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Stellar Parameters and Photospheric Abundances of Late-G Giants: Properties of the Targets of the Okayama Planet Search Program
Towards clarifying the properties of late-G giants, for which we arecurrently conducting a planet-search project at Okayama AstrophysicalObservatory, an extensive spectroscopic study has been performed for ourfirst target sample of fifty-seven G6-G9 III stars, in order toestablish the atmospheric parameters (Teff, log g,vt, and [Fe/H]), the stellar mass along with the evolutionarystatus, and the photospheric abundances of various elements. It wasconfirmed that the conventional spectroscopic method of parameterdetermination using Fe I / II lines with the assumption of LTE workssuccessfully for these evolved stars. We determined the abundances(relative to the Sun) of 19 elements, and examined how their [X/Fe]ratios behave themselves with the run of [Fe/H]. While the trends appearto be similar to those exhibited by disk dwarfs for a number ofelements, some elements (C, O, Na) showed appreciable anomalies, whichmay be interpreted as being due to a dredge-up of nuclear-processedmaterial. Since the [Fe/H] values of these stars tend to be somewhatbiased towards a subsolar regime, some mechanism of slightly reducingthe metallicity might be suspected.
| Radial-Velocity Variability of G-Type Giants: First Three Years of the Okayama Planet Search Program
We report on the radial-velocity variability of G-type giants based onthe results of precise Doppler measurements of 57 stars that wereobserved for the first 3 years of the Okayama Planet Search Program.This program aims to search for planets around intermediate-mass starsin their evolved stages as late-G giants. We found that most of thetargets with B ‑ V < 1.0 have radial-velocity scatters ofσ 10 m s-1, with the most stable reaching levels of6‑8 m s-1, while those with B ‑ V > 1.0 typically showσ 20 m s-1. In total, about 60% of the targets are stable inradial velocity to a level of σ < 15 m s-1 over 1-3 years, andabout 90% have σ < 30 m s-1. We found that 4 stars (HD 30557,HD 34559, HD 68077, and HD 85444) show significant long-termradial-velocity trends, suggesting that they are probably orbited byunseen stellar or substellar companions. Three stars (HD 79181, HD104985, and HD 141680) show periodic radial-velocity variations. HD104985 is the first planet-harboring star discovered from our survey.The properties of the variations in these 3 stars have been, and willbe, extensively discussed in separate papers. Relatively large, but notapparently periodic, radial-velocity variations of σ > 30 m s-1are found in 4 stars (HD 41597, HD 134190, HD 161178, and HD 176598).For most of the stars without showing any significant periodicity, wecan exclude companions with K > 50 m s-1, or m2sini > 1.8 MJ (a/AU)1/2(M*/Mȯ)1/2 for orbital radii a ≲ 1‑2 AU.
| Adaptive Optics Photometry and Astrometry of Binary Stars
We present astrometric and photometric measurements of 39 binary starsmade with the adaptive optics system on the 3.6 m AdvancedElectro-Optical System (AEOS) telescope, taken from 2002 November to2003 March. The binaries have separations ranging from 0.08" to 5.11"and differential magnitudes ranging from 0.096 to 7.9. Also, we includea list of observations of 23 known binaries that we were unable toresolve. In the process of these measurements, we discovered three newcompanions to two previously known binary stars. We also discuss theeffects of scintillation and anisoplanatism on measurements of binarystar photometry in adaptive optics images. Suggestions on how tominimize these effects are then given.Based on observations made at the Maui Space Surveillance Systemoperated by Detachment 15 of the US Air Force Research Laboratory'sDirected Energy Directorate.
| CCD Speckle Observations of Binary Stars from the Southern Hemisphere. III. Differential Photometry
Two hundred seventy-two magnitude difference measures of 135 double starsystems are presented. The results are derived from speckle observationsusing the Bessel V and R passbands and a fast readout CCD camera.Observations were taken at two 60 cm telescopes, namely the Helen SawyerHogg Telescope, formerly at Las Campanas, Chile, and the Lowell-TololoTelescope at the Cerro Tololo Inter-American Observatory, Chile. Thedata analysis method is presented and, in comparing the results to thoseof Hipparcos as well as to recent results using adaptive optics, we findvery good agreement. Overall, the measurement precision appears to bedependent on seeing and other factors but is generally in the range of0.10-0.15 mag for single observations under favorable observingconditions. In four cases, multiple observations in both V and R allowedfor the derivation of component V-R colors with uncertainties of 0.11mag or less. Spectral types are assigned and preliminary effectivetemperatures are estimated in these cases.
