Reference : Charon's Size And Orbit From Double Stellar Occultations
Scientific congresses and symposiums : Paper published in a book
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
Charon's Size And Orbit From Double Stellar Occultations
Sicardy, Bruno [Univ. Paris 6 & Obs. de Paris/LESIA, France]
Braga-Ribas, F. [Obs. de Paris/LESIA & Obs. Nacional, France]
Widemann, T. [Obs. de Paris/LESIA, France]
Jehin, Emmanuel mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
Gillon, Michaël mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
Manfroid, Jean mailto [Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO) >]
Ortiz, J. L. [IAA-CSIC, Spain]
Morales, N. [IAA-CSIC, Spain]
Maury, A. [SPACE, Chile]
Assafin, M. [Obs. Valongo, Brazil]
Camargo, J. I. B. [Obs. Nacional, Brazil]
Vieira Martins, R. [Obs. Valongo, Obs. Nacional, Obs. Paris/IMCCE, Brazil]
Dias Oliveira, A. [Obs. Nacional, Brazil]
Ramos Gomes, A. [Obs. Valongo, Brazil]
Vanzi, L. [PUC, Chile]
Leiva, R. [PUC, Chile]
Young, L. A. [SWRI]
Buie, M. W. [SWRI]
Olkin, C. B. [SWRI]
Young, E. F. [SWRI]
Howell, R. R. [Univ. Wyoming]
French, R. G. [Wellesley coll]
Bianco, F. B. [UCSB & LCOGT]
Fulton, B. J. [LCOGT]
Lister, T. A. [LCOGT]
Bode, H. J. [IOTA-ES, Germany]
Barnard, B. [KEASA]
Merritt, J. C. [KEASA]
Shoemaker, K. [Shoemaker Labs]
Vengel, T. [NovaSensors]
Tholen, D. J. [Univ. Hawaii]
Hall, T. [Educ. Asso. for Sci. & Astronomy]
Reitsema, H. J. [Reitsema Enterprises Inc]
Wasserman, L. H. [Lowell Obs]
Go, C. [Univ. San Carlos, Philippines)]
AAS/Division for Planetary Sciences Meeting Abstracts
DPS meeting #44
du 14 octobre 2012 au 19 octobre 2012
[en] Stellar occultations of a same star by both Pluto and Charon (double events) yield instantaneous relative positions of the two bodies projected in the plane of the sky, at 10km-level accuracy. Assuming a given pole orientation for Charon's orbit, double events provide the satellite plutocentric distance r at a given orbital longitude L (counted from the ascending node on J2000 mean equator), and finally, constraints on its orbit. A double event observed on 22 June 2008 provides r=19,564+/-14 km at L=153.483+/-0.071 deg. (Sicardy et al. 2011), while another double event observed on 4 June 2011 yields: r=19,586+/-15 km at L = 343.211+/-0.072 deg. (all error bars at 1-sigma level). These two positions are consistent with a circular orbit for Charon, with a semi-major axis of a=19,575+\-10 km. This can be compared to the circular orbit found by Buie et al. (2012), based on Hubble Space Telescope data, with a=19,573+/-2 km. The 4 June 2011 stellar occultation provides 3 chords across Charon, from which a radius of Rc= 602.4+/-1.6 km is derived. This value can be compared to that obtained from the 11 July 2005 occultation: Rc= 606.0+/-1.5 km (Person et al. 2006) and Rc= 603.6+/-1.4 km (Sicardy et al. 2006). A third double event, observed on 23 June 2011 is under ongoing analysis, and will be presented. Buie et al. (2012), AJ 144, 15-34 (2012) Person et al, AJ 132, 1575-1580 (2006) Sicardy et al., Nature 439, 52-54 (2006) Sicardy et al., AJ 141, 67-83 (2011) B.S. thanks ANR "Beyond Neptune II". L.A.Y. acknowledges support by NASA, New Horizons and National Geographic grants. We thank B. Barnard, M.J. Brucker, J. Daily, C. Erikson, W. Fukunaga, C. Harlinten, C. Livermore, C. Nance, J.R. Regester, L. Salas, P. Tamblyn, R. Westhoff for help in the observations.

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