Portal de Periódicos da CAPES

Charon's Radius and Density from the Combined Data Sets of the 2005 July 11 Occultation

2006; Institute of Physics; Volume: 132; Issue: 4 Linguagem: Inglês

10.1086/507330

1538-3881

Michael J. Person, J. L. Elliot, A. A. S. Gulbis, Jay M. Pasachoff, B. A. Babcock, S. P. Souza, Joseph W. Gangestad,

Space Exploration and Technology

The 2005 July 11 C313.2 stellar occultation by Charon was observed by three separate research groups, including our own, at observatories throughout South America. Here, the published timings from the three data sets have been combined to more accurately determine the mean radius of Charon: 606.0 ± 1.5 km. Our analysis indicates that a slight oblateness in the body (0.006 ± 0.003) best matches the data, with a confidence level of 86%. The oblateness has a pole position angle of 714 ± 104 and is consistent with Charon's pole position angle of 67°. Charon's mean radius corresponds to a bulk density of 1.63 ± 0.07 g cm-3, which is significantly less than Pluto's (1.92 ± 0.12 g cm-3). This density differential favors an impact formation scenario for the system in which at least one of the impactors was differentiated. Finally, unexplained differences between chord timings measured at Cerro Pachón and the rest of the data set could be indicative of a depression as deep as 7 km on Charon's limb.