Issue |
A&A
Volume 399, Number 1, February III 2003
|
|
---|---|---|
Page(s) | 279 - 285 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20021764 | |
Published online | 05 February 2003 |
Beppo SAX observations of CF Tucanae and TY Pyxidis
1
INAF/Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
2
INAF/Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy
Corresponding author: E. Franciosini, francio@astropa.unipa.it
Received:
24
September
2002
Accepted:
14
November
2002
We present the results of BeppoSAX observations of the RS CVn binary
systems CF Tuc and TY Pyx. A long-duration flare was detected on CF Tuc just
at the beginning of the observation; a second smaller flare occurred about
half a period later. The light curve of TY Pyx shows a significant orbital
modulation of the quiescent emission with possible evidence for eclipses,
and strong flares. We find that the coronae of the two stars are very
similar: both systems have quiescent temperatures of ∼10 and 20–25
MK, with only a factor of two difference in the emission measures. During
the flares, temperatures of ∼30–40 MK are reached; these temperatures
are not high enough to give detectable hard X-ray emission in the PDS. Both
stars have subsolar coronal metallicities: we confirm the very low coronal
abundance of CF Tuc (), while for TY Pyx we find
. For both stars the coronal metallicities are in
good agreement with their measured photospheric abundances.
Key words: stars: binaries: close / stars: activity / stars: coronae / stars: individual: CF Tuc / stars: individual: TY Pyx / X-rays: stars
© ESO, 2003
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