University of Tasmania
Browse

File(s) under permanent embargo

Constraints on Charon's orbital elements from the double stellar occultation of 2008 June 22

journal contribution
posted on 2023-05-17, 05:27 authored by Sicardy, B, Bolt, G, Broughton, J, Dobosz, T, Gault, D, Kerr, S, Benard, F, Frappa, E, Lecacheux, J, Peyrot, A, Teng-Chuen-Yu, JP, Beisker, W, Boissel, Y, Buckley, D, Colas, F, de Witt, C, Doressoundiram, A, Roques, F, Widemann, T, Gruhn, C, Batista, V, Biggs, J, Dieters, S, Greenhill, J, Groom, R, Herald, D, Lade, B, Shevill Mathers, Assafin, M, Camargo, JIB, Vieira-Martins, R, Andrei, AH, da Silva Neto, DN, Braga-Ribas, F, Behrend, R
Pluto and its main satellite, Charon, occulted the same star on 2008 June 22. This event was observed from Australia and La Réunion Island, providing the east and north Charon Plutocentric offset in the sky plane (J2000): X = + 12,070.5 ± 4 km (+ 546.2 ± 0.2 mas), Y = + 4,576.3 ± 24 km (+ 207.1 ± 1.1 mas) at 19:20:33.82 UT on Earth, corresponding to JD 2454640.129964 at Pluto. This yields Charon’s true longitude L = 153.483 ± 0◦̣071 in the satellite orbital plane (counted from the ascending node on J2000 mean equator) and orbital radius r = 19,564 ± 14 km at that time. We compare this position to that predicted by (1) the orbital solution of Tholen & Buie (the “TB97” solution), (2) the PLU017 Charon ephemeris, and (3) the solution of Tholen et al. (the “T08” solution). We conclude that (1) our result rules out solution TB97, (2) our position agrees with PLU017, with differences of ΔL = + 0.073 ± 0◦̣071 in longitude, and Δr = + 0.6 ± 14 km in radius, and (3) while the difference with the T08 ephemeris amounts to only ΔL = 0.033 ± 0◦̣071 in longitude, it exhibits a significant radial discrepancy of Δr = 61.3 ± 14 km. We discuss this difference in terms of a possible image scale relative error of 3.35 × 10−3in the 2002–2003 Hubble Space Telescope images upon which the T08 solution is mostly based. Rescaling the T08 Charon semi-major axis, a = 19, 570.45 km, to the TB97 value, a = 19636 km, all other orbital elements remaining the same (“T08/TB97” solution), we reconcile our position with the re-scaled solution by better than 12 km (or 0.55 mas) for Charon’s position in its orbital plane, thus making T08/TB97 our preferred solution.

History

Publication title

Astronomical Journal

Volume

141

Article number

67

Number

67

Pagination

1-16

ISSN

0004-6256

Department/School

School of Natural Sciences

Publisher

Institute of Physics Publishing Inc

Place of publication

United States

Rights statement

http://www.press.uchicago.edu

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the physical sciences

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC