127 lines
6.3 KiB
Plaintext
127 lines
6.3 KiB
Plaintext
API VERSION: 1.2
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API SOURCE: NASA/JPL Horizons API
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Revised: June 02, 2025 Mars 499 / 4
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PHYSICAL DATA (updated 2025-Jun-02):
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Vol. mean radius (km) = 3389.92+-0.04 Density (g/cm^3) = 3.933(5+-4)
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Mass x10^23 (kg) = 6.4171 Flattening, f = 1/169.779
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Volume (x10^10 km^3) = 16.318 Equatorial radius (km)= 3396.19
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Sidereal rot. period = 24.622962 hr Sid. rot. rate, rad/s = 0.0000708822
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Mean solar day (sol) = 88775.24415 s Polar gravity m/s^2 = 3.758
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Core radius (km) = ~1700 Equ. gravity m/s^2 = 3.71
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Geometric Albedo = 0.150
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GM (km^3/s^2) = 42828.375662 Mass ratio (Sun/Mars) = 3098703.59
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GM 1-sigma (km^3/s^2) = +- 0.00028 Mass of atmosphere, kg= ~ 2.5 x 10^16
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Mean temperature (K) = 210 Atmos. pressure (bar) = 0.0056
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Obliquity to orbit = 25.19 deg Max. angular diam. = 17.9"
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Mean sidereal orb per = 1.88081578 y Visual mag. V(1,0) = -1.52
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Mean sidereal orb per = 686.98 d Orbital speed, km/s = 24.13
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Hill's sphere rad. Rp = 319.8 Escape speed, km/s = 5.027
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Perihelion Aphelion Mean
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Solar Constant (W/m^2) 717 493 589
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Maximum Planetary IR (W/m^2) 470 315 390
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Minimum Planetary IR (W/m^2) 30 30 30
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Ephemeris / API_USER Thu Aug 14 15:51:53 2025 Pasadena, USA / Horizons
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Target body name: Mars (499) {source: mar099}
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Center body name: Sun (10) {source: DE441}
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Center-site name: BODY CENTER
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Start time : A.D. 2025-Jan-01 00:00:00.0000 TDB
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Stop time : A.D. 2025-Jan-01 00:01:00.0000 TDB
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Step-size : 1 minutes
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Center geodetic : 0.0, 0.0, 0.0 {E-lon(deg),Lat(deg),Alt(km)}
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Center cylindric: 0.0, 0.0, 0.0 {E-lon(deg),Dxy(km),Dz(km)}
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Center radii : 695700.0, 695700.0, 695700.0 km {Equator_a, b, pole_c}
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Output units : AU-D
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Calendar mode : Mixed Julian/Gregorian
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Output type : GEOMETRIC cartesian states
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Output format : 2 (position and velocity)
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Reference frame : Ecliptic of J2000.0
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JDTDB
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X Y Z
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VX VY VZ
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$$SOE
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2460676.500000000 = A.D. 2025-Jan-01 00:00:00.0000 TDB
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X =-5.216858665681381E-01 Y = 1.525234576802456E+00 Z = 4.475559803760917E-02
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VX=-1.271183490340250E-02 VY=-3.338839586395265E-03 VZ= 2.417788175776839E-04
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2460676.500694444 = A.D. 2025-Jan-01 00:01:00.0000 TDB
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X =-5.216946942223875E-01 Y = 1.525232258137904E+00 Z = 4.475576593880412E-02
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VX=-1.271180933472031E-02 VY=-3.338914323653169E-03 VZ= 2.417766240577524E-04
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$$EOE
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TIME
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Barycentric Dynamical Time ("TDB" or T_eph) output was requested. This
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continuous coordinate time is equivalent to the relativistic proper time
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of a clock at rest in a reference frame co-moving with the solar system
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barycenter but outside the system's gravity well. It is the independent
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variable in the solar system relativistic equations of motion.
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TDB runs at a uniform rate of one SI second per second and is independent
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of irregularities in Earth's rotation.
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CALENDAR SYSTEM
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Mixed calendar mode was active such that calendar dates after AD 1582-Oct-15
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(if any) are in the modern Gregorian system. Dates prior to 1582-Oct-5 (if any)
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are in the Julian calendar system, which is automatically extended for dates
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prior to its adoption on 45-Jan-1 BC. The Julian calendar is useful for
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matching historical dates. The Gregorian calendar more accurately corresponds
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to the Earth's orbital motion and seasons. A "Gregorian-only" calendar mode is
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available if such physical events are the primary interest.
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REFERENCE FRAME AND COORDINATES
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Ecliptic at the standard reference epoch
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Reference epoch: J2000.0
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X-Y plane: adopted Earth orbital plane at the reference epoch
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Note: IAU76 obliquity of 84381.448 arcseconds wrt ICRF X-Y plane
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X-axis : ICRF
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Z-axis : perpendicular to the X-Y plane in the directional (+ or -) sense
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of Earth's north pole at the reference epoch.
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Symbol meaning [1 au= 149597870.700 km, 1 day= 86400.0 s]:
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JDTDB Julian Day Number, Barycentric Dynamical Time
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X X-component of position vector (au)
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Y Y-component of position vector (au)
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Z Z-component of position vector (au)
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VX X-component of velocity vector (au/day)
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VY Y-component of velocity vector (au/day)
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VZ Z-component of velocity vector (au/day)
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ABERRATIONS AND CORRECTIONS
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Geometric state vectors have NO corrections or aberrations applied.
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Computations by ...
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Solar System Dynamics Group, Horizons On-Line Ephemeris System
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4800 Oak Grove Drive, Jet Propulsion Laboratory
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Pasadena, CA 91109 USA
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General site: https://ssd.jpl.nasa.gov/
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Mailing list: https://ssd.jpl.nasa.gov/email_list.html
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System news : https://ssd.jpl.nasa.gov/horizons/news.html
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User Guide : https://ssd.jpl.nasa.gov/horizons/manual.html
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Connect : browser https://ssd.jpl.nasa.gov/horizons/app.html#/x
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API https://ssd-api.jpl.nasa.gov/doc/horizons.html
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command-line telnet ssd.jpl.nasa.gov 6775
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e-mail/batch https://ssd.jpl.nasa.gov/ftp/ssd/horizons_batch.txt
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scripts https://ssd.jpl.nasa.gov/ftp/ssd/SCRIPTS
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Author : Jon.D.Giorgini@jpl.nasa.gov
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