietis
Ekmekçi, Fehmi
To investigate the ultraviolet (UV) activity of the bright, non-eclipsing, double-lined spectroscopic binary system UX Ari, IUE spectra (194 images) were taken from the IUE archive. The spectra, obtained during the period 1978-1996, show emission lines originating in the chromosphere and transition region. The long-wavelength low dispersion spectr…
VLT observations of the middle-aged pulsar PSR B1055-52
Mignani, R. P.; Jackson, A. C.; Spiers, A.
Context. The 535 kyear old radio pulsar B1055-52 is the oldest of the “Three Musketeers”, the group of the middle-aged pulsars (the other two being PSR B0656+14 and Geminga) with bright soft X-ray and high-energy γ-ray emission. The identification of its optical counterpart has been only recently confirmed through observations performed with the H…
Quasi-periodic Fluctuations Detected in Mars Express Coronal Radio Sounding Observations
Pätzold, M.; Bird, M. K.; Tellmann, S. +5 more
Spectral analysis of the high-quality dual-frequency data obtained with the radio sounding experiment MaRS on the ESA spacecraft Mars Express has revealed a quasi-periodic component (QPC) at heliocentric distances from 4 to 10 solar radii. The QPC typically appears as a broad maximum in the temporal frequency fluctuation spectrum centered at a fre…