1866.] 



Spectrum of a New Star in Corona Borealis. 



149 



line F of the solar spectrum, and the still stronger corresponding lines in 

 some stars, would indicate that under suitable conditions hydrogen may 

 emit a strong luminous radiation of this refrangibility *. 



The character of the spectrum of this star, taken together with its sudden 

 outburst in brilliancy and its rapid decline in brightness, suggest to us the 

 rather bold speculation that, in consequence of some vast convulsion 

 taking place in this object, large quantities of gas have been evolved from 

 it, that the hydrogen present is burning by combination with some ether 

 element and furnishes the light represented by the bright lines, also that 

 the flaming gas has heated to vivid incandescence the solid matter of the 

 photosphere. As the hydrogen becomes exhausted, all the phenomena di- 

 minish in intensity, and the star rapidly wanes. 



In connexion with this star, the observations which we made upon the 

 spectra of a Orionis and /3 Pegasi, that they contain no absorption lines of 

 hydrogen, appear to have some new interest. The spectra of these stars 

 agree in their general characters with the absorption spectrum of the new 

 star. The whole class of white stars are distinguished by having hydrogen 

 lines of extraordinary force. It may also be mentioned here that we have 

 found that the spectra of several of the more remarkable of the variable 

 stars, namely those distinguished by an orange or ruddy tint, possess a close 

 general accordance with those of a Orionis, /3 Pegasi, and the absorption 

 spectrum of the remarkable object described in this paper. The purely 

 speculative idea presents itself from these observations, that hydrogen pro- 

 bably plays an important part in the differences of physical constitution 

 which apparently separate the stars into groups, and possibly also in the 

 changes by which these differences may be brought about f. 



* On the dependence of the relative characters of the bright lines of hydrogen upon 

 conditions of pressure and temperature see Pliicker and Hittorf, Phil. Trans. 18l5, p. 21 

 t Mr. Baxendell sends us the following Table of magnitudes: — 



h m 









May 15 at 12 G.M.T., 



T Coronte 





3-6 or 



„ 16 „ 10 30 „ 



>> 





4-2 



„ 17 „ 11 „ 



>> 





4-9 



„ 18 „ 12 30 



>> 





5-3 



„ 19 „ 12 15 „ 



>> 





5-7 



„ 20 „ 12 30 „ 



M 





G"2 



» 21 „ 12 „ 







7-3 



„ 22 „ 11 15 



)> 





7-7 



„ 23 „ 10 30 „ 







7-9 



„ 24 „ 10 30 „ 







8-1 



o 2 



