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© Royal Astronomical Society. Many thanks are due to Dr Andre Maeder, who kindly sent us his unpublished main-sequence interior models. We also are very grateful to Dr Carole Jordan for her careful reading of the manuscript and for many suggestions to clarify and improve its scientific content. The authors are indebted to an anonymous referee for his valuable comments and suggestions on the first version of this paper. This work has been carried out at the Departamento de Astrofísica of the Universidad Complutense (Madrid), and is a part of the project 'Actividad estelar en estrellas de los últimos tipos espectrales' supported by the Spanish Comisión Asesora de Investigación Científica y Tecnológica (CAICYT No. 2254/83). The financial support to one of the authors (BM) with a grant of the Spanish Ministerio de Educación y Ciencia is gratefully acknowledged., In this work we try to establish a connection between the dynamo effect, which operates in the convection zone of late-type stars, and the chromospheric activity observed in these objects. We estímate in a theoretical way, for a sample of main-sequence active stars with spectral types G and K, the magnetic field generated in a region close to the base of the convection zone and the filling factor (fraction of stellar surface covered by strong magnetic fields). The analysis of the behaviour both of the filling factor and the activity indicator R(CaII + MgII) against several stellar parameters ( B-V and the Rossby number) supports the existence of a link between the interior processes and the surface activity., Comisión Asesora de Investigación Científica y Tecnológica (CAICYT), España, Ministerio de Educación y Ciencia (MEC), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© 1997 EDP Sciencies. This research has made use of the Simbad database, operated at CDS, Strasbourg, France. We greatly appreciate the comments and suggestion on this paper by the referee, R. Gratton. DBN acknowledges the support by the Universidad Complutense with a grant and by the Real Colegio Complutense at Harvard University. This work has been partially supported by the Spanish Dirección General de Investigación Científica y Técnica (DGICYT) under projects PB92-0434-c02-01 and PB94-0203., We present an extensive study of lithium abundances in dwarf components of chromospherically active binary stars (CABS). Since most of these binaries have known radii, masses and ages, this kind of data is especially useful for comparisons with theoretical models which try to explain the Li depletion phenomenon. We show that a significant part of these stars have clear Li overabundances with respect to the typical values for stars of the same mass and evolutionary stage. These excesses are evident when comparing our sample of CABS with binary and single stars belonging to open clusters of different ages, namely Pleiades, Hyades, NGC752, M67 and NGC188, which have ages ranging from 7x10^7 to 10^10 yr. The Li excesses are more conspicuous for masses in the range 0.75-0.95 M_⊙., indicating that the rate of Li depletion has been less pronounced in CABS than in single stars. This phenomenon is interpreted in the context of transport of angular momentum from the orbit to the stellar rotation due to tidal effects. This angular momentum transfer would avoid the radial differential rotation and the associated turbulent mixing of material in the stellar interior. Other explanations, however, can not be ruled out. This is the case of transport of material induced by internal gravity waves, which could be inhibited due to the presence of strong magnetic fields associated with the effective dynamo in CABS. The confirmed existence of a relation between Li abundances and the fluxes in Ca II H&K lines can also be accommodated within both scenarios., Universidad Complutense de Madrid (UCM), Real Colegio Complutense at Harvard University, Dirección General de Investigación Científica y Técnica (DGICYT), España, Ministerio de Economía y Competitividad (MINECO), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© European Southern Observatory. © The American Astronomical Society. The INT 2.5 m on the island of La Palma and the 1.23 m and 2.2 m telescopes at Calar Alto Observatory are operated, respectively, by the Royal Greenwich Observatory at the Spanish Roque de los Muchachos Observatory (Instituto de Astrofísica de Canarias), and the Max Plank Institut for Astronomie at the Centro Astronómico Hispano-Alemán of Calar Alto (Almería, Spain). We want to express our gratitude to the staff of both Observatorties for their help during the observational campaigns. This work has been supported by the Spanish Comisión Interministerial de Ciencia y Tecnología under grants PB86-0536-C02 and PB87-0235., A detailed study of the system V772 Her = HD 165590 = ADS 11060 AB is presented. The three identified components are found to be late type stars close to the zero-age main sequence with high rotational velocities. Spectroscopic observations allowed a quantitative determination of stellar activity indicators for the two members of the close binary as well as for the visual companion. An estimation of the most relevant physical parameters has been derived from the colour indices of each of the components and the close system has been found to be an eclipsing binary. This additional source of information combined with