PROCEEDINGS 
OF THE 
NATIONAL ACADEMY OF SCIENCES 
MOUNT WILSON SOLAR OBSERVATORY. CARNEGIE INSTITUTION OF WASHINGTON 
It has been known for many years that the spectrum of temporary 
stars or Novae develops in a later stage into a spectrum nearly identi- 
cal with that of planetary nebulae. First observed in the case of Nova 
Aurigae of 1891, the same result has been found to hold for all of the 
temporary stars observed since that time, including the most important 
Nova of recent years. Nova Persei of 1901. The question whether 
this nebular spectrum may be regarded as the final stage in the develop- 
ment of the spectra of temporary stars is of great importance because of 
its immediate bearing on the order of evolution of stars. In his book 
on Stellar Movements Eddington says in this connection ^'There is 
some justice in a remark of R. T. A. Innes: 'The fact that we have seen 
a star change into a nebula ought to outweigh every contrary specula- 
tion that stars originate from nebulae.' " 
The faintness of the Novae in the later stages of their history has 
made observations of their spectra exceptionally difficult. In 1906, 
however, Hartmann^ obtained an observation of Nova Persei, then 
of about the eleventh magnitude, which showed that two of the princi- 
pal nebular lines had disappeared, and he called attention to the strong 
similarity of its spectrum to that of one of the Wolf-Rayet stars. Since 
that time the work has been taken up at Mount Wilson, with the 60- 
inch reflector and extended to include observations of other Novae. 
Photographs of the spectrum of Nova Geminorum No. 2 (1912) 
taken during the past year have shown some peculiarly interesting de- 
velopments in this most recent of the temporary stars. In February 
1914, the spectrum consisted of prominent bright bands joined by a 
continuous spectrum of rather feeble intensity. These bands are 
Volume 1 
JULY 15, 1915 
Number 7 
NOVA GEMINORUM NO. 2 AS A WOLF-RAYET STAR 
By Walter S. Adams and Francis G. Pease 
Presented to the Academy. June 7, 1915 
391 
