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The Near-Infrared Size-Luminosity Relations for Herbig Ae/Be Disks
We report the results of a sensitive K-band survey of Herbig Ae/Be disksizes using the 85 m baseline Keck Interferometer. Targets were chosento span the maximum range of stellar properties to probe the disk sizedependence on luminosity and effective temperature. For most targets,the measured near-infrared sizes (ranging from 0.2 to 4 AU) support asimple disk model possessing a central optically thin (dust-free)cavity, ringed by hot dust emitting at the expected sublimationtemperatures (Ts~1000-1500 K). Furthermore, we find a tightcorrelation of disk size with source luminosity R~L1/2 for Aeand late Be systems (valid over more than two decades in luminosity),confirming earlier suggestions based on lower quality data.Interestingly, the inferred dust-free inner cavities of the highestluminosity sources (Herbig B0-B3 stars) are undersized compared topredictions of the ``optically thin cavity'' model, likely because ofoptically thick gas within the inner AU.
| Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| A study of the open cluster NGC 7209 in the Vilnius photometric system
Photoelectric photometry in the Vilnius seven-colour system is presentedfor the open cluster NGC 7209. In total 96 probable cluster members havebeen measured down to V~14.0. For all stars their spectral types,absolute magnitudes, colour excesses, interstellar reddening anddistances are derived from the Vilnius photometry. The metallicity isestimated to be [Fe/H]=-0.07. In addition, a list of suspected binariesis provided. The reddening across the cluster shows a slight trend alongthe north-south direction. The mean reddening equals E(Y-V)=0.121 [inthe UBV system E(B-V)=0.171] which corresponds to A_V=0.54. The derivedmedian distance for NGC 7209 is 1026+/-30pc (equivalent to the distancemodulus V_0-M_V=10.06+/-0.06). Theoretical isochrone fits to thecolour-magnitude diagram yield an age estimate of 0.45Gyr.
| DDO Metal Abundances of High-Luminosity Late-Type Stars in Galactic Open Clusters
Results from UBV and DDO photometry are presented for 54 high-luminositylate-type stars in the fields of 23 open clusters. The probability ofcluster membership for each observed star is evaluated using twoindependent photometric criteria. It is found that 32 stars are verylikely cluster members, the remaining ones being almost certainly fieldobjects. The recently improved calibrations of the DDO system have beenused to derive MK spectral types, effective temperatures, andmetallicities, while E(B-V) color excesses have been determined throughknown photometric and spectroscopic procedures. The DDO metallicitiesrange between values typical of moderately metal-poor ([Fe/H]=~ -0.3) tomoderately metal-rich ([Fe/H] =~ 0.2) clusters. The masses of thecluster giants range between 1 and 4 solar masses, with the scatterwithin a cluster being less than 1 solar mass. (SECTION: StellarClusters and Associations)
| The studies of proper motions in the regions of open clusters. III - NGC 7209
Relative proper motions of 4290 stars in the region of the open clusterNGC 7209 have been determined from the PDS measurements of 12 Pulkovoand one Tashkent normal astrograph plates. In a 28-arcmin-diametercircle around the cluster 148 stars have membership probabilities Pgreater than 0 percent. The total number of cluster stars obtained byweighting them with membership probabilities reaches 109. The catalog ofproper motions is complete down to m(pg) = 15.1 mag; the limiting valueis 15.6 mag.
| Spectral Classification in Nine Open Clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1962ApJ...136..788S&db_key=AST
| Spectral Classification in Some Open Clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961ApJ...134..612S&db_key=AST
| Untersuchungen der offenen Sternhaufen NGC 7092 (M 39), NGC 7209, und NCG [sic] 7243
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Osservazione e dati astrometrici
| Costellazione: | Lucertola |
| Ascensione retta: | 22h05m17.62s |
| Declinazione: | +46°29'00.6" |
| Magnitudine apparente: | 9.436 |
| Moto proprio RA: | 3.1 |
| Moto proprio Dec: | -4 |
| B-T magnitude: | 11.456 |
| V-T magnitude: | 9.603 |
Cataloghi e designazioni:
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