PLEASE NOTE:


*

CCNet DIGEST, 23 February 1999
------------------------------


(1) CCNet SURVEY RESULTS AVAILABLE ON WEB SITE
    Benny J Peiser <b.j.peiser@livjm.ac.uk>

(2) FINDING NEW TWISTS IN MEGA-SHITS
    Bob Kobres <bkobres@uga.edu>

(3) ASTEROID NAMED AFTER ESA ASTRONOMER AS A REWARD FOR DISCOVERIES
    European Space Agency <sciweb@estec.esa.nl>

(4) ASTEROID SAMPLE-RETURN MISSION
    Michael Paine <mpaine@tpgi.com.au>

(5) NEW STRUCTURE OF ESA/SSD METEOR WEB PAGES
    Detlef Koschny <dkoschny@estec.esa.nl>

(6) LANDMARK EXPERIMENT PRODUCES OXYGEN FOR HUMAN USE FROM MARTIAN
    ATMOSPHERE
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(7) HECUBA GAP VS HILDA GROUP
    S. Ferraz Mello et al., UNIVERSITY OF SAO PAULO

(8) COMPOSITIONAL CHANGE AFTER COSMIC IMPACTS
    Y. Miura et al., YAMAGUCHI UNIVERSITY

(9) STATISTICAL PROPERTIES OF ENCOUNTERS AMONG ASTEROIDS
    A. Dell Oro & P. Paolicchi, UNIVERSITY OF PISA

(10) WHAT IS THE EVIDENCE FOR CHONDRITIC MATERIAL IN THE ASTEROID
     BELT?
     A. Meibom & B.E. Clark, UNIVERSITY OF HAWAII MANOA

=====================
(1) CCNet SURVEY RESULTS AVAILABLE ON WEB SITE

From Benny J Peiser <b.j.peiser@livjm.ac.uk>

The results of the recent survey can now be found on the CCNet web
site at http://abob.libs.uga.edu/bobk/ccc/ccsurv99.html. In response
to the survey, list members will in future be able to choose and
opt-out from a number of new services which I will present in a
separate posting.

========================
(2) FINDING NEW TWISTS IN MEGA-SHITS

From Bob Kobres <bkobres@uga.edu>

New Technique For Analyzing DNA In Fossil Dung Could Help Scientists
Sort The Details Of Megafauna Extinction

http://www.sciencedaily.com/releases/1998/07/980721081204.htm

Scientists have extracted and amplified DNA from 19,000-year-old
sloth dung from Gypsum Cave in Utah, 18 miles east of Las Vegas,
Nev. The DNA comes from plants the animal ate and from cells that
lined its digestive tract.

The researchers are the first to successfully use what's called
the PCR technique to analyze DNA in coprolites, or ancient feces.
PCR, or polymerase chain reaction, is a method used to make
numerous copies of a specific segment of DNA quickly and
accurately. Their new twist on PCR includes chemical pretreatment
that removes sugars and unlocks DNA for extraction.

Their modern biotechnological feat could be a boon to those
embroiled in the controversy over why great Pleistocene beasts in
North America suddenly became extinct at around 11,000 years ago,
when humans spread over the continent. Their modified PCR
technique will be of special interest to those who suggest a new
line of argument in the controversy. The new argument is that
prehistoric humans possibly carried disease that contributed to
the demise of the large mammals, or "megafauna." Experts say the
idea might most feasibly be tested at oceanic islands where
populations of large mammals quickly died off. ...

FULL STORY
http://www.sciencedaily.com/releases/1998/07/980721081204.htm

========================
(3) ASTEROID NAMED AFTER ESA ASTRONOMER AS A REWARD FOR DISCOVERIES

From the European Space Agency <sciweb@estec.esa.nl>

If you want an asteroid named after you, make a valuable scientific
contribution to the study of these rocky mini-planets of the Solar
System.. That is what 32 year old ESA astronomer Thomas Müller did,
and now the International Astronomical Union has rewarded him by
giving the name 'Thomasmüller' to asteroid number 8793. "It's been a
great surprise", Müller said. He is part of the team working at ESA's
Infrared Space Observatory (ISO) Data Centre at Villafranca, Spain,
and his research is mostly based on ISO data. Müller's scientific
work has proved to be crucial in describing the physical properties
of an asteroid. But that is not all: it will improve the performance
of the next millennium's infrared space telescopes.
 
