PLEASE NOTE:


*

CCNet DIGEST, 18 May 1999
-------------------------


     POEM OF THE DAY

     From Malcolm Miller <stellar2@actonline.com.au>

     The stranger from space

     Rock flowed like water on that day, splashed
     like mud by a truck from a wet farm track.
     Droplets froze, the Earth rang, killer waves
     surged through air, through ground, through water.
     Expanding circles of pressure, of melting, grew large,
     converged at the antipodes, circled the reeling Earth ,
     dying under clouds and steam and dust,
     while shattered rocks fell,  missiles that reached
     the edge of space, thudding down amid the
     growing blackness.  Surging sullenly back,
     the scarred earth sprouted concentric rings of shocked
     and melted rock, thinly layered with remnant grains
     of the invader, sealing its alien isotopes in sediments
     that lay unnoticed until our urgent curiosity
     sought evidence of impacts.  How many million
     years ago was this, and will we wait for long
     until at last it is our human turn to suffer
     the astronomical reality of the last bombardment?

     Malcolm Miller
     18.5.99


(1) NAME THAT ASTEROID
    Ron Baalke <baalke@ssd.jpl.nasa.gov>

(2) AIR FORCE CONFERENCE TO COVER NEOs
    Michael Paine <mpaine@tpgi.com.au>

(3) MATHILDE ONLY GLIMPSED, PERHAPS
    Erik Asphaug <asphaug@es.ucsc.edu>

=============
(1) NAME THAT ASTEROID

From Ron Baalke <baalke@ssd.jpl.nasa.gov>

From the Planetary Society
http://planetary.org/news/contest-ds1.html

Deadline: June 15, 1999

The launch of Deep Space 1 on October 24, 1998, marked the beginning of
NASA's exciting New Millennium Program. The mission is currently
testing cutting-edge technologies that will someday get us to the most
important and fascinating destinations in the solar system.

One of the key technologies on Deep Space 1 is its ion propulsion
system, which combines the gas xenon with some of the technologies that
make television picture tubes work. This engine can provide 10 times
higher speed than a conventional liquid or solid fuel rocket for a
given amount of fuel, and its thrust is almost imperceptible.

While on its journey, Deep Space 1 will fly by an asteroid on July 29,
1999, known as 1992 KD (9969). The encounter is designed to provide a
final, extremely challenging test for Deep Space 1's autonomous
navigation system, which has so successfully guided the spacecraft on
its interplanetary cruise. The on-board navigation system will attempt
to bring the spacecraft closer to the asteroid than a jet plane is
above Earth when it is at cruising altitude.

No spacecraft has ever attempted to fly as close to a solar system body
without actually landing on it. As a bonus, the sophisticated science
instruments tested on Deep Space 1 will return exciting pictures and
other important data during this high-risk encounter.

Asteroid 1992 KD needs a name and you can help!

The Story of Asteroid 1992 KD

Asteroid 1992 KD was discovered on May 27, 1992 by E. Helin and K.
Lawrence with the 18-inch Schmidt telescope at Palomar Observatory
during the Palomar Planet-Crossing Asteroid Survey. When it was
discovered, 1992 KD appeared as a trail traveling North-Northeast in
the constellation Libra.

During this part of the mission, Deep Space 1 will take images, measure
its basic physical properties, including mineral composition, size,
shape, surface features, and brightness.

Deep Space 1 will also search for changes in the solar wind as it
interacts with the asteroid to find out if it has a magnetic field.
Solar wind is a stream of high energy particles that emanates from the
Sun.

The Contest

You are invited to submit possible names for Asteroid 1992 KD. Because
the Deep Space 1 mission is all about new high-risk technologies that
will enable future missions to probe the universe, our theme is
Inventors.

Each suggestion should be accompanied by a short explanation (50 words
maximum) of why the name is appropriate. Please use a separate page for
each suggestion. You may submit your entries by E-mail
(tps@mars.planetary.org) or send it to:

   Asteroid 1992 KD Contest
   The Planetary Society
   65 N. Catalina Avenue
   Pasadena, CA 91106
   USA

   Deadline: June 15, 1999

The winner will receive a $50 gift certificate from The Planetary
Society Store (http://planetary.org/cgi-bin/store).

