Volume 394, Number 2, November I 2002
|Page(s)||653 - 661|
|Section||Stellar structure and evolution|
|Published online||15 October 2002|
The EUVE point of view of AD Leo
INAF – Osservatorio Astronomico di Palermo G. S. Vaiana, Piazza del Parlamento, 1, Palermo, 90134, Italy
Corresponding author: J. Sanz-Forcada, firstname.lastname@example.org
Accepted: 8 August 2002
All the Extreme Ultraviolet Explorer (EUVE) observations of AD Leo, totalling 1.1 Ms of exposure time, have been employed to analyze the corona of this single M dwarf. The light curves show a well defined quiescent stage, and a distribution of amplitude of variability following a power law with a ~-2.4 index. The flaring behavior exhibits much similarity with other M active stars like FK Aqr or YY Gem, and flares behave differently from late type active giants and subgiants. The Emission Measure Distribution (EMD) of the summed spectrum, as well as that of quiescent and flaring stages, were obtained using a line-based method. The average EMD is dominated by material at log T(K) ~ 6.9, with a second peak around log T(K) ~ 6.3, and a large increase in the amount of material with log T(K) 7.1 during flares, material almost absent during quiescence. The results are interpreted as the combination of three families of loops with maximum temperatures at log T(K) ~ 6.3, ~6.9 and somewhere beyond log T(K) 7.1. A value of the abundance of [Ne/Fe] = 1.05 ± 0.08 was measured at log T(K) ~ 5.9. No significative increment of neon abundance was detected between quiescence and flaring states.
Key words: stars: coronae / stars: individual: AD Leo / X-rays: stars / stars: late-type / stars: flare / stars: low mass
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.