The Sun.
London, England, 1866-08-09 00:00:00

41..,.........

New and Variable Stars.

At the last week's sitting of the Academy of
Sciences, France, M. Faye spoke at some length on
the question of new stars and variable ones. After
adverting to the rarity of the former, and stating
that Mr. Birmingham in Ireland was the first to
perceive, on the 12th May last, the star which
appeared in Corona, and which is not a new one,
but merely No. 2,765 of Argelmnder's catalogue,
and which, being only of the ninth magnitude and
hence invisible to the naked eye, suddenly burst
forth on that date with considerable splendour. M.
Faye states that it attained its maximum brilliancy
almost immediately, and that it has now gradually
dwindled down again to its original size. M. Faye
holds the opinion that the stars hitherto mentioned
a_new are merely old ones which suddenly increase
la brightness owing to some (volcanic ?) convulsion.
We beg to illustrate this to our readers by an ex-
ample. Most geologists imagine (erroneously, we
believe) our earth to be a hollow shell enclosing, a
vast
quantity of mineral matter in a state of
igneous fusion, the shell itself being nothing but
the cooled crust formed on the surface of this
fiery liquid. This crust occasionally cracks at some
place or other, and some of the liquid (lava) issues
forth, as in the case of volcanoes, -which, by the
partisans of this view of the case, are considered as
a strong argument in favour. Let us now suppose
the shell of our earth suddenly to burg in conse-
quence of the violent action of the igneous matter,
which would then rush out and cover nearly the
whole surface. To an observer situated ou some
other celestial body our earth in its ordinary state
would either not be visible at all or scarcely so ;
but this convulsion we have described would at
once bring it conspicuously into view by the
glare of the fiery fluid. But the latter would gra-
dually cool down in course of time like a red hot
iron, which ultimately becomes black, and so, to our
observer, the earth would soon relapse into its
former lustreless state. This is the explanation
given of stars that suddenly appear and then fade
away. Returning to M. Faye, he proceeded to
adduce several arguments in favour of his own
view, which is that variable stars, and those
which are called new, belong to one and the same
class of phenomena. From 1596 to 1800 not more
than 12 or 13 variable stars were observed; but since
then the heavens have been subjected to such a
searching and unremitting exploration that since
1864 nearly a hundred of them have been ob-
served. The same is the case with new stars,
three of which have been observed since 1848,
while hardly 20 are mentioned in history pre-
vious to that time. M. Faye rejects the various
explanations attempted by the earlier astrono-
mers, simply on the ground that, as Schwabe
has shown, the sun itself is but a variable star,
the period of which is eleven years, and the
variations of whose brilliancy are owing to the
Spas which appear on its surface ; such, he
conceives, must also be the cause of the variations of
brilliancy which are the characteristic of variable stars.
The case of new ones is the same. Formerly only such
stars were known as seen with the naked eye ; now
we have catalogued upwards of 300,000 stars, and
our chances are much greater of finding in our cata-
logues some small star that may suddenly blaze
forth
in unwonted lustre. Thus, Jansen's star,
which
appeared in 1600 as a star of the third mag-
nitude,
disappeared in 1621, and reappeared in 1665,
1.8 now definitively catalogued as P Cygni, accord-
ing to Argehender. M. Faye promises to continue
the subject on a future occasion.