AD Leonis: Flares observed by XMM-Newton and Chandra

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dc.creatorBesselaar, E. J. M. van den
dc.creatorRaassen, A. J. J.
dc.creatorMewe, R.
dc.creatorvan der Meer, R. L. J.
dc.creatorGuedel, M.
dc.creatorAudard, M.
dc.date2003-09-11
dc.date.accessioned2026-07-07T02:09:31Z
dc.date.available2026-07-07T02:09:31Z
dc.descriptionThe M-dwarf AD Leonis has been observed with the Reflection Grating Spectrometers and the European Photon Imaging Camera aboard XMM-Newton and also with the Low Energy Transmission Grating Spectrometer aboard the Chandra X-ray Observatory. In the observation taken with XMM-Newton five large flares produced by AD Leo were identified and only one in the observation taken with Chandra. A quiescent level to the lightcurves is difficult to define, since several smaller flares mutually overlap each other. However, we defined a quasi-steady state outside of obvious flares or flare decays. The spectra from the flare state and the quasi-steady state are analysed separately. From these spectra the temperature structure was derived with a multi-temperature model and with a differential emission measure model. The multi-temperature model was also used to determine the relative abundances of C, N, O, Ne, Mg, Si, S, and Fe. He-like ions, such as O VII and Ne IX, produce line triplets which are used to determine or constrain the electron temperature and electron density of the corresponding ion. During the flare state a higher emission measure at the hottest temperature is found for both XMM-Newton and Chandra observations. The derived abundances suggest the presence of an inverse First Ionization Potential effect in the corona of AD Leo.
dc.description8 pages and 7 figures. Accepted for publication in Astronomy & Astrophysics
dc.identifierhttps://arxiv.org/abs/astro-ph/0309315
dc.identifierhttp://arxiv.org/abs/astro-ph/0309315
dc.identifierAstron.Astrophys. 411 (2003) 587
dc.identifierdoi:10.1051/0004-6361:20031398
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/6461
dc.subjectAstrophysics
dc.titleAD Leonis: Flares observed by XMM-Newton and Chandra
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