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Times of Minima for Some Eclipsing Binaries
Times of minima for a number of some eclipsing binaries are presented.
| Binary Star Orbits. II. Preliminary First Orbits for 117 Systems
Orbital elements are presented for 117 binary systems with no previousorbit calculation. For nearly all of these systems, these elements mustbe regarded as preliminary, but the ephemerides presented here should berelatively accurate over the next several decades. Further, the analysisof these systems should highlight the need for their continuedobservation by dedicated programs to improve the veracity of theseelements.
| BVR photometry and Hα spectroscopy of RS CVn type binary MM Herculis
The RS CVn type eclipsing binary MM Herculis wasobserved photo-electrically using B, V and R filters in 1998 and 1999and the light and colour curves were obtained. Spectroscopicobservations were carried out in 1999. The new light and colour curvesare anti-correlated with the observations of 1997, i.e. the system isbluer when it is faintest. The variations of the brightnesses at eachspecial phase (0.0, 0.25, 0.5, and 0.75) show an almost cyclic changewith a period of about 6 years. This value is in good agreement with themigration periods of the spots suggested by us previously. Theoutside-of-eclipse wave in the light curve shows a minimum at phase~0.50, and the mean colour of the system is the bluest at the samephase. When the spots located on the cooler component are seen aroundphase 0.50, the amplitude of the light variation outside eclipse islarger than the others. Such variation may be caused by the effect ofthe hotter component. Spectroscopic observations of the system werecarried out in the spectral range 5860-6700 Å. The subtraction ofa ``synthetic'' spectrum, built up with spectra of inactive standardstars, allows us to detect an Hα emission excess only from thecool component. New radial velocity measurements of the system wereobtained and analyzed for the orbital parameters. Based on observationscollected at the Ege University Observatory, Turkey, and at the CataniaAstrophysical Observatory, Italy.
| Three-Colour Photometry of MM Herculis During 1998-1999
Not Available
| The activity pattern on MM Herculis: spots and faculae
The RS CVn type eclipsing binary MM Herculis was observed using B, V,and R filters in 1997 and the light and colour curves were obtained. Thelong-term (1976-1997) variations in the brightness and colour of thesystem were revealed by examining 12 light and colour curves. The reasonfor the variations in the B-V colour curves may be the photosphericbright facular structures that surround starspots. The system is bluestwhen at its faintest. Migration periods of 5.8 and 5.9 years have beenfound for the two spots or spot groups, which are located on the coolercomponent. The spots that are located within the longitude difference of180° seem to approach each other with a period of six years. In thiscase the amplitudes of the light curves increase, the system's meanbrightness decreases and its mean colour becomes bluer.
| New Photoelectric Photometry of MM Herculis
Not Available
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| Mesures d'etoiles doubles faites a Nice, etoiles doubles nouvelles (24eme serie) decouvertes a Nice.
Table 1 gives 1182 measurements of 682 binaries observed with the 74 and50 cm refractors. Table 2 lists 26 new binaries discovered with the 50cm refractor.
| A Distortion Wave in the Light Curve of MM Herculis
Not Available
| Micrometer Measures of Double Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961ApJS....6....1K&db_key=AST
| Mesures d'étoiles doubles faites à l'Observatoire de Paris
Not Available
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Osservazione e dati astrometrici
| Costellazione: | Ercole |
| Ascensione retta: | 18h00m17.93s |
| Declinazione: | +21°53'47.5" |
| Magnitudine apparente: | 8.543 |
| Moto proprio RA: | -16.8 |
| Moto proprio Dec: | 23.5 |
| B-T magnitude: | 9.356 |
| V-T magnitude: | 8.611 |
Cataloghi e designazioni:
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