solar-sim/assets/jpl_horizon/bodies/Umbriel.txt
2025-08-15 08:50:02 +09:00

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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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