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First results from UVCS/SOHO |
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| Authors: | G Noci JL Kohl E Antonucci G Tondello MCE Huber S Fineschi LD Gardner G Naletto P Nicolosi JC Raymond M Romoli D Spadaro OHW Siegmund C Benna A Ciaravella S Giordano J Michels A Modigliani A Panasyuk C Pernechele G Poletto PL Smith L Strachan |
| Institution: | a Dipartimento di Astronomia e Scienza dello Spazio, Universitá di Firenze, I-50125, Firenze, Italy b Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, U.S.A. c Osservatorio Astronomico di Torino, I-10025, Pino Torinese, Italy d Dipartimento di Elettronica e Informatica, Universitá di Padova, I-35131, Padova, Italy e Space Science Department, ESA/ESTEC, NL-2200 AG, Noordwijk, The Netherlands f Osservatorio Astrofisico di Catania, I-95125, Catania, Italy g Osservatorio Astrofisico di Arcetri, I-50125, Firenze, Italy h Space Science Laboratory, University of California, Berkeley, CA 94720, U.S.A. |
| Abstract: | We present here the first results obtained by the Ultraviolet Coronagraph Spectrometer (UVCS) operating on board the SOHO satellite. The UVCS started to observe the extended corona at the end of January 1996; it routinely obtains coronal spectra in the 1145 Å – 1287 Å, 984 Å – 1080 Å ranges, and intensity data in the visible continuum. Through the composition of slit images it also produces monocromatic images of the extended corona. The performance of the instrument is excellent and the data obtained up to now are of great interest. We briefly describe preliminary results concerning polar coronal holes, streamers and a coronal mass ejection, in particular: the very large r.m.s. velocities of ions in polar holes (hundreds km/sec for OVI and MgX); the puzzling difference between the HI Ly- image and that in the OVI resonance doublet, for most streamers; the different signatures of the core and external layers of the streamers in the width of the ion lines and in the OVI doublet ratio, indicating larger line-of-sight (l.o.s.) and outflow velocities in the latter. |
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