Letter to the Editor

Detectability of YORP rotational slowing of asteroid 25143 Itokawa

¹ Institute of Astronomy, Charles University, V Holešovičkách 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

Corresponding author: D. Vokrouhlický, vokrouhl@mbox.cesnet.cz

Received: 14 November 2003
Accepted: 11 December 2003

Abstract

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 , significantly larger than its currently estimated uncertainty . The corresponding change of sidereal rotation phase, normalized to unity in a cycle, is in January 2004, producing  h delay of lightcurve maximum.