Letter to the Editor

Rotational brightness variations in Trans-Neptunian Object 50000 Quaoar

¹ Instituto de Astrofísica de Andalucía, CSIC, Apt 3004, 18080 Granada, Spain
² Laboratoire d'Astrophysique de Marseille, Traverse du Siphon, BP 8, 13376 Marseille Cedex 12, France
³ Centre for Astronomy and Astrophysics of the University of Lisbon / Lisbon Astronomical Observatory, Tapada da Ajuda, 1349-018 Lisbon, Portugal

Corresponding author: J. L. Ortiz, ortiz@iaa.es

Received: 14 July 2003
Accepted: 14 August 2003

Abstract

Time–resolved broad–band CCD photometry of Trans-Neptunian Object 50000 Quaoar carried out using the 1.5 m telescope at Sierra Nevada Observatory is presented. The lightcurve reveals short–term variability due to rotation of the body. The periodogram analysis shows a peak at  h with a confidence level above 99.9%. The lightcurve seems to be double–peaked, and therefore the rotation period would be  h. The amplitude of the oscillation is  mag. Under the assumption that the rotational variation is induced by an irregular shape, the minimum axial ratio of Quaoar would then be .