| CCD Speckle Observations of Binary Stars from the Southern Hemisphere. II. Measures from the Lowell-Tololo Telescope during 1999
Speckle observations of 145 double stars and suspected double stars arepresented and discussed. On the basis of multiple observations, a totalof 280 position angle and separation measures are determined, as well as23 high-quality nondetections. All observations were taken with the(unintensified) Rochester Institute of Technology fast-readout CCDcamera mounted on the Lowell-Tololo 61 cm telescope at the Cerro TololoInter-American Observatory during 1999 October. We find that themeasures, when judged as a whole against ephemeris positions of binarieswith very well-known orbits, have root mean square deviations of1.8d+/-0.3d in position angle and 13+/-2 mas in separation. Elevendouble stars discovered by Hipparcos were also successfully observed,and the change in position angle and/or separation since the Hipparcosobservations was substantial in three cases.
| Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| Speckle Observations of Binary Stars with the WIYN Telescope. I. Measures During 1997
Two hundred seventy-seven position angle and separation measures of 154double stars are presented. Three of the systems were previously unknownto be double, and 16 other systems were discovered earlier this decadeby the Hipparcos satellite. Measures are derived from speckleobservations taken with the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5 mtelescope located at Kitt Peak, Arizona. Speckle images were obtainedusing two different imaging detectors, namely, a multianode microchannelarray (MAMA) detector and a fast-readout CCD. A measurement precisionstudy was performed on a sample of binaries with extremely well knownorbits by comparing the measures obtained here to the ephemerispredictions. For the CCD, the root mean square (rms) deviation ofresiduals was found to be 3.5 milliarcseconds (mas) in separation and1.2d in position angle, while the residuals of the MAMA data varieddepending on the magnification used and seeing conditions but can becomparable or superior to the CCD values. In addition, the two cameraswere compared in terms of the detection limit in total magnitude andmagnitude difference of the systems under study. The MAMA system has theability to detect some systems with magnitude differences larger than3.5, although reliable astrometry could not be obtained on theseobjects. Reliable astrometry was obtained on a system of magnitudedifference of 5.3 with the CCD system.
| A catalog of rotational and radial velocities for evolved stars
Rotational and radial velocities have been measured for about 2000evolved stars of luminosity classes IV, III, II and Ib covering thespectral region F, G and K. The survey was carried out with the CORAVELspectrometer. The precision for the radial velocities is better than0.30 km s-1, whereas for the rotational velocity measurementsthe uncertainties are typically 1.0 km s-1 for subgiants andgiants and 2.0 km s-1 for class II giants and Ib supergiants.These data will add constraints to studies of the rotational behaviourof evolved stars as well as solid informations concerning the presenceof external rotational brakes, tidal interactions in evolved binarysystems and on the link between rotation, chemical abundance and stellaractivity. In this paper we present the rotational velocity v sin i andthe mean radial velocity for the stars of luminosity classes IV, III andII. Based on observations collected at the Haute--Provence Observatory,Saint--Michel, France and at the European Southern Observatory, LaSilla, Chile. Table \ref{tab5} also available in electronic form at CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Measurements of double stars 1993.67 - 1998.13
624 Micrometer Measurements of 224 pairs with a 32.5 cm Cassegrain, 719Measurements of 310 double stars with a 360 mm Newtonian are given.Tables 1 to 4 are available in electronic form only at the CDS130.79.128.5 or via http://cdsweb.u-strasbg.fr/Abstract.html
| Mesures de vitesses radiales. VIII. Accompagnement AU sol DU programme d'observation DU satellite HIPPARCOS
We publish 1879 radial velocities of stars distributed in 105 fields of4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbachet al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90}using the Fehrenbach objective prism method. Table 1 only available inelectronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| Observations of Double Stars and New Pairs. XVII.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..105..475H&db_key=AST
| The photoelectric astrolabe catalogue of Yunnan Observatory (YPAC).
The positions of 53 FK5, 70 FK5 Extension and 486 GC stars are given forthe equator and equinox J2000.0 and for the mean observation epoch ofeach star. They are determined with the photoelectric astrolabe ofYunnan Observatory. The internal mean errors in right ascension anddeclination are +/- 0.046" and +/- 0.059", respectively. The meanobservation epoch is 1989.51.
| Ca II H and K Filter Photometry on the UVBY System. II. The Catalog of Observations
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2828T&db_key=AST
| 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.
