Abstract Thanks to the launch of SOHO in the end of 1995 and to the continuous monitoring of the white light (WL) corona offered by the LASCO coronagraphs, it was discovered that sungrazing comets are much more common than previously thought. More than 2800 comets have been discovered so far over nearly 20years, hence slightly less than a comet every 2days is observed by coronagraphs. The WL emission seen by SOHO/LASCO and more recently also by the STEREO/SECCHi instruments provides information not only on the comet orbits (hence on their origin), but also on the dust-tail formation, dust-tail disconnection, occurrence of nucleus fragmentation and nucleus disintegration processes. Very interestingly, a few sungrazing comets have also been observed spectroscopically in the UV by the SOHO UV Coronagraph Spectrometer (UVCS), and the strong emission observed in the Hi Lyman- α 1216Å line provides direct information also on the water outgassing rate, tail chemical composition, nucleus size, and occurrence of nucleus fragmentation. Moreover, the UV cometary emission provides a new method to estimate physical parameters of the coronal plasma met by the comet (like electron density, proton temperature and solar wind velocity), so that these comets can be considered as “local probes” for the solar corona. Unique observations of comets will be provided in the near future by the METIS coronagraph on board the Solar Orbiter mission: METIS will simultaneously observe the corona in WL and in UV (Hi Lyman- α ), hence it will be a unique instrument capable of studying at the same time the transiting comets and the solar corona. Previous results and new possibilities offered by METIS on these topics are summarized and discussed here.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Study of sungrazing comets with space-based coronagraphs: New possibilities offered by METIS on board Solar Orbiter


    Beteiligte:
    Bemporad, A. (Autor:in) / Giordano, S. (Autor:in) / Raymond, J.C. (Autor:in) / Knight, M.M. (Autor:in)

    Erschienen in:

    Advances in Space Research ; 56 , 10 ; 2288-2297


    Erscheinungsdatum :

    2015-08-30


    Format / Umfang :

    10 pages




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch





    Sungrazing comets as solar probes and dust analyzers

    Huebner, W.F. | Online Contents | 2007


    Sungrazing comets as solar probes and dust analyzers

    Huebner, W.F. / Boice, D.C. / Schwadron, N.A. | Elsevier | 2006


    METIS-ESA solar orbiter mission internal straylight analysis

    Verroi, E. / Da Deppo, V. / Naletto, G. et al. | SPIE | 2017

    Freier Zugriff

    In-flight calibration of Metis coronagraph on board of Solar Orbiter

    Liberatore, A. / Fineschi, S. / Casti, M. et al. | British Library Conference Proceedings | 2021