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Sky & Telescope News Bulletin - July 10, 1998

JULY 10, 1998


Despite the intensive use of tracking antennas worldwide, as of July 8th 
ground controllers had not reestablished contact with the Solar and 
Heliospheric Observatory, which fell silent on June 25th.  In a few weeks 
changing orbital geometry may put enough sunlight on the craft's solar 
panels to restore power. However, the spacecraft's chances of returning to 
operation are considered slim, as its instruments and fuel tanks may have 
been irreparably damaged by the long deep freeze.


Astronomers in Hawaii may have discovered a new class of asteroid -- one 
that orbits the Sun completely within the orbit of the Earth. David Tholen 
and Robert Whiteley (University of Hawaii) announced their finding on July 
1st. Tholen estimates that the object, designated 1998 DK<36>, is only 
about 40 meters in diameter -- probably about the size of the object that 
burst over Siberia just more than 90 years ago. However, because the object 
set soon after dark -- and because of some equipment problems -- DK36 was 
only imaged on two nights in February using the a 2.24-meter telescope atop 
Mauna Kea. Unfortunately, because there are only four observations -- two 
sets of minutes-apart positions on consecutive days -- and they were taken 
more than five months ago, a good orbit cannot be obtained to guide 
observers for following it up. Furthermore, it is unlikely the object will 
be recovered unless some "lucky shot" captures it in the future. Its 
supposed intra-Earth orbit is also somewhat nebulous. According to Gareth 
Williams of the International Astronomical Union's Minor Planet Center, an 
Earth-crossing orbit could still fit the data. He notes that it is clear 
that the object's farthest distance from the Sun is small, but no more than 
1.1 astronomical units. Regardless, it does raise the uncomfortable fact 
that killer asteroids -- like the antagonists of summer blockbuster movies 
-- may actually be coming from where astronomers would have a hard time 
finding them.


In the predawn of July 4th (18:12 UT on July 3rd), Japan launched its first 
Mars mission from the Kagoshima Space Center on the island of Honshu. Known 
as Planet B before launch, the probe has been renamed Nozomi ("Hope"). It 
is now in a high-apogee orbit from which it will fly past the Moon twice to 
build up speed. A rocket firing in December will send Nozomi on a long 
cruise to Mars, with arrival planned for October 1999. From its Martian 
orbit, Nozomi will study the planet's atmosphere, charged particles, and 
magnetic field. Its payload consists of experiments from Japan, the U.S., 
Germany, Canada and Sweden.


Copyright 1998 Sky Publishing Corporation. S&T's Weekly News Bulletin and 
Sky at a Glance stargazing calendar are provided as a service to the 
astronomical community by the editors of SKY & TELESCOPE magazine. 
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published in any other form without permission from Sky Publishing (contact 
permissions@skypub.com or phone 617-864-7360). Illustrated versions, 
including active links to related Internet resources, are available via SKY 
Online on the World Wide Web at http://www.skypub.com/.

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