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

[LARRY KLAES]

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'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−2 s−0.5 K−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^(−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.

Comments:

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