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    Naturevolume 32page610 (1885) | Download Citation



    THE VARIABLE-STAR V CYGNI.—In Dr. Hartwig's ephemeris of the variable stars for the present year a maximum of V Cygni is doubtfully assigned to November 15. The change in the brightness of this strikingly red star was notified by the late Mr. Birmingham in May, 1881. The several determinations of the time of maximum in the following year were very discordant; thus, Dr. Lindemann (who made an interesting communication on this star to the St. Petersburg Academy in January 1884) fixed it on August 31 “auf wenige Tage sicher”; Schmidt gave July 17, while Prof. Safarik considered it was reached on June 17. This divergence induced Dr. Lindemann to commence regular observations of the star in August 1882, details of which will be found in his paper (Bulletin de l'Academie Imperial des Sciences de St. Petersburg, t. xxix.). The variation appeared to be from 6.8 m. to below 10 m., and the period indicated by the observations of 1882 and 1883 was about a year, though a longer one is now assigned. Several of Dr. Lindemann's notes are worthy of attention. On July 19, 1881, the star had a nebulous cometary aspect, with sensible diameter. On August 13 in the following year it was more stellar, and had no longer the nebulous appearance it presented in 1881, though a month later this was again suspected. On May 13, 1883, we read: “V funkelt sehr stark, leuchtet momentan auf und verschwindet dazwischen beinahe,” though a comparison star DM + 47°, 3162 showed a steady light. On July 27 it shone as steadily as the neighbouring stars, without any nebulous appearance. On October 8—“sehr verschwommen”; a week afterwards, this aspect was not remarked, though the images of surrounding stars were very indifferent. At the end of the same month V was again stellar. Variations in the intensity of the colour were also remarked.

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