To find out more about nomenclature for celestial bodies, visit the
International Astronomical Union's web page
(http://www.iau.org/).

For more information on Deep Space 1 and the New Millennium Program
visit the NASA/JPL website
(http://nmp.jpl.nasa.gov/ds1/index.html).

========================
(2) AIR FORCE CONFERENCE TO COVER NEOs

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

Dear Benny

The AMOS Conference (http://ulua.mhpcc.af.mil/AMOSUC99.html ) to be
held in Hawaii late August 1999 will include a session on NEOs. AMOS is
an Air Force program.

Oddly, I found out about from China's SCAP NEO project webpage:
http://vega.bac.pku.edu.cn/~zj/scap/scap.html

Also, I have added some fatality estimates to my calculation of the NEO
impact risk to inhabited regions. The estimated 1 in 18 chance of a
Tunguska event over an inhabited region of Earth could result in over 1
million fatalities, assumimg an average population density of 130
persons per square kilometre of inhabited land and indirect fatalities
(mainly starvation) about four times the number of "direct" deaths. This
is probably conservative, given the outcome of explosive volcanic
eruptions such as Tombora (Indonesia) in 1815 - the indirect death toll
in that region was eight times the direct death toll (also this
apparently led to the "year without summer" in the Northern Hemisphere
with severe crop failures and an unknown death toll - gruesome but good
material for modelling the effects of impacts!?).
See http://www1.tpgi.com.au/users/tps-seti/spacegd7.html#inhabit for the
calculations and links.

Michael Paine

==================
(3) MATHILDE ONLY GLIMPSED, PERHAPS

From Erik Asphaug <asphaug@es.ucsc.edu>

Dear Benny,

Malcolm Miller's excellent poem, "Mathilde exposed", is optimistic
about the science we have so far achieved:

    "Merciless interrogation of a lonely planetoid,
     stripped now of all mystery, revealed as a naked
     pile of coal-black rubble, sticky with tars, colder than ice."

That Mathilde is coal-black and cold we certainly know, but we already
knew that before NEAR's visit -- which, with all instruments but the
camera turned off to conserve power, was more of a respectful query
than a merciless interrogation.  Sticky rubble (my personal preference)
remains but a conjecture useful for explaining its huge, rimless
craters. In most respects, we know less about Mathilde today than we
knew about the Moon four decades ago.  The Moon will always be here for
us, whereas none of us, as the poem intones, will see Mathilde again,
other than as a transitory fleck in the darkest of skies.  Mathilde
glimpsed, perhaps.

Erik Asphaug
University of California, Santa Cruz
asphaug@earthsci.ucsc.edu
http://www.es.ucsc.edu/~asphaug

----------------------------------------
THE CAMBRIDGE-CONFERENCE NETWORK (CCNet)
----------------------------------------
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please contact the moderator Benny J Peiser <b.j.peiser@livjm.ac.uk>.
Information circulated on this network is for scholarly and
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*

CCNet SPECIAL, 18 May 1999
--------------------------

NEW DATA CONFIRMS THAT ASTEROID 1999 AN10 WILL COME VERY CLOSE TO EARTH
IN AUGUST 2027

ONLY FURTHER OBSERVATIONS WILL TELL CHANCES OF IMPACT AFTER 2027

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

Just over a month ago, on 13 April 1999, I drew the attention of list
members to a web paper by Andrea Milani, Steven Chesley and Giovanni
Valsecchi regarding the potential risk of asteroid 1999 AN10 hitting
the Earth in forty years time
[http://copernico.dm.unipi.it/~milani/resret]

At the time, I was criticised for making the findings of the Italian
researchers public and allerting the NEO search community about this
potentially hazardous object. NASA officials were quoted as saying that
"there was no reason for this finding to be disseminated publicly. The
asteroid is already in a part of the sky where it cannot be observed
for months, so there is no such urgency. There's nothing to do, even if
we thought it was dangerous" (Boston Globe, 14 April 1999). A number of
other critics similarly claimed that there was "nothing that may
seriously interest the general public."

