Volume 501, Number 2, July II 2009
|Page(s)||769 - 776|
|Section||Planets and planetary systems|
|Published online||13 May 2009|
New binary asteroid 809 Lundia
I. Photometry and modelling
Astronomical Observatory, Adam Mickiewicz University, Słoneczna 36, 60-286 Poznań, Poland e-mail: firstname.lastname@example.org
2 Institut de Mécanique Céleste et Calcul des Ephemerides, Observatoire de Paris, UMR8028 CNRS, 77 Av. Denfert Rochereau, 75014 Paris, France
3 Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195 Meudon, France
Accepted: 23 February 2009
CCD photometry of 809 Lundia obtained between September 2005 and January 2006 at Borowiec and Pic du Midi Observatories demonstrates that this object is a synchronous binary system with an orbital period of 15.418 ± 0.001 h. In this paper, we present the results of photometric observations of Lundia from two oppositions in 2005/2006 and 2007, as well as the first modelling of the system. For simplicity we assumed a fluid-like nature for each component with a modified Roche model and a triaxial ellipsoid shape in kinematic models. Our models provided similar results. Poles of the orbit in ecliptic coordinates are λ = 119 ± 2°, β = 28 ± 4° (modified Roche) or λ = 120 ± 5°, β = 18 ± 12° (kinematic). Triaxial ellipsoid shape solutions and a separation between components of 15.8 km are given after taking an equivalent diameter of 9.1 km from H = 11.8 mag and assuming an albedo of 0.4. The orbital period of the Lundia system obtained from modelling is the same as from the lightcurve analysis i.e., 15.418 ± 0.001 h. The bulk density of both components is 1.64 or 1.71 ± 0.01 g/cm3. The double system of Lundia probably originates from the fission process of a single body that could have been spun up by the YORP effect. The predicted lightcurves for future oppositions are also presented.
Key words: planets and satellites: formation / minor planets, asteroids / techniques: photometric
© ESO, 2009
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.