News | Published:

Our Astronomical Column

    Abstract

    NEW STARS IN SPIRAL NEBULAE.—A full account of the discovery of a new star in the spiral nebula N.G.C. 4527 is given by Dr. H. D. Curtis in Lick Observatory. Bulletin, No. 300. Photographs from various sources show that there was no trace of the star from early in 1900 until March 20, 1915, when it appeared to be of about 14th magnitude. On April 16 of the same year it had fallen to 15th magnitude, and was not cer tainly recognised in later photographs. Two novae were afterwards discovered in photographs of N.G.C. 4321, and of these also the history is fairly complete. Including Ritchey's nova in N.G.C. 6946, six novae have now been discovered in spiral nebulas, four of them about 14th magnitude, and two brighter, one of the latter being observed in the Great Andromeda nebula in 1885. Dr. Curtis considers that the appear ance of these nova? strongly supports the view that the spiral nebula? are “island universes.” The average maximum brightness of novas which have appeared in our own galaxy is about magnitude 5, and if the galactic and spiral novae have the “ame absolute brightness, the difference of about 10 magnitudes indicates that the spiral nebula? in question are of the order of 100 times as far away as the galactic novae, which are themselves known to have been very remote. Five additional nova? in spirals are included in a list given in Popular Astronomy, vol. xxv., p. 632.

    Rights and permissions

    Reprints and Permissions

    About this article

    Comments

    By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.