EDP Sciences
Free access
Volume 414, Number 2, February I 2004
Page(s) L21 - L24
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20031739

A&A 414, L21-L24 (2004)
DOI: 10.1051/0004-6361:20031739


Detectability of YORP rotational slowing of asteroid 25143 Itokawa

D. Vokrouhlický1, D. Capek1, M. Kaasalainen2 and S. J. Ostro3

1  Institute of Astronomy, Charles University, V Holesovickách 2, 180 00 Prague 8, Czech Republic
    e-mail: vokrouhl@mbox.cesnet.cz, capek@sirrah.troja.mff.cuni.cz
2  Rolf Nevanlinna Institute, University of Helsinki, PO Box 4, 00014 Helsinki, Finland, and Sodankyla Geophysical Observatory, University of Oulu, Tahtelantie 62, 99600 Sodankyla, Finland
    e-mail: mjk@rni.helsinki.fi
3  Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USA
    e-mail: ostro@reason.jpl.nasa.gov

(Received 14 November 2003 / Accepted 11 December 2003)

We predict that the YORP thermal-emission effect can be directly detected through a measurable increase in the rotation period of the several-hundred-meter near-Earth asteroid 25143 Itokawa. The fractional change of Itokawa's rotation rate in between 2001 and 2004 should be $(1{-}2)\times 10^{-4}$, significantly larger than its currently estimated uncertainty $\simeq$ $
5\times 10^{-5}$ . The corresponding change of sidereal rotation phase, normalized to unity in a cycle, is $\simeq$ (0.09-0.25) in January 2004, producing $\simeq$ (1-3) h delay of lightcurve maximum.

Key words: solar system: minor planets, asteroids -- radiations mechanisms: thermal

Offprint request: D. Vokrouhlický, vokrouhl@mbox.cesnet.cz

© ESO 2004