more articles like this
Lion and Lamb
updated: Mar 08, 2014, 11:00 AM
By Chuck McPartlin
Our March got off to a stormy start, with welcome rain, but accompanied by
damaging surf and winds. March is a month balanced between Winter and
Spring, and the changing seasons often bring unsettled weather, especially
in climates less benign than we have in Santa Barbara. As a result, you may
have heard the saying "March comes in like a Lion, but goes out like a Lamb".
Well, there's also an astronomical backdrop to that adage.
Rising in the east on early March evenings is the constellation Leo the Lion.
This is a constellation that really looks like its namesake, and many cultures
from ancient times have seen it as the king of beasts. The bright star Regulus
(Latin for Little King) anchors a distinctive asterism that looks like a
backwards question mark, called the Sickle of Leo, that represents his head
and his mane. Below the sickle are the stars making up his back and hind leg,
terminating in Denebola, usually visualized as representing the end of his
tail. Deneb means tail in Arabic, and Denebola derives from Tail of the Lion.
Here is an image from planetarium software showing Leo above the Full Moon of
March 15 at 9 PM PDT, which will help you find Leo in the sky. The Moon may
obscure some of the stars with its brightness, especially if the sky is hazy.
Regulus is about 79 light years away, and about 300 times brighter than our Sun.
Its diameter is over four times that of the Sun, and it is rotating so quickly,
once every 16 hours, that it is very oblate in shape. In comparison, our Sun has
about a 25 day rotation period. If Regulus rotated just a little bit faster, it
would tear itself apart.
Early in the morning on March 20, a kilometer wide asteroid, (163) Erigone, will
pass in front of Regulus along a path through the northeastern US. Regulus will
seem to disappear for up to 14 seconds.
Learn about it here.
Denebola is about 36 light years away, and 14 times brighter than the Sun. It is
a bit less than twice the diameter of the Sun.
Away from the plane of the Milky Way, Leo is full of galaxies for telescopic
observers. The annual Leonid meteor shower, in Mid-November, appears to radiate
from the area of the Sickle.
Meanwhile, setting in the west as Leo rises is Aries the Ram. In Greek mythology,
this is the Golden Fleece sought by Jason and the Argonauts. Aries is a relatively
dim constellation, with the three stars in his head being the only ones easy to
see under most conditions.
Here is an image of the Ram, directly opposite in the sky from the Lion, with the
Pleiades star cluster shown above to help you locate the lamb.
Hamal, meaning lamb, is about 66 light years away, and shines 90 times brighter
than the Sun, and is about 15 times wider.
Sheratan is about 60 light years away, and appears to shine 22 times brighter than
the Sun. However, it is actually two stars that orbit each other so closely that their
dual nature can only be detected through spectroscopic or interferometric instruments.
At a distance of about 204 light years, Mesarthim is a beautiful telescopic binary,
with stars 2.8 and 2.5 times the diameter of the Sun, and around 56 and 48 times
So, as Leo springs up in the sky, and Aries sinks in the west, March truly comes
in like a Lion and out like a Lamb.
References for Cloudy Evening
(The constellation images were generated using Starry Night Pro planetarium software.)
6 comments on this article. Read/Add
# # # #