[meteorite-list] Subaru Captures Crumbling Comet Schwassmann-Wachmann 3

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri May 12 12:46:11 2006
Message-ID: <200605121602.JAA12441_at_zagami.jpl.nasa.gov>

http://www.subarutelescope.org/Pressrelease/2006/05/11/index.html

Subaru Captures Crumbling Comet Schwassmann-Wachmann 3
Subaru Telescope
May 11, 2006

The Subaru Telescope on Mauna Kea has captured an image of the comet
Schwassmann-Wachmann 3 as its nucleus continues to crumble into more
than fifty pieces. Subaru observed one of these icy chunks, called
Fragment B, on May 3, 2006, using the telescope's wide-field camera
Suprime-Cam as the comet passed within 16.5 million kilometers (just
over 10 million miles) from Earth. (This is about 41 times the distance
between Earth and the Moon.) The resulting visible-light image shows gas
and dust forming the characteristic shape of a comet, with a halo-like
coma and dust tail around Fragment B. Amazingly, it also reveals at
least thirteen mini-comets that have recently broken off from the
fragment. This is five more than were found in observations on April 23,
2006 by the European Southern Observatory's VLT (Very Large Telescope)
in Chile.

A detailed analysis of the cometary fragments is yet to come. However
astronomers have determined that the small pieces are only several tens
of kilometers in diameter and are likely to disappear in a short time.
Exactly how short is one of the questions astronomers are hoping to
answer. Tetsuharu Fuse from Subaru Telescope says "the combination of
information from many telescopes including large telescopes like Subaru
and the VLT and smaller telescopes like the Ishigakijima Astronomical
Observatory in Okinawa, Japan, will give us the insight into how comets
fall apart and conversely how they hold together."

Comets are often described as "dirty snowballs," loose clumps of dust
and ice covered by a crust of dirt. As they approach the Sun, comets can
warm up and fall apart. In 1995, astronomers saw this comet become a
thousand times brighter, and found that its nucleus had broken into
three pieces. This year, observations from around the world have
confirmed that the nucleus has broken into more than 50 pieces.

Friedrich Carl Arnold Schwassmann and Arno Arthur Wachmann from Germany
discovered the comet, which is formally called 73P/Schwassmann-Wachmann
3, in 1930. It travels around the Sun in an 5.4-year-long elliptical
orbit . When the comet approaches the Sun, depending on where Earth is
in its orbit, the comet may or may not pass near us.
Schwassmann-Wachmann 3 was long known as a "mystery comet" because it
had been lost to observers for 50 years before it was rediscovered in 1979.

Over the next week, the comet will pass by Earth at a distance of 12
million kilometers (about 7.5 million miles). This is about 30 times the
distance between Earth and the Moon. Astronomers are keeping the giant
eyes of telescopes pointed at this comet, and at the Subaru telescope,
infrared light observations have already taken place.

People with binoculars or small telescopes can also see the brightest
fragments of the comet as they pass through the constellations Cygnus
and Pegasus over the next week. Viewing will probably be best after May
18th, when moonlight will not outshine the comet. Observers wishing to
track the comet can look for finder charts searching the World Wide Web
with the keywords "comet 73P chart" or going to most major astronomy web
sites.

>From Hawai'i, the best time to observe the comet is in the morning
before sunrise. The comet will be high overhead in the northeastern sky
over the next week.

Subaru is an 8.2 meter optical-infrared telescope on Mauna Kea, Hawaii,
operated by the National Astronomical Observatory of Japan, a member
institute of Japan's National Institutes of Natural Science.

The research team: Tetsuharu Fuse, Subaru Telescope, National
Astronomical Observatory of Japan (NAOJ). Hisanori Furusawa, Subaru
Telescope, NAOJ. Junichi Watanabe, NAOJ. Daisuke Kinoshita, Taiwan
National Central University. Naoyuki Yamamoto, Grid Technology Research
Center, National Institute of Advanced Industrial Science and
Technology, Japan

[Image]
Low Resolution Image (285KB)
High Resolution Image (610KB)

Object: Comet 73P/Schwassmann-Wachmann 3 Fragment B
Telescope and Focus: Subaru Telescope Prime Focus
Instrument: Suprime-Cam
Filter: R-band (0.65 micrometers)
Observation Time: May 3, 2006, UT
Exposure Time: 8 minutes
Field of View: Approximately 32.5 arcminutes x 23 arcminutes (Insert:
1.5 arcminute x 1 arcminute)
Orientation: North is up. East is left.


------------------------------------------------------------------------

[Chart]
Finding chart for the brightest fragment of Comet Schwassmann-Wachmann 3
(Fragment C) for May 12 though May 20, 2006. (Larger Image <sw3_3.jpg>)

[Image]
Mini-comets that have broken off from Fragment B of Comet 73P/
Schwassmann-Wachmann 3. The main body of Fragment B is the bright
object in the upper left corner. (Larger Image <sw3_2.jpg>)

[Image]
Comet 73P/Schwassmann-Wachmann 3, Fragment B (Larger Image <sw3_1.jpg>)

Related Links:

    * European Southern Observatory
      http://www.eso.org/
    * Hubble Space Telescope
      http://hubble.nasa.gov/index.php
    * National Astronomical Observatory of Japan, Comet SW3 Observation
      Campaign (Japanese Only)
      http://www.nao.ac.jp/phenomena/20060502/index.html
    * Ishigakijima Astronomical Observatory (Japanese Only)
      http://www.nao.ac.jp/ishigaki/
Received on Fri 12 May 2006 12:02:59 PM PDT