published measures of radial velocities, provides the absolute dimensions of the component stars (1.1 and 0.6 solar masses, and 0.9 and 0.6 solar radii) which confirm that the system is very little evolved. Moreover, a distance of 32 +/- 4 parsecs has been found to V772 Her in good agreement with available trigonometric determinations. Finally, we have compared these results with evolutionary models for main sequence stars of solar chemical composition., Comisión Interministerial de Ciencia y Tecnología (CICYT), España, Ministerio de Ciencia e Innovación (MICINN), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© ESO 2003. The authors are grateful to Prof. J. Linsky for stimulating suggestions and to Dr. D. Marinucci for useful comments., We carry out an analysis of the Mg II 2796.34 Å emission line in RS CVn stars and make a comparison with the normal stars studied in a previous paper ( Paper I). The sample of RS CVn stars consists of 34 objects with known HIPPARCOS parallaxes and observed at high resolution with IUE. We confirm that RS CVn stars tend to possess wider Mg II. lines than normal stars having the same absolute visual magnitude. However, we could not find any correlation between the logarithmic line width log W_o and the absolute visual magnitude M_v (the Wilson-Bappu relationship) for these active stars, contrary to the case of normal stars addressed in Paper I. On the contrary, we find that a strong correlation exists in the (M_v, log L_MgII) plane (L_MgII is the absolute flux in the line). In this plane, normal and RS CVn stars are distributed along two nearly parallel straight lines with RS CVn stars being systematically brighter by ≈1 dex. Such a diagram provides an interesting tool to discriminate active from normal stars. We finally analyse the distribution of RS CVn and of normal stars in the (log L_MgII, log W_o) plane, and find a strong linear correlation for normal stars, which can be used for distance determinations., Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© European Southern Observatory. © EDP Sciences. The INT 2.5m on the island of La Palma and the 2.2m telescope at Calar Alto Observatory are operated respectively, by the Royal Greenwich Observatory at the Spanish Observatorio del Roque de Los Muchachos (Instituto de Astrofísica de Canarias), and the Max Planck lnstitut für Astronomie at the Centro Astronómico Hispano-Alemán of Calar Alto (Almería, Spain). We want to express our gratitude to the staff of both Observatories for their help during the observations. This work has been supported by the Universidad Com­plutense de Madrid and the Spanish Dirección General de Investigación Científica y Técnica (DGICYT) under grant PB91-0348., We present measurements of the emission core width W_0 and the wavelength separation of the K_1 dips, W_1, of the Ca II H and K emission lines observed on high-dispersion spectra of 28 chromospherically active binary systems (RS CVn and BY Dra stars) and 18 single active stars. We test the width-luminosity correlations (the Wilson-Bappu (WB) effect, and (W_1, M_V) in these very active stars and analyse the influence of the activity level (I_K3) and the rotational broadening (Vsin i) in these correlations. We have found that for very active stars the emission widths, both W_0 and W_1, are larger than expected from previously accepted width-luminosity relations. The stars with strong emission intensities, I_K3 and large values of Vsin i seem to present larger values of W_0 than resulted from WB relation, the effect of the rotational velocity being the most remarkable. On the contrary, W_1 is strongly influenced by I_K3 but the effect of the rotational broadening is lesser. We also analyse the behaviour of the Ca II H and K line parameters in these very active stars in relation with less active stars and we found that the increase of W_1 and I_K1 With I_K3 presents a flattening for the most active stars which is different for each value of W_0. Finally we also find a Hepsilon width-luminosity correlation in the stars of the sample in which this emission line is present., Universidad Complutense de Madrid (UCM), Dirección General de Investigación Científica y Técnica (DGICYT), España, Ministerio de Economía y Competitividad (MINECO), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© 1998 EDP Sciencies. This research has made use of the Simbad database, operated at CDS, Strasbourg, France. We greatly appreciate the comments and suggestions on this paper by the referee, Dr. Sofia Randich, which helped to improve the presentation and discussion of the results. DBN acknowledges the support by the Universidad Complutense, the Real Colegio Complutense at Harvard University, and the MEC/Fulbright commission. This work has been partially supported by the Spanish Dirección General de Educación Superior (DGES) under projects PB92-0434-C02-01, PB94-0203, and PB95-1132-C02-01., We present a study of the lithium abundances of a sample of evolved components of Chromospherically Active Binary Systems. We show that a significant part of them have lithium excesses, independently of their mass and evolutionary stage. Therefore, it can be concluded that Li abundance does not depend on age for giant components of CABS. These overabundances appear to be closely related to the stellar rotation, and we interpret them as a consequence of the transfer of angular momentum from the orbit to the rotation as