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Stellar substructures in the solar neighbourhood. I. Kinematic group 3 in the Geneva-Copenhagen survey
Context. Galactic archeology is a powerful tool for investigating theformation and evolution of the Milky Way. We use this technique to studykinematic groups of F- and G-stars in the solar neighbourhood. Fromcorrelations between orbital parameters, three new coherent groups ofstars were recently identified and suggested to correspond to remnantsof disrupted satellites. Aims: We determine detailed elementalabundances in stars belonging to one of these groups and compare theirchemical composition with Galactic disc stars. The aim is to look forpossible chemical signatures that might give information about thehistory of this kinematic group of stars. Methods:High-resolution spectra were obtained with the FIES spectrograph at theNordic Optical Telescope, La Palma, and analysed with a differentialmodel atmosphere method. Comparison stars were observed and analysedwith the same method. Results: The average value of [Fe/H] forthe 20 stars investigated in this study is -0.69 ± 0.05 dex.Elemental abundances of oxygen and ?-elements are overabundant incomparison with Galactic thin-disc dwarfs and thin-disc chemicalevolution models. This abundance pattern has similar characteristics asthe Galactic thick-disc. Conclusions: The homogeneous chemicalcomposition together with the kinematic properties and ages of stars inthe investigated Group 3 of the Geneva-Copenhagen survey providesevidence of their common origin and possible relation to an ancientmerging event. The similar chemical composition of stars in theinvestigated group and the thick-disc stars might suggest that theirformation histories are linked.Table 3 is available in electronic form at http://www.aanda.org
| Recent photometry of symbiotic stars
We present new multicolour (U BV R_CI_C) photometric observations ofclassical symbiotic stars, EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1329Cyg, TX CVn, AG Dra, Draco C1, AG Peg, and AX Per, carried out between2007.1 and 2011.9. The aim of this paper is to present new data of ourmonitoring programme, to describe the main features of their lightcurves (LC) and to point problems for their future investigation. Thedata were obtained by the method of the classical photoelectric and CCDphotometry.Tables 2-16 are available at the CDS viahttp://cdsarc.u-strasbg.fr/cgi-bin/qcat?J/AN/333/242
| Bayesian inference of stellar parameters and interstellar extinction using parallaxes and multiband photometry
Astrometric surveys provide the opportunity to measure the absolutemagnitudes of large numbers of stars, but only if the individualline-of-sight extinctions are known. Unfortunately, extinction is highlydegenerate with stellar effective temperature when estimated frombroad-band optical/infrared photometry. To address this problem, Iintroduce a Bayesian method for estimating the intrinsic parameters of astar and its line-of-sight extinction. It uses both photometry andparallaxes in a self-consistent manner in order to provide anon-parametric posterior probability distribution over the parameters.The method makes explicit use of domain knowledge by employing theHertzsprung-Russell Diagram (HRD) to constrain solutions and to ensurethat they respect stellar physics. I first demonstrate this method byusing it to estimate effective temperature and extinction from BVJHKdata for a set of artificially reddened Hipparcos stars, for whichaccurate effective temperatures have been estimated from high-resolutionspectroscopy. Using just the four colours, we see the expected strongdegeneracy (positive correlation) between the temperature andextinction. Introducing the parallax, apparent magnitude and the HRDreduces this degeneracy and improves both the precision (reduces theerror bars) and the accuracy of the parameter estimates, the latter byabout 35 per cent. The resulting accuracy is about 200 K in temperatureand 0.2 mag in extinction. I then apply the method to estimate theseparameters and absolute magnitudes for some 47 000 F, G, K Hipparcosstars which have been cross-matched with Two-Micron All-Sky Survey(2MASS). The method can easily be extended to incorporate the estimationof other parameters, in particular metallicity and surface gravity,making it particularly suitable for the analysis of the 109stars from Gaia.
