Guillermo Stenborg
Max Planck Society
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Featured researches published by Guillermo Stenborg.
The solar wind nine conference | 1999
N. Srivastava; R. Schwenn; Bernd Inhester; Guillermo Stenborg; Borut Podlipnik
We present observations of slowly evolving, balloon-type solar mass ejections observed by the LASCO coronagraphs aboard SOHO. These mass ejections are typically observed to rise gradually in the solar corona for several hours (>20 hours) as large loops or balloons crossing the entire field of view of the coronagraphs. Usually, their angular extent does not change much. Analysis of several such cases of balloon-type mass ejections show that they rise with very slow speeds (less than 50 km s−1) up to a distance of 2 R⊙ and then are accelerated to higher speeds until 5 R⊙. From a distance of about 20 R⊙, the mass ejecta attain almost a constant speed ranging between 300 and 500 km s−1. The speed profiles obtained for individual mass ejections indicate that they trace out the slow solar wind and, thus, provide an insight into the initiation and the propagation of the CMEs into the solar wind.
Space Science Reviews | 1999
N. Srivastava; R. Schwenn; Bernd Inhester; Guillermo Stenborg; Borut Podlipnik
The slow solar wind (< 400 km s-1) appears to initiate from the regions in the corona where magnetic fields are closed, or from the interface between streamers and other coronal regions. The nature of the acceleration of slow solar wind is not yet well known. LASCO observations of gradually evolving mass ejections offer us a good opportunity to study the speed and acceleration profiles of the slow solar wind from a distance of 1.1 up to 30 R⊙. We present speed and acceleration profiles of slow solar wind, derived on the basis of measurements of mass flows in several cases of gradual mass ejections and present them in perspective of earlier work.
The solar wind nine conference | 1999
Bernd Inhester; Guillermo Stenborg; R. Schwenn; N. Srivastava; B. Podlipnik
We investigate the periodicity and recurrence of FeXIV and FeX emission structures with heliospheric latitude and distance above the Sun’s surface. The data was observed by the LASCO C1 coronagraph on board the SOHO spacecraft during the solar minimum activity from April 1996 to March 1997. For the green FeXIV emission line, reliable estimates of the solar rotation period could be obtained between −60 and 60 degrees in latitude and between 1.1 and 2 solar radii. Our investigation confirms the results of (3) of an almost ridgidly rotating equatorial streamer belt with a rotation period of about 27.5±0.5 days. Even coronal emissivity structures with a shorter life time between 14 and 27 days do not seem to rotate differentially. The FeX observations on the other hand do yield some indication of a reduced rotation for coronal structures over the solar poles. However, the error of the derived rotation period estimates is considerable so that the analysis of the FeX data does not allow a definite conclusion.
The solar wind nine conference | 1999
Guillermo Stenborg; R. Schwenn; N. Srivastava; Bernd Inhester; B. Podlipnik; M. Rovira; C. Francile
As part of the new German-Argentinian Solar-Observatory in El Leoncito, San Juan, Argentina, a new ground-based solar telescope (MICA: Mirror Coronagraph for Argentina) began to operate in August 1997. MICA is an advanced mirror coronagraph, its design being an almost exact copy of the LASCO-C1 instrument. Since its installation, it has been imaging the inner solar corona (1.05 to 2.0 solar radii) in two spectral ranges, corresponding to the emission lines of the Fe XIV and Fe X ions. The instrument can image the corona as fast as every minute. Thus, it is ideally suited to study fast processes in the inner corona. In this way it is a good complement for the LASCO-C1 instrument. We present a brief review of the characteristics of the instrument, and some recent observations.
Space Science Reviews | 1999
Guillermo Stenborg; R. Schwenn; N. Srivastava; Bernd Inhester; Borut Podlipnik; M. Rovira; C. Francile
Solar Physics | 2004
Andrea Costa; Guillermo Stenborg
Archive | 1999
Guillermo Stenborg; R. Schwenn; Bernd Inhester; N. Srivastava
Archive | 1999
N. Srivastava; R. Schwenn; Guillermo Stenborg
Ciencia Hoy | 2003
Luciano Rodriguez; Guillermo Stenborg
Space Science Reviews | 1999
Bernd Inhester; Guillermo Stenborg; R. Schwenn; N. Srivastava; B. Podlipnik