40 



ASTRONOMICAL PROGRESS IN 1900-1901. 



of all it- i-oii'MT.er> i-- the .-hortness of the period 

 of iwolutimi <niy four days. As \ve do not 

 know h..\\ far apart the components are, their 

 h(iulv \clocity 111 inilrs can not be ascertained, 

 hut it imi>t In- eiiormou*. 



More than t \\eiity discoveries like that men- 

 tioned above have Ix-en made at the Lick Observa- 

 tory, but this Mirpasses them all. not even ex- 

 cepting that of Capella. another spectroscopic 

 binarv latelv discovered. One significance of this 

 announcement is. that Prof. Campbell has also 

 discovered that the pole-star recedes from and 

 approaches the Earth at a velocity of about 5 

 miles a second. In two days it increases to 8.7 

 miles, it ml then gradually decreases during the 

 next two days to ^ miles. He concludes that 

 the visible star is revolving round a dark and 

 invisible body, in an orbit not greatly different 

 from the size Of our Moon's orbit round the Earth, 

 once in four days, surpassing in speed everything 

 known except 'light and electricity. From the 

 shifting of the spectral lines toward the violet it 

 is supposed that the entire triple system of Polaris 

 is approaching the earth at the rate of 15 miles a 

 second. 



Mrs. Fleming, of Harvard College Observa- 

 tory, has discovered Zeta Centauri to be a spectro- 

 soopie binary, and Miss Cameron has lately found 

 Pi Scorpii to be one, by the shifting to and fro 

 of the lines in their spectra. Herr Belopolsky 

 calls the attention of spectroscopists to the star 

 Iota Pegasi, whose motion in. the line of sight 

 seems to show a variation in a period as short as 

 one day, surpassing in this element all other spec- 

 troscopie binaries. The spectrum resembles that 

 of the dog-star, with heavy hydrogen lines and 

 narrow lines of iron. 



A noteworthy result in the work of the past 

 year is that a great number of stars are found to 

 nave variable velocity, thus indicating beyond 

 doubt that they are spectroscopic trinaries. From 

 a list of 40 the following are transcribed, being 

 mostly of short period: 



Alpha Virginia 4. 013 days. 



Alpha 1 .Scorpii 1 .46 day. 



Alpha 1 Oeminorum 2 93 days 



EtA Pexasi 2.' 85 



Delta Leonis 1 93 



Mu Scorpii (shortest known) 1 .458 



Omejf a Leonis 14 . 25 



Alpha Aurigee 104 



Kappa Pegasi 6 days. One 



component of Burnham's binary. Dark companion. 



In the Astrophysical Journal for January, 1901, 

 Prof. Campbell publishes a list of 6 with specially 

 large motions in the line of sight, 3 of which have 

 motions of 02 miles a second. Included in the 

 list is the well-known parallax and proper-motion 

 star Mu C'assiopeia, with a velocity of Cl miles a 

 second. Assuming for the parallax 0.275, and for 

 the proper motion 3.95" a y ear , the star's velocity 

 right angles to the line of sight would be 41 

 miles a second, about a third of which, however, 

 should be ascribed to the motion of the solar sys- 

 tem in space. It is perhaps worth noting that 

 this star, being one of the nearer stars and ex- 

 ceptionally rapid in its motion, should also be one 

 the first to show a change in brightness due to 

 hanging distance. A short computation from 

 the figures givon shows that the change in its dis- 

 tance should make it brighter by a tenth of a 

 nagnitude in about two thousand years, or a full 

 m ^Z lltu ln twent y thousand years 

 The New Star in Perseus.-Another wonder 



t SSSfcfB* 11 *- in the 8ky ' which has been 



watched with intense interest by every astronomer 

 in the northern hemisphere, and enough has been 



written on the subject to fill a dozen large vol- 

 umes. Not since the writer's remembrance has. 

 any unexpected astronomical phenomenon oc- 

 curred that has taken so deep a hold on the 

 popular as well as the scientific mind. It was 

 discovered Feb. 21, 1901, at 14& 40 Green- 

 wich mean time, by Rev. Dr. Anderson, who 

 watches the heavens for variable and temporary 

 stars. It was then of the 2.7 magnitude, which 

 at seven o'clock on the 22d had increased to 0.3 

 of a magnitude brighter than the first-magnitude 

 star Aldebaran. At 8 h 10 m it was 0.2 brighter 

 than Capella, a much brighter star than Alde- 

 baran, almost equaling Sirius, the brightest of all 

 the stars, commonly called the dog-star. It ap- 

 peared in the Constellation Perseus, in right as- 

 cension 3h 24m 24.12s, declination north 43 33' 

 39.51" for epoch 1900.0. On Oct. 18, 1894, a photo- 

 graph was taken of the region with the 24-inch 

 Bruce photo-telescope at Harvard College Observ- 

 atory, with an exposure of fifteen minutes, which 

 showed stars down to the 12J magnitude, but re- 

 vealed no star at the place of the new star. An- 

 other photograph of the same region was taken 

 on Feb. 19, 1901, with the Cook lens, revealing 

 stars down to the seventh magnitude, with an ex- 

 posure of sixty-six minutes, and it showed not a 

 trace of the new star. The last photograph was 

 taken only two days before its visual discovery. 

 Only twenty-eight hours before its discovery by 

 Dr. Anderson, Mr. Stanley Williams photographed 

 the same region, when the star, if it existed, must 

 have been as faint as of 12J magnitude, so that in 

 twenty-eight hours it must have increased in 

 brightness 100,000 times. At its maximum it was 

 the brightest temporary star that history records, 

 except the celebrated Tycho Brahe's star of 1572 r 

 which was visible to the naked eye at noonday. 



In the past thirty years a dozen novce, as they 

 are called by astronomers, have suddenly ap- 

 peared, but none were equal to this in the bril- 

 liance and color and extent of its fluctuations,, 

 the latter being a characteristic feature of them 

 all. The line must be sharply drawn between tem- 

 porary and variable stars described elsewhere, as 

 the two phenomena are entirely dissimilar. Many 

 theories have been advanced to account for their 

 sudden increase in brightness and anomalous be- 

 havior while visible such as collision of star with 

 star, star with a planet to some other star, star 

 with a nebula, star with a meteoric stream, star 

 with an asteroid, and asteroid with an asteroid; 

 but all appear untenable. It seems strange that 

 no one has suggested the collision of a star with 

 a comet, which to the writer's mind seems the 

 most plausible, not only to account for its sudden 

 increase in brightness, but also for fluctuations in 

 brilliance and final extinction in a few weeks or 

 months. All comets are of enormous size; that 

 of 1811 was the largest object on which the eye of 

 man has ever rested, being 1,250,000 miles in 

 diameter, in comparison with which our Sun is a 

 dwarf; its tail was nearly 1,000,000 miles in di- - 

 ameter and 50,000,000 miles in length. Should a 

 star enter the coma of such a comet, its light 

 would gradually increase to its maximum on its 

 arrival at its nucleus, and gradually dimmish as 

 they all do. On the other hand, should a star 

 collide with a star, both would in a moment be 

 converted into a white-hot liquid, if not a gas, 

 and the increase of light would be at its maxi- 

 mum in an instant instead of gradually, as ob- 

 served, and would require thousands of years to 

 cool below bright luminosity. Should such a 

 cornet fall into our Sun, the effect would be ap- 

 palling, and the inhabitants of a planet belong- 

 ing to some other sun would be spectators of 



