Gore John Ellard
Astronomical Curiosities: Facts and Fallacies
The largest “proper motion” now known is that of a star of the 8½ magnitude in the southern hemisphere, known as Cordoba Zone V. No. 243. Its proper motion is 8·07 seconds of arc per annum, thus exceeding that of the famous “runaway star,” 1830 Groombridge, which has a proper motion of 7·05 seconds per annum. This greater motion is, however, only apparent. Measures of parallax show that the southern “runaway” is much nearer to us than its northern rival, its parallax being 0″·32, while that of Groombridge 1830 is only 0″·14. With these data the actual velocity across the line of sight can be easily computed. That of the southern star comes out 80 miles a second, while that of Groombridge 1830 is 148 miles a second. The actual velocity of Arcturus is probably still greater.
The poet Barton has well said —
“The stars! the stars! go forth at night,
Lift up thine eyes on high,
And view the countless orbs of light,
Which gem the midnight sky.
Go forth in silence and alone,
This glorious sight to scan,
And bid the humbled spirit own
The littleness of man.”
CHAPTER XV
Double and Binary Stars
Prof. R. G. Aitken, the eminent American observer of double stars, finds that of all the stars down to the 9th magnitude – about the faintest visible in a powerful binocular field-glass – 1 in 18, or 1 in 20, on the average, are double, with the component stars less than 5 seconds of arc apart. This proportion of double stars is not, however, the same for all parts of the sky; while in some regions double stars are very scarce, in other places the proportion rises to 1 in 8.
For the well-known binary star Castor (α Geminorum), several orbits have been computed with periods ranging from 232 years (Mädler) to 1001 years (Doberck). But Burnham finds that “the orbit is absolutely indeterminate at this time, and likely to remain so for another century or longer.”313 Both components are spectroscopic binaries, and the system is a most interesting one.
The well-known companion of Sirius became invisible in all telescopes in the year 1890, owing to its near approach to its brilliant primary. It remained invisible until August 20, 1896, when it was again seen by Dr. See at the Lowell Observatory.314 Since then its distance has been increasing, and it has been regularly measured. The maximum distance will be attained about the year 1922.
The star β Cephei has recently been discovered to be a spectroscopic binary with the wonderfully short period of 4h 34m 11s. The orbital velocity is about 10½ miles a second, and as this velocity is not very great, the distance between the components must be very small, and possibly the two component bodies are revolving in actual contact. The spectrum is of the “Orion type.”315
According to Slipher the spectroscopic binary γ Geminorum has the comparatively long period (for a spectroscopic binary) of about 3½ years. This period is comparable with that of the telescopic binary system, δ Equulei (period about 5·7 years). The orbit is quite eccentric. I have shown elsewhere316 that γ Geminorum has probably increased in brightness since the time of Al-Sufi (tenth century). Possibly its spectroscopic duplicity may have something to do with the variation in its light.
With reference to the spectra of double stars, Mr. Maunder suggests that the fact of the companion of a binary star showing a Sirian spectrum while the brighter star has a solar spectrum may be explained by supposing that, on the theory of fission, “the smaller body when thrown off consisted of the lighter elements, the heavier remaining in the principal star. In other words, in these cases spectral type depends upon original chemical constitution, and not upon the stage of stellar development attained.”317
A curious paradox with reference to binary stars has recently come to light. For many years it was almost taken for granted that the brighter star of a pair had a larger mass than the fainter component. This was a natural conclusion, as both stars are practically at the same distance from the earth. But it has been recently found that in some binary stars the fainter component has actually the larger mass! Thus, in the binary star ε Hydræ, the “magnitude” of the component stars are 3 and 6, indicating that the brighter star is about 16 times brighter than the fainter component. Yet calculations by Lewis show that the fainter star has 6 times the mass of the brighter, that is, contains 6 times the quantity of matter! In the well-known binary 70 Ophiuchi, Prey finds that the fainter star has about 4 times the mass of the brighter! In 85 Pegasi, the brighter star is about 40 times brighter than its companion, while Furner finds that the mass of the fainter star is about 4 times that of the brighter! And there are other similar cases. In fact, in these remarkable combinations of suns the fainter star is really the “primary,” and is, so far as mass is concerned, “the predominant partner.” This is a curious anomaly, and cannot be well explained in the present state of our knowledge of stellar systems. In the case of α Centauri the masses of the components are about equal, while the primary star is about 3 times brighter than the other. But here the discrepancy is satisfactorily explained by the difference in character of the spectra, the brighter component having a spectrum of the solar type, while the fainter seems further advanced on the downward road of evolution, that is, more consolidated and having, perhaps, less intrinsic brightness of surface.
