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

García-Álvarez, D.; Foing, B. H.; Montes, D.; Oliveira, J. M.; Doyle, J. G.; Messina, S.; Lanza, A. F.; Rodonò, M.; Abbott, Jay B.; Ash, T. D. C.; Baldry, I. K.; Bedding, T. R.; Buckley, D.; Cami, J.; Cao, Huifen; Catala, C.; Cheng, K. P.; Souza, A. Domiciano de; Donati, J.‐F.; Hubert, A. M.; Janot-Pacheco, E.; Hao, Jinxin; Kaper, L.; Kaufer, A.; Leister, N. V.; Neff, J. E.; Neiner, C.; Orlando, S.; O'Toole, S. J.; Schafer, Donald W.; Smartt, S. J.; Stahl, O.; Telting, J. H.; Tubbesing, S.

doi:10.1051/0004-6361:20021481

Cited by 42 publications

(36 citation statements)

References 38 publications

(66 reference statements)

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“…This mechanism presented by Matese & Whirtmere (1983) and developed by Applegate (1992) and Lanza et al (1998), has been used in the study of several RS CVn systems such as SZ Psc (Kalimeris et al 1995), RT Lac, RS CVn, WW Dra, etc. (Lanza & Rodonó 1999), XY UMa (Sowell et al 2001) and HR 1099 (García-Álvarez et al 2003;Frasca & Lanza 2005;Lanza 2006). Applegate (1992), described the initial model in which the orbital period variation is due to the gravitational coupling of the orbit to changes in the quadrupole moment (rotational oblateness) of a magnetically active star in the system.…”

Section: Discussionmentioning

confidence: 99%

Multiwavelength optical observations of chromospherically active binary systems

Gálvez

Montes²,

Fernández-Figueroa³

et al. 2007

A&A

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Context. This is the fifth paper in a series aimed at studying the chromospheres of active binary systems using several optical spectroscopic indicators to obtain or improve orbital solution and fundamental stellar parameters. Aims. We present here the study of FF UMa (2RE J0933+624), a recently discovered, X-ray/EUV selected, active binary with strong Hα emission. The objectives of this work are, to find orbital solutions and define stellar parameters from precise radial velocities and carry out an extensive study of the optical indicators of chromospheric activity. Methods. We obtained high resolution echelle spectroscopic observations during five observing runs from 1998 to 2004. We found radial velocities by cross correlation with radial velocity standard stars to achieve the best orbital solution. We also measured rotational velocity by cross-correlation techniques and have studied the kinematic by galactic space-velocity components (U, V, W) and Eggen criteria. Finally, we have determined the chromospheric contribution in optical spectroscopic indicators, from Ca ii H & K to Ca ii IRT lines, using the spectral subtraction technique.Results. We have found that this system presents an orbital period variation, higher than previously detected in other RS CVn systems. We determined an improved orbital solution, finding a circular orbit with a period of 3.274 days. We derived the stellar parameters, confirming the subgiant nature of the primary component (M P = 1.67 M and R sin i P = 2.17 R ) and obtained rotational velocities (v sin i), of 33.57 ± 0.45 km s −1 and 32.38 ± 0.75 km s −1 for the primary and secondary components respectively. From our kinematic study, we can deduce its membership to the Castor moving group. Finally, the activity study has given us a better understanding of the possible mechanisms that produce the orbital period variation.

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Section: Discussionmentioning

confidence: 99%

Multiwavelength optical observations of chromospherically active binary systems

Gálvez

Montes²,

Fernández-Figueroa³

et al. 2007

A&A

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“…However, in some cases, no clear rotational modulation of chromospheric diagnostics has been detected despite the contemporaneous wave-like behaviour in the photometry (see, e.g., Catalano et al 2000). In such cases, the distribution of the active regions, as revealed by the Hα emission, may be more homogeneously distributed in the base of the chromosphere than in the photosphere or in other atmospheric layers, as proposed, e.g., by García-Alvarez (2003). In addition, the Hα line may originate in other physical processes, like flares and prominences.…”

Section: Hα Linementioning

confidence: 96%

The young active star SAO 51891 (V383 Lacertae)

