Issue |
A&A
Volume 375, Number 2, August IV 2001
|
|
---|---|---|
Page(s) | 492 - 497 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20010693 | |
Published online | 15 August 2001 |
The coronal FeXXI λ1354.094 line in AB Doradus *
1
Observatory, Box 14, 00014 University of Helsinki, Finland e-mail: vilhu@astro.helsinki.fi, muhli@astro.helsinki.fi
2
SRON Laboratory for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands e-mail: R.Mewe@sron.nl
3
Tuorla Observatory, University of Turku, Finland e-mail: pahakala@astro.utu.fi
Corresponding author: O. Vilhu, osmi.vilhu@helsinki.fi
Received:
10
April
2001
Accepted:
10
May
2001
The active late-type star AB Doradus was observed in February 1996
with the Goddard High Resolution Spectrograph of the Hubble Space Telescope using the low resolution G140L grating. The observations covered one half
of the star's rotation cycle ( d) with 11.5 min time resolution.
The strong coronal FeXXI λ1354.094 line formed at 107 K was analysed
and its emission measure (EM) derived. This EM is much higher than that
derived from recent XMM-Newton observations (Güdel et al. 2001), and
earlier EXOSAT (Collier Cameron et al. 1988) and ASCA/EUVE (Mewe et al. 1996)
data, as well, requiring a variability by a factor of 5. The physical reason
for the variability remains unknown, since (outside flares) the observed
broad band variability of AB Dor is much smaller.
Key words: stars: coronae / stars: activity / stars: individual: AB Dor / ultraviolet: stars
© ESO, 2001
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