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Multi-Wavelength Observations of EV Lacertae

Published online by Cambridge University Press:  26 May 2016

Rachel A. Osten ,
Suzanne L. Hawley ,
Joel Allred ,
Christopher M. Johns-Krull ,
Christine Roark ,
Carol Ambruster ,
Alexander Brown ,
Thomas R. Ayres  and
Jeffrey L. Linsky
Rachel A. Osten
Affiliation:
Jansky Fellow, National Radio Astronomy Observatory, Charlottesville, VA 22903, USA
Suzanne L. Hawley
Affiliation:
University of Washington, Seattle, WA, USA
Joel Allred
Affiliation:
University of Washington, Seattle, WA, USA
Christopher M. Johns-Krull
Affiliation:
Rice University, Houston, TX, USA
Christine Roark
Affiliation:
University of Iowa, Ames, lA, USA
Carol Ambruster
Affiliation:
Villanova University, Villanova, PA, USA
Alexander Brown
Affiliation:
University of Colorado, Boulder, CO, USA
Thomas R. Ayres
Affiliation:
University of Colorado, Boulder, CO, USA
Jeffrey L. Linsky
Affiliation:
University of Colorado, Boulder, CO, USA

Abstract

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We report on a large, multi-wavelength campaign to observe variability across the electromagnetic spectrum in the M dwarf flare star EV Lacertae, in 2001 September. The campaign involved X-ray (Chandra ACIS-S+HETG), UV (HST/STIS), and optical (McDonald) spectra, as well as optical photometry and multi-frequency radio (VLA) observations. EV Lac demonstrated both frequent and extreme variability during the course of the two day intensive recordings. Dispersed X-ray spectra confirm the metal underabundance seen in other active stars. The increase in continuum fluxes at short X-ray wavelengths during flare intervals compared to quiescent intervals signals the creation of high temperature plasma, a signature of the flare process. Multi-wavelength comparisons reveal interesting trends: X-ray flare frequencies are within the range predicted by optical observations, yet there is no correspondence between X-ray flares and optical flares in our data. Two UV flares occur during the rise stages of X-ray flares; a major radio flare is accompanied by a large optical flare, which has no apparent counterpart in the X-ray. The results give conflicting evidence for the applicability of the Neupert effect interpretation in stellar coronae.

Type
Part 5: Stellar Magnetic Activity and Evolution
Information
Symposium - International Astronomical Union , Volume 219: Stars as Suns : Activity, Evolution and Planets , 2004 , pp. 249 - 253
Copyright
Copyright © Astronomical Society of the Pacific 2004 

References

Ambruster, C. W., et al. 1994, BAAS, 26, 866.Google Scholar
Caillault, J.-P., Drake, S., & Florkowski, D., 1988, AJ, 95, 887.CrossRefGoogle Scholar
Delfosse, X., Forveille, T., Perrier, C., & Mayor, M. 1998 A&A, 331, 581.Google Scholar
Dennis, B. R., & Schwartz, R. A. 1989, Sol. Phys., 121, 75.Google Scholar
Güdel, M., Benz, A. O., Schmitt, J. H. M. M., & Skinner, S. L. 1996 ApJ, 471, 1002.Google Scholar
Favata, F., Reale, F., Micela, G., Sciortino, S., Maggio, A., & Matsuomoto, H. 2000, A&A, 353, 9987.Google Scholar
Johns-Krull, C. M., & Valenti, J. 1996, ApJ, 459, L95.Google Scholar
Kodaira, K., Ichimura, K., & Nishimura, S. 1976, PASJ, 28, 665.Google Scholar
Leto, G., Pagano, I., Buemi, C. S., & Rodonò, M., 1997 A&A, 327, 1114.Google Scholar
Osten, R.A., Ayres, T. R., Brown, A., Linsky, J. L., and Krishnamurthi, A., 2003 ApJ 582, 1073.Google Scholar
Saar, S. H. 1994 IAU Symp. 154 Infrared Solar Physics, ed. Rabin, D. M. et al.Google Scholar
Sciortino, S., Maggio, A., Favata, F., & Orlando, S., 1999, A&A, 342, 502.Google Scholar
White, S. M., Jackson, P. D., & Kundu, M. R., 1989, ApJS, 71, 895.Google Scholar