Astron. Astrophys. 359, 159-167 (2000)

Rotational modulation and flares on RS CVn and BY Dra stars

XX. Photometry and spectroscopy of CC Eri in late 1989

P.J. Amado ¹, J.G. Doyle ¹, P.B. Byrne  ^* , G. Cutispoto ², D. Kilkenny ³, M. Mathioudakis ⁴ and J.E. Neff <sup>5

1</sup> Armagh Observatory, College Hill, Armagh BT61 9DG, Ireland
² Catania Astrophysical Observatory, Viale A. Doria, 6. 95125 Catania, Italy
³ South African Astronomical Observatory, P.O. Box 7, Observatory 7935, South Africa
⁴ Queens University of Belfast, Department of Pure and Applied Physics, Belfast BT7 1NN, Ireland
⁵ College of Charleston, Department of Physics and Astronomy, Charleston, SC 29424, USA

Received 12 November 1999 / Accepted 14 April 2000

Abstract

The active flaring binary CC Eri was studied via multi-wavelength observations involving multi-based photometry and ground- and space-based spectroscopy. Combining early spectroscopic data with the present implies an orbital period of  days. Furthermore, the spectroscopic data suggests spectral types of K7 and M3 for the system. The optical photometry indicated a small spot coverage in late 1989, consistent with data taken a year later which showed CC Eri entering its brightest-to-date phase.

Two flares were detected in the ultraviolet spectral data. These flares radiated erg and erg in the CIV line alone, each with a total estimated radiative energy budget of erg. For the higher-temperature lines, such as CIV , there was no systematic variability with phase. The lower-temperature lines show a slight indication of rotational modulation. However, there is a much larger scatter in the individual measurements of the MgII and CIV fluxes than would be expected from measurement errors alone, consistent with an atmosphere showing continual small-scale activity.

Key words: stars: activity stars: binaries: spectroscopic stars: chromospheres stars: individual: CC Eri stars: late-type ultraviolet: stars

* Deceased

Present address: Instituto de Astrofísica de Andalucía-CSIC, Apartado 3004, 18080 Granada, Spain (pja@iaa.es)

Send offprint requests to: P.J. Amado

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observational data
  • 2.1. Photometry
    • 2.1.1. Photometry-European Southern Observatory
    • 2.1.2. Photometry-South African Astronomical Observatory
  • 2.2. Optical spectroscopy
  • 2.3. UV spectroscopy
  • 2.4. EUVE Fluxes
• 3. Results
  • 3.1. Contemporaneous optical photometry
  • 3.2. Orbit and system parameters
  • 3.3. Emission line fluxes
  • 3.4. Flares
• 4. Discussion and conclusions
  • 4.1. Physical parameters of the binary system from the orbital solution
  • 4.2. Spot distribution
  • 4.3. Ultraviolet line fluxes and evidence for rotational modulation
  • 4.4. Emission measure and quiescent radiative losses
  • 4.5. Flares
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: June 30, 2000
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