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A photometric study of BL Herculis
Photometric observations of the prototype variable BL Her are described.The reddening, metallicity, temperature, and surface gravity of the starare determined. A Baade-Wesselink analysis is made to determine theradius and distance to the variable. The mass of the star is determinedto be 0.75 solar, placing it in the range of RR Lyrae variables. Themetallicity of +0.20, however, is greater than that of any known RRLyrae variable.
| Revised photometric properties for the multiperiodic variable HD 200925
The spectroscopic data collected on the HD 200925 variable star in theuvby and beta systems have been analyzed. The results indicate that thisvariable is multiperiodic, with a reddening value, E(b-y), equal to0.029 mag. The reddening-corrected normals for y, (b-y), and c(1)yielded a mean effective temperature of 7020 K, mean log surface gravityof 3.44, and a mean bolometric magnitude of 0.8 mag. A preliminary meanradius of 4.1 solar radii has been determined. The m(1) data show thatthe blanketing is high, but this index varied in an anomalous way whichprecluded a definitive determination of Fe/H. Two possible explanationsare considered for the behavior of the m(1) index: (1) a highmicroturbulence excited by the secondary pulsation mode, and (2) theAm/Fm phenomenon.
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Observation and Astrometry data
| Constellation: | Hercules |
| Right ascension: | 18h01m52.04s |
| Declination: | +20°08'40.9" |
| Apparent magnitude: | 8.289 |
| Distance: | 121.065 parsecs |
| Proper motion RA: | -7.3 |
| Proper motion Dec: | -9.9 |
| B-T magnitude: | 8.723 |
| V-T magnitude: | 8.325 |
Catalogs and designations:
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