In the case of Sirius and its faint attendant, the mass of the bright star is about twice the mass of the satellite, while its light is about 40,000 times greater! Here the satellite is either a cooled-down sun or perhaps a gaseous nebula. There seems to be no other explanation of this curious paradox. The same remark applies to Procyon, where the bright star is about 100,000 times brighter than its faint companion, although its mass is only 5 times greater.
The bright star Capella forms a curious anomaly or paradox. Spectroscopic observations show that it is a very close binary pair. It has been seen “elongated” at the Greenwich Observatory with the great 28-inch refractor – the work of Sir Howard Grubb – and the spectroscopic and visual measurements agree in indicating that its mass is about 18 times the mass of the sun. But its parallax (about 0″·08) shows that it is about 128 times brighter than the sun! This great brilliancy is inconsistent with the star’s computed mass, which would indicate a much smaller brightness. The sun placed at the distance of Capella would, I find, shine as a star of about 5½ magnitude, while Capella is one of the brightest stars in the sky. As the spectrum of Capella’s light closely resembles the solar spectrum, we seem justified in assuming that the two bodies have pretty much the same physical composition. The discrepancy between the computed and actual brightness of the star cannot be explained satisfactorily, and the star remains an astronomical enigma.
Three remarkable double-star systems have been discovered by Dr. See in the southern hemisphere. The first of these is the bright star α Phœnicis, of which the magnitude is 2·4, or only very slightly fainter than the Pole Star. It is attended by a faint star of the 13th magnitude at a distance of less than 10 seconds (1897). The bright star is of a deep orange or reddish colour, and the great difference in brightness between the component stars “renders the system both striking and difficult.” The second is μ Velorum, a star of the 3rd magnitude, which has a companion of the 11th magnitude, and only 2½″ from its bright primary (1897). Dr. See describes this pair as “one of the most extraordinary in the heavens.” The third is η Centauri, of 2½ magnitude, with a companion of 13½ magnitude at a distance of 5″·65 (1897); colours yellow and purple. This pair is “extremely difficult, requiring a powerful telescope to see it.” Dr. See thinks that these three objects “may be regarded as amongst the most splendid in the heavens.”
The following notes are from Burnham’s recently published General Catalogue of Double Stars.
The Pole Star has a well-known companion of about the 9th magnitude, which is a favourite object for small telescopes. Burnham finds that the bright star and its faint companion are “relatively fixed,” and are probably only an “optical pair.” Some other companions have been suspected by amateur observers, but Burnham finds that “there is nothing nearer” than the known companion within the reach of the great 36-inch telescope of the Lick Observatory (Cat., p. 299).
The well-known companion to the bright star Rigel (β Orionis) has been suspected for many years to be a close double star. Burnham concludes that it is really a binary star, and its “period may be shorter than that of any known pair” (Cat., p. 411).
Burnham finds that the four brighter stars in the trapezium in the great Orion nebula (in the “sword”) are relatively fixed (Cat., p. 426).
γ Leonis. This double star was for many years considered to be a binary, but Burnham has shown that all the measures may be satisfactorily represented by a straight line, and that consequently the pair merely forms an “optical double.”
42 Comæ Berenices. This is a binary star of which the orbit plane passes nearly through the earth. The period is about 25½ years, and Burnham says the orbit “is as accurately known as that of any known binary.”
σ Coronæ Borealis. Burnham says that the orbits hitherto computed – with periods ranging from 195 years (Jacob) to 846 years (Doberck) are “mere guess work,” and it will require the measures of at least another century, and perhaps a much longer time, to give an approximate period (Cat., p. 209). So here is some work left for posterity to do in this field.
70 Ophiuchi. With reference to this well-known binary star, Burnham says, “the elements of the orbit are very accurately known.” The periods computed range from 86·66 years (Doolittle) to 98·15 years (Powell). The present writer found a period of 87·84 years, which cannot be far from the truth. Burnham found 87·75 years (Cat., p. 774). In this case there is not much left for posterity to accomplish.
