We report on coordinated thermal and optical measurements of trans-Neptunian object (20000) Varuna obtained in January-February 2002, respectively from the IRAM 30-m and IAA 1.5 m telescopes. The optical data show a lightcurve with a period of 3.176+/-0.010 hr, a mean V magnitude of 20.37+/-0.08 and a 0.42+/-0.01 magnitude amplitude. They also tentatively indicate that the lightcurve is asymmetric and double-peaked. The thermal observations indicate a 1.12+/-0.41 mJy flux, averaged over the object's rotation. Combining the two datasets, we infer that Varuna has a mean 1060(+180/-220) km diameter and a mean 0.038(+0.022/-0.010) V geometric albedo, in general agreement with an earlier determination using the same technique.
@article{arxiv.astro-ph/0206486,
title = {Coordinated thermal and optical observations of Trans-Neptunian object (20000) Varuna from Sierra Nevada},
author = {E. Lellouch and R. Moreno and J. L. Ortiz and G. Paubert and A. Doressoundiram and N. Peixinho},
journal= {arXiv preprint arXiv:astro-ph/0206486},
year = {2009}
}
Comments
Accepted for publication in Astronomy & Astrophysics (7 pages, including 3 figures)