2003A&A...411..587V -
Astronomy and Astrophysics, volume 411, 587-593 (2003/12-1)
AD Leonis: Flares observed by XMM-Newton and Chandra.
VAN DEN BESSELAAR E.J.M., RAASSEN A.J.J., MEWE R., VAN DER MEER R.L.J., GUEDEL M. and AUDARD M.
Abstract (from CDS):
The 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 OVII and NeIX, 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.
Abstract Copyright:
∼
Journal keyword(s):
stars: individual: AD Leonis - stars: coronae - stars: flare - X-rays: stars - missions: XMM-Newton, Chandra
Simbad objects:
3
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2003A&A...411..587V and select 'bookmark this link' or equivalent in the popup menu