125 lines
6.2 KiB
Plaintext
125 lines
6.2 KiB
Plaintext
API VERSION: 1.2
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API SOURCE: NASA/JPL Horizons API
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Revised: April 12, 2021 Mercury 199 / 1
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PHYSICAL DATA (updated 2024-Mar-04):
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Vol. Mean Radius (km) = 2439.4+-0.1 Density (g cm^-3) = 5.427
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Mass x10^23 (kg) = 3.302 Volume (x10^10 km^3) = 6.085
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Sidereal rot. period = 58.6463 d Sid. rot. rate (rad/s)= 0.00000124001
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Mean solar day = 175.9421 d Core radius (km) = ~1600
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Geometric Albedo = 0.106 Surface emissivity = 0.77+-0.06
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GM (km^3/s^2) = 22031.86855 Equatorial radius, Re = 2440.53 km
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GM 1-sigma (km^3/s^2) = Mass ratio (Sun/plnt) = 6023682
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Mom. of Inertia = 0.33 Equ. gravity m/s^2 = 3.701
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Atmos. pressure (bar) = < 5x10^-15 Max. angular diam. = 11.0"
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Mean Temperature (K) = 440 Visual mag. V(1,0) = -0.42
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Obliquity to orbit[1] = 2.11' +/- 0.1' Hill's sphere rad. Rp = 94.4
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Sidereal orb. per. = 0.2408467 y Mean Orbit vel. km/s = 47.362
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Sidereal orb. per. = 87.969257 d Escape vel. km/s = 4.435
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Perihelion Aphelion Mean
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Solar Constant (W/m^2) 14462 6278 9126
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Maximum Planetary IR (W/m^2) 12700 5500 8000
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Minimum Planetary IR (W/m^2) 6 6 6
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*******************************************************************************
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Ephemeris / API_USER Thu Aug 14 16:19:24 2025 Pasadena, USA / Horizons
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Target body name: Mercury (199) {source: DE441}
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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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*******************************************************************************
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JDTDB
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X Y Z
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VX VY VZ
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$$SOE
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2460676.500000000 = A.D. 2025-Jan-01 00:00:00.0000 TDB
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X =-3.873030085256687E-01 Y =-1.617241946342014E-01 Z = 2.230772540124238E-02
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VX= 5.024430196457658E-03 VY=-2.474345331076241E-02 VZ=-2.482923861184285E-03
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2460676.500694444 = A.D. 2025-Jan-01 00:01:00.0000 TDB
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X =-3.872995189658449E-01 Y =-1.617413774324715E-01 Z = 2.230600112712438E-02
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VX= 5.025502090388155E-03 VY=-2.474300570104969E-02 VZ=-2.482985597610005E-03
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$$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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