| The PASTEL catalogue of stellar parameters
Aims: The PASTEL catalogue is an update of the [Fe/H] catalogue,published in 1997 and 2001. It is a bibliographical compilation ofstellar atmospheric parameters providing (T_eff, log g, [Fe/H])determinations obtained from the analysis of high resolution, highsignal-to-noise spectra, carried out with model atmospheres. PASTEL alsoprovides determinations of the one parameter T_eff based on variousmethods. It is aimed in the future to provide also homogenizedatmospheric parameters and elemental abundances, radial and rotationalvelocities. A web interface has been created to query the catalogue onelaborated criteria. PASTEL is also distributed through the CDS databaseand VizieR. Methods: To make it as complete as possible, the mainjournals have been surveyed, as well as the CDS database, to findrelevant publications. The catalogue is regularly updated with newdeterminations found in the literature. Results: As of Febuary2010, PASTEL includes 30151 determinations of either T_eff or (T_eff,log g, [Fe/H]) for 16 649 different stars corresponding to 865bibliographical references. Nearly 6000 stars have a determination ofthe three parameters (T_eff, log g, [Fe/H]) with a high qualityspectroscopic metallicity.The catalogue can be queried through a dedicated web interface at http://pastel.obs.u-bordeaux1.fr/.It is also available in electronic form at the Centre de DonnéesStellaires in Strasbourg (http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/pastel),at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/515/A111
| The spectroscopic evolution of the symbiotic star AG Draconis. I. The O VI Raman, Balmer, and helium emission line variations during the outburst of 2006-2008
Context. AG Dra is one of a small group of low metallicity S-typesymbiotic binaries with K-type giants that undergoes occasionalshort-term outbursts of unknown origin. Aims: Our aim is to studythe behavior of the white dwarf during an outburst using the opticalRaman lines and other emission features in the red giant wind. The goalis to determine changes in the envelope and the wind of the gainer inthis system during a major outburst event and to study the couplingbetween the UV and optical during a major outburst. Methods:Using medium and high resolution groundbased optical spectra andcomparisons with archival FUSE and HST/STIS spectra, we study theevolution of the Raman O VI features and the Balmer, He I, and He IIlines during the outburst from 2006 Sep. through 2007 May and includemore recent observations (2009) to study the subsequent evolution of thesource. Results: The O VI Raman features disappeared completelyat the peak of the major outburst and the subsequent variation differssubstantially from that reported during the previous decade. The He Iand He II lines, and the Balmer lines, vary in phase with the Ramanfeatures but there is a double-valuedness to the He I 6678, 7065relative to the O VI Raman 6825 Å variations in the period between2006-2008 that has not been previously reported. Conclusions: Thevariations in the Raman feature ratio through the outburst interval areconsistent with the disappearance of the O VI FUV resonance wind linesfrom the white dwarf and of the surrounding O+5 ionizedregion within the red giant wind provoked by the expansion and coolingof the white dwarf photosphere.
| The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics
Context: Ages, chemical compositions, velocity vectors, and Galacticorbits for stars in the solar neighbourhood are fundamental test datafor models of Galactic evolution. The Geneva-Copenhagen Survey of theSolar Neighbourhood (Nordström et al. 2004; GCS), amagnitude-complete, kinematically unbiased sample of 16 682 nearby F andG dwarfs, is the largest available sample with complete data for starswith ages spanning that of the disk. Aims: We aim to improve theaccuracy of the GCS data by implementing the recent revision of theHipparcos parallaxes. Methods: The new parallaxes yield improvedastrometric distances for 12 506 stars in the GCS. We also use theparallaxes to verify the distance calibration for uvby? photometryby Holmberg et al. (2007, A&A, 475, 519; GCS II). We add newselection criteria to exclude evolved cool stars giving unreliableresults and derive distances for 3580 stars with large parallax errorsor not observed by Hipparcos. We also check the GCS II scales of T_effand [Fe/H] and find no need for change. Results: Introducing thenew distances, we recompute MV for 16 086 stars, and U, V, W,and Galactic orbital parameters for the 13 520 stars that also haveradial-velocity measurements. We also recompute stellar ages from thePadova stellar evolution models used in GCS I-II, using the new valuesof M_V, and compare them with ages from the Yale-Yonsei andVictoria-Regina models. Finally, we compare the observed age-velocityrelation in W with three simulated disk heating scenarios to show thepotential of the data. Conclusions: With these revisions, thebasic data for the GCS stars should now be as reliable as is possiblewith existing techniques. Further improvement must await consolidationof the T_eff scale from angular diameters and fluxes, and the Gaiatrigonometric parallaxes. We discuss the conditions for improvingcomputed stellar ages from new input data, and for distinguishingdifferent disk heating scenarios from data sets of the size andprecision of the GCS.Full Table 1 is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/941
| Recent photometry of symbiotic stars
We present new photometric observations of 15 symbiotic stars coveringtheir last orbital cycle(s) from 2003.9 to 2007.2. We obtained our databy both classical photoelectric and CCD photometry. Main results are: EGAnd brightened by ˜ 0.3 mag in U from 2003. A ˜0.5 mag deepprimary minimum developed in the U light curve (LC) at the end of 2006.Z And continues its recent activity that began during the 2000 autumn. Anew small outburst started in summer of 2004 with a peak U magnitude of˜ 9.2. During the spring of 2006 the star entered a massiveoutburst. It reached its historical maximum at U˜ 8.0 in 2006July. AE Ara erupted in 2006 February with Δ m_vis ˜ 1.2 mag.BF Cyg entered a new active stage in 2006 August. A brightness maximum(U˜ 9.4) was measured during 2006 September. CH Cyg persists in aquiescent phase. During 2006 June-December a ˜ 2 mag decline inall colours was measured. CI Cyg started a new active phase during 2006May-June. After 31 years it erupted by about 2 mag in U. TX CVnmaintains a bright stage with U ˜ 10.5 from 2003. AG Dra entered anew major outburst in 2006 June. It reached its maximum at U ˜ 8.0in 2006 September. AR Pav persists at a low level of the activity. AGPeg's LC profile varies markedly during different orbital cycles. AX Percontinues its quiescent phase.The Tables of this article are available at the CDS viahttp://cdsarc.u-strasbg.fr/ftp/cats/J/other/AN/328.909
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Effective temperature scale and bolometric corrections from 2MASS photometry
We present a method to determine effective temperatures, angularsemi-diameters and bolometric corrections for population I and II FGKtype stars based on V and 2MASS IR photometry. Accurate calibration isaccomplished by using a sample of solar analogues, whose averagetemperature is assumed to be equal to the solar effective temperature of5777 K. By taking into account all possible sources of error we estimateassociated uncertainties to better than 1% in effective temperature andin the range 1.0-2.5% in angular semi-diameter for unreddened stars.Comparison of our new temperatures with other determinations extractedfrom the literature indicates, in general, remarkably good agreement.These results suggest that the effective temperaure scale of FGK starsis currently established with an accuracy better than 0.5%-1%. Theapplication of the method to a sample of 10 999 dwarfs in the Hipparcoscatalogue allows us to define temperature and bolometric correction (Kband) calibrations as a function of (V-K), [m/H] and log g. Bolometriccorrections in the V and K bands as a function of T_eff, [m/H] and log gare also given. We provide effective temperatures, angularsemi-diameters, radii and bolometric corrections in the V and K bandsfor the 10 999 FGK stars in our sample with the correspondinguncertainties.
| A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)
The LSPM catalog is a comprehensive list of 61,977 stars north of theJ2000 celestial equator that have proper motions larger than 0.15"yr-1 (local-background-stars frame). The catalog has beengenerated primarily as a result of our systematic search for high propermotion stars in the Digitized Sky Surveys using our SUPERBLINK software.At brighter magnitudes, the catalog incorporates stars and data from theTycho-2 Catalogue and also, to a lesser extent, from the All-SkyCompiled Catalogue of 2.5 million stars. The LSPM catalog considerablyexpands over the old Luyten (Luyten Half-Second [LHS] and New LuytenTwo-Tenths [NLTT]) catalogs, superseding them for northern declinations.Positions are given with an accuracy of <~100 mas at the 2000.0epoch, and absolute proper motions are given with an accuracy of ~8 masyr-1. Corrections to the local-background-stars propermotions have been calculated, and absolute proper motions in theextragalactic frame are given. Whenever available, we also give opticalBT and VT magnitudes (from Tycho-2, ASCC-2.5),photographic BJ, RF, and IN magnitudes(from USNO-B1 catalog), and infrared J, H, and Ks magnitudes(from 2MASS). We also provide an estimated V magnitude and V-J color fornearly all catalog entries, useful for initial classification of thestars. The catalog is estimated to be over 99% complete at high Galacticlatitudes (|b|>15deg) and over 90% complete at lowGalactic latitudes (|b|>15deg), down to a magnitudeV=19.0, and has a limiting magnitude V=21.0. All the northern starslisted in the LHS and NLTT catalogs have been reidentified, and theirpositions, proper motions, and magnitudes reevaluated. The catalog alsolists a large number of completely new objects, which promise to expandvery significantly the census of red dwarfs, subdwarfs, and white dwarfsin the vicinity of the Sun.Based on data mining of the Digitized Sky Surveys (DSSs), developed andoperated by the Catalogs and Surveys Branch of the Space TelescopeScience Institute (STScI), Baltimore.Developed with support from the National Science Foundation (NSF), aspart of the NASA/NSF NStars program.
| The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of 14 000 F and G dwarfs
We present and discuss new determinations of metallicity, rotation, age,kinematics, and Galactic orbits for a complete, magnitude-limited, andkinematically unbiased sample of 16 682 nearby F and G dwarf stars. Our63 000 new, accurate radial-velocity observations for nearly 13 500stars allow identification of most of the binary stars in the sampleand, together with published uvbyβ photometry, Hipparcosparallaxes, Tycho-2 proper motions, and a few earlier radial velocities,complete the kinematic information for 14 139 stars. These high-qualityvelocity data are supplemented by effective temperatures andmetallicities newly derived from recent and/or revised calibrations. Theremaining stars either lack Hipparcos data or have fast rotation. Amajor effort has been devoted to the determination of new isochrone agesfor all stars for which this is possible. Particular attention has beengiven to a realistic treatment of statistical biases and errorestimates, as standard techniques tend to underestimate these effectsand introduce spurious features in the age distributions. Our ages agreewell with those by Edvardsson et al. (\cite{edv93}), despite severalastrophysical and computational improvements since then. We demonstrate,however, how strong observational and theoretical biases cause thedistribution of the observed ages to be very different from that of thetrue age distribution of the sample. Among the many basic relations ofthe Galactic disk that can be reinvestigated from the data presentedhere, we revisit the metallicity distribution of the G dwarfs and theage-metallicity, age-velocity, and metallicity-velocity relations of theSolar neighbourhood. Our first results confirm the lack of metal-poor Gdwarfs relative to closed-box model predictions (the ``G dwarfproblem''), the existence of radial metallicity gradients in the disk,the small change in mean metallicity of the thin disk since itsformation and the substantial scatter in metallicity at all ages, andthe continuing kinematic heating of the thin disk with an efficiencyconsistent with that expected for a combination of spiral arms and giantmolecular clouds. Distinct features in the distribution of the Vcomponent of the space motion are extended in age and metallicity,corresponding to the effects of stochastic spiral waves rather thanclassical moving groups, and may complicate the identification ofthick-disk stars from kinematic criteria. More advanced analyses of thisrich material will require careful simulations of the selection criteriafor the sample and the distribution of observational errors.Based on observations made with the Danish 1.5-m telescope at ESO, LaSilla, Chile, and with the Swiss 1-m telescope at Observatoire deHaute-Provence, France.Complete Tables 1 and 2 are only available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/989
| Photometry of symbiotic stars. XI. EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, RW Hya, AR Pav, AG Peg, AX Per, QW Sge, IV Vir and the LMXB V934 Her
We present new photometric observations of EG And, Z And, BF Cyg, CHCyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, RW Hya, AG Peg, AX Per, IV Virand the peculiar M giant V934 Her, which were made in the standardJohnson UBV(R) system. QW Sge was measured in the Kron-Cousin B, V,RC, IC system and for AR Pav we present its newvisual estimates. The current issue gathers observations of theseobjects to December 2003. The main results can be summarized as follows:EG And: The primary minimum in the U light curve (LC) occurred at theend of 2002. A 0.2 -- 0.3 mag brightening in U was detected in theautumn of 2003. Z And: At around August 2002 we detected for the firsttime a minimum, which is due to eclipse of the active object by the redgiant. Measurements from 2003.3 are close to those of a quiescent phase.BF Cyg: In February 2003 a short-term flare developed in the LC. Adifference in the depth of recent minima was detected. CH Cyg: This starwas in a quiescent phase at a rather bright state. A shallow minimumoccurred at JD 2 452 730, close to the position of the inferiorconjunction of the giant in the inner binary of the triple-star model ofCH Cyg. CI Cyg: Our observations cover the descending branch of a broadminimum. TX CVn: At/around the beginning of 2003 the star entered abright stage containing a minimum at JD 2 452 660. AG Dra: Newobservations revealed two eruptions, which peaked in October 2002 and2003 at 9.3 in U. AR Pav: Our new visual estimates showed atransient disappearance of a wave-like modulation in the star'sbrightness between the minima at epochs E = 66 and E = 68 and itsreappearance. AG Peg: Our measurements from the end of 2001 showedrather complex profile of the LC. RW Hya: Observations follow behaviourof the wave-like variability of quiet symbiotics. AX Per: In May 2003 a0.5 mag flare was detected following a rapid decrease of the light to aminimum. QW Sge: CCD observations in B, V, RC, ICbands cover a period from 1994.5 to 2003.5. An increase in the star'sbrightness by about 1 mag was observed in all passbands in 1997. Lesspronounced brightening was detected in 1999/2000. V934 Her: Ourobservations did not show any larger variation in the optical as areaction to its X-ray activity.
| Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
We complete construction of a catalog containing improved astrometry andnew optical/infrared photometry for the vast majority of NLTT starslying in the overlap of regions covered by POSS I and by the secondincremental Two Micron All Sky Survey (2MASS) release, approximately 44%of the sky. The epoch 2000 positions are typically accurate to 130 mas,the proper motions to 5.5 mas yr-1, and the V-J colors to0.25 mag. Relative proper motions of binary components are measured to 3mas yr-1. The false-identification rate is ~1% for11<~V<~18 and substantially less at brighter magnitudes. Theseimprovements permit the construction of a reduced proper-motion diagramthat, for the first time, allows one to classify NLTT stars intomain-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We inturn use this diagram to analyze the properties of both our catalog andthe NLTT catalog on which it is based. In sharp contrast to popularbelief, we find that NLTT incompleteness in the plane is almostcompletely concentrated in MS stars, and that SDs and WDs are detectedalmost uniformly over the sky δ>-33deg. Our catalogwill therefore provide a powerful tool to probe these populationsstatistically, as well as to reliably identify individual SDs and WDs.
| Search for variations in circular-polarization spectra of the magnetic white dwarf LP 790-29
We present highly time resolved circular-polarization and flux spectraof the magnetic white dwarf LP 790-29 taken with the VLT UT1 in order totest the hypothesis that LP 790-29 is a fast rotator with a period ofthe order of seconds to minutes. Due to low time resolution of formerobservations this might have been overlooked - leading to the conclusionthat LP 790-29 has a rotational period of over 100 years. The opticalspectrum exhibits one prominent absorption feature with minima at about4500, 4950, and 5350 Å, which are most likely C_2 Swan-bandsshifted by about 180 Å in a magnetic field between 50 MG and 200MG. At the position of the absorption structures the degree of circularpolarization varies between -1% and +1%, whereas it amounts to +8 to+10% in the blue and red continuum. With this very high degree ofpolarization LP 790-29 is very well suited to a search for short timevariations, since a variation of several percent in the polarization canbe expected for a magnetic field oblique to the rotational axis. Fromour analysis we conclude that variations on time scales from 50 to 2500s must have amplitudes ?0.7% in the continuum and ?2% in thestrongest absorption feature at 4950 Å. While no short-termvariations could be found a careful comparison of our polarization dataof LP 790-29 with those in the literatures indicates significantvariations on time scales of decades with a possible period of about24-28 years. Based on observations collected at the European SouthernObservatory, Paranal, Chile (ESO Programme 65.H-0293).
| Recent Outburst of AG DRA has Finished
Not Available
| Photometric study of the eclipsing binary EG CEP
New photoelectric B and V observations of EG Cep were taken and 11 newminima times were determined. They confirm the long-term increase of theorbital period. The light-curve analysis shows that the system issemi-detached. Mass transfer from the less to the more massive componentis responsible for the observed orbital period increase. Variations inthe transferred matter projected onto the surface of the components areresponsible for the colour dependent variable shift of the minima. Thiseffect, more pronounced in the secondary minima, explains also thedisagreement of the limb-darkening coefficient of the secondarycomponent with the theoretical value.
| UBV Observations of AG DRA during the 1996-1997 Active Phase
UBV photometric data of the symbiotic system AG Dra have been obtainedin 1996 and 1997 during active phase. Two light maxima have beendetected, followed by a decline of the star's brightness almost to itsquiescent magnitude. It is concluded that the growth of the UBV fluxesresults from an increase of the emission measure of the nebula, causedby a larger production of both the ionizing photons and the hot starwind, which developed during the outburst.
