API VERSION: 1.2
API SOURCE: NASA/JPL Horizons API

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 Revised: Jan 29, 2025             Umbriel / (Uranus)                       702

 SATELLITE PHYSICAL PROPERTIES:
  Radius (km)           = 584.7  +- 2.8     Density (g cm^-3)   =  1.52 +- 0.04
  GM (km^3/s^2)         =  85.40 +- 1.9     Geometric Albedo    =  0.18 
                                            V(1,0)              = +2.10

 SATELLITE ORBITAL DATA (mean elements referred to equatorial plane & IAU pole):
  Semi-major axis, a (km) = 266.0 (10^3)    Orbital period      = 4.144 d
  Eccentricity, e         =   0.0050        Rotational period   = Synchronous
  Inclination, i  (deg)   =  179.64
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Ephemeris / API_USER Thu Aug 14 16:19:48 2025 Pasadena, USA      / Horizons
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Target body name: Umbriel (702)                   {source: ura183_merged}
Center body name: Sun (10)                        {source: DE441}
Center-site name: BODY CENTER
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Start time      : A.D. 2025-Jan-01 00:00:00.0000 TDB
Stop  time      : A.D. 2025-Jan-01 00:01:00.0000 TDB
Step-size       : 1 minutes
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Center geodetic : 0.0, 0.0, 0.0                   {E-lon(deg),Lat(deg),Alt(km)}
Center cylindric: 0.0, 0.0, 0.0                   {E-lon(deg),Dxy(km),Dz(km)}
Center radii    : 695700.0, 695700.0, 695700.0 km {Equator_a, b, pole_c}
Output units    : AU-D
Calendar mode   : Mixed Julian/Gregorian
Output type     : GEOMETRIC cartesian states
Output format   : 2 (position and velocity)
Reference frame : Ecliptic of J2000.0
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JDTDB
   X     Y     Z
   VX    VY    VZ
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$$SOE
2460676.500000000 = A.D. 2025-Jan-01 00:00:00.0000 TDB 
 X = 1.110253678329407E+01 Y = 1.609490555702174E+01 Z =-8.286998450094619E-02
 VX=-1.219602563560983E-03 VY= 1.849034126664038E-03 VZ= 1.801100761916168E-03
2460676.500694444 = A.D. 2025-Jan-01 00:01:00.0000 TDB 
 X = 1.110253593696041E+01 Y = 1.609490684083643E+01 Z =-8.286873448230965E-02
 VX=-1.217838766094139E-03 VY= 1.848352214682835E-03 VZ= 1.798952584612123E-03
$$EOE
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TIME

  Barycentric Dynamical Time ("TDB" or T_eph) output was requested. This
continuous coordinate time is equivalent to the relativistic proper time
of a clock at rest in a reference frame co-moving 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 SYSTEM

  Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15
(if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any)
are in the Julian calendar system, which is automatically extended for dates
prior to its adoption on 45-Jan-1 BC.  The Julian calendar is useful for
matching historical dates. The Gregorian calendar more accurately corresponds
to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is
available if such physical events are the primary interest.

REFERENCE FRAME AND COORDINATES

  Ecliptic at the standard reference epoch

    Reference epoch: J2000.0
    X-Y plane: adopted Earth orbital plane at the reference epoch
               Note: IAU76 obliquity of 84381.448 arcseconds wrt ICRF X-Y plane
    X-axis   : ICRF
    Z-axis   : perpendicular to the X-Y plane in the directional (+ or -) sense
               of Earth's north pole at the reference epoch.

  Symbol meaning [1 au= 149597870.700 km, 1 day= 86400.0 s]:

    JDTDB    Julian Day Number, Barycentric Dynamical Time
      X      X-component of position vector (au)
      Y      Y-component of position vector (au)
      Z      Z-component of position vector (au)
      VX     X-component of velocity vector (au/day)                           
      VY     Y-component of velocity vector (au/day)                           
      VZ     Z-component of velocity vector (au/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/horizons_batch.txt
                  scripts        https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS
    Author      : Jon.D.Giorgini@jpl.nasa.gov
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