Stella Two New Robotic Telescopes for Binary Star Research

Strassmeier The AIP STELLA team* Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract Several new robotic telescopes had or will see first light in 2005 2006 and are designed for either wide-field imaging, high-precision photometry or even for highresolution echelle spectroscopy. These telescopes are in the 1-2 m class and therefore will focus on very specific tasks. Here, I present an update of the robotic STELLA facility currently...

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Fig. 3 The best fit solutions in latitude-temperature plots with corresponding filling factors ( ). Heavy gray color denotes solutions with minimum x2 (0-0.5) while light gray denotes solutions with x2 up to 2.0 Fig. 4 Spot temperature vs. time. Vertical solid and dotted lines represent the solution in the x2 0.0-0.5 and x2 0.5-1.0 range, respectively. Downward and upward arrows represent upper and lower limits. The brightness variations are plotted in the upper panel to better show the...

Disentangling Effective Temperatures of Individual Eclipsing Binary Components by Means of Color Index Constraining

Limb Darkening Eclipsing Binaries

Received 30 September 2005 Accepted 28 November 2005 Springer Science + Business Media B.V. 2006 Abstract Eclipsing binary stars are gratifying objects because of their unique geometrical properties upon which all important physical parameters such as masses, radii, temperatures, luminosities and distance may be obtained in absolute scale. This poses strict demand on the model to be free of systematic effects that would influence the results later used for calibrations, catalogs and evolution...

Doppler Imaging of Rapidly Rotating M Stars

Received i November 2005 Accepted i February 2006 Springer Science + Business Media B.V. 2006 Abstract With the advent of 8-i2m-class telescopes and powerful new spectrographs, we can now extend the Dopplerimaging technique to the cool (and faint) end of the main sequence. At a spectral type of approximately M2, stars are thought to become fully convective and cannot possess an overshoot layer between a radiative core and a convective envelope which, as in the case of the Sun and similar stars,...

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Where ri,j is the residual of the j-th measurement of the i-th run and ait j is its uncertainty. The sum is over all the measurements in a run and then over the M runs. The x2 is the known function where the sum is over all N observations. Dividing by x2 assures that, in contrast to x2 itself, A is not sensitive to a systematic overestimation or underestimation of the uncertainties. It is easy to see that A is minimal when the residuals alternate between positive and negative values, and that...

Table Of Contents

Alvaro Gim nez, Edward Guinan, Panagiotis Niarchos and Slavek Rucinski Preface 1-2 Edward F. Guinan and Scott G. Engle The Brave New World of Binary Star Studies 3-9 E. Budding, C. Bembrick, B.D. Carter, N. Erkan, M. Jardine, S.C. Marsden, R. Osten, P. Petit, M. Semel, O.B. Slee and I. Waite Multisite, Multiwavelength Studies of the Active Cool Binary CC Eri 11-14 Antonio Frasca, Ettore Marilli, Patrick Guillout, Rubens Freire Ferrero, Elvira Covino and Juan M. Alcala Late-type X-ray Emitting...

The Enigmatic Behaviour of the Old Nova RR

Linda Schmidtobreick Claus Tappert Alessandro Ederoclite Ivo Saviane Elena Mason Received i November 2005 Accepted i February 2006 Springer Science + Business Media B.V. 2006 Abstract We report preliminary results of an observing run at the i-m telescope at CTIO during which we followed RR Pic over several nights in February 2005. The resulting light curves show no sign of an eclipse. Apart from the 3.48 h period, which is usually interpreted as the orbital one, we find an additional period at...

Synthesis of Line Profiles and Radial Velocity Curves for XRay Binary Systems

Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract Line profiles and radial velocity curves for optical stars in X-ray binaries are calculated taking into account ellipticity of the optical star and X-ray heating effect. Keywords Line profiles. Synthesis. X-ray binary system . Masses. Relativistic objects Tidal deformation of the optical star in X-ray binaries and its heating by the companion's radiation lead to changes of its projected shape...

Xrays from the Symbiotic Star RX

Spectrum Xmm Newton Binary Semi Detached

Sokoloski Roberto D. D. Costa Received i November 2005 Accepted i February 2006 Springer Science + Business Media B.V. 2006 Abstract We describe X-ray and optical observations of the symbiotic star RX Pup. From low resolution optical spectra, we obtain a reddening for RX Pup of E(B - V) 0.79. We use the neutral column density corresponding to this reddening as a lower limit for the X-ray spectra fits. The X-ray spectra can be fitted with either a two-temperature thermal...

T Borkovits Sz Csizmadia L Patkos

Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract In order to improve the light curve solutions we suggest to use a new approach. A library of the Fourier-coefficients (up to 20th term) of (several millions of) light curves was constructed each of the light curves has different input parameters. A light curve solution is made in a very fast way its discrete Fourier-transform yields not more than some simple number which are compared to the...

LU Vel GJ 375 A M35Ve Flare and Double Lined Spectroscopic Binary

Fernandez-Figueroa I. Crespo-Chacon Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract High resolution echelle spectroscopic observations taken with the FEROS spectrograph at the 2.2 m telescope ESO confirm the binary nature of the flare M3.5V star LU Vel (GJ 375, RE J0958-462) previously reported by Christian and Mathioudakis (2002). Emission of similar intensity from both components is detected in the Balmer, Na...

HD 172189 a Cluster Member Binary System with a Scuti Component in the Field of View of COROT

Amado Susana Mart n-Ru z Juan Carlos Su rez Armando Arellano Ferro Andres Moya Ignasi Ribas Ennio Poretti Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract Photometric and spectroscopic results for the star HD172189, member of the open cluster IC4756 in the summer field of the space mission COROT, are presented. From photometric observations in the Stromgren system carried out at various epochs, its binary nature as well as the...

Disentangling of the Spectra of Binary Stars Principles Results and Future Development

Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract The method of spectra disentangling is reviewed in context with related techniques. New generalizations (disentangling with constraints) and applications (for spectroas-trometry) are also described. Keywords Spectroscopic binaries . Spectra disentangling . Line-profile variations Disentangling of spectra of multiple stellar systems is one of techniques for interpretation of spectroscopic data....

On Possible Nature of Preeclipse Dips in Light Curves of Semidetached Systems with Steadystate Disks

A. Boyarchuk O. A. Kuznetsov Received i November 2005 Accepted i February 2006 Springer Science + Business Media B.V. 2006 Abstract In order to explain pre-eclipse dips at phases 0.7 in light curves of cataclysmic variables, the hypothesis of the thickening at the outer edge of the accretion disk is usually used. Shock-free nature of the interaction between the stream and the steady-state disk in the stationary solution poses the question on the cause of the...

Multisite Multiwavelength Studies of the Active Cool Binary CC

Carter N. Erkan M. Jardine S. C. Marsden R. Osten P. Petit M. Semel O. B. Slee I. Waite Received 7 October 2005 Accepted 20 April 2006 Springer Science + Business Media B.V. 2006 Abstract New data acquired on the active, cool binary CC Eri ranged across the spectrum from Chandra X-ray to broadband photometry and microwave observations using the VLA and ATCA. Also, high-dispersion spectropolarimetry using the AAT enabled Zeeman-Doppler imaging to be performed. Our...

The Brave New World of Binary Star Studies

Received 23 February 2006 Accepted 6 June 2006 Springer Science + Business Media B.V. 2006 Abstract In this paper we discuss some of the new and exciting developments in the study of binary stars. Recent technological advances (such as CCDs) now make it possible (even easy) to study faint, astrophysically important binaries that in the past could only be done with large 4 + meter class telescopes. Also, the panoramic nature of CCDs (and the use of mosaics), permit large numbers of stars to be...

Evolutionary Status of Latetype Contact Binaries Case of a 12 1 M Binary

Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract It is argued that typical W UMa-type stars are old, advanced evolutionary objects, similar to Algols, in the sense that they are past mass exchange resulting in a mass ratio inversion. Their secondaries are oversized due to depletion of hydrogen, and in many cases they possess small helium cores. An alternative evolutionary scenario leading to such a configuration is presented. Differences...

Eccentricities of Planets in Binary Systems

Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract The most puzzling property of the extrasolar planets discovered by recent radial velocity surveys is their high orbital eccentricities, which are very difficult to explain within our current theoretical paradigm for planet formation. Current data reveal that at least 25 of these planets, including some with particularly high eccentricities, are orbiting a component of a binary star system. The...

Modelling Eclipsing Binaries with Dense Spot Coverage

Received 1 November 2005 Accepted 1 February 2006 Springer Science + Business Media B.V. 2006 Abstract To synthesise images of stellar photospheres with high spot filling factors, we model an extrapolated solar size distribution of spots on an immaculate SV Cam. These models of starspot coverage show that the primary star is peppered with a large number of subresolution spots. Using these model starspot distributions we generate a photometric lightcurve, which is then used as input to an...

Ogle Lmcsg21 40876

Taken in part from Aleock et al. (2002) Eclipsing Binary with Cepheid Component in the Large Magellanic Cloud Cepheid (F5-G1 I-II) Pvar 4 . 9827d < V> 16.7 + 0.1 Cepheid (F5-G1 I-II) Pvar 4 . 9827d < V> 16.7 + 0.1 A0 II V 14.82 + 0.04 Teff 9686 K log g 2.30 Bprln a 0-052 Fig. 6 A model for the LMC EB SC21 which contains a (possible Type II) Cepheid stars in eclipsing binaries offers a splendid opportunity to investigate the structure and evolution of a wide variety of pulsating...

Chromospheric Activity and Orbital Solution of Six New Latetype Spectroscopic Binary Systems

Fernandez-Figueroa J. Lopez-Santiago Received 1 November 2005 Accepted 1 December 2005 Springer Science + Business Media B.V. 2006 Abstract We present here the results of our high resolution echelle spectroscopic observations of six recently identified spectroscopic binary systems with late-type stellar components (HD 82159 (BD +11 2052 A) HIP 63322 (BD +39 2587) HD 160934 (RE J1738 +611) HD 89959 (BD +41 2078) HD 143705 (BD +29 2752) HD 138157 (OX Ser)). The orbital...

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