| Evolved GK stars near the Sun. 2: The young disk population
From a sample of nearly 2000 GK giants a group of young disk stars withwell determined space motions has been selected. The zero point of theluminosity calibrations, both from the ultraviolet flux (modifiedStroemgren system) and that in the region of 4200 to 4900 A (DDOsystem), show a discontinuity of about a half magnitude at the border ofthe young disk and old disk domains. The population separation is basedon the space velocity components, which are also an age discriminant,with the population interface near 2 x 109 yr, based onmodels with convective overshoot at the core. This age corresponds togiant masses near 1.7 solar mass, near the critical mass separating theyoung stars that do not burn helium in degenerate cores from older starsthat do. Ten percent of both populations show CN anomalies in that thederived value of P(Fe/H) from CN (Cm) and fromFe(M1) differ by more than 0.1 dex and the weak and strong CNstars occur equally in the old disk but the weak CN stars predominate inthe young disk. Peculiar stars, where flux distortions affect theluminosity calibrations, are of the CH+(Ba II) and CH-(weak G band)variety and represent less than 1% of the stars in both populations. Theyoung disk giants are restricted to ages greater than about109 yr, because younger stars are bright giants orsupergiants (luminosity class 2 or 1), and younger than about 2 x109 yr, because the old disk-young disk boundary occurs near1.7 solar mass. The distribution of heavy element abundances, P(Fe/H),for young disk giants is both more limited in range (+/- 0.4 dex) and isskewed toward higher abundances, compared with the nearly normaldistribution for old disk giants. The distribution of (U,V) velocityvectors gives (U,V,W) and their dispersions = (+17.6 +/- 18.4, -14.8 +/-8.4, -6.9 +/- 13.0) and (+3.6 +/- 38.4, -20.7 +/- 27.5, -6.7 +/-17.3)km/s for young and old disk giants, respectively.
| Observations of double stars and new pairs. XV
The study reports visual and photographic measures listed for 1150 pairsobtained in the time frame 1989.91-1992.15, including 221 new doublestars. Magnitudes were estimated for a part of the objects, especiallythe fainter ones. Plate orientations were calculated from field stars ofknown positions and were precessed to the epoch; numbers of nights andof measured exposures are given. Reobservation of faint, neglected pairsreveal many corrections to the data from the old discovery lists.
| Large and Kinematically Unbiased Samples of G- and K-Type Stars. III. Evolved Young Disk Stars in the Bright Star Sample
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989PASP..101...54E&db_key=AST
| Large and kinematically unbiased samples of G- and K-type stars. II - Observations of evolved stars in the Bright Star sample. III - Evolved young disk stars in the Bright Star sample
Four color and RI observations were obtained for a large sample ofG-type and K-type stars in the Bright Star Catalogue. Data are firstpresented for 110 evolved stars. Photometry of evolved young diskpopulation stars have then been calibrated for luminosity, reddening,and metallicity on the basis of results for members of the Hyades andSirius superclusters. New DDO results are given for 120 stars.
| Ultraviolet and optical studies of binaries with luminous cool primaries and hot companions. II - BVRI observations
Johnson system BVRI measurements are presented for 117 stars, most ofthem with no previous R and I photometry and many with no previous B andV. The prime objects for measurement are unresolved or nearly unresolvedbinaries containing a late-type giant or supergiant and an early-typecompanion. Other objects on the program include suspected binaries andother F-G giants and supergiants lacking at least R and I magnitudes.The variable F and G supergiants 1 Mon, 89 Her, HR 7308, HR 8157, HR8752, and rho-Cas and the eclipsing systems W Ser and ST Aqr wereobserved; HR 8752 showed significant dimming and cooling over 125 days.Several of Halliwell's (1979) candidates for nearby stars were measured.
| Uvby-Beta Photometry of Equatorial and Southern Bright Stars - Part Two
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&AS...42..311H&db_key=AST
| MK spectral types for some F and G stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1979PASP...91...83C&db_key=AST
| DDO intermediate-band photometry of moving-group stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975PASP...87...17B&db_key=AST
| MK classifications for F-and G-type stars. 3.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974AJ.....79..682H&db_key=AST
| The red giants in the Hyades group
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972PASP...84..406E&db_key=AST
| Strong-Cyanogen Stars: Photometry and Kinematics
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971ApJ...165..561J&db_key=AST
| Catalog of Indidual Radial Velocities, 0h-12h, Measured by Astronomers of the Mount Wilson Observatory
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJS...19..387A&db_key=AST
| KURZE MITTEILUNG. Zur Expansion der Assoziation Cep III
Not Available
| UBV photometry of 550 F, G and K type stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1966MNRAS.133..475A&db_key=AST
| On the structure of the Hyades cluster
Not Available
| Some spectral criteria for the determination of absolute stellar magnitudes.
Not Available
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| Takýmyýldýz: | Avci |
| Sað Açýklýk: | 05h50m02.60s |
| Yükselim: | +09°52'16.0" |
| Görünürdeki Parlaklýk: | 5.8 |
| Uzaklýk: | 102.354 parsek |
| özdevim Sað Açýklýk: | 13.3 |
| özdevim Yükselim: | -5.8 |
| B-T magnitude: | 7.061 |
| V-T magnitude: | 5.972 |
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