Our Astronomical Column

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    Abstract

    THE ALGOL VARIABLE + 17° 4367 W DELPHINI.—Prof. E. C. Pickering publishes in the Astrophysical Journal for December the ephemeris and light equation of this variable for the present year. No modification is made in the formula of reduction (JD 2412002˙500 + 4˙8064 E), although the observations indicate a slight change in the period, making the minima occur about fifteen minutes before the computed times. Prof. Pickering adds, however, that by diminishing the period by about two seconds this difference, caused by an inexact knowledge of the light curve when the ephemeris was first computed, would disappear. A set of photometric measurements with the adjacent star + 17° 4368, exceeding four thousand in number, and made by Mr. O. C. Wendell, has given a very accurate light curve, which Prof. Pickering reproduced in his note. The average deviation between the photometric measurements and the smooth curve amounts to between one or two hundredths of a magnitude. The observations are not, however, quite sufficiently distributed over the whole curve to eliminate all doubt as to its form in some parts. The light curves of U Cephei, β Persei, and U Ophiuchi have also been similarly determined. W Delphini varies 2˙71 magnitudes, a variation greater than any other star of the same class. U Cephei comes second, with a variation of 2˙44 magnitudes, while those of β Persei and U Ophiuchi are 1˙04 and 0˙66 respectively.

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    Our Astronomical Column. Nature 55, 260–261 (1897) doi:10.1038/055260a0

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