Search Publications
End-of-life disposal of high elliptical orbit missions: The case of INTEGRAL
Armellin, Roberto; San-Juan, Juan F.; Lara, Martin
Nowadays there is international consensus that space activities must be managed to minimize debris generation and risk. The paper presents a method for the end-of-life (EoL) disposal of spacecraft in high elliptical orbits (HEO). The time evolution of HEO is strongly affected by Earth's oblateness and luni-solar perturbation, and this can cause in…
Initiation of CMEs associated with filament eruption, and the nature of CME related shocks
Fainshtein, V. G.; Egorov, Ya. I.
Using data from SDO, PROBA2 and other spacecraft, Fainshtein and Egorov (2013) have discovered processes accompanying initiation of six limb CMEs and have studied features of their motion. The said CMEs occurred after eruption of prominence or hot emission loop and were associated with X-ray flares. The follow-up study of the CMEs, associated with…
Solar cycle variations in the powers and damping rates of low-degree solar acoustic oscillations
Nakariakov, V. M.; Broomhall, A. -M.; Pugh, C. E.
Helioseismology uses the Sun's natural resonant oscillations to study the solar interior. The properties of the solar oscillations are sensitive to the Sun'2019;s magnetic activity cycle. Here we examine variations in the powers, damping rates, and energy supply rates of the most prominent acoustic oscillations in unresolved, Sun-as-a-star data, o…
Doubts about the crucial role of the rising-tube mechanism in the formation of sunspot groups
Ishikawa, R.; Getling, A. V.; Buchnev, A. A.
Some preliminary processing results are presented for a dataset obtained with the Solar Optical Telescope on the Hinode satellite. The idea of the project is to record, nearly simultaneously, the full velocity and magnetic-field vectors in growing active regions and sunspot groups at a photospheric level. Our ultimate aim is to elaborate observati…
A novel sparse boosting method for crater detection in the high resolution planetary image
Wang, Yan; Yang, Gang; Guo, Lei
Impact craters distributed on planetary surface become one of the main barriers during the soft landing of planetary probes. In order to accelerate the crater detection, in this paper, we present a new sparse boosting (SparseBoost) method for automatic detection of sub-kilometer craters. The SparseBoost method integrates an improved sparse kernel …
A study of the main resonances outside the geostationary ring
Celletti, Alessandra; Galeş, Cătălin
We investigate the dynamics of satellites and space debris in external resonances, namely in the region outside the geostationary ring. Precisely, we focus on the 1:2, 1:3, 2:3 resonances, which are located at about 66 931.4 km, 87 705.0 km, 55 250.7 km, respectively. Some of these resonances have been already exploited in space missions, like XMM…
Where does the Thermospheric Ionospheric GEospheric Research (TIGER) Program go?
Schmidt, W.; Haberreiter, M.; Kretzschmar, M. +22 more
At the 10th Thermospheric Ionospheric GEospheric Research (TIGER/COSPAR) symposium held in Moscow in 2014 the achievements from the start of TIGER in 1998 were summarized. During that period, great progress was made in measuring, understanding, and modeling the highly variable UV-Soft X-ray (XUV) solar spectral irradiance (SSI), and its effects on…
How do fast impulse CMEs related to powerful flares but unrelated to eruptive filaments appear and move?
Fainshtein, V. G.; Zagainova, Iu. S.
GOES-12/SXI and SDO/AIA data were used to examine the formation and initial stage of movement for several fast pulse 'halo'-type coronal mass ejections (HCMEs) that were related to GOES M and X class flares but unrelated to solar filament eruptions. According to their formation, the HCMEs under study can be subdivided into three groups: (i) Most o…
Small-scale magnetic and velocity inhomogeneities in a sunspot light bridge
Louis, Rohan E.
High resolution spectro-polarimetric observations of a sunspot light bridge by Hinode, reveal small-scale inhomogeneities in the magnetic field and velocity. These inhomogeneities arise as a consequence of a weak, secondary lobe in the Stokes V profile which have a polarity opposite that of the sunspot and very large (>5 km s-1) Dopp…
Martian electron density profiles retrieved from Mars Express dual-frequency radio occultation measurements
Cui, J.; Zhang, S. J.; Guo, P. +4 more
The S- and X-band dual-frequency Doppler radio occultation observations obtained by the Mars Express Radio Science (MaRS) experiments are reduced in this study. A total of 414 Martian electron density profiles are retrieved covering the period from DOY 93 2004 to DOY 304 2012. These observations are well distributed over both longitude and latitud…