3 2 4 



SCIENCE- G OS SIP. 



October 2tfth. fomid Nova Norinae, of the seventh 

 magnitude, which gave a spectrum that is practi- 

 cally the duplicate of Nova Aurigae. and now also 

 •appears to be nebula. The same lady discovered 

 another in Carina in 1895, which in three months 

 fell from the eighth to the eleventh magnitude, 

 having a similar spectrum and finally a similar 

 ending. In the same year, on July Sth. she dis- 

 covered another of seventh magnitude in Centaurus, 

 R.A. 13h. 34-3 in.. Dec. 31° 8' S., which whilst it 

 gave a somewhat different spectrum became nebula. 

 The nest, and last Nova that demands oiir 

 attention is that in Perseus, which was discovered 

 by Dr. T. D. Anderson, of Edinburgh, the dis- 

 coverer of Nova Auriga, on the early morning of 

 February 22nd. when the star had a very low 

 altitude. Its colour was then bluish-white, and its 

 magnitude 2*7 : but the same evening, just before 

 seven o'clock. Dr. Copeland found it brighter than 

 Aldebaran, and little more than an hour later con- 

 sidered it equal to Procyon. which it resembled in 

 colour. Twenty-four hours afterwards Dr. Halm 

 found it 0-2 magnitude brighter than Capella, or 

 brighter than any temporary star since that of 

 1604. On this evening the spectroscope was brought 

 to bear. At Potsdam it was described as like that of 

 Rigel. the spectrum having no bright lines. At 

 Edinburgh with a direct vision prism on the (5-inch 

 refractor it appeared to have a perfectly continuous 

 spectrum ; but with a larger spectroscope, on the 

 15-inch achromatic. Drs. Halm and Copeland found 

 about half a dozen delicate dark lines from near 

 D to F. The same evening, but presumably a few 

 hours later, Professor Pickering, of Harvard Col- 

 lege Observatory, recorded many bright lines, but 

 on the 25th he telegraphed : " S. greatly changed. 

 now resembles N. Aurigae." By this time its light 

 had begun to decrease, but on that evening its 

 position at Greenwich was found to be R A. 

 3h. 24 m. 28-21 s.. Dec. 43° 33' 54"-8 N.. a place 

 where no star previously appears on the map. The 

 district had been photographed at Harvard on 

 February 19th, at which time it certainly could 

 not have exceeded eleventh magnitude. So late as 

 midnight on February 21st it is said that it cer- 

 tainly could not have been so bright as third 

 magnitude, as an English observer was examining 

 that region of the sky. On and after the 27th the 

 colour of the star became of a warm yellow or 

 reddish tint, the spectroscope showing the reason, 

 as the brilliant C line of hydrogen was most vivid. 

 On March 3 I turned our 3-inch " Wray Science- 

 Gossip " achromatic telescope on the newcomer. 

 It was an ordinary-looking, golden-yellow star, 

 quite sharp, surrounded by diffraction ring*, like 

 any other. When, however, the cylindrical lens 

 and prism were used its brilliant red line was 

 most striking ; with the Thorp diffraction grating. 

 the rest of the spectrum became visible, six broad 

 bright lines, especially C (red) and F of hydrogen, 

 the vellow helium and srreen masrnesium lines 



being readily seen. On the violet side of each 

 bright line there was a black line visible. At thi> 

 time the Nova was barely brighter than Algol 

 (/8 Persei). On the same evening the Rev. Walter 

 Sidgreaves, of Stonyhurst College Observatory, 

 obtained a photograph of the spectrum, which he 

 has kindly permitted us to reproduce. " The ex- 

 treme brightest broad line," he writes. " is H/3. v 

 There is first to be noted the broad bright lines of 

 great width which Sir Norman Lockyer has found, 

 from comparison with the spectra of other stars, 

 to occupy about their normal position in the 

 spectrum, indicating a condition of rest. Next 

 there is a spectrum of dark lines violently dis- 

 placed towards the violet, so much so as to indicate- 

 that the matter yielding it is rushing towards us 

 with a velocity of about 700 miles a second. There 

 is yet another point of interest in the spectrum. 

 Nearly down the centre of each bright line of 

 hydrogen and calcium, but probably too delicate 

 for reproduction, there is a fine dark line — most 

 likely a reversal — which Sir Norman considers will 

 be of great service in accurately determining the 

 wave-length of the other bright lines. The star is 

 still fading ; as I write on March 11th it is between 

 third and fourth magnitudes, but. although less 

 vivid, its spectrum appears' to be much as on the 

 3rd of the month. 



The cause of the outburst would seem to be a 

 mass or swarm of meteoric matter crashing into 

 nebula, the force of the coUision producing the 

 great amount of heat necessary to raise both a 

 quantity of the solid matter as well as of gas to a 

 condition of incandescence. Already we see the 

 cooling in progress, and probably after a few 

 months it will relapse into the condition of a 

 minute faint planetary nebula. Doubtless there 

 will be many watchers to see if this really occurs. 



Perhaps we may wonder when the collision took 

 place. Many months must elapse before we can 

 get any definite, or even indefinite, knowledge on 

 this point, not until it can be known whether the 

 object yields a sensible parallax. It is probable 

 that at the least a century has passed since the 

 outburst occurred, probably longer : and seeing that 

 all this time light has been travelling earthward at 

 a rate of 11,179,800 miles per minute, the real dis- 

 tance is entirely beyond the human mind to grasp. 

 One most remarkable fact is to be noted, which 

 is that nearly all these temporary stars make their 

 appearance within the bounds, or upon the borders, 

 of the Milky Way, the reason being not at present 

 known. Perhaps our last visitor may help to throw 

 some bight on this interesting subject. 



The new star appears to have also been dis- 

 covered simultaneously by Herr Grimmler, in 

 Bavaria, and a lady student at Yassar College. 

 In conclusion I desire to express my thanks both 

 to Sir William Huggins and to Father Sidgreaves 

 for their kindly help. 

 London. March 1901. 



