Page:Popular Science Monthly Volume 41.djvu/413

From Wikisource
Jump to navigation Jump to search
This page has been validated.

served in August, 1885, in the great nebula in Andromeda forms no exception, for in Dr. Boeddicker's beautiful drawing of the galaxy, which has just been published, a faint extension of nebulous light is shown stretching from Cassiopeia's Chair to the nebula referred to.

A better example of a true temporary star is that which appeared in November, 1876, near Rho Cygni. It was first seen by Schmidt at Athens, soon after sunset, on the evening of November 24th, when it was about the third magnitude, and slightly brighter than Eta Pegasi. The appearance of this object was also probably sudden, for between November 1st and 20th Schmidt observed the vicinity, and was certain that no star of even the fifth magnitude could have escaped detection. Between November 20th and 24th the sky was, unfortunately, cloudy, so that the exact time of its appearance is unknown. This star was quite new, as it does not appear in any star-chart or catalogue. Like most of these curious objects, its light faded very rapidly. In the forty-eight hours following the night of November 27th it diminished to the extent of one and a half magnitude, and on November 30th it was reduced to the fifth magnitude. It afterward decreased with tolerable regularity, and in September, 1877, it was below the tenth magnitude. In subsequent years it became very faint. Ward found the star only sixteenth magnitude in October, 1881, and it was estimated of the fifteenth magnitude, at Mr. Wigglesworth's Observatory, in September, 1885. It was examined with the spectroscope a few days after its discovery, and its spectrum showed bright lines similar to the star in Corona Borealis. Subsequent observations seem to show that this extraordinary object changed into a small planetary nebula!

The star which appeared in August, 1885, in the great nebula in Andromeda (31 Messier) has been already referred to. It seems to have been independently noticed by several observers toward the end of August. It was, however, certainly seen by Mr. T. W. Ward, of Belfast, on August 19th, at 11 p. m., when he estimated it at nine and a half magnitude. On September 3rd the star was observed at seven and a half magnitude, at Dunecht, by Lord Crawford and Dr. Copeland, and its spectrum was found to be "fairly continuous." The star gradually faded away, and on February 7, 1886, was estimated only sixteenth magnitude with the twenty-six-inch refractor of the Naval Observatory at Washington. Dr. Auwers has pointed out the similarity between this outburst and the star of 1860 in the cluster 80 Messier, and thinks it very probable that both phenomena were due to physical changes in the nebulæ in which they occurred.

The most recent example of a new star is one discovered by Mr. T. D. Anderson, of Edinburgh, in the last week of January