Enjoy our starry night
Be a considerate neighbor: Reduce nighttime glare.
Shield your outside lights downward, so no glare goes up to dull
the night sky (or in your neighbor’s bedroom windows) and
enjoy the beautiful, stars above.
Photograph of the monster star, Eta Carinae, by
the Hubble Space Telescope WFPC2, June 10, 1996
February 2008 Night Sky—The Unstable Southern Monster
Just below the horizon for most Americans is a monster star called
Eta Carinae in the constellation Carina. If you live along the southernmost
U.S. or better yet, in Hawaii or the Caribbean, this star barely
gets above the southern horizon. Located about eight thousand light
years (47,028,000,000,000,000 miles) away, Eta Carinae is one of
the brightest stars known in our galaxy, shining as bright as five
Between 1822 and 1855, Eta Carinae had several major temper tantrums.
In 1820, Eta Carinae began to brighten. By 1822, it had brightened
from a fourth magnitude to a second magnitude (smaller magnitude
numbers are brighter and negative numbers are brighter still) and
first magnitude by 1827. It faded for about five years before becoming
a zero magnitude star. After another fading period, it glowed almost
at a magnitude of -1.0 in April 1843, outshining all stars in the
sky except Sirius (remember, planets are not stars). The result
of this outburst was the Homunculus Nebula. Much of the light leaving
Eta Carinae is absorbed, scattered, and generally dimmed by this
nebula, resulting in a fifth magnitude star as seen from Earth.
The reason for this type of behavior is its size. You may have
heard of supergiant stars; that does not even begin to describe
Eta Carinae’s size. Astronomers call it a hypergiant. Eta
Carinae weighs in at more than 150 times the mass of our Sun. Other
stars in the rarefied category of hypergiant include P Cygni, in
the heart of Cygnus the Swan, and Rho Cassiopiae in Cassiopeia,
but neither can match Eta Carinae.
Scientists called the mid-1800s outburst a “supernova impostor.”
It looked like a supernova, but the star survived. As unstable as
this star seems to be, its lifetime will be very limited. Massive
stars have a short lifetime, roughly one million years. Eta Carinae
must have formed “recently” in the cosmic sense. It
is located in the active star forming nebula NGC 3372. It will probably
end its life in a supernova (or would hypernova fit better?) explosion
in ten thousand or twenty thousand years. The end result will be
the addition of material to the Homunculus Nebula with a central
So what happens to us when Eta Carinae goes nova? Researchers have
suggested that one or more mass extinctions during the past few
hundred million years might have been triggered by a supernova.
In a supernova, large amounts of “star stuff” are flung
trillions of miles into space along with dangerous gamma rays. The
worst of the gamma rays are concentrated in two oppositely directed
beams leaving the rotational poles of the former star. Among the
negative effects of a large dose of gamma rays is a sudden depletion
of Earth’s protective ozone layer. Left naked, the Earth could
be fried by the UV rays of our own Sun.
Fortunately in the case of Eta Carinae, most people who study this
star think that the rotational axis is along the symmetry axis of
the Homunculus Nebula. This axis is tilted by about forty-five degrees
to our line of sight, which means that most of the dangerous gamma
radiation would not be directed at us. However, there might be enough
radiation to disable communication and other satellites, and perhaps
astronauts, in orbit. To be really dangerous to Earth, the nova
would need to be within thirty light years (176,355,000,000,000
One effect earthlings will notice is just how bright the nova will
be. For about six months or so, not only will the afterglow of the
blast cast a bluish glow in the southern night sky strong enough
to read by, it will also be visible during the day.
So, why are astronomers worried now? Eta Carinae suddenly and unexpectedly
doubled its brightness in 1998–1999 from eighth to fifth magnitude.
Is this the start of another outburst, or is this the beginning
of an unexpectedly early supernova? Stay tuned; only time will tell.
The Planets and the Moon
• Mercury will be in the glow of the rising sun most of the
month. But, on the 27th, use binoculars about forty-five minutes
before sunrise, at about 7:00 a.m., to look for Mercury positioned
above and slightly left of Venus.
• Venus will rise in the east-southeast about thirty minutes
before sunrise. On the 1st, look for Jupiter and Venus very close
together as they rise at about 7:00 a.m. It will be worth a look
as Venus rises just ahead of Jupiter.
• Mars will be high in the east at sunset. The Moon and Mars
will make a spectacular grouping on the night of the 15th. Aldebaran
will be to the right of the Moon with Orion below.
• Jupiter rises about an hour before sunrise, ahead of Venus,
in the east-southeast most of the month. Look again at 6:35 a.m.
on the 4th as the crescent Moon, only two days from new, joins Jupiter
and Venus as they rise. Jupiter will be leading the pack this time
• Saturn rises just after sunset early in the month but disappears
in the sunset late in the month in the east-northeast.
• If you have a good telescope, you will find Pluto about
ten degrees above Venus in the morning sky this month.
• Are you ready for a lunar eclipse? It happens on the evening
of the 20th. The show begins at 6:09 p.m. MST before moonrise in
New Mexico. Moon rise here is at 6:42 p.m. Totality starts at 8:00
p.m. and lasts for fifty-one minutes. The Moon will be partially
eclipsed until 10:00 p.m. Check out Saturn to the lower left of
the Moon that evening. The 20th is also the night of the “Full
Snow” Full Moon. The next partial or full lunar eclipse visible
in the U.S. will not be until 2010. The New Moon is on the 6th.
If you have a question or comment for Charlie, you may email him
Celebrate Lunar New Year—build a dragon
at the Placitas Library
The Placitas Community Library invites everyone—adults and
children of all ages—to join with the millions of people in
or from Far East countries in some traditional, and not so traditional,
ways of marking the Lunar New Year 4705. This year’s celebration,
in honor of the Year of the Rat, will be held at the library on
Saturday, February 16 from 10:00 a.m. to 4:00 p.m., with special
activities planned from 10:00 to 11:30 a.m.
Learn your Chinese zodiac sign and what the Year of the Rat holds
for you. Enjoy stories about Lunar New Year customs, play trivia
games and word searches, create your own Chinese lanterns and snack
on traditional New Year candies and fruits. Special guest Choon
Fritch will create New Year’s cards for children personalized
in Korean calligraphy while her son Chan David and his friends will
present a demonstration of a traditional martial art, Tae Kwon Do,
around 10:30 a.m. There will be activities for all ages, prizes,
decorations to add to the festivities, and the official presentation
of the New Year Dragon.
The library encourages the entire community to help create this
special dragon by stopping in at the library beginning February
2 and making an outline of your hand on construction paper. Put
your name on your hand print and it will be added as a scale to
form the dragon’s body. Large and small, all hand prints are
welcome. They ask that everyone “give them a hand” to
make this the biggest, best dragon Placitas has ever seen.