Issue |
A&A
Volume 448, Number 3, March IV 2006
|
|
---|---|---|
Page(s) | 1165 - 1168 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361:20054238 | |
Published online | 03 March 2006 |
Search for radial velocity and magnetic field pulsational variations in the roAp star γ Equulei
1
Astrophysical Institute Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany e-mail: isavanov@aip.de
2
Crimean Astrophysical Observatory, Nauchny, Crimea, Ukraine and Isaac Newton Institute of Chile, Crimean Branch
3
European Southern Observatory, Casilla 19001, Santiago 19, Chile
4
Centre for Astrophysics, University of Central Lancashire, Preston PR1 1HE, UK
Received:
22
September
2005
Accepted:
7
December
2005
Aims.A new continuous 3.5 h series of
high-resolution spectroscopic observations of the roAp star
γ Equ, with about 12 points per pulsation cycle, is
presented to study the mean magnetic field modulus variability with the
pulsation period.Methods.Radial velocity variations with amplitudes of up to
approximately 400 m s-1 are clearly detected in the rare earth
lines present in the covered spectral range. Two frequencies are
resolved in their analysis, which are consistent with frequencies
previously observed in the star. No significant radial velocity
variation is detected for the line
. The mean magnetic field modulus
derived from measurement of the wavelength separation of the
magnetically resolved components of this line does not show any
variation, with a
upper limit of ~10 G. Results.While our results are consistent with the conclusion of the previous
studies,
difficulties to reconcile this result with those
of other works may be attributed, in part at least, to the use
of different diagnostic lines in different works and to the failure
of all studies so far to fully resolve all the pulsation frequencies
of γ Equ.
© ESO, 2006
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