61 Cygni. With reference to this famous star Burnham says, “So far the relative motion is practically rectilinear. If the companion is moving in a curved path, it will require the measures of at least another half-century to make this certain. The deviation of the measured positions during the last 70 years from a right line are less than the average errors of the observations.”
Burnham once saw a faint companion to Sirius of the 16th magnitude, and measured its position with reference to the bright star (280°·6: 40″·25: 1899·86). But he afterwards found that it was “not a real object but a reflection from Sirius” (in the eye-piece). Such false images are called “ghosts.”
With reference to the well-known double (or rather quadruple) star ε Lyræ, near Vega, and supposed faint stars near it, Burnham says, “From time to time various small stars in the vicinity have been mapped, and much time wasted in looking for and speculating about objects which only exist in the imagination of the observer.” He believes that many of these faint stars, supposed to have been seen by various observers, are merely “ghosts produced by reflection.”
The binary star ζ Boötis, which has long been suspected of small and irregular variation of light, showed remarkable spectral changes in the year 1905,318 somewhat similar to those of a nova, or temporary star. It is curious that such changes should occur in a star having an ordinary Sirian type of spectrum!
A curious quadruple system has been discovered by Mr. R. T. A. Innes in the southern hemisphere. The star κ Toucani is a binary star with components of magnitudes 5 and 7·7, and a period of revolution of perhaps about 1000 years. Within 6′ of this pair is another star (Lacaille 353), which is also a binary, with a period of perhaps 72 years. Both pairs have the same proper motion through space, and evidently form a vast quadruple system; for which Mr. Innes finds a possible period of 300,000 years.319
It is a curious fact that the performance of a really good refracting telescope actually exceeds what theory would indicate! at least so far as double stars are concerned. For example, the famous double-star observer Dawes found that the distance between the components of a double star which can just be divided, is found by dividing 4″·56 by the aperture of the object-glass in inches. Now theory gives 5″·52 divided by the aperture. “The actual telescope – if a really good one – thus exceeds its theoretical requirements. The difference between theory and practice in this case seems to be due to the fact that in the ‘spurious’ star disc shown by good telescopes, the illumination at the edges of the star disc is very feeble, so that its full size is not seen except in the case of a very bright star.”320
CHAPTER XVI
Variable Stars
In that interesting work A Cycle of Celestial Objects, Admiral Smyth says (p. 275), “Geminiano Montanari, as far back as 1670, was so struck with the celestial changes, that he projected a work to be intituled the Instabilities of the Firmament, hoping to show such alterations as would be sufficient to make even Aristotle – were he alive – reverse his opinion on the incorruptibility of the spangled sky: ‘There are now wanting in the heavens,’ said he, ‘two stars of the 2nd magnitude in the stem and yard of the ship Argo. I and others observed them in the year 1664, upon occasion of the comet that appeared in that year. When they first disappeared I know not; only I am sure that on April 10, 1668, there was not the least glimpse of them to be seen.’” Smyth adds, “Startling as this account is – and I am even disposed to question the fact – it must be recollected that Montanari was a man of integrity, and well versed in the theory and practice of astronomy; and his account of the wonder will be found – in good set Latin – in page 2202 of the Philosophical Transactions for 1671.”
There must be, I think – as Smyth suggests – some mistake in Montanari’s observations, for it is quite certain that of the stars mentioned by Ptolemy (second century A.D.) there is no star of the 2nd magnitude now missing. It is true that Al-Sufi (tenth century) mentions a star of the third magnitude mentioned by Ptolemy in the constellation of the Centaur (about 2° east of the star ε Centauri) which he could not find. But this has nothing to do with Montanari’s stars. Montanari’s words are very clear. He says, “Desunt in Cœlo duæ stellæ Secundæ Magnitudinis in Puppi Navis ejusve Transtris Bayero β et γ, prope Canem Majoris, à me et aliis, occasione præsertim Cometæ A. 1664 observatæ et recognitæ. Earum Disparitionem cui Anno debeam, non novi; hoc indubium, quod à die 10 April, 1668, ne vestigium quidem illarum adesse amplius observe; cæteris circa eas etium quartæ et quintæ magnitudinis, immotis.” So the puzzle remains unsolved.
Sir William Herschel thought that “of all stars which are singly visible, about one in thirty are undergoing an observable change.”321 Now taking the number of stars visible to the naked eye at 6000, this would give about 200 variable stars visible at maximum to the unaided vision. But this estimate seems too high. Taking all the stars visible in the largest telescopes – possibly about 100 millions – the proportion of variable stars will probably be much smaller still.
The theory that the variation of light in the variable stars of the Algol type is due to a partial eclipse by a companion star (not necessarily a dark body) is now well established by the spectroscope, and is accepted by all astronomers. The late Miss Clarke has well said “to argue this point would be enforcer une porte ouverte.”
According to Dr. A. W. Roberts, the components of the following “Algol variables” “revolve in contact”: V Puppis, X Carinæ, β Lyræ, and υ Pegasi. Of those V Puppis and β Lyræ are known spectroscopic binaries. The others are beyond the reach of the spectroscope, owing to their faintness.
A very curious variable star of the Algol type is that known as R R Draconis. Its normal magnitude is 10, but at minimum it becomes invisible in a 7½-inch refracting telescope. The variation must, therefore, be over 3 magnitudes, that is, at minimum its light must be reduced to about one-sixteenth of its normal brightness. The period of variation from maximum to minimum is about 2·83 days. The variation of light near minimum is extraordinarily rapid, the light decreasing by about 1 magnitude in half an hour.322
A very remarkable variable star has been recently discovered in the constellation Auriga. Prof. Hartwig found it of the 9th magnitude on March 6, 1908, the star “having increased four magnitudes in one day, whilst within eight days it was less than the 14th magnitude.”323 In other words its light increased at least one-hundredfold in eight days!
The period of the well-known variable star β Lyræ seems to be slowly increasing. This Dr. Roberts (of South Africa) considers to be due to the component stars slowly receding from each other. He finds that “a very slight increase of one-thousandth part of the radius of the orbit would account for the augmentation in time, 30m in a century.” According to the theory of stellar evolution the lengthening of the period of revolution of a binary star would be due to the “drag” caused by the tides formed by each component on the other.324
M. Sebastian Albrecht finds that in the short-period variable star known as T Vulpeculæ (and other variables of this class, such as Y Ophiuchi), there can be no eclipse to explain the variation of light (as in the case of Algol). The star is a spectroscopic binary, it is true, but the maximum of light coincides with the greatest velocity of approach in the line of sight, and the minimum with the greatest velocity of recession. Thus the light curve and the spectroscopic velocity curve are very similar in shape, but one is like the other turned upside down. “That is, the two curves have a very close correspondence in phase in addition to correspondence of shape and period.”325
The star now known as W Ursæ Majoris (the variability of which was discovered by Müller and Kempf in 1902), and which lies between the stars θ and υ of that constellation, has the marvellously short period of 4 hours (from maximum to maximum). Messrs. Jordan and Parkhurst (U.S.A.), find from photographic plates that the star varies from 7·24 to 8·17 magnitude.326 The light at maximum is, therefore, more than double the light at minimum. A sun which loses more than half its light and recovers it again in the short period of 4 hours is certainly a curious and wonderful object.
In contrast with the above, the same astronomers have discovered a star in Perseus which seems to vary from about the 6th to the 7th magnitude in the very long period of 7½ years! It is now known as X Persei, and its position for 1900 is R.A. 3h 49m 8s, Dec. N. 30° 46′, or about one degree south-east of the star ζ Persei. It seems to be a variable of the Algol type, as the star remained constant in light at about the 6th magnitude from 1887 to 1891. It then began to fade, and on December 1, 1897, it was reduced to about the 7th magnitude.
On the night of August 20, 1886, Prof. Colbert, of Chicago, noticed that the star ζ Cassiopeiæ increased in brightness “by quite half a magnitude, and about half an hour afterwards began to return to its normal magnitude.”327 This curious outburst of light in a star usually constant in brightness is (if true) a very unusual phenomenon. But a somewhat similar fluctuation of light is recorded by the famous German astronomer Heis. On September 26, 1850, he noted that the star “ζ Lyræ became, for a moment, very bright, and then again faint.” (The words in his original observing book are: “ζ Lyræ wurde einen Moment sehr hell und hierauf wieder dunkel.”) As Heis was a remarkably accurate observer of star brightness, the above remark deserves the highest confidence.328
The variable star known as the V Delphini was found to be invisible in the great 40-inch telescope of the Yerkes Observatory on July 20, 1900. Its magnitude was, therefore, below the 17th. At its maximum brightness it is about 7½, or easily visible in an ordinary opera-glass, so that its range of variation is nearly, or quite, ten magnitudes. That is, its light at maximum is about 10,000 times its light at minimum. That a sun should vary in light to this enormous extent is certainly a wonderful fact. A variable discovered by Ceraski (and numbered 7579 in Chandlers’ Catalogue) “had passed below the limit of the 40-inch in June, 1900, and was, therefore, not brighter than 17 mag.”329
The late Sir C. E. Peck and his assistant, Mr. Grover, made many valuable observations of variable stars at the Rousden Observatory during many years past. Among other interesting things noted, Peck sometimes saw faint stars in the field of view of his telescope which were at other times invisible for many months, and he suggested that these are faint variable stars with a range of brightness from the 13th to the 20th magnitude. He adds, “Here there is a practically unemployed field for the largest telescopes.” Considering the enormous number of faint stars visible on stellar photographs the number of undiscovered variable stars must be very large.
Admiral Smyth describes a small star near β Leonis, about 5′ distant, of about 8th magnitude, and dull red. In 1864 Mr. Knott measured a faint star close to Smyth’s position, but estimated it only 11·6 magnitude. The Admiral’s star would thereupon seem to be variable.330
The famous variable star η Argus, which Sir John Herschel, when at the Cape of Good Hope in 1838, saw involved in dense nebulosity, was in April, 1869, “seen on the bare sky,” with the great Melbourne telescope, “the nebula having disappeared for some distance round it.” Other changes were noticed in this remarkable nebula. The Melbourne observers saw “three times as many stars as were seen by Herschel.” But of course their telescope is much larger – 48 inches aperture, compared with Herschel’s 20 inches.
Prof. E. C. Pickering thinks that the fluctuations of light of the well-known variable star R Coronæ (in the Northern Crown), “are unlike those of any known variable.” This very curious object – one of the most curious in the heavens – sometimes remains for many months almost constant in brightness (just visible to the naked eye), and then rapidly fades in light by several magnitudes! Thus its changes of light in April and May, 1905, were as follows: —
Thus between April 1 and May 1, its light was reduced by over 5 magnitudes. In other words, the light of the star on May 1 was reduced to less than one-hundredth of its light on April 1. If our sun were to behave in this way nearly all life would soon be destroyed on the face of the earth.
M. H. E. Lau finds that the short-period variable star δ Cephei varies slightly in colour as well as in light, and that the colour curve is parallel to the light curve. Near the minimum of light the colour is reddish yellow, almost as red as ζ Cephei; a day later it is pure yellow, and of about the same colour as the neighbouring ε Cephei.331 But it would not be easy to fully establish such slight variations of tint.
A remarkably bright maximum of the famous variable Mira Ceti occurred in 1906. In December of that year it was fully 2nd magnitude. The present writer estimated it 1·8, or nearly equal to the brightest on record – 1·7 observed by Sir William Herschel and Wargentin in the year 1779. From photographs of the spectrum taken by Mr. Slipher at the Lowell Observatory in 1907, he finds strong indications of the presence of the rather rare element vanadium in the star’s surroundings. Prof. Campbell finds with the Mills spectrograph attached to the great 36-inch telescope of the Lick Observatory that Mira is receding from the earth at the apparently constant velocity of about 38 miles a second.332 This, of course, has nothing to do with the variation in the star’s light. Prof. Campbell failed to see any trace of the green line of hydrogen in the star’s spectrum, while two other lines of the hydrogen series “glowed with singular intensity.”
Mr. Newall has found evidence of the element titanium in the spectrum of Betelgeuse (α Orionis); Mr. Goatcher and Mr. Lunt (of the Cape Observatory) find tin in Antares (and Scorpii). If the latter observation is confirmed it will be the first time this metal has been found in a star’s atmosphere.333
It is a curious fact that Al-Sufi (tenth century) does not mention the star ε Aquilæ, which lies closely north-west of ζ Aquilæ, as it is now quite conspicuous to the naked eye. It was suspected of variation by Sir William Herschel. It was first recorded by Tycho Brahé about 1590, and he called it 3rd magnitude. Bayer also rated it 3, and since his time it has been variously estimated from 3½ to 4. If it was anything like its present brightness (4·21 Harvard) in the tenth century it seems difficult to explain how it could have escaped Al-Sufi’s careful scrutiny of the heavens, unless it is variable. Its colour seems reddish to me.
Mr. W. T. Lynn has shown – and I think conclusively – that the so-called “new star” of A.D. 389 (which is said to have appeared near Altair in the Eagle) was really a comet.334
Near the place of Tycho Brahé’s great new star of 1572 (the “Pilgrim Star”), Hind and W. E. Plummer observed a small star (No. 129 of d’Arrest’s catalogue of the region) which seemed to show small fluctuations of light, which “scarcely include a whole magnitude.” This may possibly be identical with Tycho Brahé’s wonderful star, and should be watched by observers. The place of this small star is (for 1865) R.A. 0h 17m 18s, N.P.D. 26° 37′·1. The region was examined by Prof. Burnham in 1890 with the 36-inch telescope of the Lick Observatory. “None of the faint stars near the place presented any peculiarity worthy of remark, but three double stars were found.”335
With reference to the famous Nova (T) Coronæ – the “Blaze Star” of 1866 – Prof. Barnard finds from careful comparisons with small stars in its vicinity that “the Nova is now essentially of the same brightness it was before the outburst of 1866 … there seems to be no indication of motion in the Nova.”
With reference to the cause of “temporary” stars, or novæ, as they are now called by astronomers – the late Prof. H. C. Vogel said —
“A direct collision of two celestial bodies is not regarded by Huggins as an admissible explanation of the Nova; a partial collision has little probability, and the most that can be admitted is perhaps the mutual penetration and admixture of the outer gaseous envelopes of the two bodies at the time of their closest approach. A more probable explanation is given by an hypothesis which we owe to Klinkerfues, and which has more recently been further developed by Wilsing, viz. that by the very close passage of two celestial bodies enormous tidal disturbances are produced and thereby changes in the brightness of the bodies. In the case of the two bodies which form the Nova, it must be assumed that these phenomena are displayed in the highest degree of development, and that changes of pressure have been produced which have caused enormous eruptions from the heated interior of the bodies; the eruptions are perhaps accompanied by electrical actions, and are comparable with the outbursts in our own sun, although they are on a much larger scale.”336
It will be noticed that this hypothesis agrees with the fundamental assumption of the “Planetesimal Hypothesis” advocated by Professors Chamberlin and Moulton (see my Astronomical Essays, p. 324).
The rush of a comparatively small body through a mass of gaseous matter seems also a very plausible hypothesis. This idea was originally advanced by Prof. Seeliger, and independently by Mr. Monck.
With reference to the nebula which was observed round the great new star of 1901 – Nova Persei – Prof. Lewis Bell supports the theory of Seeliger, which accounts for the apparent movements of the brightest portions of the nebula by supposing that the various parts of the highly tenuous matter were successively lighted up by the effects of a travelling electro-magnetic wavefront, and he shows that this theory agrees well with the observed phenomenon.337 The “collision theory” which explained the sudden outburst of light by the meeting of two dark bodies in space, seems to be now abandoned by the best astronomers. The rapid cooling down of the supposed bodies indicated by the rapid decrease of light is quite inconsistent with this hypothesis.
The rapid diminution in the light of some of these “new stars” is very remarkable. Thus the new star which suddenly blazed out near the nucleus of the great nebula in Andromeda in August, 1885, faded down in 5 months from “the limit of visibility to the naked eye to that of a 26-inch telescope”! A large body could not cool in this way.
Mr. Harold K. Palmer thinks that the “complete and astonishingly rapid changes of spectral type observed in the case of Nova Cygni and Nova Aurigæ, and likewise those observed in Nova Normæ, Nova Sagittarii and Nova Persei, leave little doubt that the masses of these objects are small.”338
No less than 3748 variable stars had been discovered up to May, 1907. Of these 2909 were found at Harvard Observatory (U.S.A.) chiefly by means of photography.339
The star 14. 1904 Cygni has a period of only 3 hours 14 minutes, which is the shortest period known for a variable star.
A very interesting discovery has recently been made with reference to the star μ Herculis. It has been long suspected of variable light with a period of 35 or 40 days, or perhaps irregular. Frost and Adams now find it to be a spectroscopic binary, and further observations at Harvard Observatory show that it is a variable of the Algol (or perhaps β Lyræ) type. The Algol variation of light was suggested by MM. Baker and Schlesinger. The period seems to be about 2·05 days.340