The Breakup of
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Comet LINEAR blew apart
so thoroughly last week that astronomers can't find any sizable
pieces from its fractured icy core. New groundbased images of
the comet posted today revealed no fragments brighter than 22nd
magnitude. The new data are fueling speculation that Comet LINEAR
itself might have been the fragment of a larger body that passed
through the inner solar system centuries ago.
Right: This R-filtered image
of Comet LINEAR's inner coma reveals no fragments brighter than
22nd magnitude. The core has seemingly dissolved into an amorphous
haze of gas and dust. Credit: R. Corradi and N. O'Mahoney, 2.5-m
Isaac Newton Telescope.
Above: The same R band image
as above, covering a 22 arcminute field with stretched contrast
to highlight the tail. Credit: R. Corradi and N. O'Mahoney, 2.5-m
Isaac Newton Telescope.
July 31, 2000
Meltdown! Intense solar heating apparently triggered a massive
disruption of comet LINEAR's fragile icy core when it passed
close to the Sun last week.
This image obtained on July 31, 2000, by astronomer Javier Mendez at the Jacobus
Kapteyn Telescope shows the comet's elongated coma fading
rapidly. Mark Kidger, who communicated the image, says "The
poor comet really does look a bit sad now. As previously,
there is a sharp leading edge to the coma, but the peak brightness
of the debris cloud is a fair distance down-tail. [It] has just
July 28, 2000
Comet LINEAR did
not become a spectacular naked-eye object as many stargazers
had hoped, but it is intriguing astronomers with its peculiar
July 27, 2000
There is mounting evidence
that the active
comet C/1999 S4 (LINEAR) may not have survived its closest
approach to the Sun on July 26th intact. In the International
Astronomical Union Circular #7467,
Kidger (Instituto de Astrofisica de Canarias) reported images
he obtained using the Jacobus
Kapteyn Telescope showing what appears to be a substantial
disruption of the comet's nucleus. A first-hand account of Kidger's
observations is available at cometlinear.com.
Other telescopes have confirmed the dramatic changes. See International Astronomical Union Circular
#7468 for details.
These R-filtered images of comet LINEAR were captured by M. Kidger
at the Kapteyn Telescope on the island of La
Palma. On July 23rd, the comet's coma was centrally condensed.
Since then it has steadily elongated, probably as a result of
internal disruption. (The two bright objects near the bottom
of the July 27th image are stars, not comet fragments.)
Below: The breakup of comet LINEAR. Contours represent
lines of constant brightness in Kapteyn Telescope R-band images
of comet LINEAR (credit: Mark Kidger). This 5 frame sequence
spanning the interval from July 23rd to 27th shows the progressive
elongation and disruption of the comet's core. Each contour map
is 40 arcseconds on a side, centered approximately on the core
of the comet.
"I think that we'll see the comet
practically disappear in a couple of nights," says Kidger.
Amateur and professional astronomers are encouraged to monitor
the comet for signs of additional activity. On July 27th comet
LINEAR's visual magnitude was still between +6.0 and +7.0,
well within the reach of small telescopes. Visit Sky
& Telescope for finder charts.