Sky & Telescope's News Bulletin - Jan 9

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* * * SKY & TELESCOPE's WEEKLY NEWS BULLETIN - January 9, 2004 * * *

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Welcome to S&T's Weekly News Bulletin. Images, the full text of stories
abridged here, and other enhancements are available on our Web site,
SkyandTelescope.com, at the URLs provided below. (If the links don't work, just
manually type the URLs into your Web browser.) Clear skies!

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FOOTPRINT OF A MAGNETIC EXOPLANET

For the first time, astronomers appear to have identified an extrasolar planet
with a magnetic personality. The planet orbits HD 179949, a 6.3-magnitude
solar-type star (spectral type F8) located 90 light-years away in Sagittarius.
After observing the star during three observing runs in 2001-02, a Canadian
team led by Evgenya Shkolnik (University of British Columbia) has identified a
hot spot that rotates around the star every 3.093 days -- exactly the same
period with which the planet orbits the star. The hot spot has kept right in
step with the planet for more than 100 orbits.

"This is the first glimpse of a magnetic field of an extrasolar planet," said
Shkolnik at a Wednesday press conference at the American Astronomical Society
meeting in Atlanta....

http://SkyandTelescope.com/news/article_1151_1.asp

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DIVING GLOBULAR CLUSTER MAKES A STARRY SPLASH

Two astronomers have made a surprising and unsuspected cosmic connection by
suggesting that a naked-eye open star cluster in Scorpius was spawned by the
action of a binocular globular cluster in the neighboring constellation Ara.
Richard F. Rees Jr. (Westfield State College) and Kyle M. Cudworth (Yerkes
Observatory) propose that when the 6th-magnitude globular NGC 6397 passed
through the plane of the Milky Way some 5 million years ago, it triggered the
formation of the open cluster NGC 6231, which marks the core of the large
Scorpius OB1 Association. Rees and Cudworth presented their proposal at the
203rd meeting of the American Astronomical Society on Wednesday....

http://SkyandTelescope.com/news/article_1150_1.asp

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MORE GALAXIES THAT JUMP THE GUN

Yet another group of astronomers has found signs that we don't know as much as
we thought about how galaxies formed after the Big Bang. An international team
has located a streamer of galaxies 300 million light-years long that had
already taken shape when the universe was only a fifth of its present age -- at
redshift 2.38, when the universe was just 2.8 billion years old.

Such a galaxy string would be no big deal in the present-day universe. It's
similar to the famous Great Wall of galaxies just a few hundred million
light-years away. But the best models of structure formation predict no
gatherings so big appearing so early in cosmic history. "The universe was
growing up faster than we thought it was," said Povilas Palunas (McDonald
Observatory), one of the discoverers, at the American Astronomical Society
meeting on Wednesday....

http://SkyandTelescope.com/news/article_1149_1.asp

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EXPLAINING SUPERNOVA EXPLOSIONS

Time and again, astronomers have been embarrassed by the fact that they don't
really understand one of their most important tools, Type Ia supernovae, which
serve as invaluable "standard candles" for measuring cosmic distances. But if
new work announced Tuesday at the American Astronomical Society meeting in
Atlanta, Georgia, holds up, they may have taken a big step in the right
direction.

Because they can be used to measure distances as great as several billion
light-years, Type Ia supernovae have enabled cosmologists to gauge how fast the
universe is expanding and how the expansion rate has changed through time. Six
years ago, the exploding stars provided the first evidence that the universe's
expansion has been speeding up, due to an all-pervasive "dark energy" that no
one expected. Type Ia supernovae also affect our daily lives: most of the iron
in everything from frying pans to steel girders was forged within these stellar
furnaces.

But what are Type Ia supernovae, exactly...?

http://SkyandTelescope.com/news/article_1147_1.asp

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A GALACTIC STRIPTEASE

Pity C153. Astronomers using a broad suite of instruments have caught this
spiral galaxy performing an involuntary striptease act as it plunges through
the heart of a massive galaxy cluster at nearly 2,000 kilometers per second.

Images and spectra in radio, optical, and X-ray wavelengths show a galaxy's
worth of gas being stripped from C153, creating a 200,000-light-year-long wake
that resembles the tail of a comet. Countless other galaxies have undoubtedly
endured the same humiliation, which explains why extremely massive galaxy
clusters in the local universe contain so few spirals....

http://SkyandTelescope.com/news/article_1146_1.asp

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THE SUN'S CLOSEST TWINS

No two people are exactly alike, but if you were to sort through millions of
faces, you might find someone who is uncannily similar to you today, others who
are similar to you when you were younger, and some who look exactly as you will
in the future. You might learn a lot from these people. Similarly, several
astronomers at Villanova University think they can learn a lot about our Sun by
finding near-twins of it at all the different stages expected in its long
lifetime.

