Contact binaries are found throughout the Solar System. The recent discovery of Selam, the satellite of main-belt asteroid (152830) Dinkinesh, by the NASA Lucy mission has made it clear that the term 'contact binary' covers a variety of different types of bimodal mass distributions and formation mechanisms. Only by modelling more contact binaries can this population be properly understood. We determined a spin state and shape model for the Apollo group contact binary asteroid (388188) 2006 DP using ground-based optical and radar observations collected between 2014 and 2023. Radar delay-Doppler images and continuous-wave spectra were collected over 2 d in February 2014, while 16 light curves in the Cousins R and SDSS-r filters were collected in 2014, 2022, and 2023. We modelled the spin state using convex inversion before using the shape modelling software to include the radar observations in modelling concavities and the distinctive neck structure connecting the two lobes. We find a spin state with a period of h and pole solution of and with morphology indicating a 520 m long bilobed shape. The model's asymmetrical bimodal mass distribution resembles other small near-Earth asteroid contact binaries such as (85990) 1999 JV or (8567) 1996 HW, which also feature a smaller'head' attached to a larger'body'. The final model features a crater on the larger lobe, similar to several other modelled contact binaries. The model's resolution is 25 m, comparable to that of the radar images used.
Shape and spin state model of contact binary (388188) 2006 DP14using combined radar and optical observations
Bozza, Valerio;Rota, Paolo;
2025
Abstract
Contact binaries are found throughout the Solar System. The recent discovery of Selam, the satellite of main-belt asteroid (152830) Dinkinesh, by the NASA Lucy mission has made it clear that the term 'contact binary' covers a variety of different types of bimodal mass distributions and formation mechanisms. Only by modelling more contact binaries can this population be properly understood. We determined a spin state and shape model for the Apollo group contact binary asteroid (388188) 2006 DP using ground-based optical and radar observations collected between 2014 and 2023. Radar delay-Doppler images and continuous-wave spectra were collected over 2 d in February 2014, while 16 light curves in the Cousins R and SDSS-r filters were collected in 2014, 2022, and 2023. We modelled the spin state using convex inversion before using the shape modelling software to include the radar observations in modelling concavities and the distinctive neck structure connecting the two lobes. We find a spin state with a period of h and pole solution of and with morphology indicating a 520 m long bilobed shape. The model's asymmetrical bimodal mass distribution resembles other small near-Earth asteroid contact binaries such as (85990) 1999 JV or (8567) 1996 HW, which also feature a smaller'head' attached to a larger'body'. The final model features a crater on the larger lobe, similar to several other modelled contact binaries. The model's resolution is 25 m, comparable to that of the radar images used.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
