# [FPSPACE] Thermal inertia of near-Earth asteroids and implications for the magnitude of th

LARRY KLAES ljk4 at msn.com
Wed Apr 18 16:45:54 EDT 2007

Thermal inertia of near-Earth asteroids and implications for the magnitude
of the Yarkovsky effect

Authors: Marco Delbo (INAF-Osservatorio Astronomico Di Torino, Oca), Aldo
Dell&apos;oro (INAF-Osservatorio Astronomico Di Torino), Alan W. Harris (DLR
Institute of Planetary Research), Stefano Mottola (DLR Institute of
Planetary Research), Michael Mueller (DLR Institute of Planetary Research)

(Submitted on 15 Apr 2007)

Abstract: Thermal inertia determines the temperature distribution over the
surface of an asteroid and therefore governs the magnitude the Yarkovsky
effect. The latter causes gradual drifting of the orbits of km-sized
asteroids and plays an important role in the delivery of near-Earth
asteroids (NEAs) from the main belt and in the dynamical spreading of
asteroid families. At present, very little is known about the thermal
inertia of asteroids in the km size range. Here we show that the average
thermal inertia of a sample of NEAs in the km-size range is 200 $\pm$ 40 J
m&#8722;2 s&#8722;0.5 K&#8722;1. Furthermore, we identify a trend of
increasing thermal inertia with decreasing asteroid diameter, D. This
indicates that the dependence of the drift rate of the orbital semimajor
axis on the size of asteroids due to the Yarkovsky effect is a more complex
function than the generally adopted D^(&#8722;1) dependence, and that the
size distribution of objects injected by Yarkovsky-driven orbital mobility
into the NEA source regions is less skewed to smaller sizes than generally
assumed. We discuss how this fact may help to explain the small difference
in the slope of the size distribution of km-sized NEAs and main-belt
asteroids.

Icarus (30/03/2007) in press

Subjects:

Astrophysics (astro-ph)

DOI:

10.1016/j.icarus.2007.03.007

Cite as:

arXiv:0704.1915v1 [astro-ph]

Submission history

From: Marco Delbo [view email]

[v1] Sun, 15 Apr 2007 19:20:24 GMT (964kb)

http://arxiv.org/abs/0704.1915