But new observational data by Australian astronomer F. Zoltowski shows
that asteroid 1999 AN10 will come rather close to Earth in the year
2027. On the basis of these observations, Brian Marsden and Garreth
Williams of the Minor Planet Center at the Smithsonian Astrophysical
Observatory have calculated a nominal approach distance by AN10 to
the Earth of 0.00038 AU on August 7, 2027. Yet the MINIMUM POSSIBLE
distance on that day is only 0.00026 AU. In other words, the km-wide
object might approach Earth as close as ~38,000 km.

We already knew from the paper by Andrea Milani, Steven Chesley and
Giovanni Valsecchi that an impact was not possible in that year. But
the new calculations confirm their initial speculation that the
asteroid might approach within the Earth's sphere of influence and thus
could, theoretically, be perturbed in such a way that it might impact
some years later.

We also know that the chaotic behaviour of this asteroid makes it
practically impossible to predict all possible approaches for more than
a few decades following any close encounter, and that the orbit will
remain dangerously close to the orbit of the Earth for about 600 years.

It would appear that the publicity surrounding AN10 has actually helped
to focus some observers on this interesting PHA. Only these
observations will help us to refine its orbit and calculate its future
evolution. The current uncertainty in the calculated miss distance does
not allow a conclusive answer to the question as to whether or not the
impact probability has increased due to this new data. Just like the
XF11 case, the answers to AN10 entirely rely on further observational
data.

Benny J Peiser


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

M.P.E.C. 1999-K07                                Issued 1999 May 17, 23:21 UT

     The Minor Planet Electronic Circulars contain information on unusual
         minor planets and routine data on comets.  They are published
   on behalf of Commission 20 of the International Astronomical Union by the
          Minor Planet Center, Smithsonian Astrophysical Observatory,
                          Cambridge, MA 02138, U.S.A.

             BMARSDEN@CFA.HARVARD.EDU or GWILLIAMS@CFA.HARVARD.EDU
          URL http://cfa-www.harvard.edu/iau/mpc.html  ISSN 1523-6714


                                   1999 AN10

                           Revision to MPEC 1999-B03

Observations:
     J99A10N  C1999 05 15.83400 00 32 51.60 -05 55 59.8          20.7 V      426
     J99A10N  C1999 05 15.84031 00 32 51..85 -05 55 43.9          20.4 V      426
     J99A10N  C1999 05 15.84669 00 32 52.05 -05 55 26.5          20.2 V      426
     J99A10N  C1999 05 16.82984 00 33 27.94 -05 12 30.5          20.9 V      426
     J99A10N  C1999 05 16.83622 00 33 28.13 -05 12 13.8          20.5 V      426
     J99A10N  C1999 05 16.84244 00 33 28.38 -05 11 56.7          20.9 V      426

Observer details:
426 Woomera.  Observer F. B. Zoltowski.  0.30-m f/3.3 Schmidt-Cassegrain + CCD.

First and last observations above in comparison with prediction:
Residuals in seconds of arc and reference
990515 426  6.8+  5.7+    990516 426  7.0+  6.4+    MPC 34039