| Photometry of the 1994-1995 Active Phase of AG Dra
Not Available
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| The general catalogue of trigonometric [stellar] paralaxes
Not Available
| UBVR Photometry of the Symbiotic Star AG Dra in its 1994 Outburst
Not Available
| AG Draconis
IAUC 6073 available at Central Bureau for Astronomical Telegrams.IAUC 6073 available at Central Bureau for Astronomical Telegrams.
| The light variation of AG Draconis in its quiet state
Light curves of the yellow symbiotic star AG Draconis are constructed in11 intermediate and narrow wavelength bands from the near ultraviolet tothe far red, using observations made while the star was in its normalstate. The curves from Stromgren uvby, 4428 A, and at wide and narrowH-beta are obtained over the entire 1311-day observing interval. Theperiodic variation of the system is the largest by far at u, and becomessmaller with increasing wavelength until it disappears in the red. Theflux at y passes through a minimum with u, but dips again as, orslightly after, u goes through maximum. The latter event probablyrepresents a secondary eclipse of the K giant by the orbiting gasaccreting onto the dwarf companion, from which a gas-cloud diameter ofabout 1.6 AU can be inferred. Superimposed on the smooth u light curveare relatively sudden variations with amplitudes of less than about 0.1mag that occur within intervals of a few days.
| New subdwarfs. VI - Kinematics of 1125 high-proper-motion stars and the collapse of the Galaxy
The UVW velocity components, planar eccentricities, and angular momentaof 878 high-proper-motion stars are determined using the radial-velocitydata of Fouts and Sandage (1986) and compared with chemical abundancesand photometric parallaxes from the UBV photometry of Sandage and Kowal(1986). The results are presented, along with published data on 247additional stars, in extensive tables and graphs and characterized indetail. Two approximately equal components are differentiated: alow-velocity component identified as part of the thick disk described byGilmore and Reid (1983) and a high-velocity halo component. The data arefound to support a model of Galactic collapse (with concomitant spinupand progressive chemical enrichment) which includes a rotating bulge(the thick disk) with kinematic and metallicity properties between thoseof the old thin disk and the halo.
| UBV Observations of Symbiotic Stars in July and October 1982
Not Available
| Spectral classification of high-proper-motion stars
Spectral types have been found for about 900 stars of high proper motioncontained in the Lowell Observatory Northern Hemisphere proper-motionstar survey using all blue-region objective prism plates. The spectralclassification criteria are given. About eighty stars of largetangential velocity have been classified using slit spectrograms takenwith a 36-in. reflector. A new calibration of Luyten's absolutemagnitude vs reduced proper motion relation is made, and its dependenceon spectral type is investigated.
| Photoelectric Observations of the Symbiotic Stars Ch-Cygni Ag-Draconis and the Peculiar Object Pu-Vulpeculae during the Maximum of Their Activity in the Years 1981-1982
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1984CoSka..12..261C&db_key=AST
| Erratum - Errors or Omissions in Star-Identifications in the General Catalogue of Trigonometric Stellar Parallaxes
Not Available
| Three-dimensional motion of dwarf stars and RR Lyrae variables
A collection of 220 high-velocity dwarfs, 532 low-velocity dwarfs, and114 RR Lyrae variables is given in tables with calculations ofkinematical quantities in a three-dimensional model of galactic space. Ametal indicator, Delta-S, for RR Lyrae variables is transformed into theultraviolet excess, delta (0.6), which is utilized for a statisticalstudy of kinematics under the same metallicity classification. It isfound that the primordial Galaxy contracted by a factor of at least 20in the radial direction as compared to at least 50 in the Z direction.
| Spectral types for proper motion stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975AJ.....80..239B&db_key=AST
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Группы:
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Наблюдательные данные и астрометрия
| Созвездие: | Дракон |
| Прямое восхождение: | 16h05m20.53s |
| Склонение: | +66°47'22.3" |
| Видимая звёздная величина: | 9.862 |
| Собственное движение RA: | -144.2 |
| Собственное движение Dec: | 170.7 |
| B-T magnitude: | 10.615 |
| V-T magnitude: | 9.925 |
Каталоги и обозначения:
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