Hostname: page-component-669899f699-rg895 Total loading time: 0 Render date: 2025-04-24T23:20:11.662Z Has data issue: false hasContentIssue false
  • English
  • Français

A Multiwavelength Study of CC Eridani

Published online by Cambridge University Press:  05 March 2013

O. B. Slee ,
E. Budding ,
B. D. Carter ,
M. W. Mengel ,
I. Waite  and
J.-F. Donati
O. B. Slee
Affiliation:
Australia Telescope National Facility, PO Box 76, Epping NSW 2121, Australia. (e-mail: Bruce.Slee@atnf.csiro.au)
E. Budding
Affiliation:
Carter Observatory, P.O. Box 2909, Wellington, New Zealand.
B. D. Carter
Affiliation:
Centre for Astronomy, Solar Radiation and Climate, Faculty of Sciences, University of Southern Queensland, Toowoomba QLD 4350, Australia; (e-mail: carterb@usq.edu.au)
M. W. Mengel
Affiliation:
Centre for Astronomy, Solar Radiation and Climate, Faculty of Sciences, University of Southern Queensland, Toowoomba QLD 4350, Australia; (e-mail: mengelm@usq.edu.au)
I. Waite
Affiliation:
Centre for Astronomy, Solar Radiation and Climate, Faculty of Sciences, University of Southern Queensland, Toowoomba QLD 4350, Australia
J.-F. Donati
Affiliation:
Observatoire Midi-Pyrénées, 14 avenue Edouard Belin, 31400 Toulouse, France. (e-mail: jean-francois.donati@ast.obs-mip.fr)
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Radio and optical observations from December 2001 and January 2002 of the active RS CVn-like binary CC Eri are presented. The star was monitored at 4.80 and 8.64 GHz over 3 × 12 h allocations with the Australia Telescope Compact Array on 28 to 30 December 2001. The Anglo-Australian Telescope was used for simultaneous optical spectropolarimetry during a 0.5 h period on 30 December. Data from four nights of broadband photometry gathered around the same period are also included in this present multiwavelength study.

The low levels of radio emission were circularly polarised at ∼20% with slightly positive spectral indices of ∼0.26. Two flare-like increases were observed on successive nights with steep positive spectral indices and no detectable polarisation. Cross-correlation analysis of the 4.80 and 8.64 GHz intensities over the stronger flare showed that the higher frequency emission preceded that at the lower frequency by ∼5 min, a result consistent with the propagation of a hydromagnetic disturbance outwards through the corona. On the same night, a significant cross-correlation in the ‘quiescent’ emission indicates the presence of micro-flaring, although its low intensity does not permit the evaluation of a time delay. The emission parameters on the three nights are compatible with a gyrosyncrotron mechanism, in which the radio source becomes optically thick during strong flaring. We develop a simple model, which is based on assuming that the number of radiating electrons is a given function of the magnetic field in the source region, and derive feasible values for the field, source radius, and number of emitting electrons, which are not strongly dependent on the field modelling function or the aspect ratio of the source. Spectropolarimetry demonstrates the presence of a strong surface magnetic field. Optical photometry, covering a sufficient amount of the orbit, indicates a maculation region of significant size (∼14° radius).

The results help develop a three-dimensional picture of a large stellar magnetically active region and encourage more detailed follow-up multiwavelength studies of this and similar stars.

Keywords

stars: activitystars: coronaestars: individual: CC Eriradio continuum: starstechniques: miscellaneoustechniques: Zeeman Doppler Imaging.
Type
Research Article
Information
Publications of the Astronomical Society of Australia , Volume 21 , Issue 1 , 2004 , pp. 72 - 81
Copyright
Copyright © Astronomical Society of Australia 2004