the stars evolve: in and off the Main Sequence, in a similar way as it happens in the dwarf components of the same systems and in the Tidally Locked Binaries belonging to the Hyades and M67., Universidad Complutense de Madrid (UCM), Real Colegio Complutense at Harvard University, Ministerio de Educación y Ciencia (MEC), España, Spanish Dirección General de Educación Superior (DGES), Comisión Fulbright, España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© 1988 American Astronomical Society. The JKT on the island of La Palma and the l.5 m Tele­scope at Calar Alto are operated, respectively, by the Royal Greenwich Observatory at the Spanish Roque de los Mucha­chos Observatory (Instituto de Astrofísica de Canarias), and Observatorio Astronómico Nacional at the Spanish Ca­lar Alto Observatory (Almería). We want to express our gratitude to the staffs of the observatories for their help dur­ing the observational campaigns. This work has been sup­ported by the Spanish Comisión Asesora de Investigación Cientifica y Técnica (CAICYT No. 2254/83 and No. 3455/ 83)., From 1984 to 1986, we made several observational campaigns at Calar Alto and La Palma Observator­ies using the uvby and ß photometric systems to monitor a selected sample of late-type variable stars. In this paper we present the ß values for 38 uvby standard stars to contribute to the uvby-ß calibration works on late-type stars. In the final discussion, the ß computed values are plotted against the Ström­gren b - y, m_1, and c_1 indices., Comisión Asesora de Investigación Cientifica y Técnica (CAICYT), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© 2001 RAS. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. This research has made use the of the SIMBAD data base, operated at CDS, Strasbourg, France, and the ARI Database for Nearby Stars, Astronomisches Rechen-Institut, Heidelberg. We thank Dr D. Barrado y Navascués for providing us with some additional candidates to our initial sample of late-type stars. We also thank the anonymous referee for suggesting several improvements and helpful comments. This work was supported by the Universidad Complutense de Madrid and the Spanish Dirección General de Enseñanza Superior e Investigación Científica (DGESIC) under grant PB97-0259., This is the first paper of a series aimed at studying the properties of late-type members of young stellar kinematic groups. We concentrate our study on classical young moving groups such as the Local Association (Pleiades moving group, 20-150 Myr), IC 2391 supercluster (35 Myr), Ursa Major group (Sirius supercluster, 300 Myr), and Hyades supercluster (600 Myr), as well as on recently identified groups such as the Castor moving group (200 Myr). In this paper we compile a preliminary list of single late-type possible members of some of these young stellar kinematic groups. Stars are selected from previously established members of stellar kinematic groups based on photometric and kinematic properties as well as from candidates based on other criteria such as their level of chromospheric activity, rotation rate and lithium abundance. Precise measurements of proper motions and parallaxes taken from the Hipparcos Catalogue, as well as from the Tycho-2 Catalogue, and published radial velocity measurements are used to calculate the Galactic space motions (U, V W) and to apply Eggen's kinematic criteria in order to determine the membership of the selected stars to the different groups. Additional criteria using age-dating methods for late-type stars will be applied in forthcoming papers of this series. A further study of the list of stars compiled here could lead to a better understanding of the chromospheric activity and their age evolution, as well as of the star formation history in the solar neighbourhood. In addition, these stars are also potential search targets for direct imaging detection of substellar companions., Universidad Complutense de Madrid (UCM), Dirección General de Enseñanza Superior e Investigación Científica (DGESIC), España, Ministerio de Educación, Cultura y Deporte (MECD), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© European Southern Observatory, Far ultraviolet emission lines in a sample of seven stars of spectral type later than F5 and different luminosity class have been analyzed to calculate the electron density and pressure in the formation region of the lines. Three different methods were used. We obtain electron pressures larger than solar for all dwarf stars of the sample. The low resolution observations were made with the IUE satellite., Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© 2006. The American Astronomical Society. All rights reserved. This work was supported by the Universidad Complutense de Madrid and the Spanish Ministerio de Educación y Ciencia (MEC), Programa Nacional de Astronomía y Astrofísica under grants AYA 2004-03749 and AYA 2005-02750. I. C. C. acknowledges support from MEC under AP2001-0475. We would like to thank the referee for useful comments that have helped improve the manuscript., The latest results in the research of forming planetary systems have led several authors to compile a sample of candidates for searching for planets in the vicinity of the Sun. Young stellar associations are indeed excellent laboratories for this study, but some of them are not close enough to allow the detection of planets through adaptive optics techniques. However, the