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(meteorobs) Excerpts from "CCNet, 14 October 1999"
------- Forwarded Message
From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: CCNet, 14 October 1999
Date: Thu, 14 Oct 1999 09:29:07 -0400 (EDT)
CCNet, 14 October 1999
------------------------
QUOTE OF THE DAY
"A group of astronomers has discovered that a new molecule,=20
nitrogen sulfide (NS), is contained within comets. The discovery=20
is intriguing because scientists have long suspected that many=20
molecules on Earth were brought here by comets. 'Could this=20
material perhaps even be relevant to the origin of life?'"
-- University of Massachusetts-Amherst, 13 October 1999
(1) NEW COMET MAY PUT ON A SHOW NEXT YEAR
SpaceViews, 13 October 1999=20
(2) CHEMISTRY OF COMET HALE-BOPP MAY OFFER CLUES ABOUT EARLY =20
SOLAR SYSTEM
Andrew Yee <ayee@nova.astro.utorontodot ca>
(3) FIRST TUNGUSKA99 RESULTS
Luigi Foschini <L.Foschini@isao.bo.cnrdot it>=20
[...]
(6) WEB LINKS ON IMPACTS & IMPACT CRATERS
Michael Paine <mpaine@tpgi.com.au>=20
[...]
========================================================
(1) NEW COMET MAY PUT ON A SHOW NEXT YEAR
>From SpaceViews, 13 October 1999=20
http://www.spaceviews.com/1999/10/13b.html
A comet discovered last month may become bright enough to be visible to =
the naked eye come the middle of next year, although it is unlikely to=20
be as brilliant as two other comets visible this decade.
Comet C/1999 S4 LINEAR was discovered last month by the LINEAR=20
automated telescope in New Mexico as part of an asteroid and comet
search program. First classified as an asteroid when discovered,=20
followup observations by other astronomers revealed a distinct fuzzy=20
coma around the body, evidence that the object is a comet.
Based on 18 observations in late September, astronomers at the Minor=20
Planet Center of the Smithsonian Astrophysical Observatory calculated a
parabolic, highly-inclined trajectory for the comet, passing about 0.75 =
AU (112 million km, 70 million mi.) from the Sun at its closest=20
approach in late July.
While the comet is very dim at the moment -- about magnitude 16,=20
requiring moderate to large telescopes to see it -- it will brighten=20
considerably as it approaches the Sun. Taking into account both
the comet's distance from the Earth and the Sun, it may brighten to as=20
much as magnitude 3 or 4 and thus be visible to the naked eye by July.
Predicting the brightness of comets is difficult, as it is hard to=20
estimate in advance not only the size of the comet but how much gas and =
dust it will produce as it approaches the Sun and warms up. However,=20
current indications are that the comet will not be anywhere as bright=20
as comet Hyakutake in March 1996 or Hale-Bopp one year later.
The best time to observe the comet will likely be in mid-July, when the =
comet is near its peak brightness. It will be seen in the northwest sky =
after sunset in the northern hemisphere.
Copyright 1999, SpaceViews
MODERATOR'S NOTE: For further information about comet C/1999 S4 LINEAR
and how it was identified, see the IAU=92s CBAT webpage at=20
<http://cfa-www.harvarddot edu/iauc/07200/07267.html#Item1>
========================================================
(2) CHEMISTRY OF COMET HALE-BOPP MAY OFFER CLUES ABOUT EARLY =20
SOLAR SYSTEM
>From Andrew Yee <ayee@nova.astro.utorontodot ca>
News Office
University of Massachusetts-Amherst
Contact: Elizabeth Luciano, luciano@admin.umassdot edu
Release: Oct. 13, 1999
CHEMISTRY OF COMET HALE-BOPP MAY OFFER CLUES ABOUT THE EARLY SOLAR
SYSTEM, UMASS ASTRONOMER SAYS
Findings to be presented at meeting of the American Astronomical =
Society
AMHERST, Mass. -- A group of astronomers led by William Irvine of the=20
University of Massachusetts has discovered that a new molecule,=20
nitrogen sulfide (NS), is contained within comets. Although scientists=20
have long known that the molecule exists within dense interstellar=20
clouds, this is the first time it has been seen in a comet. The=20
findings are being presented during the annual meeting of the Division=20
of Planetary Sciences of the American Astronomical Society, currently=20
underway in Padua, Italy.
"The finding is significant," Irvine explains, "because astronomers=20
believe that comets hold the best samples of materials from which the=20
solar system was formed." Comets are icy masses which appeared in the=20
outer regions of the solar system when it was formed, 4.5 billion years =
ago. Their distance from the sun has resulted in comets being heated=20
only minimally, preserving frozen gases that may give scientists clues=20
about what materials existed in space when the solar system formed.
