Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign



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Montes Gutiérrez, David and otros, ... (2003) Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign. Astronomy & Astrophysics, 397 (1). pp. 285-303. ISSN 0004-6361

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We present simultaneous and continuous observations of the Hα, Hβ, He I D_3, Na I D_1,D_2 doublet and the Ca II H&K lines for the RS CVn system HR 1099. The spectroscopic observations were obtained during the MUSICOS 1998 campaign involving several observatories and instruments, both echelle and long-slit spectrographs. During this campaign, HR 1099 was observed almost continuously for more than 8 orbits of 2^d.8. Two large optical flares were observed, both showing an increase in the emission of Hα, Ca II H K, Hβ and He I D_3 and a strong filling-in of the Na I D_1, D_2 doublet. Contemporary photometric observations were carried out with the robotic telescopes APT-80 of Catania and Phoenix-25 of Fairborn Observatories. Maps of the distribution of the spotted regions on the photosphere of the binary components were derived using the Maximum Entropy and Tikhonov photometric regularization criteria. Rotational modulation was observed in Hα and He I D_3 in anti-correlation with the photometric light curves. Both flares occurred at the same binary phase (0.85), suggesting that these events took place in the same active region. Simultaneous X-ray observations, performed by ASM on board RXTE, show several flare-like events, some of which correlate well with the observed optical flares. Rotational modulation in the X-ray light curve has been detected with minimum flux when the less active G5 V star was in front. A possible periodicity in the X-ray flare-like events was also found.

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© ESO 2003.
Artículo firmado por 34 autores.
We wish to thanks all those who have contributed to the MUSICOS 98 campaign. Research at Armagh Observatory is grant-aided by the Department of Culture, Arts and Leisure for Northern Ireland. DGA wishes to thank the Space Science Department at ESTEC for financial support. DM is supported by the Spanish Programa Nacional de Astronomía y Astrofísica, under grant AYA2001-1448. JMO research work was supported by the Praxis XXI grant BD9577/96 from the Fundação para a Ciência e a Tecnologia, Portugal. This paper made use of quick look data provided by the RXTE ASM team at MIT and GSFC. Stellar activity research at Catania Astrophysical Observatory of the National Institute of Astrophysics and at Department of Physics and Astronomy of Catania University is supported by the MIUR “Ministero dell’Istruzione, Universitá e Ricerca” and by the Regione Sicilia that are gratefully acknowledged. We also thank the referee M. Guedel for helpful comments.

Uncontrolled Keywords:High-resolution spectrograph; Chromospherically active binaries; Orbital period modulation; Term starspot evolution; HR 1099; II-PEG; Flaring activity; Magnetic cycles; Stellar coronae; Close binaries
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:37878
Deposited On:26 May 2016 14:07
Last Modified:10 Dec 2018 15:05

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