Orbital elements:
1999 AN10                                                            PHA 0.015A
Epoch 1999 Aug. 10.0 TT = JDT 2451400.5                 Marsden
M  70.04852              (2000.0)            P               Q
n   0.55940463     Peri.  268.25207     -0.56757200     +0.68457399
a   1.4587650      Node   314.55292     -0.21819432     -0.66076313
e   0.5621474      Incl.   39.93223     -0.79388492     -0.30781574
P   1.76           H   18.0           G   0.15           U   4
Residuals in seconds of arc
990113 704  1.1+  0.9+    990121 046  0.4+  0.1-    990208 704  0.3-  0.1+
990113 704 (0.0   2.4-)   990121 046  0.0   0.0     990208 704  0.7-  0.8+
990113 704  0.7-  0.4-    990121 587  0.3-  0.4-    990208 900  0.3-  0.1+
990113 704  0.3+  0.5+    990121 587  0.2-  0.2-    990208 900  0.3+  0.4-
990113 704  2.0-  0.1-    990123 071  0.1-  0.2+    990208 402  0.1-  0.3-
990114 557  0.3-  0.4-    990123 071  0.0   0.1+    990208 402  0.0   0.8-
990114 557  0.1-  0.1+    990124 046  0.3+  0.0     990208 402  0.3+  0.8-
990115 046  0.0   0.1+    990124 046  0.3+  0.0     990209 360  0.4+  0.1+
990115 046  0.1-  0.3+    990124 046  0.1-  0.2-    990209 360  0.6+  0.4+
990115 046  0.3-  0.4-    990124 046  0.8+  0.2-    990209 360  0.3+  0.2+
990115 046  0.2-  0.2-    990124 658  0.2+  0.5-    990212 587  0.1-  0.8+
990115 046  0.4-  0.2+    990124 658  0.2-  0.3-    990212 587  0.0   0.8-
990115 587  0.7+  0.8+    990124 658  0.2+  0.5-    990212 587  0.0   0.1-
990115 587  0.1-  1.1+    990126 071  0.3+  0.5+    990214 587  0.5-  0.1+
990116 704  0.6+  0.3-    990126 071 (0.3-  2.9+)   990214 587  1.0-  0.2-
990116 704  0.2+  0.1+    990126 402  0.4+  0.8+    990214 587  0.2+  0.2+
990116 704  0.8-  0.4+    990126 402  0.3-  0.3+    990215 046  0.6-  0.3-
990116 704  0.2+  0.6+    990126 402  0.4+  0.7+    990215 046  0.2+  0.6+
990117 046  0.0   0.1+    990126 360  0.3+  0.3+    990215 046  0.0   0.6+
990117 046  0.1+  0.2-    990126 360  0.1-  0.6+    990215 046  0.2+  0.5+
990117 046  0.0   0.2+    990126 360  0.3+  0.4+    990218 104  0.0   1.0-
990117 046  0.0   0.0     990127 587  0.5-  0.1+    990218 587  0.1-  1.0+
990117 402  0.5-  0.2+    990127 587  0.3-  0.3-    990218 587  0.9-  0.3-
990117 402  0..2-  0.0     990130 402  0.7+  0.6+    990218 587  0.5+  0.7+
990117 402  0.4-  0.2+    990130 402  0.0   0.2-    990218 587  0.9+  0.8-
990117 540  0.7-  0.3+    990130 402  0.1+  0.3-    990220 428  0.7+  0.8-
990117 540  0.6-  0.2+    990204 402  0.2+  0.0     990220 428  0.9+  1.4-
990117 540 (2.1-  0.2+)   990204 402  0.0   0.1-    990515 426  0.2-  0.4+
990119 151  0.9-  0.2-    990207 587  0.4+  0.1-    990515 426  0.3+  0.3-
990119 151  0.6+  0.2+    990207 587  0.7+  0.4+    990515 426  0.1+  0.4+
990119 151 (3.4-  1.4+)   990207 587  0.5+  0.4-    990516 426  0.2-  0.0
990119 587  0.1+  0.0     990208 704 (0.8+  2.9+)   990516 426  0.7-  0.1+
990119 587  0.2-  0.2+    990208 704  0.5+  0.3+    990516 426  0.3-  0.9+
990121 046  0.1-  0.2-    990208 704  0.5-  0.8+

Ephemeris:
1999 AN10                a,e,i = 1.46, 0.56, 40                  q = 0.6387
Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase     V
1999 05 12    00 30.69   -08 45.0    1.035    0.837    48.3    64.3    20.0
1999 05 17    00 33.56   -05 05.2    1.059    0.883    50.5    62.0    20.1
1999 05 22    00 36.80   -01 29.5    1.077    0.931    52.8    60.0    20.2
1999 05 27    00 40.24   +02 02.1    1.092    0.979    55.3    58.3    20.2
1999 06 01    00 43.73   +05 29.5    1.103    1.028    57.9    56.7    20.3
1999 06 06    00 47.16   +08 53.4    1.110    1.076    60.6    55.3    20.4
1999 06 11    00 50.44   +12 13.9    1.114    1.124    63.5    54.0    20.5
1999 06 16    00 53.44   +15 31.5    1.116    1.171    66.4    52.7    20.5
1999 06 21    00 56.05   +18 46.6    1.115    1.217    69.5    51.4    20.6
1999 06 26    00 58.20   +21 59.4    1.112    1.262    72.6    50.2    20.6
1999 07 01    00 59.75   +25 10.2    1.108    1.307    75.8    49.0    20.6
1999 07 06    01 00.59   +28 18.9    1.102    1.350    79.1    47.7    20.7
1999 07 11    01 00.57   +31 25.4    1.096    1.393    82.4    46.4    20.7
1999 07 16    00 59.51   +34 29.1    1.089    1.434    85.8    45.0    20.7
1999 07 21    00 57.23   +37 29.3    1.082    1.474    89.2    43.6    20.7
1999 07 26    00 53.51   +40 24.6    1.076    1.513    92.6    42.1    20.7
1999 07 31    00 48.14   +43 13.5    1.070    1.551    96.1    40.6    20.7
1999 08 05    00 40.88   +45 53.9    1.066    1.588    99.4    39.1    20.7
1999 08 10    00 31.50   +48 22.8    1.064    1.624   102.8    37.5    20.7
1999 08 15    00 19.85   +50 36.8    1.064    1.658   106.0    36.0    20.7
1999 08 20    00 05.89   +52 32.2    1.066    1.692   109.0    34.4    20.7
1999 08 25    23 49.82   +54 05.4    1.071    1.724   111.8    33.0    20.7
1999 08 30    23 32.05   +55 13.1    1.080    1.756   114.3    31.6    20.7
1999 09 04    23 13.24   +55 53.3    1.092    1.786   116.5    30.3    20.8
1999 09 09    22 54.25   +56 05.2    1.107    1.816   118.3    29.2    20.8
1999 09 14    22 36.00   +55 50.1    1.127    1.844   119.6    28.3    20.8
1999 09 19    22 19.31   +55 11.0    1.150    1.872   120.5    27.6    20.9
1999 09 24    22 04.73   +54 12..0    1.177    1.898   120.9    27.0    21.0
1999 09 29    21 52.53   +52 58.0    1.208    1.924   120.8    26.6    21.0
1999 10 04    21 42.78   +51 33.4    1.242    1.948   120.2    26.3    21.1
1999 10 09    21 35.38   +50 02.3    1.280    1.972   119.3    26.2    21.2
1999 10 14    21 30.15   +48 28.3    1.322    1.994   118.0    26.2    21.3
1999 10 19    21 26.86   +46 54.4    1.366    2.016   116.3    26.3    21.4
1999 10 24    21 25.27   +45 22.8    1.413    2.037   114.5    26.4    21.5
1999 10 29    21 25.15   +43 55.2    1.462    2.057   112.4    26.5    21.6
1999 11 03    21 26.29   +42 32.5    1.514    2.076   110.1    26.7    21.7
1999 11 08    21 28.54   +41 15.8    1.567    2.094   107.7    26.8    21.8
1999 11 13    21 31.74   +40 05.4    1.623    2.111   105.2    26.9    21.9
1999 11 18    21 35.77   +39 01.9    1.679    2.127   102.7    27.0    22.0

     Computations by B. G. Marsden and G. V. Williams show that the above
orbital elements yield a NOMINAL approach distance to the earth of 0.00038
AU on 2027 Aug. 7.42 UT.  The MINIMUM POSSIBLE distance on that day is 0.00026
AU.  A generous estimate of the MAXIMUM miss distance on that day is 0.010 AU,
corresponding to a temporal uncertainty of +/- 0.6 day, significantly down
from the 0.2 AU and +/- 12 days of the MPC 34039 orbit.  This result therefore
means that not only the general but many of the specific conclusions of Milani
et al. (http://copernico.dm.unipi.it/~milani/resret/; Astron. Astrophys.
Letters, in press) are still valid.  Additional observations during the next
several months will be useful, because there are no other reasonable
observing opportunities until at least 2004.

Brian G. Marsden             (C) Copyright 1999 MPC           M.P.E.C. 1999-K07


----------------------------------------
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CCCMENU CCC for 1999

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