More at:
http://sci.esa.int/newsitem.cfm?TypeID=1&ContentID=4010&Storytype=18

=====================
(4) ASTEROID SAMPLE-RETURN MISSION

From Michael Paine <mpaine@tpgi.com.au>

Dear Benny,

The following text is within a JPL press release that otherwise might
go unnoticed by subscribers (the title is "Artificial muscles to be
used on robotic space explorers"):

"This mission, led by the Japanese space agency ISAS, is designed to
land the palm-sized rover on an asteroid following its 2002 launch,
and return a sample of the asteroid to Earth." see
http://www.jpl.nasa.gov/releases/99/artificialmuscles.html
and http://www.muses-c.isas.ac.jp/ (MUSES-C Homepage)

Michael Paine

========================
(5) NEW STRUCTURE OF ESA/SSD METEOR WEB PAGES

From Detlef Koschny <dkoschny@estec.esa.nl>

Please note that I restructured the meteor-related web pages of our
institute. Please update all links accordingly. Not all pages are in
their final shape yet, but the structure won't change any more. Of
course you are kindly invited to visit the pages and comment on them!

All our pages can be accessed via the top page:

"Meteor observations at ESA/SSD" at
http://www.so.estec.esa.nl/planetary/meteors/index.html

Specialized sites which you might have referenced before in my personal
space (.../~dkoschny/...) were moved to:

"Leonids 98 as observed by ESA/SSD" at
http://www.so.estec.esa.nl/planetary/meteors/leonids98/index.html

"The SIV Project - introduction and contents"
http://www.so.estec.esa.nl/planetary/meteors/siv/index.html

"ViDAS - The Video Data Archiving System for meteor data"
http://www.so.estec.esa.nl/planetary/meteors/vidas/index.html

There is also some new stuff on there, like a report on the Meteorendag
1999 which we hosted and more. Check it out!

Detlef Koschny                      email: dkoschny@estec.esa.nl
European Space Agency
ESTEC Sci/SO
Keplerlaan 1                              phone: +31-71-565-4828
NL-2201 AZ Noordwijk ZH                     fax: +31-71-565-4697

========================
(6) LANDMARK EXPERIMENT PRODUCES OXYGEN FOR HUMAN USE FROM MARTIAN
    ATMOSPHERE

From Andrew Yee <ayee@nova.astro.utoronto.ca>

News Services
University of Arizona

Contact(s):
K.R. Sridhar, 520-621-6111, sridhar@shakti.ame.arizona.edu

February 18, 1999

Landmark experiment produces oxygen for human use from Martian
atmosphere

Professor K.R. Sridhar and his 20-member team at The University of
Arizona Aerospace and Mechanical Engineering (AME) Department are
building an Oxygen Generating Subsystem (OGS). In January 2002, it
will suck in Martian atmospheric gases -- predominately carbon
dioxide -- and process them to produce pure oxygen.

"This is a landmark experiment," Sridhar says. "It is the first time
in human history that we will produce a consumable of use to humans
from extraterrestrial resources."

It will be the space exploration equivalent of standing on the brink
of the Industrial Revolution, but with a gigantic resource base --
all the materials found on planets, their satellites, and asteroids
in the solar system.

The oxygen could be used as propellant in rocket motors or for life
support for humans on Mars. Since this is a demonstration experiment,
the oxygen will not be put to immediate use on the Mars Surveyor 2001
lander.

But Sridhar hopes to have an experiment aboard the Mars Surveyor 2003
mission that will produce both fuel and oxygen from Martian
resources. In that case, the oxygen and fuel would be used to launch
a small rocket from the surface of Mars or to power a drill that
would take core samples of the Martian surface.

"In the larger scheme of things, in 2007 we hope to perform a sample
return mission that will rely on the propellant production technology
we are developing to produce both the fuel and oxygen for a rocket to
bring the sample back to earth," Sridhar says. "We are working very
vigorously on this."

The OGS will fly to Mars aboard Mars Surveyor 2001, which is
scheduled to land on the Red Planet on Jan. 22, 2002.

Once on Mars, it will use solid oxide electrolysis to produce oxygen.
The technology is based on an electrochemical cell that works as a
solid state filter for oxygen. The electrolyte used in the OGS will
transfer only oxygen ions across its crystal structure.

The unit weighs about two pounds and will consume less than 15 watts
of electrical power to produce more than one cubic centimeter of
oxygen per minute. This is twice the amount NASA specified in its
contractual requirements for the oxygen generator.

"The challenges were to miniaturize the technology and to make the
process very energy efficient, while producing a device that is
rugged enough to withstand launch loads up to 35 Gs (35 times the
force of gravity at sea level)," Sridhar says.

The space-qualified OGS is being built entirely in the UA AME Space
Technologies Laboratory, where Program Manager Matthias Gottmann is
supervising a team made up of staff engineers, graduate students,
undergraduates, post docs, and exchange students.

OGS construction includes producing ceramic heating elements from
scratch that heat up faster and go to higher temperatures than
commercially available ones.

Producing resources in situ has many advantages, Sridhar explains.
"By using extraterrestrial resources, you lower the launch mass from
Earth and thereby reduce the cost. You also reduce the overall risk
of a mission because you can produce safety caches of valuable
consumables that will be available to humans at the destination."

But, he adds, perhaps the most significant aspect of in situ resource
utilization is that it is the enabling technology that will make
possible permanent settlements on other planets and their satellites.

********************
PHOTO/ASSIGNMENT EDITORS: The AME Space Technologies Laboratory
includes equipment that will make good visuals. Photos of the Oxygen
Generating Subsystem can be viewed online at the web site,
http://ares.ame.arizona.edu/~oxygen/press.
********************

LINKS:
http://ares.ame.arizona.edu/~oxygen/press

=====================
(7) HECUBA GAP VS HILDA GROUP

S. Ferraz Mello*), T.A. Michtchenko, D. Nesvorny, F. Roig, A. Simula:
The depletion of the Hecuba gap vs the long-lasting Hilda group.
PLANETARY AND SPACE SCIENCE, 1998, Vol.46, No.11-12, pp.1425-1432

*) UNIVERSITY OF SAO PAULO,INST ASTRON & GEOFIS,AV MIGUEL STEFANO
4200,BR-04301904 SAO PAULO,BRAZIL

This paper presents a comparative analysis of the 2/1 and 3/2
asteroidal resonances based on several analytical and numerical
tools. The frequency map analysis was used to obtain a refined
estimation of the chaotic transport. Fourier and wavelet analyses
were used to construct the web of inner resonances and showed that
they are the seat of the strongly unstable motion observed in the
numerical simulations. The most regular regions in both resonances
were classified. A fast symplectic mapping allowed a number of direct
runs over 10(8) years of the orbits initially in these regions. The
stability of orbits over the age of the solar system was discussed
and compared to the distribution of the observed asteroids in both
resonances. (C) 1998 Elsevier Science Ltd. All rights reserved.

====================
(8) COMPOSITIONAL CHANGE AFTER COSMIC IMPACTS

Y. Miura*), S. Fukuyama, A. Gucsik: Impact metamorphosed compositions
of the Fe-Si-Ni-S system. JOURNAL OF MATERIALS PROCESSING TECHNOLOGY,
1999, Vol.85, No.1-3, pp.188-191

*) YAMAGUCHI UNIVERSITY,FAC SCI,GRAD SCH SCI & ENGN,DEPT CHEM & EARTH
   SCI,YAMAGUCHI 753,JAPAN

The characterization of impact materials is discussed from the point
of view of compositional change after an impact event. Various
compositions of impact-metamorphosed materials can be explained by
vapor condition found as (a) reduction phase with vaporized phases,
(b) melted condition as mixed amorphous grains of projectile and
target materials, and (c) high-pressure conditions as solid phases of
target materials. The composition of projectile materials is largely
changed under different impact conditions. In fact, Fe-Ni metal
phases of a projectile cannot be obtained as the same phases after
impact by mixing with target materials, which are found in fine-
grained or spherulitic particles in meteoritic impact craters or the
Cretaceous-Tertiary (K/T) boundary. This is mainly because Fe-Ni
phases formed by long annealing time within the closed system of
asteroids cannot recrystallize as a single metallic phase after a
short impact reaction. (C) 1999 Published by Elsevier Science S.A.
All rights reserved.

======================
(9) STATISTICAL PROPERTIES OF ENCOUNTERS AMONG ASTEROIDS

A. Dell Oro, P. Paolicchi: Statistical properties of encounters among
asteroids: A new, general purpose, formalism. ICARUS, 1998, Vol.136,
No.2, pp.328-339


UNIVERSITY OF PISA,DIPARTIMENTO FIS,PIAZZA TORRICELLI 2,I-56127
PISA,ITALY

The statistical properties of asteroid mutual encounters have been
studied by several authors, with the main purpose of estimating
collisional rates (and thus mean collisional lifetimes) and the
distribution of encounter velocities. In this paper we present a new
approach, conceptually not really different with respect to the
classical ones, but implemented with a rather different mathematical
formalism and consequently more flexible. When a comparison is
possible our results are very similar to those obtained by means of
other techniques. We exploited the peculiar flexible features of the
present formalism to study-in a quantitative way-what happens when
special dynamical conditions occur, such as a clustering of
longitudes of perihelia (as in the so-called Kresak effect) or
of the longitudes of the sample around the longitude (variable in
time) of Jupiter, as in the case of Trojans. These dynamical
situations have never been explored in the past using statistical
approaches, and the development of the present one can avoid the use
of heavy N-body integrations. Concerning the Trojan asteroids, the
results of our analysis, although discussed here in a simplified
version, are satisfactorily compared with those emerging from a
detailed numerical integration of the orbits (Marzari et al., 1996,
Icarus 119, 192-201). Finally, we used our approach to analyze the
statistical properties of impacts among very large samples of objects
with a moderate amount of computer time, thanks to the numerical
algorithm, based on a Monte Carlo technique of integration. We have
tested this numerical procedure by comparing our results with
previous ones published in the literature; we find an amazing
agreement with the more standard and refined numerical methods. (C)
1998 Academic Press.

=====================
(10) WHAT IS THE EVIDENCE FOR CHONDRITIC MATERIAL IN THE ASTEROID
     BELT?

A. Meibom*), B.E. Clark: Evidence for the insignificance of ordinary 
chondritic material in the asteroid belt. METEORITICS & PLANETARY
SCIENCE, 1999, Vol.34, No.1, pp.7-24

*) UNIVERSITY OF HAWAII MANOA,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII
   INST GEOPHYS & PLANETOL,HONOLULU,HI,96822