Biazzo

Frasca

Marilli

et al. 2009

A&A

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Aims. The aim of this work is to investigate the surface inhomogeneities of a young, late-type star, SAO 51891, at different atmospheric levels, from the photosphere to the upper chromosphere, analyzing contemporaneous optical high-resolution spectra and broad-band photometry. Methods. The full spectral range of FOCES@CAHA (R 40 000) is used to perform the spectral classification and to determine the rotational and radial velocities. The lithium abundance is measured to obtain an age estimate. The BVRIJHK s photometric bands are used to construct the spectral energy distribution (SED). The variations in the observed BV fluxes and effective temperature are used to infer the presence of photospheric spots and observe their behavior over time. The chromospheric activity is studied applying the spectral subtraction technique to Hα, Ca ii H & K, H , and Ca ii IRT lines.Results. We find SAO 51891 to be a young K0-1V star with a lithium abundance close to the Pleiades upper envelope, confirming its youth (∼100 Myr), which is also inferred from its kinematical membership of the Local Association. No infrared excess is detected from analysis of its SED, limiting the amount of remaining circumstellar dust. We detect a rotational modulation of the luminosity, effective temperature, Ca ii H & K, H , and Ca ii IRT total fluxes. A simple spot model with two main active regions, about 240 K cooler than the surrounding photosphere, fits the observed light and temperature curves very well. The small-amplitude radial velocity variations are also well reproduced by our spot model. The anti-correlation of light curves and chromospheric diagnostics indicates chromospheric plages spatially associated with the spots. The largest modulation amplitude is observed for the H flux suggesting that this line is very sensitive to the presence of chromospheric plages. Conclusions. SAO 51891 is a young active star, lacking significant amounts of circumstellar dust or any evidence of low mass companions, and displays the typical phenomena produced by magnetic activity. The spots are larger and warmer than those in less active main-sequence stars. If some debris is still present around the star, it will only be detectable by future far-infrared and sub-mm observations (e.g., Herschel or ALMA). The RV variation produced by the starspots has an amplitude comparable with those induced by Jupiter-mass planets orbiting close to the host star. SAO 51891 is another good example of an active star in which the detection of planets may be hampered by the high activity level.

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“…Figure 2 shows the light curves for both observations; note that both light curves are relatively flat and devoid of large flare activity. Several authors have reported coronal rotational modulation on active stars (e.g., Drake et al 1994;Audard et al 2001;García-Alvarez et al 2003), including AB Dor (Kuerster et al 1997). However, as shown in Figure 2 (bottom), no obvious modulation of the coronal emission with orbital phase was seen on either star, although in the case of AB Dor, the observation only covers slightly more than one rotational period.…”

Section: Photometrymentioning

confidence: 99%

The Coronae of AB Doradus and V471 Tauri: Primordial Angular Momentum versus Tidal Spin‐up

García-Álvarez

Drake

Lin

et al. 2005

ApJ

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The zero-age main-sequence star AB Dor and the K dwarf component of the V471 Tau close binary have essentially identical rotation rates and spectral types. An analysis of their high-resolution Chandra X-ray spectra reveals remarkably similar coronal characteristics in terms of both temperature structure and element abundances. Both stars show depletions of low first ionization potential (FIP) elements by factors of $3, with higher FIP elements showing more mild depletions. No evidence for enhancements of very low FIP (<7 eV) elements, such as Na, Al, and Ca, as compared to other low-FIP elements, was found. The abundance anomaly pattern for AB Dor and V471 Tau is similar to, although less extreme than, the abundance anomalies exhibited by active RS CVn-type binaries. While we find statistically significant structure in the underlying differential emission measure distributions of these stars over narrow temperature intervals, this structure is strongly dependent on the lines used in the analysis and is probably spurious. On the basis of their X-ray similarities, we conclude that the exact evolutionary state of a star has little effect on coronal characteristics and that the parameters that dominate coronal structure and composition are simply the rotation rate and spectral type.

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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

Cited by 42 publications

References 38 publications

Multiwavelength optical observations of chromospherically active binary systems

Multiwavelength optical observations of chromospherically active binary systems

The young active star SAO 51891 (V383 Lacertae)

The Coronae of AB Doradus and V471 Tauri: Primordial Angular Momentum versus Tidal Spin‐up

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