[meteorite-list] Comet Tempel 1 Went Back to Sleep

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Jul 14 14:24:07 2005
Message-ID: <200507141737.j6EHbl327393_at_zagami.jpl.nasa.gov>

http://www.hq.eso.org/outreach/press-rel/pr-2005/pr-19-05.html

ESO Press Release 19/05
14 July 2005

For immediate release

Comet Tempel 1 Went Back to Sleep

Astronomers Having Used ESO Telescopes Start Analysing Unique
Dataset on the Comet Following the Deep Impact Mission

Ten days after part of the Deep Impact spacecraft plunged onto Comet
Tempel 1 with the
aim to create a crater and expose pristine material from beneath the
surface, astronomers are back in the ESO Offices in Santiago, after more
than a week of observing at the ESO La Silla Paranal Observatory. In
this unprecedented observing campaign - among the most ambitious ever
conducted by a single observatory - the astronomers have collected a
large amount of invaluable data on this comet.

The astronomers have now started the lengthy process of data reduction
and analysis. Being all together in a single place, and in close
contacts with the space mission' scientific team, they will try to
assemble a clear picture of the comet and of the impact.

The ESO observations were part of a worldwide campaign to observe this
unique experiment. During the campaign, ESO was connected by phone,
email, and videoconference with colleagues in all major observatories
worldwide, and data were freely exchanged between the different groups.
This unique collaborative spirit provides astronomers with data taken
almost around the clock during several days and this, with the largest
variety of instruments, making the Deep Impact observing campaign
one of the most successful of its kind, and
thereby, ensuring the greatest scientific outcome.

>From the current analysis, it appears most likely that the impactor did
not create a large new zone of activity and may have failed to liberate
a large quantity of pristine material from beneath the surface.

ESO PR Photo 22/05 <images/phot-22-05-preview.jpg>

ESO PR Photo 22/05

Evolution of Comet Tempel 1 (FORS2/VLT)

[Preview - JPEG: 400 x 701 pix - 128k] <images/phot-22-05-preview.jpg>
[Normal - JPEG: 800 x 1401 pix - 357k] <images/phot-22-05-normal.jpg>

ESO PR Photo 22/05 <images/phot-22-05.gif>

Animated Gif

Caption: ESO PR Photo 22/05 shows the evolution of Comet Tempel 1 as
observed with the FORS2 instrument on Antu (VLT).

The images obtained at the VLT show that after the impact, the
morphology of Comet Tempel 1 had changed, with the appearance of a new
plume-like structure, produced by matter being ejected with a speed of
about 700 to 1000 km/h (see ESO PR Photo 23/05). This structure,
however, diffused away in the following days, being more and more
diluted and less visible, the comet taking again the appearance it had
before the impact. Further images obtained with, among others, the
adaptive optics NACO instrument on the Very
Large Telescope, showed the same jets that were visible
prior to impact, demonstrating that the comet activity survived widely
unaffected by the spacecraft crash.

The study of the gas in Comet Tempel 1 (see "Looking for Molecules"
<http://deepimpact.eso.org/obseso4.html>), made with UVES
on Kueyen (UT2 of the VLT), reveals a small
flux increase <#note2> the first night following the impact. At that
time, more than 17 hours after the impact, the ejected matter was fading
away but still measurable thanks to the large light collecting power of
the VLT. The data accumulated during 10 nights around the impact have
provided the astronomers with the best ever time series of optical
spectra of a Jupiter Family comet, with a total of more than 40 hours of
exposure time. This unique data set has already allowed the astronomers
to characterize the normal gas activity of the comet and also to detect,
to their own surprise, an active region. This active region is not
related to the impact as it was also detected in data collected in June.
It shows up about every 41 hours, the rotation period of the comet
nucleus determined by the Deep Impact spacecraft. Exciting measurements
of the detailed chemical composition (such as the isotopic ratios) of
the material released by the impact as well as the one coming from that
source will be performed by the astronomers in the next weeks and months.

Further spectropolarimetric observations with FORS1
have confirmed the surface of the comet to
be rather evolved - as expected - but more importantly, that the dust is
not coming from beneath the surface. These data constitute another
unique high-quality data set on comets.

Comet Tempel 1 may thus be back to sleep but work only starts for the
astronomers.

