The Caldwell Objects

anch of cold, dark material. Indeed, no less
than eight star clusters lie in or near the nebula,
and four of those lie very close to the nebula's
heart. The Eta Carinae complex harbors one of
the highest concentrations of early O-type stars
known in the galaxy. And it is these hot, young
stars, perhaps just a few million years old, which
energize the entire nebula. Furthermore, in the
nebula's bright northern fan we find the most
intriguing star in the night sky — the enigmatic
novalike variable Eta Carinae, one of the most
powerful laboratories available for investigating
the early evolution of the most massive stars.
Eta Carinae has roughly 100 times the Sun's
mass and (at the time of this writing) 4 million
times its luminosity. Over the years, though, its
brightness has varied most spectacularly.
Historical records show the star ranging from
magnitude -0.7 (outshining nearly all the night
sky's stars) to about magnitude 7.6 (well below
naked-eye visibility). Little is known about its
intensity prior to
92
Halley's 1677 observation. However, German
orientalist Peter Jensen believes this star's fluctuations
have been known since almost prehistoric
times. The star, he says, is mentioned in
Babylonian inscriptions. Apparently Eta Carinae
was a temple star associated with Ea, or la,
otherwise known as Oannes, the mysterious
human fish and the greatest god in the kingdom
of Eridhu (the Holy City). This implies that Eta
Carinae shined magnificently near the dawn of
human civilization. In his Star Names: Their Lore
and Meaning, Richard Hinckley Allen adds that in
ancient China, Eta Carinae was known as Tseen
She (Heaven's Altars) — yet another moniker
implying greatness on high. But little else has
been uncovered about the star or its nebula. Even
Halley's observation has an aura of mystery. John
Herschel credited Halley with first recording the
star's brightness (4th magnitude). But, as Allen
notes, Eta Carinae does not appear in Halley's
Catalogues Stellarum Australium, the compendium
of 341 stars he observed while at St.
The Caldwell Objects 363