 |
 |
Astron. Astrophys. 359, 635-638 (2000)
A spectroscopic study of the magnetic chemically peculiar star ![[FORMULA]](img1.gif)
Fornacis
F. Leone * 1,
G. Catanzaro 2 and
S. Malaroda ** 3
1 Osservatorio Astrofisico di Catania, Città Universitaria, 95125 Catania, Italy (fleone@sunct.ct.astro.it)
2 Center for Astrophysical Sciences, The Johns Hopkins University, Department of Physics and Astronomy, Bloomberg Center, 3400 N. Charles str., Baltimore, MD 21218, USA
3 Complejo Astronómico El Leoncito, Casilla de Correo 467, 5400 San Juan, Argentina
Received 3 April 2000 / Accepted 10 May 2000
Abstract
The magnetic chemically peculiar star
![[FORMULA]](img2.gif)
Fornacis is known to be a periodic
magnetic and luminosity variable. In the framework of the Oblique
Rotator Model, For presents a mainly
dipolar magnetic field, whose symmetry axis is tilted with respect to
the rotational axis, non solar abundances and a non homogeneous
distribution of elements on the stellar surface. The variability
period is the stellar rotational period. Thus, spectral variabilities
are also expected for this star.
By analysing the Hipparcos photometry and data from the literature,
the luminosity period of For has been
found equal to 1.89232 days. This value also represents the
variability of the effective magnetic field measurements available in
the literature.
To investigate the, up to now unknown, spectroscopic behaviour of
For, we have performed time-resolved
spectroscopy of this star in the 400-600 nm range. The equivalent
widths are found to be also variable with the previous period and have
been used to derive abundances.
Phase relations, between light, spectral and magnetic variabilities have been established. According to the hypothesis that light variations are due to a non-homogeneous distribution of elements on the stellar surface and high metallicity regions are responsible for blocking of ultraviolet flux and its redistribution towards the visible wavelengths, iron is the main origin of the light variability.
Key words: stars:
abundances 
stars: chemically
peculiar
stars: individual: HD
12767
stars: magnetic fields
* Visiting astronomer, Complejo Astrónomico El Leoncito, operated under agreement between the Consejo Nacional de Investigationes Cientifícas y Técnicas (CONICET) and the National Universities of La Plata, Córdoba and San Juan
** Member of the Carrera del Investigador de la Comision de Investigaciones Cientifícas y Técnicas de la Provincia de Buenos Aires, Argentina
Send offprint requests to: F. Leone (fleone@sunct.ct.astro.it)
Contents
- 1. Introduction
- 2. Observations and data reduction
- 3. Abundances
- 4. Photometric, spectral and magnetic variability
- 5. Discussion and conclusion
- Acknowledgements
- References
© European Southern Observatory (ESO) 2000
Online publication: July 7, 2000
helpdesk@link.springer.de