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Colour excesses of F-G supergiants and Cepheids from Geneva photometry.
A reddening scale for F-G supergiants and Cepheids is presented.Supergiants with low reddenings or in clusters form the basis of thecalibration. In this sense, it is entirely empirical. The data have beenobtained in the Geneva photometric system. Comparisons with otherreddening scales show no disagreement. The only problem is with Fernie'sscale for Cepheids (1990), where a systematic trend exists. Its originis not clear. It is suggested to extend the number of supergiants withindependently obtained colour excesses in order to test the existence ofa possible luminosity dependence of the calibration. A period-colourrelation for Cepheids is deduced, on the basis of the present reddeningcorrections. It gives strong support for V473 Lyr being a secondovertone pulsator.
| Kinematics of Sandage-Fouts stars in three cardinal directions
V and (B - V) for 429, 442, and 427 stars are observed in the directionsof the anticenter, Cygnus, and the NGP, respectively, and DDO colors forthose stars G0 and later. The samples observed are ones for whichSandage and Fouts (1987) have published radial velocities. W, V, and Wcomponents of space velocity are derived from DDO distances withavailable proper motions. A clear correlation was found to exist betweenthe velocity dispersions and Fe/H with the dispersions decreasing asFe/H increases to about + 0.00, where V then becomes significantlynegative. The 'thick disk' component is clearly recognized, with sigma(W) approximately equal to 36 km/sec. In the 'old thin disk' and the'young thin disk', 43 percent and 42 percent of the stars have negativeV values, respectively.
| U, V, W velocity components for the old disk using radial velocities of 1295 stars in the three cardinal Galactic directions
New radial velocities are presented for 1295 stars chosen at random nearthe three cardinal Galactic directions of l = 180 deg, b = 0; l = 90deg, b = 0 deg; and b = 90 deg, giving the distribution in U, V, and W,respectively, from the radial velocities alone. The measurements weremade with the coude spectrograph of the Mount Wilson 100 in. Hookerreflector. The purpose of the program is to set limits on the densitynormalization in the solar neighborhood of the old thin disk, the oldthick disk, and the halo. Many more high-velocity stars are present inthe unbiased sample than expected from previous estimates of thenormalization. The data suggest the density ratios in the solarneighborhood to be about 90 percent, 10 percent, and about 0.5 percentfor the thin disk, thick disk, and halo populations, respectively.
| UBV photometry of stars whose positions are accurately known. IV
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1987A&AS...68..211O&db_key=AST
| Photoelectric V and (B-V) for McCuskey stars near the Galactic anticenter
V and (B-V) for 135 stars near the Galactic anticenter were obtained.The ultimate purpose of the study is to establish accurate colors which,in conjunction with DDO-derived spectral and luminosity classes, willenable interstellar absorption correction. Ninety-four of these starsalso have been observed by McCuskey for a stellar density analysis ofthe Galactic anticenter. The specific objective here is to establish therelationship between the presented photoelectric and McCuskey'sphotographic colors and magnitudes. Small but significant systematicdifferences exist between the two systems. These differences, ifuniversal for McCuskey's entire sample, increase his distances by about20 percent and decrease his densities by about 40 percent.
| Accuracy of two-dimensional spectral classes derived through DDO photometry.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977AJ.....82..832Y&db_key=AST
| Photometric data for 139 supergiants.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972AJ.....77..150F&db_key=AST
| The stellar distribution in the galactic anticenter.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1967AJ.....72.1199M&db_key=AST
| Color Excesses for Supergiants and Classical Cepheids.VI. on the Intrinsic Colors and the Hess Diagram of Late-Type Supergiants.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961ApJ...134..850K&db_key=AST
| Color Excesses from Six-Color Photometry of Supergiant Stars
Not Available
| Spectral Classification of Stars Noted on Case Objective Prism Plates. II
Not Available
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Boga |
| Sað Açýklýk: | 05h53m30.32s |
| Yükselim: | +25°04'24.3" |
| Görünürdeki Parlaklýk: | 7.516 |
| Uzaklýk: | 1612.903 parsek |
| özdevim Sað Açýklýk: | 3.3 |
| özdevim Yükselim: | -2.4 |
| B-T magnitude: | 8.853 |
| V-T magnitude: | 7.627 |
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