EDP Sciences
Free access
Volume 407, Number 3, September I 2003
Page(s) 1139 - 1147
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20030850

A&A 407, 1139-1147 (2003)
DOI: 10.1051/0004-6361:20030850

Photometry of the Kuiper-Belt object 1999 TD $_{\sf\sl 10}$ at different phase angles

P. Rousselot1, J.-M. Petit1, F. Poulet2, P. Lacerda3 and J. Ortiz4

1  Besançon Observatory, BP 1615, 25010 Besançon Cedex, France
2  Institut d'Astrophysique Spatiale, Bâtiment 121, Université Paris-Sud, 91405 Orsay Cedex, France
3  Leiden Observatory, University of Leiden, Postbus 9513, 2300 RA Leiden, The Netherlands
4  Instituto de Astrofísica de Andalucia, CSIC, Apt 3004, 18080 Granada, Spain

(Received 8 January 2003 / Accepted 28 May 2003)

We present photometric observations of the Kuiper-Belt object 1999 TD 10 at different phase angles and for three different broad band filters ( B, V and R). This object was observed with the Danish 1.54-m telescope of ESO in Chile during six different observing nights corresponding to a phase angle of 0.30, 0.37, 0.92, 3.43, 3.48 and 3.66°. Extra observations were obtained in September 2002 with the VLT UT1/FORS1 combination to confirm that 1999 TD 10 does not exhibit any cometary activity, and in October 2001 with the Sierra Nevada Observatory 1.50-m telescope in order to add relative magnitudes to improve the determination of the rotation period.

The observations are compatible with a single-peaked rotational lightcurve with a ${\rm 7h41.5min}\pm0.1$ min period or a double-peaked lightcurve with a ${\rm 15h22.9min}\pm0.1$ min period. If a single-peaked rotational lightcurve is assumed the amplitude is $0.51\pm 0.03$, $0.49\pm 0.05$ and $0.60\pm 0.09$ mag for the R, V and B bands, respectively. We present the phase curve obtained when assuming that the lightcurve is single-peaked. This phase curve reveals clearly an increase of about 0.3 mag and of similar importance for the three bands when phase angle decreases from 3.7° to 0.3°. The phase curve reveals a linear increase of the brightness with the decreasing phase angle and, consequently, does not permit a modeling of the opposition surge. Neverthless the poor repartition of the observational data does not permit a firm conclusion concerning the presence or absence of an opposition surge on the phase angle range covered by our data. Complementary observations are needed.

Key words: solar system: general -- Kuiper Belt -- techniques: photometric

Offprint request: P. Rousselot, philippe@obs-besancon.fr

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