existence of very close young moving groups can solve this problem. Here we have compiled the members of the nearest young moving groups, as well as a list of new candidates from our catalog of late-type stars that are possible members of young stellar kinematic groups, studying their membership through spectroscopic and photometric criteria., Universidad Complutense de Madrid (UCM), Ministerio de Educación y Ciencia (MEC), España, Programa Nacional de Astronomía y Astrofísica (MCYT), Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© European Southern Observatory. © EDP Sciencies. We are grateful to Drs. M. Penston and A. Heck, VILPSA assistant astronomers, for help during the course of observations and also to the VILPSA team responsible for training and data reduction., The structure of the outer stellar regions is investigated for four G type dwarfs observed with the IUE satellite. Line fluxes of the Si II lines at 1817 Å, 1808 A, and 1309 Å and Si III at 1206 Å are used to obtain temperatures and electronic densities. A temperature of 16,000 K is found from the lines at 1817 Å and 1808 Å, 26,000 K from the 1309 A line and 50,000 K from that at 1206 A. Predicted fluxes are compared with the observed ones. The significance of the results is discussed in terms of line formation regions., Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© ESO 2010. Part of this work was co-supported by the Spanish MICINN, Ministerio de Ciencia e Innovación project numbers: AYA2008- 00695 and AYA2008-06423-C03-03. J. López Santiago is a postdoctoral fellow of the ASTROCAM (Red de Astrofísica en la CAM) with project number S-0505/ESP/000237 of the IV PRICIT Plan Regional de Investigación Científica e Innovación Tecnológica de la Comunidad de Madrid. The authors would like to thank the referee for useful comments and suggestions that allowed us to improve our work., Aims. We present a compilation of spectroscopic data from a survey of 144 chromospherically active young stars in the solar neighborhood, which may be used to investigate different aspects of its formation and evolution in terms of kinematics and stellar formation history. The data have already been used by us in several studies. With this paper, we make all these data accessible to the scientific community for future studies on different topics. Methods. We performed spectroscopic observations with echelle spectrographs to cover the entirety of the optical spectral range simultaneously. Standard data reduction was performed with the IRAF echelle package. We applied the spectral subtraction technique to reveal chromospheric emission in the stars of the sample. The equivalent width of chromospheric emission lines was measured in the subtracted spectra and then converted to fluxes using equivalent width-flux relationships. Radial and rotational velocities were determined by the cross-correlation technique. Kinematics, equivalent widths of the lithium line lambda 6707.8 angstrom and spectral types were also determined. Results. A catalog of spectroscopic data is compiled: radial and rotational velocities, space motion, equivalent widths of optical chromospheric activity indicators from Ca II H & K to the calcium infrared triplet and the lithium line in lambda 6708 angstrom. Fluxes in the chromospheric emission lines and R(HK)' are also determined for each observation of a star in the sample. We used these data to investigate the emission levels of our stars. The study of the Ha emission line revealed two different populations of chromospheric emitters in the sample, clearly separated in the log F(H alpha)/F(bol) - (V - J) diagram. The dichotomy may be associated with the age of the stars., Spanish MICINN, Ministerio de Ciencia e Innovación, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© Royal Astronomical Society. The authors are indebted to Dr Carole Jordan for her valuable comments to clarify the content of this paper. We are also grateful to the referee , Professor J. L. Linsky, for his suggestions to improve some points of the original version. This work was carried out at the Departamento de Astrofísica of the Universidad Complutense (Madrid) and it is a part of the project 'Actividad estelar en estrellas de los últimos tipos espectrales' supported by the Spanish Comisión Asesora de Investigación Científica y Técnica (CAICYT No. 2254/83). The financial support to one of the authors (BM) with a grant of the Spanish Ministerio de Educación y Ciencia is also gratefully acknowledged., In this work we analyse the behaviour of 22 members of the RS CVn family whose absolute parameters are known by observation. We have carried out a study in comparison with detached and normal-evolution systems in order to obtain some general properties of this group of active binaries and test the evolutionary status. A comparison with evolutionary tracks of several metallicities and helium contents shows that there is a trend in these stars to have metal abundances equal to or larger than the solar one. The results are discussed in the light of the peculiar characteristics of this kind of binaries ., Comisión Asesora de Investigación Científica y Técnica (CAICYT), España, Ministerio de Educación y Ciencia (MEC), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© European Southern Observatory. © 1993 EDP Sciencies. The authors acknowlege valuable discussion with and suggestion from Roberto Pallavicini. The Calar Alto