Flare observation of the Sun as a star by SUMER/SOHO in the hydrogen Lyman continuum

TitleFlare observation of the Sun as a star by SUMER/SOHO in the hydrogen Lyman continuum
Publication TypeJournal Article
Year of Publication2004
AuthorsLemaire, P., Gouttebroze P., Vial J.-C., Curdt W., Schühle U., and Wilhelm K.
JournalAstronomy and Astrophysics
Volume418
Pagination737-742
Date PublishedMay
Abstract

During the execution of the programme ``Sun as a star'', while the SUMER (Solar Ultraviolet Emission of Emitted Radiation)/SOHO (SOlar and Heliospheric Observatory) slit was collecting the scattered radiation from the telescope mirror far away from the solar disk image, a class X5.3/3b flare erupted on the solar disk, on 25 August 2001. During the first phase of the flare a relative increase of a few percent was detected at the head of the hydrogen Lyman continuum. After correction from the instrumental parameters, the relative signal increase is 70% at the head of the Lyman continuum (910 Å), and 190% in the C II 904 Å multiplet. Accounting for the area of the flare region, the local increase of the radiance of the Lyman continuum and of the C II lines is estimated to be a factor of several thousands. We compare this result with other solar observations and models. Appendix A is only available in electronic form at http://www.edpsciences.org

DOI10.1051/0004-6361:20034405