S&T News Bulletin - Mar 31



Two galaxies have been discovered on the outskirts of our Local Group of
galaxies, the fourth and fifth such neighbors found in the last two years.
 Marshall McCall (York University) and Ronald Buta (University of Alabama)
found the faint, amorphous bodies on the border between Cassiopeia and
Perseus in 1992, roughly a half degree south of the elliptical galaxy
Maffei 1.  They revealed themselves at a near-infrared wavelength of 0.8
micron but are invisible in blue light.  As reported in this June's issue
of the *Astronomical Journal*, the larger object is roughly 3.5 arc
minutes long and possibly a barred spiral. The smaller object, 1.4 arc
minutes across, is most likely a dwarf irregular galaxy. If physically
associated with Maffei 1, these objects would lie roughly three times
farther away than M31.


On October 3, 1962, inhabitants of the Katsina Province in Nigeria saw a
20-kg meteorite fall to Earth.  Later named Zagami, this stone has a
composition so unusual that it's believed to have come from Mars.  Now
five geochemists led by Kurt Marti (Univ. of California, San Diego) have
analyzed noble gases trapped within shards of glass from the meteorite. 
These glasses were shock-melted when the rock was blasted off the Martian
surface and into interplanetary space, and they preserve critical
information about the Martian atmosphere as it existed hundreds of
millions of years ago.  Marti reports that the gas samples from Zagami are
very similar to what two Viking spacecraft found when they landed on Mars
in 1976.  Curiously, not all of the 11 recognized Martian meteorites
contain these trapped gases.  Marti speculates that the Zagami stone must
have resided on or near the surface, so that it had intimate contact with
the Martian atmosphere before being propelled into space.


Astronomers John Spencer and Jim Harrigan report that the new volcanic
eruption on Jupiter's moon Io, which burst forth on March 2nd, is still
going strong.  They reobserved the hot spot on March 30th at the infrared
wavelengths of 1.7 and 2.3 microns, using the 72-inch telescope at Lowell


David Dunham notes that the 11-magnitude asteroid 105 Artemis occults a
slightly fainter star on Tuesday night.  This is not an easy observation;
Dunham recommends at least a 12-inch scope in good seeing.  For U.S.
observers, the path begins along eastern Florida at 5:28 Universal Time on
April 5th, then moves northward along a route that includes Georgia,
Indiana, and Michigan.  But the path could shift as far east as New Jersey
and as far west as New Orleans.  For more info, call Dunham's occultation
hotline: 301-474-4945.


NGC 3628, a nice edge-on galaxy just under the tail of Leo, will have a
visitor this week.  The 10th-magnitude asteroid 9 Metis will pass just 4
arc-minutes to its north on the evenings of April 2nd and 3rd. This close
encounter should be within the reach of a 6-inch telescope. See page 74 of
SKY & TEL's April issue for more details.

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   | Stuart Goldman         Internet: sgoldman@cfa.harvard.edu  |
   * Associate Editor                 mrastro@aol.com           *
   | Sky & Telescope                                            |
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   | Belmont, MA  02178           Magazine of Astronomy         |