*******************************************************************************
 Revised: April 12, 2021             Mercury                            199 / 1

 PHYSICAL DATA (updated 2021-Apr-12):
  Vol. Mean Radius (km) =  2440+-1        Density (g cm^-3)     = 5.427
  Mass x10^23 (kg)      =     3.302       Volume (x10^10 km^3)  = 6.085  
  Sidereal rot. period  =    58.6463 d    Sid. rot. rate (rad/s)= 0.00000124001
  Mean solar day        =   175.9421 d    Core radius (km)      = ~1600 
  Geometric Albedo      =     0.106       Surface emissivity    = 0.77+-0.06
  GM (km^3/s^2)         = 22031.86855     Equatorial radius, Re = 2440 km
  GM 1-sigma (km^3/s^2) =                 Mass ratio (Sun/plnt) = 6023682
  Mom. of Inertia       =     0.33        Equ. gravity  m/s^2   = 3.701     
  Atmos. pressure (bar) = < 5x10^-15      Max. angular diam.    = 11.0"   
  Mean Temperature (K)  = 440             Visual mag. V(1,0)    = -0.42 
  Obliquity to orbit[1] =  2.11' +/- 0.1' Hill's sphere rad. Rp = 94.4 
  Sidereal orb. per.    =  0.2408467 y    Mean Orbit vel.  km/s = 47.362 
  Sidereal orb. per.    = 87.969257  d    Escape vel. km/s      =  4.435
                                 Perihelion  Aphelion    Mean
  Solar Constant (W/m^2)         14462       6278        9126
  Maximum Planetary IR (W/m^2)   12700       5500        8000
  Minimum Planetary IR (W/m^2)   6           6           6
*******************************************************************************
 
 
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Ephemeris / WWW_USER Tue Dec  7 04:13:54 2021 Pasadena, USA      / Horizons
*******************************************************************************
Target body name: Mercury (199)                   {source: DE441}
Center body name: Solar System Barycenter (0)     {source: DE441}
Center-site name: BODY CENTER
*******************************************************************************
Start time      : A.D. 2020-Jan-02 00:00:00.0000 TDB
Stop  time      : A.D. 2020-Jan-02 00:01:00.0000 TDB
Step-size       : 60 minutes
*******************************************************************************
Center geodetic : 0.00000000,0.00000000,0.0000000 {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.00000000,0.00000000,0.0000000 {E-lon(deg),Dxy(km),Dz(km)}
Center radii    : (undefined)                                                  
Output units    : KM-D
Output type     : GEOMETRIC cartesian states
Output format   : 3 (position, velocity, LT, range, range-rate)
Reference frame : ICRF
*******************************************************************************
JDTDB
   X     Y     Z
   VX    VY    VZ
   LT    RG    RR
*******************************************************************************
$$SOE
2458850.500000000 = A.D. 2020-Jan-02 00:00:00.0000 TDB 
 X =-6.706875219569503E+06 Y =-6.044461660946982E+07 Z =-3.175166955207460E+07
 VX= 3.346870045424018E+06 VY=-1.701434977841626E+04 VZ=-3.560819216270942E+05
 LT= 2.648646033796148E-03 RG= 6.860541065849553E+07 RR=-1.473997213270023E+05
$$EOE
*******************************************************************************
 
TIME

  Barycentric Dynamical Time ("TDB" or T_eph) output was requested. This
continuous relativistic coordinate time is equivalent to the relativistic
proper time of a clock at rest in a reference frame comoving with the
solar system barycenter but outside the system's gravity well. It is the
independent variable in the solar system relativistic equations of motion.

  TDB runs at a uniform rate of one SI second per second and is independent
of irregularities in Earth's rotation.

  Calendar dates prior to 1582-Oct-15 are in the Julian calendar system.
Later calendar dates are in the Gregorian system.

REFERENCE FRAME AND COORDINATES

  International Celestial Reference Frame (ICRF)

    The ICRF is an adopted reference frame whose axes are defined relative to 
    fixed extragalactic radio sources distributed across the sky.

    The ICRF was aligned with the prior FK5/J2000 dynamical system at the ~0.02 
    arcsecond level but is not identical and has no associated standard epoch.

  Symbol meaning [1 day=86400.0 s]:

    JDTDB    Julian Day Number, Barycentric Dynamical Time
      X      X-component of position vector (km)
      Y      Y-component of position vector (km)
      Z      Z-component of position vector (km)
      VX     X-component of velocity vector (km/day)                           
      VY     Y-component of velocity vector (km/day)                           
      VZ     Z-component of velocity vector (km/day)                           
      LT     One-way down-leg Newtonian light-time (day)
      RG     Range; distance from coordinate center (km)
      RR     Range-rate; radial velocity wrt coord. center (km/day)

ABERRATIONS AND CORRECTIONS

 Geometric state vectors have NO corrections or aberrations applied.

Computations by ...

    Solar System Dynamics Group, Horizons On-Line Ephemeris System
    4800 Oak Grove Drive, Jet Propulsion Laboratory
    Pasadena, CA  91109   USA

    General site: https://ssd.jpl.nasa.gov/
    Mailing list: https://ssd.jpl.nasa.gov/email_list.html
    System news : https://ssd.jpl.nasa.gov/horizons/news.html
    User Guide  : https://ssd.jpl.nasa.gov/horizons/manual.html
    Connect     : browser        https://ssd.jpl.nasa.gov/horizons/app.html#/x
                  API            https://ssd-api.jpl.nasa.gov/doc/horizons.html
                  command-line   telnet ssd.jpl.nasa.gov 6775
                  e-mail/batch   https://ssd.jpl.nasa.gov/ftp/ssd/hrzn_batch.txt
                  scripts        https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS
    Author      : Jon.D.Giorgini@jpl.nasa.gov
*******************************************************************************

!$$SOF
command = 199
TABLE_TYPE = 'VECTORS'
REF_PLANE = 'FRAME'
START_TIME = '2020-Jan-02 00:00:00.0000'
STOP_TIME = '2020-Jan-02 00:01:00.0000'
STEP_SIZE = '1 hours'
OUT_UNITS = 'KM-D'
CENTER = 500@0