We review the meteoritical and astronomical literature to answer the
question: What is the evidence for the importance of ordinary
chondritic material to the composition of the asteroid belt? From the
meteoritical literature, we find that currently (1) our meteorite
collections sample at least 135 different asteroids; (2) out of 25+
chondritic meteorite parent bodies, 3 are (by definition) ordinary
chondritic; (3) out of 14 chondritic grouplets and unique chondrites,
11 are affiliated with a carbonaceous group/clan of chondrites; (4)
out of 24 differentiated groups of meteorites, only the IIE iron
meteorites clearly formed from ordinary chondritic precursor
material; (5) out of 12 differentiated grouplets and unique
differentiated meteorites, 8 seem to have had carbonaceous chondritic
precursors; (6) a high frequency of carbonaceous clasts in ordinary
chondritic breccias suggests that ordinary chondrites have been
embedded in a swarm of carbonaceous material. The rare occurrence
(only one example) of ordinary chondritic clasts in carbonaceous
chondritic breccias indicates that ordinary chondritic material has
not been widespread in the asteroid belt; (7) cosmic spherules,
micrometeorites, and stratospheric interplanetary dust
particles-believed to represent a less biased sampling of asteroidal
material-show that only a very small fraction (less than similar to
1%) of asteroidal dust has an ordinary chondritic composition. From
the astronomical literature, we find that currently (8) spectroscopic
surveys of the main asteroid belt are finding more and more
nonordinary chondritic primitive material in the inner main belt; (9)
the increase in spectroscopic data has increased the inferred
mineralogical diversity of main belt asteroids; and (10) no ordinary
chondritic asteroids have been directly observed in the main belt.
These lines of evidence strongly suggest a scenario in which ordinary
chondritic asteroids were never abundant in the main belt. The S-type
asteroids may currently be primarily differentiated, but the
precursor material is more likely to have been carbonaceous
chondritic, not ordinary chondritic. Historically, carbonaceous
material could have dominated the entire main belt. This could
explain the presence in the inner main belt of asteroids linked to
the primitive carbonaceous chondrites, and the absence of asteroids
linked to the ordinary chondrites. The implications of this scenario
for the asteroid heating mechanism(s) are briefly discussed.
Copyright 1999, Institute for Scientific Information Inc.

----------------------------------------
THE CAMBRIDGE-CONFERENCE NETWORK (CCNet)
----------------------------------------
The CCNet is a scholarly electronic network. To subscribe/unsubscribe,
please contact the moderator Benny J Peiser at <b.j.peiser@livjm.ac.uk>.
Information circulated on this network is for scholarly and educational
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*

LETTERS TO THE MODERATOR, 23 February 1999
------------------------------------------

(1) WHAT ARE PLANETS ANYWAY?
    Tom Stallard <tss@star.ucl.ac.uk>

(2) THOUGHTS ON THE STATUS OF PLUTO
    Andrew Hollis <A.J.Hollis@open.ac.uk>

==============
(1) WHAT ARE PLANETS ANYWAY?

From Tom Stallard <tss@star.ucl.ac.uk>

Re: NASA TO KEEP PLUTO DEBATE WIDE OPEN

We are about to reach a very important juncture in the study of
planetary sciences, if we haven't already reached it.  Up until
recently, it has been fairly easy to say what a planet is - basically a
primary orbiter of the sun that isn't an asteroid.  Everything fitted
so nicely into groups that we didn't see the need to worry about what
we were going to call a planet.

Now suddenly, our conceptions of what constitutes a planet is under
attack at both ends of our scale. Why is Pluto a planet and Triton a
moon, when such similar bodies that are only slightly smaller are not?
Why are Brown Dwarfs a type of star, and yet 70 Vir B is a type of
planet?

The dictionary meaning of the word is particularly no-specific, a
heavenly body that changes position from night to night with respect to
background of stars. We can't be very much more specific than this
without deciding first whether Pluto or 70 Vir B are planets or not.

Dr Jewitt throws no light on the situation, "Pluto has a higher albedo
(60%) than we suspect for the other KBOs, but this is an artifact of
size" The fact Pluto only varies from most KBOs because it has a
tenuous atmosphere due to its larger gravity may be true, but then you
could argue that the same is true of Jupiter.

So, are planets bodies above a given size, perhaps 1000km radius, and
below a given mass, that of the smallest brown dwarf?  Shouldn't we
perhaps consider other factors in our description of what a planet is.
Maybe it is even time to go further and accept that Jupiter is as
different a planetary body to the Earth as Pluto is, and in the future
of exoplanetology, we are going to have to catalogue an even greater
variety of 'heavenly bodies'.

Perhaps this is an answer in itself.  Stars are found in amazing
variety, and everyone calls them stars.  Of course, astronomers know
better, that there is a progression of different stars, marked by a
combination of initial mass, composition and the evolution that they
follow. The same could be said of planets, and in the future we may
well produce a planetary equivalent to the Hertzsprung-Russell diagram,
a way to catalogue the planets in a scientific way.

The public will always call planets those bodies which match those that we
already have, Pluto included. It's so obvious really, they are those
heavenly bodies that change position from night to night. Excluding of
course, asteroids.

Tom Stallard, London.

============================
(2) THOUGHTS ON THE STATUS OF PLUTO

From Andrew Hollis <A.J.Hollis@open.ac.uk>

Benny

I wrote this for the BAA Journal about three weeks ago.  Looking at
the CCNet Digest last week perhaps I was being more serious than I
thought.

Andy

More about the status of Pluto and other Solar System bodies

In the February 1999 issue of the BAA Journal I contributed a paper on
observation and research related to Pluto.  A section heading for this
was "The Status of Pluto".

In this section I noted that Pluto was unlike both the Terrestrial
Planets and the Gas Giants. I noted that the nearest body to it known
at present was Triton and that there appeared to be significant
differences between it and other bodies in the Edgeworth-Kuiper Belt.
After reporting that there were those who wished to demote Pluto to the
status of a super-asteroid or comet I confirmed my view that it should
retain its historical status as a major planet though it could
eventually become the first of a hierachy of remote solar system
objects.

This was written in December 1997. Since December 1998 there has been
a significant debate about the status of Pluto. In part this has been
occasioned by the advent of asteroid numbering reaching 10000 (in the
February 1999 batch of Minor Planet Circulars) and the need for this
asteroid to be significant.  In addition a number of the
Edgeworth-Kuiper Objects have orbits known where the precision is
sufficient for them to be numbered and it would be satisfying if the
first object to be found in this region to be the first numbered.

The thrust of the argument is that Pluto is so small it hardly
warrants the importance of a major planet, and additionally we now
know there are many others in similar orbits (those EKOs known as
Plutinos).

So apparently the IAU and MPC started a discussion to sound out anyone
prepared to comment whether Pluto should be given the asteroid number
10000. Initially it was considered this was a demotion.  Later the idea
was for Pluto to have a dual status.  Whilst there was a slight bias in
favour of this the prevailing view was not decisive.

This does however raise several valid points for consideration.

Firstly what is a planet or indeed a major planet?  How does it differ
from asteroids and comets?  What are the distinguishing features?

This is not an idle question because in recent years there have been
several reported planetary systems identified round nearby stars and
they are presumably (if real) only vaguely like the Sun's family as
most of the planets are several times more massive than Jupiter.

If we consider the Sun's family we find the Gas Giants - large
independent bodies which, though not undergoing nuclear reactions,
emit more radiation than they receive from the Sun.  Then there are
the Terrestrial planets - inert independent rocky bodies -  and the
Main Belt asteroids appear similar.  Pluto appears to be an icy
independent body as do the outer asteroids, the EKOs and indeed most
comets.


On this basis one could suggest that there are only four major planets
- Jupiter, Saturn, Uranus and Neptune. These are big enough to
significantly perturb passing comets and asteroids. We then have many
thousand minor planets the largest of which would be the Earth - with
a much lower perturbing influence on passing bodies. Finally the
comets - that is the icy bodies which outgas when approaching the Sun,
as occurred with Pluto and Chiron near perihelion and all those
traditionally known as comets.

On this approach members of each group are similar to each other and
different from the other classes which is not the case at present. The
planetary satellites could be attributed to the correct type based on
composition.

This is idle speculation and pretty silly.  But then again so are many
of the comments that have been passed on this subject.

Dr Andrew J Hollis
Tel UK 01606 883331

-----------------
CCNet-LETTERS is the open discussion forum of the Cambridge-Conference
Network. Contributions to the on-going debate about near-Earth objects,
the cosmic environment of our planet and how to deal with it are
welcome. To subscribe or unsubscribe from CCNet-LETTERS, please contact
Benny J Peiser at b.j.peiser@livjm.ac.uk. The electronic archive of the
CCNet can be found at http://abob.libs.uga.edu/bobk/cccmenu.html



CCCMENU CCC for 1999

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