From: sgoldman%cfa4.DECNET@cfa.harvard.edu
(Sky & Telescope Magazine)
Subject: S&T News Bulletin - May 27
SATURN'S THIN RINGS
Earth's first of three passages through the plane of Saturn's rings
occurred as predicted on May 21st, and astronomers around the globe were
watching. Giant reflectors like the 10-meter Keck telescope, took images
as the rings tilted edge-on. According to Imke de Pater of the
University of California at Berkeley, images with the Keck telescope
taken just before and after the ring-plane crossing reveal several small
moonlets within the rings. If you observe Saturn right now you're not
likely to see much except the planet's distinctly flattened ball. Saturn
rises only a few hours before dawn, so it's not particularly well placed
for viewing. If you have a good-size telescope you might try to watch
the planet's larger satellites play tag. Tethys, Dione, Rhea, and Titan
are undergoing eclipses and occultations by Saturn and one another. A
complete observing guide for Saturn's ring crossings begins on page 68
of SKY & TELESCOPE's May issue.
NEW SMALL STAR
A new low-mass star has been found, just tipping the scales to allow
thermonuclear reactions. Using a coronagraph to block the light from
the star Gliese 105A -- a dwarf star 27 light-years away -- David A.
Golimowski of Johns Hopkins University and three Caltech colleagues
discovered a 16th-magnitude star only 3.3 arcseconds from it. While the
companion was expected on the basis of observed wobbles in the
primary's proper motion, the companion, dubbed Gliese 105C, evaded
detection by other high-resolution techniques. While this star's
characteristics are not known to high certainty, its provisional
near-infrared brightness suggests a mass at most 10 percent above the
minimum required to sustain nuclear fusion. The star's physical
quantities will become better known as astronomers follow the 60-year
orbit of this possibly substellar component.
SOLAR HOT WATER
Need some hot water? You might find some on the Sun, of all places.
This week in the journal Science, Lloyd Wallace of Kitt Peak National
Observatory and other astronomers reported confirming the presence of
water on the Sun. Analysis of some unusual infrared sunspot spectra led
the astronomers to conclude that the odd absorption lines they were
seeing came from water vapor. The astronomers were able to reproduce
the spectral signature by heating samples of water in a laboratory to
1,500 deg. Celsius. Sunspots, which have lower temperatures than the
surrounding solar atmosphere, are cool enough to allow oxygen and
hydrogen to combine. While this water is hardly a resource to be
capitalized upon, it does suggest that other interesting chemistry is
possible in the solar atmosphere.
REPRODUCED FROM SKY & TELESCOPE'S NEWS BULLETIN MAY 26, 1995
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- T o d d E. V a n H o o s e a r -
``'''vanhoose@lalaland.cl.msu.edu - vanhoose@msu.edu - vanhoose@lalaland.cl.msu.edu
(._.) Michigan State University - East Lansing, MI USA
(_) Computer Laboratory - Department of Communication
`---' <A HREF="http://lalaland.cl.msu.edu/~vanhoose/">My Home Page</A>
"Error, no keyboard - press F1 to continue."
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