Search Publications
Late stages of stellar evolution - Herschel's contributions
Decin, Leen
Cool objects glow in the infrared. The gas and solid-state species that escape the stellar gravitational attraction of evolved late-type stars in the form of a stellar wind are cool, with temperatures typically ≲1500 K, and can be ideally studied in the infrared. These stellar winds create huge extended circumstellar envelopes with extents approac…
New insights into SNR evolution revealed by the discovery of recombining plasmas
Yamaguchi, Hiroya; Ozawa, Midori; Ohnishi, Takao
We report the discovery of recombining plasmas in three supernova remnants (SNRs) with the Suzaku X-ray astronomy satellite. During SNR's evolution, the expanding supernova ejecta and the ambient matter are compressed and heated by the reverse and forward shocks to form an X-ray emitting hot plasma. Since ionization proceeds slowly compared to sho…
Quasi-periodic frequency fluctuations observed during coronal radio sounding experiments 1991-2009
Pätzold, M.; Bird, M. K.; Efimov, A. I. +5 more
Coronal radio sounding experiments were carried out using the dual-frequency signals of the spacecraft Ulysses, Galileo, Mars Express, Venus Express, and Rosetta. The change in differential frequency recorded at the NASA and ESA ground stations, a quantity sensitive only to the plasma along the radio ray path from spacecraft to receiver, has been …
Solar and interplanetary parameters of CMEs with and without type II radio bursts
Moon, Y. -J.; Shanmugaraju, A.; Umapathy, S. +1 more
We have analyzed 101 CMEs, and their associated ICMEs and interplanetary (IP) shocks observed during the period 1997-2005. The main aim of the present work is to study the interplanetary characteristics of metric and DH type II associated CMEs such as, shock strength, IP shock speed, ICME speed, stand off distance and transit time. Among these 101…
Application of electrical propulsion for an active debris removal system: a system engineering approach
Covello, Fabio
One of the main challenge in the design of an active removal system for space debris is the high ΔV required both to approach space debris lying in different orbits and to de-orbit/re-orbit them. Indeed if the system does not target a number of objects during its lifetime the cost of the removal will be far too high to be considered as the basis o…
Particle acceleration and gamma rays in solar flares: Recent observations and new modeling
Gan, W. Q.; Miroshnichenko, L. I.
Experiments on SMM, GAMMA, Yohkoh, GRANAT, Compton GRO, INTEGRAL, RHESSI and CORONAS-F satellites over the past three decades have provided copious data for fundamental research relating to particle acceleration, transport and energetics of flares and to the ambient abundance of the solar corona, chromosphere and photosphere. We summarize main res…
The first results from the Herschel-HIFI mission
van der Tak, Floris
This paper contains a summary of the results from the first years of observations with the HIFI instrument onboard ESA's Herschel space observatory. The paper starts by outlining the goals and possibilities of far-infrared and submillimeter astronomy, the limitations of the Earth's atmosphere, and the scientific scope of the Herschel-HIFI mission.…
Solar cycle and latitude dependence of high-beta suprathermal plasma conditions in interplanetary space between 1.3 and 5.4 AU
Marhavilas, Panagiotis K.
The analysis of energetic particles and magnetic field measurements from the Ulysses spacecraft has shown that in a series of events, the energy density contained in the suprathermal tail particle distribution is comparable to or larger than that of the magnetic field, creating conditions of high-beta plasma. In this work we analyze periods of hig…
Synoptic magnetic field in cycle 23 and in the beginning of the cycle 24
Benevolenskaya, E. E.; Ponyavin, Yu. D.
The SOHO/MDI data provide the uniform time series of the synoptic magnetic maps which cover the period of the cycle 23 and the beginning of the cycle 24. It is very interesting period because of the long and deep solar minimum between the cycles 23 and 24. Synoptic structure of the solar magnetic field shows variability during solar cycles. It is …
MHD simulation of magnetic field configuration above the active region NOAA 10365
Podgorny, I. M.; Podgorny, A. I.
The current sheet (CS) creation before a flare in the vicinity of a singular line above the active region NOAA 10365 is shown in numerical experiments. Such a way the possibility of energy accumulation for a solar flare is demonstrated. These data and results of observation confirm the electrodynamical solar flare model that explains solar flares …