1892.] on the New Star in Auriga. 623 



its light are probably caused by the presence of one or more bodies 

 in the system, besides the bright star and the dusky one which 

 partially eclipses it. To a similar cause are probably due the minor 

 irregularities which form so prominent a feature in the waxing and 

 waning of the variable stars as a class. We know that the stellar 

 orbits are usually very eccentric. In the case of y Virginis the 

 eccentricity is as great as 0*9, and Auwers has recently found the 

 very considerable eccentricity of • 63 for Sirius. 



The great relative velocity of the component stars of the Nova, 

 however, seems to force us to look rather to the casual near approach 

 of bodies possessing previously considerable motion, unless we are 

 willing to concede to them a mass very great as compared with that 

 of our sun. Such a near approach of two bodies of great size is very 

 greatly less improbable than would be their actual collision. The 

 phenomena of the new star scarcely permit us to suppose even a 

 partial collision ; though if the bodies were very diffuse, or the 

 approach close enough, there may have been possibly some mutual 

 interpenetration and mingling of the rarer gases near their boundaries. 



A more reasonable explanation of the phenomena, however, may be 

 found in a view put forward many years ago by Klinkerfues, and 

 recently developed by Wilsing, that under such circumstances of near 

 approach enormous disturbances of a tidal nature would be set up, 

 amounting it may well be to partial deformation in the case of gaseous 

 bodies, and producing sufficiently great changes of pressure in the 

 interior of the bodies to give rise to enormous eruptions of the hotter 

 matter from within, immensely greater, but similar in kind, to solar 

 eruptions ; and accompanied probably by large electrical disturb- 

 ances. 



In such a state of things we should have conditions so favourable 

 for the production of reversals undergoing continual change, similar 

 to those exhibited by the bright and dark lines of the Nova, that we 

 could not suppose them to be absent ; while the integration of the 

 light from all parts of the disturbed surfaces of the bodies would 

 give breadth to the lines, and might account for the varying inequal- 

 ities of brightness at the two sides of the lines. 



The source of the light of the continuous spectrum upon which 

 were seen the dark lines of absorption shifted towards the blue, must 

 have remained, as seen by us, behind the cooler absorbing gas, so as 

 to form a background to it ; indeed, must have formed with it the 

 body which was approaching us, unless we assume that both bodies 

 were moving exactly in the line of sight, or that the absorbing gas 

 was of enormous extent. 



The circumstance that the receding body emitted bright lines 

 while the one approaching us gave a continuous spectrum with broad 

 absorption lines similar to a white star, may, perhaps, be accounted 

 for by the two bodies being in different evolutionary stages, and con- 

 sequently differing in diffuseness and in temperature. Indeed, in the 

 variable star /3 Lyree, we have probably a binary system, of which 



