THE ORIGIN OF THE NOV&AELIG

Abstract

That the novae after throwing off an extensive gaseous atmosphere for a few weeks then later settle down for a long period into planetary nebulae now seems extremely likely, and that these nebulae finally develop into wide double and multiple stars, and perhaps also into solar systems appears plausible. (Popular Astronomy, 28, 77, 1920). The faintness of the central star may well be in part due to absorption by its surroundings, but why the original explosion of the nova takes place is still open to question. Half a dozen hypotheses have already been suggested. The first was that the star blew up of itself, then that two stars collided, then that a star ran into a nebula, then that two stars ran into one another and scraped off a luminous portion, and then that two stars passed near one another, and caused the disturbance by tidal action. Finally it was suggested that besides the stars, innumerable smaller nonluminous bodies existed in the universe, particularly in the vicinity of the galaxy. It was proposed to call these hypothetical bodies planetoids, because they were supposed to resemble the planets in size. They were believed to move freely about in space, possibly in swarms, like stars in clusters. A swarm possessing the same mass as an average star would contain anywhere from one hundred thouand to several million of these