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Astron. Astrophys. 364, 179-190 (2000)


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Spots and plages on a young main-sequence solar-type star: HD 206860 *

A. Frasca 1, R. Freire Ferrero 2, E. Marilli 1 and S. Catalano 1

1 Osservatorio Astrofisico di Catania, via S. Sofia 78, 95125 Catania, Italy
2 Observatoire Astronomique, 11 rue de l'Université, 67000 Strasbourg, France

Received 20 June 2000 / Accepted 18 October 2000

Abstract

The young solar type star HD 206860 is known to be a photometric variable with emission in the core of Ca II H & K lines, several times more intense than the Sun when observed as a star.

The photometric and spectroscopic monitoring of HD 206860 from near contemporaneous observations at Serra La Nave (Catania, Italy) and at the Observatoire de Haute Provence (OHP, France) shows that chromospheric spectral-line flux and photometric variations follow the same period (4.74 days).

From Strömgren photometry and Ca II and H[FORMULA] chromospheric emission clearly anti-correlated variations have been found.

This result suggests that spots and plages in this single solar-type star are spatially associated, as frequently observed for the largest sun-spot groups and for some very active RS CVn systems.

A spot/plage model applied to the observed flux curves allows a crude reconstruction of the 3D structure of the external atmosphere of this star.

Key words: stars: activity – stars: individual: HD 206860

* Based on observations collected at the Observatoire de Haute Provence (CNRS), France, and at the Osservatorio Astrofisico di Catania, Italy

Send offprint requests to: A. Frasca (afr@sunct.ct.astro.it)

© European Southern Observatory (ESO) 2000

Online publication: December 15, 2000

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