+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   138P/Shoemaker-Levy 7 Classification: Jupiter-family Comet          SPK-ID: 1000137 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] [ show orbit diagram ] alternate orbits: [epoch=2005-Aug-30.0] 19 (default) [epoch=1998-Aug-15.0] SAO/1998 [epoch=1991-Oct-31.0] SAO/1991 Orbital Elements at Epoch 2453612.5 (2005-Aug-30.0) TDB Reference: JPL 19 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .5294518760783127 4.0298e-07   a 3.628326437681936 1.5093e-07 au q 1.707302198226694 1.4914e-06 au i 10.07952060977841 4.6085e-05 deg node 309.4417698756743 0.00011706 deg peri 95.64910660338207 0.00017981 deg M 5.860581634597394 6.9623e-05 deg tp 2453571.404319544281 (2005-Jul-19.90431954) 0.00048715 TDB period 2524.398751946602 6.91 0.00015751 4.312e-07 d yr n .1426082150145252 8.898e-09 deg/d Q 5.549350677137179 2.3083e-07 au Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A2 [EST] -9.70461262058737E-11 2.247E-12   Orbit Determination Parameters    # obs. used (total)      100      data-arc span      9765 days (26.74 yr)      first obs. used      1991-11-13      last obs. used      2018-08-08      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .58997      source      ORB      producer      Shantanu Naidu      solution date      2018-Sep-24 14:56:05   Additional Information  Earth MOID = .751048 au   Jupiter MOID = .897804 au   T_jup = 2.829  [ show covariance matrix ] [ 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 16.7   0.5 19 2 parameter fit from 45 observations, autocmod 2.6n comet total magnitude slope K1 8.   n/a 19 autocmod 2.6n [ show close-approach data ] Alternate Designations  Perihelion  Year (est.)  New-Style  Desig Roman  Numeral  Year/  Letter   1998.6   138P/1998 O1         1991.7   138P/1991 V2   1991 XIX   1991d1  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] 2021-Mar-05 10:35 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin