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Speckle Observations of Binary Stars with the WIYN Telescope. VII. Measures during 2008-2009
Five hundred thirty-one speckle measures of binary stars are reported.These data were taken mainly during the period 2008 June through 2009October at the WIYN 3.5 m Telescope at Kitt Peak and represent the lastdata set of single-filter speckle observations taken in the WIYN speckleprogram prior to the use of the current two-channel speckle camera. Theastrometric and photometric precision of these observations isconsistent with previous papers in this series: we obtain a typicallinear measurement uncertainty of approximately 2.5 mas, and themagnitude differences reported have typical uncertainties in the rangeof 0.1-0.14 mag. In combination with measures already in the literature,the data presented here permit the revision of the orbit of A 1634AB (=HIP 76041) and the first determination of visual orbital elements forHDS 1895 (= HIP 65982).The WIYN Observatory is a joint facility of the University ofWisconsin-Madison, Indiana University, Yale University, and the NationalOptical Astronomy Observatories.
| 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.
| Observations of Binary Stars with the Differential Speckle Survey Instrument. II. Hipparcos Stars Observed in 2010 January and June
The results of 497 speckle observations of Hipparcos stars and selectedother targets are presented. Of these, 367 were resolved into componentsand 130 were unresolved. The data were obtained using the DifferentialSpeckle Survey Instrument at the WIYN 3.5 m Telescope. (The WIYNObservatory is a joint facility of the University of Wisconsin-Madison,Indiana University, Yale University, and the National Optical AstronomyObservatories.) Since the first paper in this series, the instrument hasbeen upgraded so that it now uses two electron-multiplying CCD cameras.The measurement precision obtained when comparing to ephemeris positionsof binaries with very well known orbits is approximately 1-2 mas inseparation and better than 0fdg6 in position angle. Differentialphotometry is found to be in very good agreement with Hipparcos measuresin cases where the comparison is most relevant. We derive preliminaryorbits for two systems.
| 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.
| Mesures d'etoiles doubles faites aux lunettes de 74 et 50 CM de l'Observatoire de la Cote d'Azur
We give 657 measurements of double stars, Table 1 by R. Gili with CCDcamera, Table 2 by P. Couteau with filar micrometer. Tables 1 and 2 areonly available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html.
| Measurements of double stars at Nice with 74-cm and 50-cm refractors
A total of 717 measures of 287 binaries made at the 74-cm and 50-cmrefractors are presented. These are mostly very close binariesdiscovered recently, for which a rapid orbital motion is evident forabout 30 percent.
| New binary stars /17th series/ discovered at Nice
The discovery of 150 new binary stars by means of a 50 cm telescope isreported. The stars observed are listed, along with the magnitude, rightascension, type, separation, annual path, and probable period.
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| Takýmyýldýz: | Av Kopekleri |
| Sað Açýklýk: | 13h29m16.22s |
| Yükselim: | +48°46'39.9" |
| Görünürdeki Parlaklýk: | 10.568 |
| özdevim Sað Açýklýk: | -87.7 |
| özdevim Yükselim: | 49.7 |
| B-T magnitude: | 11.679 |
| V-T magnitude: | 10.66 |
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