References

Allen, C. W. 1974, Astrophysical Quantities (Athlone Press, London)Google Scholar
Ayres, T. R., et al. 2000, BAAS, 197, 4407 Google Scholar
Bessell, M. S. 1996, in PEP5 Conf. Proc., AustJA, 6, 211 Google Scholar
Budding, E. 1977, Ap&SS, 48, 207 Google Scholar
Budding, E. 1993, Introduction to Astronomical Photometry (Cambridge, UK: CUP)Google Scholar
Budding, E., Jones, K. L., Slee, O. B., & Watson, L. 1999, MNRAS, 305, 966 CrossRefGoogle Scholar
Budding, E., Lim, J., Slee, O. B., & White, S. M. 2002, New A, 7, 35 Google Scholar
Cameron, A. C., & Robinson, R. D. 1989, MNRAS, 238, 657 Google Scholar
Cutispoto, G., Messina, S., & Rodono, M. 2001, A&A, 367, 910 Google Scholar
Donati, J.-F., Semel, M., Carter, B. D., Rees, D. E., & Cameron, A. C. 1997, MNRAS, 291, 658 Google Scholar
Dempsey, R. C., Linsky, J. L., Schmitt, J. H. M. M., & Fleming, T. A. 1993, ApJ, 413, 333 Google Scholar
Drake, S. A., Simon, T., & Linksy, J. L. 1992, ApJS, 82, 311 CrossRefGoogle Scholar
Dulk, G. A. 1985, ARA&A, 23, 169 Google Scholar
Evans, D. S. 1959, MNRAS, 119, 526 Google Scholar
Franciosini, E., & Chiuderi Drago, F. 1995, A&A, 297, 535 Google Scholar
Gary, D. E. 1985, ApJ, 297, 799 CrossRefGoogle Scholar
Henry, G. W., Eaton, J. A., Hamer, J., & Hall, D. S. 1995, ApJS, 97, 513 Google Scholar
Jardine, M., Cameron, A. C., & Donati, J.-F. 2002, 333, 339 CrossRefGoogle Scholar
James, D. J., Jardine, M. M., Jeffries, R. D., Randich, S., Cameron, A. C., & Ferreira, M. 2000, MNRAS, 318, 1217 CrossRefGoogle Scholar
Jones, K. L., Brown, A., Stewart, R. T., & Slee, O. B. 1996, MNRAS, 283, 1331 CrossRefGoogle Scholar
Lane, D. J. 1995, ToFits at ftp://hercules.stmarys.ca/pub/tofits/to-fits.exe Google Scholar
Manchester, R. 1991, AdSpR, 11, 403 Google Scholar
Mestel, L., & Spruit, H. C. 1987, MNRAS, 226, 57 Google Scholar
Osten, R. A., Brown, A., Ayres, T. R., Linsky, J. L., Drake, S. A., Gagné, M., & Stern, R. A. 2000, ApJ, 544, 953 Google Scholar
Osten, R. A., Brown, A., Wood, B. E., & Brady, P. 2002, ApJS, 138, 99 CrossRefGoogle Scholar
Popper, D. M. 1980, ARA&A 18, 115.Google Scholar
Rucinski, S. M., Krogulec, M., & Seaquist, E. R. 1993, AJ, 105, 2308 Google Scholar
Sault, R., & Killeen, N. 1996, Multichannel Image Reconstruction, Image Analysis and Display (MIRIAD), User's Guide, ATNF, CSIROGoogle Scholar
Slee, O. B., et al. 1987, MNRAS, 227, 446 Google Scholar
Slee, O. B., & Stewart, R. T. 1989, MNRAS, 236, 129 Google Scholar
Stetson, P. B. 1990, PASP 102, 932.Google Scholar
Stewart, R. T., Innis, J. L., Slee, O. B., Nelson, G. J., & Wright, A. E. 1988, AJ, 96, 371 Google Scholar
Strassmeier, K. G., Hall, D. S., Fekel, F. C., & Scheck, M. 1993, A&AS, 100, 173 Google Scholar
Vilhu, O., Tsuru, T., Cameron, A. C., Budding, E., Banks, T., Slee, B., Ehrenfreund, P., & Foing, B. H. 1993, A&A, 278, 467 Google Scholar
Waite, I. A. 1999, M. Phil. Thesis, Univ. Southern Queensland, Australia Google Scholar
Watson, L. 1999, PhD Thesis, Univ. Canterbury Google Scholar