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HORIZONS Web-Interface
This tool provides a web-based limited interface to JPL's HORIZONS system which can be used to generate ephemerides for solar-system bodies. Full access to HORIZONS features is available via the primary telnet interface. HORIZONS system news shows recent changes and improvements. A web-interface tutorial is available to assist new users.

Current Settings

Ephemeris Type [change] :  VECTORS
Target Body [change] :  Earth [Geocenter] [399]
Coordinate Origin [change] :  Solar System Barycenter (SSB) [500@0]
Time Span [change] :  Start=2015-08-29, Stop=2015-08-30, Step=1 d
Table Settings [change] :  output units=KM-S
Display/Output [change] :  default (formatted HTML)

Object Data Page

Revised: Jul 31, 2013                  Earth                                399
 
PHYSICAL PROPERTIES (revised Sep 18, 2013):
 Mean radius, km          = 6371.01+-0.01   Mass, 10^24 kg = 5.97219+-0.0006
 Equ. radius, km          = 6378.14+-0.01   Mass layers:
 Polar axis, km           = 6356.752          Atmos          = 5.1   x 10^18 kg
 Flattening               = 1/298.257         oceans         = 1.4   x 10^21 kg
 Density, gm cm^-3        = 5.515             crust          = 2.6   x 10^22 kg
 J2  (GEM T2, 1990)       = 0.0010826265      mantle         = 4.043 x 10^24 kg
 gp, m s^-2 (polar)       = 9.8321863685      outer core     = 1.835 x 10^24 kg
 ge, m s^-2 (equatorial)  = 9.7803267715      inner core     = 9.675 x 10^22 kg
 go, m s^-2               = 9.82022         Fluid core rad   = 3480 km
 GM, km^3 s^-2            = 398600.440      Inner core rad   = 1215 km
 Mean rot. rate, rad s^-1 = 7.292115*10^-5  Surface Area:
 Sidereal period, hr      = 23.93419          land           = 1.48 x 10^8 km
 Mean solar day, days     = 1.002738          sea            = 3.62 x 10^8 km
 Moment of inertia        = 0.3308          Love no., k2     = 0.299
 Mean Temperature, K      = 270             Atm. pressure    = 1.0 bar
 Solar constant, W/m^2    = 1367.6          Vis. mag. V(1,0) = -3.86
 Volume, 10^10 km^3       = 108.321         Geometric albedo = 0.367 

DYNAMICAL CHARACTERISTICS:
 Obliquity to orbit, deg  = 23.45           Sidereal period  = 1.0000174  yrs
 Orbit velocity, km s^-1  = 29.7859         Sidereal period  = 365.25636  days
 Mean daily motion, n     = 0.9856474 deg/d Escape velocity  = 11.186 km s^-1
 Hill's sphere radius     = 234.9           Magnetic moment  = 0.61 gauss Rp^3

Results

*******************************************************************************
Ephemeris / WWW_USER Wed May 23 05:34:58 2018 Pasadena, USA      / Horizons    
*******************************************************************************
Target body name: Earth (399)                     {source: DE431mx}
Center body name: Solar System Barycenter (0)     {source: DE431mx}
Center-site name: BODY CENTER
*******************************************************************************
Start time      : A.D. 2015-Aug-29 00:00:00.0000 TDB
Stop  time      : A.D. 2015-Aug-30 00:00:00.0000 TDB
Step-size       : 1440 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-S                                                         
Output type     : GEOMETRIC cartesian states
Output format   : 3 (position, velocity, LT, range, range-rate)
Reference frame : ICRF/J2000.0                                                 
Coordinate systm: Ecliptic and Mean Equinox of Reference Epoch                 
*******************************************************************************
JDTDB
   X     Y     Z
   VX    VY    VZ
   LT    RG    RR
*******************************************************************************
$$SOE
2457263.500000000 = A.D. 2015-Aug-29 00:00:00.0000 TDB 
 X = 1.376368513677354E+08 Y =-6.342242292720988E+07 Z =-2.196418258551881E+04
 VX= 1.203162796791987E+01 VY= 2.691852057718956E+01 VZ=-9.423706264577447E-05
 LT= 5.055043307947790E+02 RG= 1.515463858586119E+08 RR=-3.381301634392637E-01
2457264.500000000 = A.D. 2015-Aug-30 00:00:00.0000 TDB 
 X = 1.386567636393730E+08 Y =-6.108772457269292E+07 Z =-2.196580001194030E+04
 VX= 1.157690924441596E+01 VY= 2.712427563778175E+01 VZ= 4.564582931187999E-05
 LT= 5.054063914656761E+02 RG= 1.515170243864053E+08 RR=-3.415029553896776E-01
$$EOE
*******************************************************************************
Coordinate system description:

  Ecliptic and Mean Equinox of Reference Epoch

    Reference epoch: J2000.0
    XY-plane: plane of the Earth's orbit at the reference epoch
              Note: obliquity of 84381.448 arcseconds wrt ICRF equator (IAU76)
    X-axis  : out along ascending node of instantaneous plane of the Earth's
              orbit and the Earth's mean equator at the reference epoch
    Z-axis  : perpendicular to the xy-plane in the directional (+ or -) sense
              of Earth's north pole at the reference epoch.

  Symbol meaning:

    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/sec)                           
      VY     Y-component of velocity vector (km/sec)                           
      VZ     Z-component of velocity vector (km/sec)                           
      LT     One-way down-leg Newtonian light-time (sec)                       
      RG     Range; distance from coordinate center (km)                       
      RR     Range-rate; radial velocity wrt coord. center (km/sec)            

Geometric states/elements have no aberrations applied.

 Computations by ...
     Solar System Dynamics Group, Horizons On-Line Ephemeris System
     4800 Oak Grove Drive, Jet Propulsion Laboratory
     Pasadena, CA  91109   USA
     Information: http://ssd.jpl.nasa.gov/
     Connect    : telnet://ssd.jpl.nasa.gov:6775  (via browser)
                  http://ssd.jpl.nasa.gov/?horizons
                  telnet ssd.jpl.nasa.gov 6775    (via command-line)
     Author     : Jon.D.Giorgini@jpl.nasa.gov
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