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(meteorobs) Excerpts from "CCNet DIGEST, 6 May 1999"
------- Forwarded Message
From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: CCNet DIGEST, 6 May 1999
Date: Thu, 6 May 1999 10:39:04 -0400 (EDT)
CCNet DIGEST, 6 May 1999
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[...]
(4) A LINEAR MODEL FOR THE YARKOVSKY EFFECT
D. Vokrouhlicky, CHARLES UNIVERSITY
[...]
(8) US SPACE ROCKETS GROUNDED
BBC Online Network, 6 May 1999
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(4) A LINEAR MODEL FOR THE YARKOVSKY EFFECT
=20
D. Vokrouhlicky: A complete linear model for the Yarkovsky thermal=20
force on spherical asteroid fragments. ASTRONOMY AND ASTROPHYSICS,=20
1999, Vol.344, No.1, pp.362-366
=20
CHARLES UNIVERSITY, ASTRON INST,CZ-18000 PRAGUE 8,CZECH REPUBLIC
=20
A linear theory for heat conduction in a spherical, solid and rotating=20
body illuminated by solar radiation is developed. The recoil force due=20
to the thermally re-emitted radiation by the surface of the body is=20
computed, including all the terms depending both on the body's rotation =
frequency and the mean motion of its revolution about the Sun. The=20
present solution thus overcomes a drawback of the previous approaches,=20
which have been tailored separately either to the diurnal or to the=20
seasonal variant of the so-called Yarkovsky effect, corresponding to=20
different Limiting cases of the current theory. We pay a special=20
attention to compute the secular effects on the semimajor axis of the=20
body's orbit about the Sun. The results from the general model coincide =
with those of the previous approaches to a high level of accuracy, as=20
the relative size of the additional ''mixed'' terms is smaller than=20
10(-3) for plausible parameter choices. This confirms that the use of=20
the simplified formulae is warranted in the relevant Solar System=20
applications. Copyright 1999, Institute for Scientific Information Inc.
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(8) US SPACE ROCKETS GROUNDED
>From the BBC Online Network, 6 May 1999
http://news.bbc.codot uk/hi/english/sci/tech/newsid_336000/336592.stm
All United States rockets capable of launching large satellites are=20
grounded as an investigation begins into a series of launch failures.=20
The latest launch to misfire was a Delta III carrying a communications=20
satellite. It was an unprecedented sixth failure in nine months.=20
FULL STORY at=20
http://news.bbc.codot uk/hi/english/sci/tech/newsid_336000/336592.stm
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