+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   251P/LINEAR Classification: Jupiter-family Comet          SPK-ID: 1000495 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2453813.5 (2006-Mar-19.0) TDB Reference: JPL 32 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .5097838091900158 4.5103e-07   a 3.491387520746516 5.9051e-07 au q 1.711534691061872 1.4842e-06 au i 23.5097808150622 3.3681e-05 deg node 219.5544197659631 2.6616e-05 deg peri 30.87913279279607 0.00025658 deg M 96.41549159793094 8.6948e-05 deg tp 2453175.324938388360 (2004-Jun-18.82493839) 0.00046861 TDB period 2382.843445307088 6.52 0.00060453 1.655e-06 d yr n .151080005154768 3.8329e-08 deg/d Q 5.27124035043116 8.9155e-07 au Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A1 [EST] 5.157078889980294E-9 4.806E-10 A2 [EST] 2.239543052419328E-10 1.864E-11   Orbit Determination Parameters    # obs. used (total)      401      data-arc span      4905 days (13.43 yr)      first obs. used      2004-04-17      last obs. used      2017-09-21      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      1      norm. resid. RMS      .67964      source      ORB      producer      Otto Matic      solution date      2017-Oct-03 10:47:43   Additional Information  Earth MOID = .732911 au   Jupiter MOID = .210227 au   T_jup = 2.783  [ hide covariance matrix ] Orbit Covariance (8×8)   e q tp node peri i A1 A2 e 2.034295022231767E-13 -6.585886663965709E-13 1.439544364847831E-10 -1.606259447277415E-12 7.521432625174366E-11 -1.161225681681378E-11 1.393488718912319E-16 -4.637777391999688E-18 q -6.585886663965709E-13 2.202812437181203E-12 -4.262524523555949E-10 4.451817040357627E-12 -2.168038667287436E-10 3.634713538043725E-11 -5.218643133374513E-16 1.089536689609847E-17 tp 1.439544364847831E-10 -4.262524523555949E-10 2.195980259038835E-7 -4.188127559517539E-9 1.190573505205712E-7 -1.002514227530999E-8 8.457147538976185E-14 -5.844864313126462E-15 node -1.606259447277415E-12 4.451817040357627E-12 -4.188127559517539E-9 7.084361856403677E-10 -2.80664950327669E-9 4.769216879075802E-10 -1.524506696611829E-15 8.784036317757122E-17 peri 7.521432625174366E-11 -2.168038667287436E-10 1.190573505205712E-7 -2.80664950327669E-9 6.583141023576633E-8 -5.80954374290049E-9 3.442064787189734E-14 -3.384940016058793E-15 i -1.161225681681378E-11 3.634713538043725E-11 -1.002514227530999E-8 4.769216879075802E-10 -5.80954374290049E-9 1.134385693296003E-9 -5.380959983311553E-15 3.342536884225499E-16 A1 1.393488718912319E-16 -5.218643133374513E-16 8.457147538976185E-14 -1.524506696611829E-15 3.442064787189734E-14 -5.380959983311553E-15 2.30956465052084E-19 6.85476953602898E-22 A2 -4.637777391999688E-18 1.089536689609847E-17 -5.844864313126462E-15 8.784036317757122E-17 -3.384940016058793E-15 3.342536884225499E-16 6.85476953602898E-22 3.474789789561697E-22 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes comet total magnitude M1 9.6   1. 32 2 parameter fit from 167 observations, autocmod 2.6i comet total magnitude slope K1 34.   n/a 32 autocmod 2.6i comet nuclear magnitude M2 17.1   0.9 32 from 134 observations, autocmod 2.6i comet nuclear magnitude slope K2 5.   n/a 32 autocmod 2.6i comet nuclear phase coefficient PC 0.03   n/a 32 autocmod 2.6i [ show close-approach data ] Alternate Designations  Perihelion  Year (est.)  New-Style  Desig Roman  Numeral  Year/  Letter   2011.0   251P/2011 J1         2004.5   251P/2004 HC18        [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] 2021-Jan-19 10:16 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin