erroneously early date for the super- 
nova. 
An analysis by one of the three 
scholars mentioned above convinced 
him that 3 Cassiopeiae was in fact 
the supernova. Another of the three, 
however, a specialist on Cas A at the 
David Dunlap Observatory in Toronto, 
reached the opposite conclusion. He 
thinks there probably never was a 3 
Cassiopeiae. Instead, he believes that 
Flamsteed goofed and measured the 
arc from Scheat to a fifth-magnitude 
star and mistakenly measured the arc 
from Algol to a different, seventh- 
magnitude star, which he confused 
with the fifth-magnitude object. Thus, 
in mistaking one star for another, 
Flamsteed would have derived his 
published position for 3 Cassiopeiae 
from the two sextant measurements. 
This second interpretation implies that 
Flamsteed in fact made a double blun- 
der, confusing the two stars with each 
other despite their different bright- 
nesses and different positions. Nev- 
ertheless, there is no way today to 
tell whether Flamsteed’s 3 Cassiopeiae 
was the supernova or whether his mea- 
surements were incorrect. 
Since the interpretation of Flam- 
steed’s records is ambiguous, we can 
only rely on modern observations to 
investigate the nature of the exploding 
star. They give us some useful hints 
about how the star evolved before'the 
explosion, but nothing definitive about 
the event itself. The astronomer who 
has done the most comprehensive job 
of putting the observational data to- 
gether and explaining what they mean 
is Susan Lamb of the University of 
Illinois (Urbana-Champaign). An ex- 
pert on the evolution of massive stars, 
Lamb has deduced that the Cas A 
presupernova underwent two intervals 
of heavy loss of mass before the ex- 
plosion occurred. Her reasoning goes 
like this: The high speeds of the knot 
structures prove that they were 
ejected in the explosion itself, while 
the lower velocities of the flocculi 
structures indicate that they were shed 
at least 10,000 years before the ex- 
plosion (a fact already known). But 
the strange composition of the flocculi, 
with their heavy ratio of nitrogen to 
hydrogen, means that they did not 
come from the surface of a normal 
star since no stars have been found 
with such a heavy nitrogen concen- 
tration. Computations show, however, 
that such concentrations do form un- 
seen, deep inside massive stars in the 
young blue supergiant stage. As the 
supergiant converts hydrogen to he- 
lium in the nuclear furnace of its core, 
it increases the ratio of nitrogen to 
hydrogen simply by diminishing the 
latter. A powerful stellar wind, acting 
over many hundreds of thousands of 
years, can blow off most or all of 
the unburned hydrogen layer that sur- 
rounds the zone of enhanced nitrogen. 
(Winds of sufficient power have been 
observed in young blue supergiants 
by the Copernicus and International 
Ultraviolet Explorer satellites.) Ac- 
cording to Lamb’s theory, this oc- 
curred a very long time ago, giving 
the windblown unburned hydrogen 
layer time to disperse in space beyond 
the possibility of recognition. Then, 
only 10,000 or so years ago, as the 
aging star approached its end, the 
wind picked up again, blowing off the 
nitrogen-enhanced material to form 
the flocculi. Heavy winds of the kind 
required by Lamb’s hypothesis have 
been found in older red supergiant 
stars. Finally, about 300 to 325 years 
ago, the theory goes, the by then much 
smaller star exploded, creating the 
knots of Cas A. 
Lamb’s theory is consistent with 
Chevalier’s idea that the supernova 
was dim because the exploding star 
was unusually small. The theory also 
doesn’t seem to contradict Shklovsky’s 
deduction that a black hole formed, 
although Lamb told me that she be- 
lieves the presupernova star was 
wholly disrupted. Can we at least con- 
clude that either there is a black hole 
in Cas A or that no condensed object 
was left by the explosion? Even on 
this question, the jury is still out. The 
possibility exists that some neutron- 
star-like objects are formed of sub- 
atomic particles called quarks, 
thought by physicists to be the ul- 
timate building blocks of matter. Such 
a tiny neutron-star-like object, or 
quark star, would cool more rapidly 
than a neutron star and would thus 
not show up in the Einstein satellite 
survey for small hot spots in Cas A. 
Advances in observational technol- 
ogy may ultimately make it possible 
for astronomers to determine what, 
if anything, still lurks within Cas A. 
Nevertheless, we will never know with 
certainty whether anyone actually saw 
the supernova. 
Stephen P. Maran is a senior staff 
scientist in the Laboratory for As- 
tronomy and Solar Physics at 
NASA’s Goddard Space Flight Cen- 
ter in Greenbelt, Maryland. 
□ Rush me your Information Portfolio includ- 
ing complete details on the new Shelburne 
Fireplace-Stove, insulation sample swatch, and 
direct-from-manufacturer prices. Enclosed is $1 
to help cover mailing costs. 
I The Vermont Stove Company 
I Dept. 2415 , Route 7, Shelburne , Vt. 05482 
■ 802-985-2593 
(Black a 
inCludC oiMunc 
through batfling 
system to flue) 
(A) Doors may be opened to view the fire (B) Air is preheated as it 
enters downdraft and secondary air tubes fa Rrebrick-lined W' 
steel firebox (D) Automatic thermostat (E) Pull-out ash pan (F) 
Fan with speed control (G) 40" baffling system (H) Ranges in 
choice of 3 widths permit installation in over 80% ot all fire- 
places. ^ 1961 Vermont Stove Co., Inc. 
The Shelburne 
Fireplace Stove 
Its graceful design is timeless, its 
engineering as new as tomorrow. 
Those crackling flames can lift your spirits, 
but your open fireplace actually wastes more 
heat than it delivers. Perhaps you've discovered 
that tubular grates, glass doors and ordinary 
fireplace inserts offer only a partial solution at 
best. Yet a black metal woodstove on your 
hearth would be an affront to your room decor. 
Efficiency on wheels 
The Shelburne can transform your fireplace 
into a super-efficient heat producer without 
compromising the visual and soul-warming 
pleasures it provides. You enjoy a visible fire 
behind safe Coming Pryoceram glass. Down- 
draft combustion, 2000°F space-capsule insula- 
tion and a 40” baffle system help account for its 
amazing performance. And the Shelburne rolls 
out on your hearth for easy chimney cleaning. 
81 