The astronomers made the observation in March 1997, while conducting=20
separate research using the James Clerk Maxwell Telescope on Mauna Kea=20
Mountain in Hawaii. Collaborators on the project were Henry Matthews,=20
Joint Astronomy Center, in Hilo, Hawaii; Roland Meier, of the Institute =
for Astronomy, University of Hawaii; Irvine, Matthew Senay, and Ricardo
Metz, of UMass; and Douglas McGonagle, formerly of UMass. The research
was sponsored in part by NASA.
The compound is the only known molecule in comets that contains both=20
nitrogen and sulfur. The molecule is a "radical," which means that it's =
highly reactive, chemically. The discovery raises the question of=20
whether the NS in Comet Hale-Bopp has existed since the start of the=20
solar system, or if it was produced as a result of other compounds in=20
the comet breaking apart. Scientists will be able to determine that,=20
Irvine said, by examining exactly where in comets the NS lies. An=20
abundance in the head, or nucleus, would suggest original material, but =
the amount cannot be measured from Earth. The way in which the=20
abundance of NS varies in the comet's atmosphere, called the coma,=20
would indicate whether the molecule is the result of other compounds=20
breaking apart due to the effect of sunlight, or whether it was=20
produced by chemical reactions. To make such a determination, the NS=20
molecule must be found in other comets.
The discovery is further intriguing because scientists have long=20
suspected that many molecules on Earth were brought here by comets.=20
"Could comets have provided molecules that became part of the oceans=20
and the atmosphere?" Irvine asks. "Could this material perhaps even be=20
relevant to the origin of life?"
========================================================
(3) FIRST TUNGUSKA99 RESULTS
>From Luigi Foschini <L.Foschini@isao.bo.cnrdot it>=20
=3D=3D PRESS RELEASE 12 OCTOBER 1999 =3D=3D=3D
=20
Poster presentation at DPS/AAS
=20
The first scientific results of the italian scientific expedition=20
Tunguska99 will be presented at the 31st Annual Meeting of the Division =
for Planetary Sciences of the American Astronomical Society (Padova,
Italy, October 10-15 1999). The poster will be presented in the Session
59 (late papers) on Thursday 14 october (6:00-7:30 PM). Moreover, the
abstract will be published on the "Bulletin of the American =
Astronomical
Society", vol. 31, n. 5, (1999) - see the attached file for winword.
=20
Processing of the data is in progress, but preliminary analysis of data
collected on the lake suggests that the origin of the lake be not=20
related to the 1908 event. It constitutes, more likely, an ancient=20
volcanic depression filled up by a more than 50 m thick sedimentary=20
deposit of fluviatile origin. The future work will focus on the core=20
analysis, and on the detection of possible physical effects within the=20
sedimentary successions (i.e. gravitative failures of the slopes) that
could give important insights on the energy of the event.
=20
In the poster will be available other notes about:
- - the aerophotosurvey and GPS measurements, that will be used to
re-examine the material recorded in 1938 by Kulik;
- - collected samples (wood, peat, pollen, rocks, gravel);
- - gamma ray in-flight measurements; nearby the lake Cheko daughter
radionuclides from the 238U and 232Th natural chains have been recorded
(work is in progress to see for possible isotopes derived from man-made
activities).
Other information at http://www-th.bo.infndot it/tunguska/
=20
For the Tunguska99 Press Office:
Luigi Foschini (mailto:L.Foschini@isao.bo.cnrdot it)
========================================================
(6) WEB LINKS ON IMPACTS & IMPACT CRATERS
>From Michael Paine <mpaine@tpgi.com.au>=20
Dear Benny,
Here are some links concerning Owen Fox's questions:
1. Aorounga - estimated age < 345 million years
http://gdcinfo.agg.nrcan.gcdot ca:80/cgi-bin/crater/list_crater_html?e+Aoro=
unga+/crater/africa_craters.html
(a frame from
http://gdcinfo.agg.nrcan.gcdot ca:80/toc.html?/crater/world_craters.html )
2a. Ocean impact site off Tasmania. Can't find any links. I recall=20
hearing about some deep sea surveys of a possible impact site. It is
unlikely to be a few thousand years old.=20
2b. Tsunami and the South Coast of New South Wales (Shoalhaven) - the
last one may have hit less than 300 years ago.
http://wwwrses.anudot edu.au/~edelvays/tsunami1.html
(from http://www1.tpgi.com.au/users/tps-seti/spacegd7.html )
Thanks for posting my latest Explorezone article. The series is, of
course, aimed at people who are completely unfamiliar with NEOs. I
enjoyed Malcolm's poem.
Michael Paine
----------------------------------------
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