P_constants (PcK) SPICE kernel file Orientation constants for Phobos =================================================================== Author : Nicolas Rambaux Sebastien Le Maistre May 2015 Version description -------------------------------------------------------- This is a PcK file for the ESPaCe project. This version corrects the version of the 2013 August 5 (sign in W). The data are based on the Rambaux etal 2012 [1] and Le Maistre etal 2013 [2] papers. Sources -------------------------------------------------------- The sources for the constants listed in this file are: [1] Rambaux, N., Castillo-Rogez, J.C., Le Maistre, S., & Rosenblatt, P., 2012, Rotational motion of Phobos, Astronomy and Astrophysics, Vol 548, id.A14, 11pp. [2] Le Maistre, S., Rosenblatt, P., Rambaux, N., Castillo-Rogez, J.C., Mary J.C. & Dehant V., 2013, Phobos libration determination using Doppler and Star Tracker measurements, Planetary and Space Science, 85:106–122, September 2013. doi: 10.1016/j.pss.2013.06.015. [3] Archinal, B.A., A'Hearn, M.F., Bowell, E., Conrad, A., Consolmagno, G.J., Courtin, R., Fukushima, T., Hestroffer, D., Hilton, J.L., Krasinsky, G.A., Neumann, G., Oberst, J., Seidelmann, P.K., Stooke, P., Tholen, D.J., Thomas, P.C., and Williams, I.P. "Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2011." Explanatory Notes -------------------------------------------------------- This file works exactly as the PCK file pck00010.tpc available at naif website. Here the updated values are for the variables: BODY4_NUT_PREC_ANGLES BODY401_POLE_RA BODY401_POLE_DEC BODY401_PM BODY401_NUT_PREC_RA BODY401_NUT_PREC_DEC BODY401_NUT_PREC_PM Caution : this SPK should not be used if you studied Deimos. Body numbers and names ---------------------------------------------------------- Barycenters: 4 Mars barycenter Mass centers: 401 Phobos 10 Sun Orientation Constants for the Sun and Planets -------------------------------------------------------- The 2003 IAU report defines M2, the second nutation precession angle, by: 2 192.93 + 1128.4096700 d + 8.864 T We truncate the M2 series to a linear expression, because the PCK software cannot handle the quadratic term. Again, the linear terms are scaled by 36525.0: -0.4357640000000000 --> -15916.28010000000 1128.409670000000 --> 41215163.19675000 -1.8151000000000000E-02 --> -662.9652750000000 The Phases are in degreess and frequencies in deg/cy Old Values BODY4_NUT_PREC_ANGLES = ( 169.51 -15916.2801 192.93 41215163.19675 53.47 -662.965275 36.53 662.965275 ) The updated file contains 10 terms. \begindata BODY4_NUT_PREC_ANGLES = ( 10.575 15915.1991 42.123 56845351.3967 27.510 25616767.5047 21.114 31830.3982 -18.006 15598397.6742 266.642 56763067.4108 159.229 19140.0935 162.689 25699051.4906 9.271 41215163.0862 122.580 25645854.3360 ) \begintext Orientation constants for the satellites -------------------------------------------------------- Satellites of Mars Phobos Old values: Values of Archinal 2011 report [3] The quadratic prime meridian term is scaled by 1/36525**2: 8.864000000000000 ---> 6.6443009930565219E-09 BODY401_POLE_RA = ( 317.68 -0.108 0. ) BODY401_POLE_DEC = ( 52.90 -0.061 0. ) BODY401_PM = ( 35.06 6.6443009930565219E-09 ) BODY401_LONG_AXIS = ( 0. ) BODY401_NUT_PREC_RA = ( 1.79 0. 0. 0. ) BODY401_NUT_PREC_DEC = ( -1.08 0. 0. 0. ) BODY401_NUT_PREC_PM = ( -1.42 -0.78 0. 0. ) Current values: \begindata BODY401_POLE_RA = ( 317.6517 -0.108 0. ) BODY401_POLE_DEC = ( 52.8753 -0.061 0. ) BODY401_PM = ( 34.7808 1128.8445850 9.519700204401831E-09 ) BODY401_LONG_AXIS = ( 0. ) BODY401_NUT_PREC_RA = ( 1.7883 -0.0462 -0.0300 0.0222 0.0166 0.0157 0.0107 0.0103 0.0 0.0 ) BODY401_NUT_PREC_DEC = ( 1.0781 0.0279 0.0181 0.0 0.0101 0.0 0.0 0.0 0.0 0.0 ) BODY401_NUT_PREC_PM = ( -1.4272 0.0368 0.0239 -0.0228 -0.0133 -0.0125 0.0 0.0 1.0998 0.0167 )