Observatory is operated jointly by the Max-Planck-Institut für Astronomie (Heidelberg) and the Spanish Comisión Nacional de Astronomía. We thank the Calar Alto staff for their help during the observations. This work has been supported in part by the Universidad Complutense de Madrid., Observations of the Li i doublet at 6707.8 angstrom for a sample of active binary systems RS CVn and By Dra have been carried out at the Calar Alto Observatory with the 2.2 m telescope. In addition, some single stars with different chromospheric activity levels have also been observed mainly for comparison purposes. Gaussian fits have been performed in order to separate the Fe I line at 6707.4 angstrom which is usually blended with the Li I doublet. Once the fit was achieved, the equivalent width was measured for each separated line. The contributions due to the continuum from both components have been taken into account to correct the equivalent width measurements. A curve-of-growth method has been used to derive lithium abundances. We have obtained a Li excess in the binary systems, in particular the K type stars. A correlation of the Li abundance with the activity levels is confirmed, as it was found by other authors, but RS CVn and BY Dra systems are 0.5 dex more active than single stars for the same Li abundance., Universidad Complutense de Madrid (UCM), Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© European Southern Observatory. © EDP Sciencies The Isaac Newton Telescope, on the island of La Palma, is operated by the Royal Greenwich Observatory at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. We are grateful to the VILSPA staff for the use of their facil­ities. We thank Dr. R. González Riestra and Dr. J. Zamorano for help with IHAP use. The authors are indebted to an anonymous referee for his critical reading of the manuscript and valuable comments. This work has been supported by the Spanish Comisión Asesora de Investigación Científica y Técnica (CAICYT No. 2254/83)., We report here new Ca II H and K emission line fluxes and equivalent widths for seven RSCVn binary systems, observed at several orbital phases. All the stars show enhanced chromospheric activity. With information from available spectra, an in­ dividual study for each star has been done. Double emission has been found for some systems in which perhaps the hotter compo­nent could be the more active. We have tested spectroscopically the model of localized active regions for the prototype RSCVn., Comisión Asesora de Investigación Científica y Técnica (CAICYT), España, Comisión Interministerial de Ciencia y Tecnología (CICYT), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© European Southern Observatory. The authors are very grateful to Dr. F.M. Walter for many valuable comments and suggestions., We have studied a sample of ten RS CVn systems by means of IUE high resolution long wavelength spectra. A general trend toward decreasing chromospheric activity (R_hk) for slower rotating stars has been found. Considering the R_hk values and their relation with structural parameters (T_eff, logg, log P_rot) we suggest that there are two pos­sible different activity levels. The less active systems have Rhk chromospheric activity levels similar to the single cool stars showing the same general trend. A relation between R_hk and the inverse Rossby number has been obtained, in which the RS CVn stars fill the gap found by Rucinski between W UMa and the main-sequence stars., Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

En este trabajo se ha realizado un estudio espectroscopico en una muestra de 83 sistemas binarios cromosfericamente activos (rs cvn y bydra), a traves de la tecnica de substraccion espectral en las lineas halfa, H y k de ca ii y h que ha permitido profundizar en el conocimiento del comportamiento de la actividad en estos sistemas y establecer comparaciones con estrellas aisladas. Utilizando la tecnica de substraccion espectral se ha determinado la anchura equivalente y el flujo superficial del exceso de emision h alfa en 51 sistemas binarios y en h y k de ca ii en 73 sistemas binarios y en 19 estrellas aisladas. Se han encontrado sistemas que presentan variaciones de la emision en h y k de ca ii con la fase orbital y sistemas con variaciones de la emision de una epoca a otra probablemente relacionadas con la existencia de ciclos de actividad. Ha sido posible determinar la emision en la linea h en un gran numero de sistemas, Encontrando que en general los que presentan h en emision son sistemas muy activos en h y k de ca ii y en h Alfa. La determinacion de las anchuras, w0(k) y w1(k) asi como las intensidades ik1 y ik3 en 28 sistemas binarios y en 30 estrellas aisladas ha permitido realizar un estudio de la relacion de wilson-bappu que ha puesto de manifiesto la importante influencia del nivel de actividad y del ensanchamiento rotacional en las relaciones anchura-luminosidad asi como el efecto de la propia anchura en las relaciones entre otros parámetros de la linea k de ca ii. En cuanto a la rotacion, los diagramas actividad-rotacion indican una disminucion de la actividad hacia periodos de rotacion mas largos y hacia numeros de rossby, r0, mayores, con una saturacion para periodos de rotacion muy cortos. Se han comparado los flujos h alfa con los medidos en las lineas K de ca ii y h encontrando que existe una buena correlacion entre estos tres indicadores de actividad cromosferica.

En este proyecto se ha trabajado con espectros de alta resolución de estrellas frías previamente realizados y reducidos por el grupo de Astrofísica Estelar del Dpto de Astrofísica de la UCM. Los espectros han sido realizados con varios espectrógrafos con resoluciones espectrales del orden de 40000 a 80000 cubriendo el rango de tipos espectrales de la estrellas frías (de F a M). Se han utilizado también espectros disponibles en la red, el Observatorio Virtual o archivos de observatorios astronómicos. El alumno se ha familiarizado con todo el proceso de análisis de este tipo de espectros y realizado una identificacion y selección de líneas espectrales adecuadas para poder determinar anchuras equivalentes de muchas líneas espectrales de una forma automática y aplicar los modelos correspondientes para poder calcular parámetros estelares y abundancias.

We have compiled a catalog of late-type stars (F5-M) members of representative, young disk, stellar kinematic groups: the Local Association (20-150 Myr), Ursa Mayor group (300 Myr), Hyades supercluster (600 Myr), IC 2391 supercluster (35 Myr), and Castor moving group (200 Myr). Stars have been selected from previously established members of stellar kinematic groups based in photometric and kinematic properties as well as from candidates based in other criteria as their level of chromospheric activity, rotation rate, lithium abundance. Precise measurements of proper motions and parallaxes taken from Hipparcos Catalogue, and published radial velocity measurements are used to calculate Galactic space motions (U, V, W) in order to determine the membership of the selected stars to the different stellar kinematic groups.

En este trabajo se ha realizado un estudio espectroscopico en una muestra de 83 sistemas binarios cromosfericamente activos (rs cvn y bydra), a traves de la tecnica de substraccion espectral en las lineas halfa, H y k de ca ii y h que ha permitido profundizar en el conocimiento del comportamiento de la actividad en estos sistemas y establecer comparaciones con estrellas aisladas. Utilizando la tecnica de substraccion espectral se ha determinado la anchura equivalente y el flujo superficial del exceso de emision h alfa en 51 sistemas binarios y en h y k de ca ii en 73 sistemas binarios y en 19 estrellas aisladas. Se han encontrado sistemas que presentan variaciones de la emision en h y k de ca ii con la fase orbital y sistemas con variaciones de la emision de una epoca a otra probablemente relacionadas con la existencia de ciclos de actividad. Ha sido posible determinar la emision en la linea h en un gran numero de sistemas, Encontrando que en general los que presentan h en emision son sistemas muy activos en h y k de ca ii y en h Alfa. La determinacion de las anchuras, w0(k) y w1(k) asi como las intensidades ik1 y ik3 en 28 sistemas binarios y en 30 estrellas aisladas ha permitido realizar un estudio de la relacion de wilson-bappu que ha puesto de manifiesto la importante influencia del nivel de actividad y del ensanchamiento rotacional en las relaciones anchura-luminosidad asi como el efecto de la propia anchura en las relaciones entre otros parámetros de la linea k de ca ii. En cuanto a la rotacion, los diagramas actividad-rotacion indican una disminucion de la actividad hacia periodos de rotacion mas largos y hacia numeros de rossby, r0, mayores, con una saturacion para periodos de rotacion muy cortos. Se han comparado los flujos h alfa con los medidos en las lineas K de ca ii y h encontrando que existe una buena correlacion entre estos tres indicadores de actividad cromosferica.