[meteorite-list] Surf the Web to see the Sun-dancing comet

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:27 2004
Message-ID: <200302170547.VAA13246_at_zagami.jpl.nasa.gov>

ESA Science News
http://sci.esa.int

12 Feb 2003

Surf the Web to see the Sun-dancing comet

Only the most dedicated of sky watchers will have seen the
latest comet, called C/2002 V1 (NEAT). It has hovered near
the limits of naked-eye visibility in the evening sky since
January 2003. However, you would need a pair of binoculars,
pointed in exactly the right direction, to see anything.
Log onto the Internet instead, and let the ESA/NASA space
probe SOHO show you more about this comet than you would
usually see.

The Solar and Heliospheric Observatory (SOHO) is an
ESA/NASA space probe to study the Sun. One of its
instruments is the Large Angle and Spectrometric
Coronagraph (LASCO) that blots out the disc of the Sun,
creating an artificial total eclipse. LASCO is a
spectacular comet-observing tool because of its
combination of high sensitivity and large field of view.

The Sun's large gravitational field provides the central
force for comet orbits. Comets themselves are icy
messengers, often from the outer Solar System that fall
through the inner solar system, before heading back into
the celestial reaches. On the way, they provide observers
on Earth and in space with fleeting opportunities to
catch a glimpse. Astronomers discover comets all the time.
If first seen by individual observers, they are named
after the discoverer. Nowadays, more and more comets are
first seen by automated telescope patrols, designed to
scan the skies looking for objects that could pass
close to Earth. These discoveries are given catalogue
references, as is the case for Comet C/2002 V1.

The last comet to pass through the SOHO field of view
made its journey during the last week of January 2003.
Now, armchair observers all around the world have a
chance to view another comet, C/2002 V1. This time, the
show may be more spectacular because C/2002 V1 (NEAT)
will pass very closely by the Sun.

The comet was discovered by NASA's Near Earth Asteroid
Tracking programme (NEAT). At that time, it was 25,000
times fainter than the human eye can perceive. Initially,
the comet became so bright that astronomers wondered
whether they would be able to see it during the day, as
it rounded the Sun.

During January 2003, the comet failed to brighten as
hoped. Now, it is expected to disappear from view to
Earth-bound observers about 11 February 2003, as it
heads towards the Sun for its closest approach on 18
February 2003. It will not be lost from all sight,
however, as in space, SOHO will be watching. Astronomers
expect C/2002 V1 (NEAT) to pass into LASCO instrument's
field of view, early on 16 February and stay there until
20 February.

It will pass by the Sun at less than a tenth of the
distance between the Earth and the Sun. There is a small
chance that the Sun's gravitational field could pull it
to pieces. "Even if that doesn't happen, the fly-by
itself should be impressive enough," says Bernhard Fleck,
SOHO Project Scientist.

Watch the comet's journey live on the Internet:

     http://sohowww.nascom.nasa.gov/data/realtime-images.html
or

     http://soho.estec.esa.nl/data/realtime-images.html

USEFUL LINKS FOR THIS STORY

* More about Comet C/2002 V1 (NEAT)
  http://spdext.estec.esa.nl/content/doc/cc/31436_.htm
* SOHO's Pick of the Week images
  http://soho.estec.esa.nl/pickoftheweek/old/27jan2003/index.html
* More about SOHO
  http://sci.esa.int/home/soho/

IMAGE CAPTIONS:

[Image 1:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=14&cid=12&oid=31434&ooid=31438]
True-colour (LRGB) image of Comet C/2002 V1 (NEAT), obtained
on 29 January 2003 (18h44-18h57UT) with 60-cm, f/3.3
Deltagraph telescope, photometric filters and CCD. Image is
a composite of 3x60s B, 3x60s V and 3x60s R images added
together. The light image (L) was made by adding all 9
images. Image scale is 2.49 arc sec/pixel. Copyright © 2003
by B. Dintinjana and J. Skvarc.

[Image 2:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=14&cid=12&oid=31434&ooid=12343]
SOHO is stationed 1.5 million kilometres away from the
Earth, directly in line of the Sun. There, it constantly
watches the Sun for activity, returning spectacular
pictures and data of the storms that rage across its
surface. SOHO was launched in 1995 by a NASA Atlas-IIAS/
Centaur rocket and was designed to work for three years.
It is still working today.

[Image 3:
http://sci.esa.int/content/searchimage/searchresult.cfm?aid=14&cid=12&oid=31434&ooid=12366]
SOHO spacecraft sees two comets plunge into the Sun. In
a rare celestial spectacle, two comets were observed
plunging into the Sun's atmosphere in close succession,
on 1 and 2 June 2000. This unusual event on Earth's own
star was followed on 2 June 2000 by a likely unrelated
but also dramatic ejection of solar gas and magnetic
fields on the southwest (or lower right) limb of the Sun.
Received on Mon 17 Feb 2003 12:47:53 AM PST