More information

On July 4, 2005, the NASA Deep Impact spacecraft launched a 360 kg
impactor onto Comet 9P/Tempel 1. This experiment is seen by many as the
first opportunity to study the crust and the interior of a comet,
revealing new information on the early phases of the Solar System. ESO
actively participated in pre- and post-impact observations. Apart from a
long-term monitoring of the comet, for two days before and six days
after, all major ESO telescopes - i.e. the four Unit Telescopes of the
Very Large Telescope Array at Paranal, as well as the
3.6m, 3.5m NTT and the 2.2m ESO/MPG telescopes at La Silla
<../../../lasilla/> - have been observing Comet 9P/Tempel 1, in a
coordinated fashion and in very close collaboration with the space
mission' scientific team. The simultaneous use of all ESO telescopes
with all together 10 instruments has an enormous potential, since it
allows for observation of the comet at different wavelengths in the
visible and infrared by imaging, spectroscopy and polarimetry. Such
multiplexing capabilities of the instrumentation do not exist at any
other observatory in the world.

More information is available at the dedicated Deep Impact at ESO
<http://deepimpact.eso.org> web site.
      
Notes

[1]: Leading scientists of the ESO DI campaign: H. Boehnhardt (MPI,
Lindau, Germany), O. Hainaut (ESO), H.U. Kaufl (ESO), H. Rauer (DLR,
Germany).

Members of the ESO DI observing team on site: N. Ageorges (ESO, Chile),
S. Bagnulo (ESO, Chile), L. Barrera (UMCE, Chile), H. Boehnhardt (MPS,
Germany), T. Bonev (Astr. Inst. Sofia, Bulgaria) , O. Hainaut (ESO,
Chile), E. Jehin (ESO, Chile), H.U. Kaufl (ESO, Germany), F. Kerber
(ESO, Germany), J. Manfroid (U.Li?ge, Belgium), O. Marco (ESO, Chile),
E. Pantin (CEA, France), E. Pompei (ESO, Chile), H. Rauer (DLR,
Germany), C. Sterken (Vrije Universiteit Brussel, Belgium), G.P. Tozzi
(Obs. Arcetri, Italy), M. Weiler (DLR, Germany)

Members of the ESO DI observing team not on site: C. Arpigny (U.Li?ge,
Belgium), A. Cochran (McDonald, USA), C. Delahodde (Univ. Florida, USA),
Y. Fernandez (Univ. Hawaii, USA), D. Hutseme kers (U.Li?ge, Belgium), H.
Kawakita (Gunma, Japan), J. Knollenberg (DLR, Germany), L. Kolokolova
(Univ. Maryland, USA), M. Kretlow (MPS, Germany), M. Kueppers (MPS,
Germany), E. Kuehrt (DLR, Germany), L. Lara (IAA, Spain), J. Licandro
(IAC, Spain), C. Lisse (Univ. Maryland, USA), K . Meech (U.Hawaii, USA),
R. Schulz (ESTEC, The Netherlands), G. Schwehm (ESTEC, The Netherlands),
M. Sterzik (ESO, Chile), J.A. St?we (Leide n, The Netherlands), I.
Surdej (Univ. Li?ge, Belgium and ESO, Garching), D. Wooden (Ames, USA),
J.-M. Zucconi (Besancon, France).

[2]: This image <images/UVES-di-22-05.gif> is a of the CN (388 nm)
spectrum of comet Tempel 1 observed from Paranal just before the impact
(in black), the 03 of July (at UT 02:00), and the 04 of July at UT 24:00
(in red), which is the first observation after the impact. An artificial
wavelength shift has been added for clarity. The post impact spectrum is
clearly higher than the pre-impact one.
      
Contacts

Hermann Boehnhardt
MPI-Lindau
Email: boehnhardt_at_linmpi.mpg.de

Olivier Hainaut
ESO Chile
Phone: +56 2 463 3118
Email: ohainaut_at_eso.org

Hans-Ulrich K?ufl
ESO Garching
Email: hukaufl_at_eso.org

Heike Rauer
DLR, Germany
Email: Heike.Rauer_at_dlr.de
Received on Thu 14 Jul 2005 01:37:46 PM PDT