Bibcode
DOI
García-Alvarez, David; Drake, Jeremy J.; Lin, LiWei; Kashyap, Vinay L.; Ball, B.
Referencia bibliográfica
The Astrophysical Journal, Volume 621, Issue 2, pp. 1009-1022.
Fecha de publicación:
3
2005
Revista
Número de citas
30
Número de citas referidas
28
Descripción
The zero-age main-sequence star AB Dor and the K dwarf component of the
V471 Tau close binary have essentially identical rotation rates and
spectral types. An analysis of their high-resolution Chandra X-ray
spectra reveals remarkably similar coronal characteristics in terms of
both temperature structure and element abundances. Both stars show
depletions of low first ionization potential (FIP) elements by factors
of ~3, with higher FIP elements showing more mild depletions. No
evidence for enhancements of very low FIP (<7 eV) elements, such as
Na, Al, and Ca, as compared to other low-FIP elements, was found. The
abundance anomaly pattern for AB Dor and V471 Tau is similar to,
although less extreme than, the abundance anomalies exhibited by active
RS CVn-type binaries. While we find statistically significant structure
in the underlying differential emission measure distributions of these
stars over narrow temperature intervals, this structure is strongly
dependent on the lines used in the analysis and is probably spurious. On
the basis of their X-ray similarities, we conclude that the exact
evolutionary state of a star has little effect on coronal
characteristics and that the parameters that dominate coronal structure
and composition are simply the rotation rate and spectral type.