At the American Astronomical Society meeting, Edward Guinan described an
ongoing program called "The Sun In Time" that is identifying and studying solar
analogues. Working at every wavelength, from radio to X-rays, the group is
researching stars that have sizes, masses, temperatures, and heavy-element
contents that are similar to those of the present-day Sun -- as well as
solar-twin stars at every age from birth onward....

http://SkyandTelescope.com/news/article_1145_1.asp

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A TASTE OF THINGS TO COME

As more images come to Earth from the Spirit rover on Mars, astronomers are
being ever more tantalized by Gusev Crater. On Tuesday NASA released the
highest resolution picture ever taken of Mars. The mosaic image, 4,000 by 3,000
pixels, is of the area in front of the rover and was shot while Spirit remained
in its "seated" position. Engineers predict the rover could start to roll to
targets next week.

The detailed view shows rocks of various sizes and shapes. Most are smooth,
perhaps due to thousands of years of sand-blasting from Mars's dusty winds....

http://SkyandTelescope.com/news/article_1144_1.asp

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DISSECTING A MICROQUASAR

For 25 years astronomers have been scratching their heads over the energetic
binary star SS 433, a so-called microquasar in Aquila. And even though lots of
new data were unveiled Monday at the American Astronomical Society meeting last
week in Atlanta, Georgia, the experts are scratching their heads still.

Astronomers are keenly interested in SS 433 because it seems to be a miniature,
million-times-scaled-down version of the engines that power quasars and other
active galactic nuclei. This bizarre system consists of a fairly normal star
and an extremely dense object -- either a neutron star or a black hole -- that
orbit each other every 13 days. A stream of gas is spilling from the "normal"
star into the dense companions's deep gravitational field, where it swirls into
a hot, brilliantly glowing disk. Somehow, much of the material in the disk ends
up within two narrow, oppositely directed jets that shoot away from the
collapsed object at a quarter the speed of light.

That much has been known for years. But what type of star is fueling the disk
and jets? And is the compact object a neutron star or a black hole...?

http://SkyandTelescope.com/news/article_1143_1.asp

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OLD GALAXIES IN THE YOUNG UNIVERSE

Astronomers thought they had a nice, clear picture of how galaxies formed
billions of years ago -- but now the picture is suddenly turning muddy. A team
studying the faintest galaxies ever to have their spectra taken is finding far
too many big, mature galaxies similar to our Milky Way much too early in cosmic
history. "Theorists are not yet at the point of panic, but they're getting
there," team member Roberto Abraham (University of Toronto) told a press
conference at the American Astronomical Society meeting being held last week in
Atlanta....

http://SkyandTelescope.com/news/article_1142_1.asp

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THE MOST MASSIVE STAR

There's no Guinness Book of Astronomy Records, but if there were, Stephen
Eikenberry (University of Florida) thinks he would have a new entry for it. At
the January 2004 American Astronomical Society meeting in Atlanta, Eikenberry
claimed to have identified the most massive and perhaps the most luminous star
ever discovered....

http://SkyandTelescope.com/news/article_1141_1.asp

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PLOTTING SPIRIT'S COURSE

Remember the name "Sleepy Hollow." In images released on Monday by scientists
working with the Spirit rover on Mars, the newly discovered, light-colored
feature (the first Spirit-site landmark to be given a name) will likely be the
initial objective for the rover when it starts to roll around next week.

At a press conference on Monday, Mars Exploration Rover principal investigator
Steven W. Squyres (Cornell University) reported "more good news." The craft is
alive and healthy, and so far all its instruments appear to be in perfect
working order....

http://SkyandTelescope.com/news/article_1140_1.asp

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COMET CATCHER

On January 2nd, after a nearly five-year journey, NASA's comet-catching
spacecraft Stardust successfully arrived at Comet 81P/Wild 2 and scooped up
dust samples before heading back to Earth. In the process it passed through the
comet's coma, snapped some images of the nucleus from the scant distance of 240
kilometers (149 miles), and discovered some surprising surface features....

http://SkyandTelescope.com/news/article_1138_1.asp

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ASTRO NEWS BRIEFS

Mars Express Fails to Hear Beagle 2

The first attempt for the European Space Agency's Mars Express orbiter to hear
from the Beagle 2 lander was unsuccessful. The spacecraft passed over Beagle
2's landing site at about 12:15 Universal Time Wednesday (7:15 a.m. Eastern
Standard Time) but it did not detect a signal from below. "We have not lost
hope yet to contact Beagle 2," says ESA's director of science David Southwood,
who explained that additional attempts would be made. "But we also know that it
has landed on an unforgiving planet."

http://SkyandTelescope.com/news/article_1148_1.asp

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HIGHLIGHTS OF THIS WEEK'S SKY

* Last-quarter Moon on Wednesday January 14th.
* Saturn (magnitude -0.4, in Gemini) is just a couple weeks past opposition.
* Mercury (magnitude 0) is having a good apparition in the dawn sky. Look for
it above the southeast horizon about 50 or 60 minutes before sunrise.

For details, see This Week's Sky at a Glance and Planet Roundup:

http://SkyandTelescope.com/observing/ataglance/

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| Sky & Telescope |
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