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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.
| Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm
| Multiperiodicity in the atypical delta SCT star AN Lyn
New uvby data collected of AN Lyn together with the reanalysis of olddata establish that this star is a multiperiodic pulsator. Threeindependent frequencies (nu _1=10.1756, nu _2=18.1309 and nu _3=9.5598cd(-1) ) and some interactions between them are found to be present inthe light curve. Changes in amplitude with a large time scale areconfirmed for the main frequency. Moreover, changes in amplitude arealso present for the secondary frequencies, especially for nu _3. Aftersubtraction of the secondary frequencies from the light curves, theclassical O-C method has been used to analyse the behaviour of the mainperiod. A comparison is made between AN Lyn and the other two knowndelta Sct stars with atypical light curves, i.e., V1719 Cyg and V798Cyg. New uvby data have been also collected for V1719 Cyg and the O-Cmethod has been used to analyse the behaviour of the main period. It isfound that the main pulsation of this star can be well described bymeans of a linear ephemeris with a period of P=0.(d) 26729700 over thelast eighteen years. Finally, analysis of the different data setsavailable in the literature do not reveal significative changes in theamplitude of the main frequency of V1719 Cyg. Table 5 will be accessibleonly in electronic form at the CDS
| AN Lyn: an unusual medium amplitude δ SCT star.
Simultaneous uvbyβ photometric observations of the medium amplitudeδ Sct star AN Lyn have been collected and new times of lightmaxima have been obtained. The Fourier transform and classical O-Cmethods are used to analyse the pulsation of this star. The light curvesare peculiar in the sense that the descending branches are steeper thanthe ascending ones. Amplitude variations are shown to be present fromseason to season. The analysis of the phase shifts between observedlight and colour variations suggests that this star is a radialpulsator. In addition, intrinsic b-y, m_1_ and c_1_ values are alsoderived and the physical parameters are determined indicating that thisvariable is a nearly cold and evolved δ Sct star showing solarmetal abundances and pulsating in the second overtone.
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
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Osservazione e dati astrometrici
| Costellazione: | Lince |
| Ascensione retta: | 09h10m07.02s |
| Declinazione: | +42°56'25.4" |
| Magnitudine apparente: | 8.769 |
| Distanza: | 207.469 parsec |
| Moto proprio RA: | -13.2 |
| Moto proprio Dec: | -6.2 |
| B-T magnitude: | 9.051 |
| V-T magnitude: | 8.793 |
Cataloghi e designazioni:
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