1998/06/16 by D. Montes, Montes, D., Lawrence W. Ramsey +2
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9806227
Latex file with 5 figures tar'ed gzip'ed. Full postscript (text and figures) available at http://www.ucm.es/OTROS/Astrof/fgkmsl/rej0743.html Presented at the: 192nd Meeting of the AAS (June 7-11 1998), to be published in Bull. American Astron. Soc
arxiv created 1998/06/16 · openalex publication_date 1998/06/16 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We report the detection of a long-duration optical flare in the recenltly discovered, X-ray selected, chromospherically binary 2RE J0743+224. The high resolution echelle spectroscopic observations taken in 12-21th January 1998 exhibit a dramatic increase in the chromospheric emissions (Halpha and CaII IRT lines) that we interpret as a flare based on: the temporal evolution of the event, the broad component observed in the Halpha line profile, the detection of the HeI D3 in emission and a filled-in HeI 6678 A. During these obsevations we detect a LiI 6708 A line enhancement which is clearly related with the temporal evolution of the flare. The maximum LiI enhancement occurs just after the maximum chromospheric emission observed in the flare. A significant increase of the 6Li/7Li isotopic ratio is also detected. From all this we suggest that this LiI enhancement is produced by spallation reactions during the flare. This is the first time that such LiI enhancement associate with a stellar flare is reported, and probably the long-duration of this flare is a key factor for this detection. A large fraction of the stellar surface seems to be covered by starspots during the event, as we deduce for the analysis of the TiO 7055 A band. Thus taking into account that LiI line is very temperature sensitive, we can not discard that the LiI variations are related the presence of starspots. However, the correlation with the temporal evolution of the flare, lack of detection of changes in the other photospheric absorption lines, and the large changes observed in the core of the LiI, as predict the models, argue in favour of the hypothesis that the LiI is produced during the flare.