Astron. Astrophys. 357, 548-552 (2000)

4. HD 86592

Bidelman (1981) classified HD 86592 as a SrEu star. Babel & North (1997) discovered a very strong magnetic field of 15 to 16 kG, estimated v sin i = 162 km s^-1, and found photometric variability from 24 photometric measurements in the Geneva system:

HJD (max. flux Geneva B mag.)
= 2446896.801 + (2.8866690.00030)E.

Forty-five and 77 sets of good Strömgren differential observations were made with the FCAPT during the 1997-98 and 1998-99 observing seasons, respectively (Table 4). The period finding techniques yield the same period as Babel & North whose photometry covers a much long time period, but whose coverage is far sparser. The new photometry defines more subtle variations in the light curves. These values are plotted in Fig. 3. The B light curve of Babel & North shows the same minimum as those of u , b , and v which are in phase. It will require another set of observations to improve the ephemeris.

Fig. 3. Differential FCAPT uvby photometry of HD 86592 (filled circles) plotted with the ephemeris HJD (max Geneva B mag.) = 2446896.801 + 2.886669 E. Note the variation of y is crudely out of phase with those of u , v , and b .

HD 86582 is a large amplitude variable in v (0.13 mag.) while in u , b , and y the amplitudes are 0.04, 0.04, and 0.018 mag., respectively. The variability in y is very crudely, but not perfectly in antiphase with those of u , v , and b as its maximum occurs near phase 0.5 rather than 0.35. Thus there must be an approximately non-variable wavelength region between the mean wavelengths of b and y . The halt in the rise of the rising branch of the light curve near phase 0.75 which is seen in v may also weakly occur in b .

© European Southern Observatory (ESO) 2000

Online publication: June 5, 2000
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