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
----------------------------------------
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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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educational use only. The attached information may not be copied
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copyright holders. The fully indexed archive of the CCNet, from
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