API VERSION: 1.2 API SOURCE: NASA/JPL Horizons API ******************************************************************************* JPL/HORIZONS 117P/Helin-Roman-Alu 1 2025-Dec-12 17:54:16 Rec #:90001009 (+COV) Soln.date: 2025-Mar-06_13:57:36 # obs: 4892 (2010-2025) IAU76/J2000 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs): EPOCH= 2458283.5 ! 2018-Jun-14.0000000 (TDB) RMSW= n.a. EC= .2550540605354052 QR= 3.047755862991364 TP= 2459767.0402351567 OM= 58.87682926160608 W= 222.501936526872 IN= 8.701788200865561 A= 4.091244346108978 MA= 183.3066210199441 ADIST= 5.134732829226591 PER= 8.2754444826842 N= .119102519 ANGMOM= .033643622 DAN= 4.71094 DDN= 3.21967 L= 281.0485261 B= -5.866731 MOID= 2.03875995 TP= 2022-Jul-06.5402351567 Comet physical (GM= km^3/s^2; RAD= km): GM= n.a. RAD= 4.5 M1= 6.1 M2= 11.4 k1= 14.25 k2= 5. PHCOF= .030 Comet non-gravitational force model (AMRAT=m^2/kg;A1-A3=au/d^2;DT=days;R0=au): AMRAT= 0. DT= -105.5403 A1= 2.267039489746E-7 A2= 1.167054748535E-7 A3= 4.127646923065E-8 Standard model: ALN= .1112620426 NK= 4.6142 NM= 2.15 NN= 5.093 R0= 2.808 COMET comments 1: soln ref.= JPL#K222/101, data arc: 2010-11-03 to 2025-03-03 2: k1=14.25, k2=5., phase coef.=0.03; ******************************************************************************* ******************************************************************************* Ephemeris / API_USER Fri Dec 12 17:54:16 2025 Pasadena, USA / Horizons ******************************************************************************* Target body name: 117P/Helin-Roman-Alu 1 {source: JPL#K222/101} Center body name: Earth (399) {source: DE441} Center-site name: GEOCENTRIC ******************************************************************************* Start time : A.D. 2030-Nov-26 00:00:00.0000 UT Stop time : A.D. 2030-Nov-28 00:00:00.0000 UT Step-size : 180 minutes ******************************************************************************* Target pole/equ : undefined Target radii : 4.5 km Center geodetic : 0.0, 0.0, -6378.137 {E-lon(deg),Lat(deg),Alt(km)} Center cylindric: 0.0, 0.0, 0.0 {E-lon(deg),Dxy(km),Dz(km)} Center pole/equ : ITRF93 {East-longitude positive} Center radii : 6378.137, 6378.137, 6356.752 km {Equator_a, b, pole_c} Target primary : Sun Vis. interferer : MOON (R_eq= 1737.400) km {source: DE441} Rel. light bend : Sun {source: DE441} Rel. lght bnd GM: 1.3271E+11 km^3/s^2 Small-body perts: Yes {source: SB441-N16} Atmos refraction: NO (AIRLESS) RA format : HMS Time format : CAL Calendar mode : Mixed Julian/Gregorian EOP file : eop.251212.p260310 EOP coverage : DATA-BASED 1962-JAN-20 TO 2025-DEC-12. PREDICTS-> 2026-MAR-09 Units conversion: 1 au= 149597870.700 km, c= 299792.458 km/s, 1 day= 86400.0 s Table cut-offs 1: Elevation (-90.0deg=NO ),Airmass (>38.000=NO), Daylight (NO ) Table cut-offs 2: Solar elongation ( 0.0,180.0=NO ),Local Hour Angle( 0.0=NO ) Table cut-offs 3: RA/DEC angular rate ( 0.0=NO ) ******************************************************************************* Initial IAU76/J2000 heliocentric ecliptic osculating elements (au, days, deg.): EPOCH= 2458283.5 ! 2018-Jun-14.0000000 (TDB) RMSW= n.a. EC= .2550540605354052 QR= 3.047755862991364 TP= 2459767.0402351567 OM= 58.87682926160608 W= 222.501936526872 IN= 8.701788200865561 Equivalent ICRF heliocentric cartesian coordinates (au, au/d): X=-1.155003085441280E+00 Y= 4.345300803323425E+00 Z= 2.477596070703014E+00 VX=-6.311009144576721E-03 VY=-1.768270815646143E-03 VZ=-5.459952004671577E-06 Comet physical (GM= km^3/s^2; RAD= km): GM= n.a. RAD= 4.5 M1= 6.1 M2= 11.4 k1= 14.25 k2= 5. PHCOF= .030 Comet non-gravitational force model (AMRAT=m^2/kg;A1-A3=au/d^2;DT=days;R0=au): AMRAT= 0. DT= -105.5403 A1= 2.267039489746E-7 A2= 1.167054748535E-7 A3= 4.127646923065E-8 Standard model: ALN= .1112620426 NK= 4.6142 NM= 2.15 NN= 5.093 R0= 2.808 ******************************************************************************* Date__(UT)__HR:MN r rdot ************************************************** $$SOE 2030-Nov-26 00:00 3.169575680242 -0.0076088 2030-Nov-26 03:00 3.169575185884 -0.0060871 2030-Nov-26 06:00 3.169574801380 -0.0045654 2030-Nov-26 09:00 3.169574526730 -0.0030436 2030-Nov-26 12:00 3.169574361933 -0.0015219 2030-Nov-26 15:00 3.169574306990 -0.0000002 2030-Nov-26 18:00 3.169574361900 0.0015215 2030-Nov-26 21:00 3.169574526662 0.0030432 2030-Nov-27 00:00 3.169574801276 0.0045648 2030-Nov-27 03:00 3.169575185742 0.0060865 2030-Nov-27 06:00 3.169575680059 0.0076082 2030-Nov-27 09:00 3.169576284227 0.0091299 2030-Nov-27 12:00 3.169576998244 0.0106515 2030-Nov-27 15:00 3.169577822111 0.0121732 2030-Nov-27 18:00 3.169578755827 0.0136948 2030-Nov-27 21:00 3.169579799391 0.0152164 2030-Nov-28 00:00 3.169580952803 0.0167381 $$EOE ******************************************************************************* Column meaning: TIME Times PRIOR to 1962 are UT1, a mean-solar time closely related to the prior but now-deprecated GMT. Times AFTER 1962 are in UTC, the current civil or "wall-clock" time-scale. UTC is kept within 0.9 seconds of UT1 using integer leap-seconds for 1972 and later years. Conversion from the internal Barycentric Dynamical Time (TDB) of solar system dynamics to the non-uniform civil UT time-scale requested for output has not been determined for UTC times after the next July or January 1st. Therefore, the last known leap-second is used as a constant over future intervals. Time tags refer to the UT time-scale conversion from TDB on Earth regardless of observer location within the solar system, although clock rates may differ due to the local gravity field and no analog to "UT" may be defined for that location. Any 'b' symbol in the 1st-column denotes a B.C. date. First-column blank (" ") denotes an A.D. date. 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. NOTE: "n.a." in output means quantity "not available" at the print-time. 'r rdot' = The Sun's apparent range ("r", light-time aberrated) and range-rate ("rdot") relative to the target center, as seen by the observer. A positive "rdot" means the target center was moving away from the Sun, negative means moving toward the Sun. Units: AU and KM/S 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 *******************************************************************************