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Astron. Astrophys. 342, 709-716 (1999)

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The radio spectrum of Algol-type systems: RZ Cassiopeiae

G. Umana 1, P. Leto 1,4, C. Trigilio 1, R.M. Hjellming 2 and S. Catalano 3

1 Istituto di Radioastronomia del C.N.R., Stazione VLBI di Noto, C.P. 141 Noto, Italy
2 National Radio Astronomy Observatory, Socorro, NM, USA
3 Osservatorio Astrofisico di Catania, Viale A. Doria 6, I-95125 Catania, Italy
4 Universitá degli studi di Messina, Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, Salita Sperone 31, I-98166 Messina, Italy

Received 4 March 1997 / Accepted 21 October 1998


We present multifrequency radio observations of the Algol-type binary system RZ Cas, performed in different epochs from 1991 October to 1992 April. During this period the system shows variability in the radio flux that cannot be attributed to geometrical effects due to a partial eclipse of the radio source.

Instead, differences between radio spectra can be reproduced assuming a core-halo morphology for the radio source, where physical conditions vary as a consequence of magnetic activity. Almost simultaneous X-ray observations, carried out by other authors, allow to further constrain the physical parameters of the radio emitting region and are consistent with a co-spatial model for the X-ray and radio emitting source.

Key words: stars: activity – stars: binaries: close – stars: coronae – stars: individual: RZ Cas – radio continuum: stars

Send offprint requests to: G. Umana (umana@ira.noto.cnr.it)

© European Southern Observatory (ESO) 1999

Online publication: February 23, 1999