+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   151P/Helin Classification: Jupiter-family Comet          SPK-ID: 1000115 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2455165.5 (2009-Nov-30.0) TDB Reference: JPL 33 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .5703733600209818 1.2038e-06   a 5.809605650687495 1.3479e-06 au q 2.495961355307986 7.3524e-06 au i 4.735505041376388 4.7182e-05 deg node 143.564015036869 0.00038758 deg peri 215.4915432331094 0.0012176 deg M 209.5705580268369 0.00020918 deg tp 2457302.717647255686 (2015-Oct-07.21764726) 0.0037065 TDB period 5114.679300274938 14.00 0.00178 4.873e-06 d yr n .07038564470320716 2.4495e-08 deg/d Q 9.123249946067006 2.1167e-06 au Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A1 [EST] 4.707174748429356E-8 3.571E-8 A2 [EST] -3.83674675929215E-10 1.749E-10   Orbit Determination Parameters    # obs. used (total)      412      data-arc span      10382 days (28.42 yr)      first obs. used      1987-08-24      last obs. used      2016-01-26      planetary ephem.      DE431      SB-pert. ephem.      SB431-BIG16      condition code      1      norm. resid. RMS      .56738      source      ORB      producer      Otto Matic      solution date      2016-Apr-25 12:34:25   Additional Information  Earth MOID = 1.49415 au   Jupiter MOID = .234972 au   T_jup = 2.626  [ 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 8.4   0.8 33 2 parameter fit from 196 observations, autocmod 2.6f comet total magnitude slope K1 22.   n/a 33 autocmod 2.6f comet nuclear magnitude M2 14.9   0.5 33 from 141 observations, autocmod 2.6f comet nuclear magnitude slope K2 5.   n/a 33 autocmod 2.6f comet nuclear phase coefficient PC 0.03   n/a 33 autocmod 2.6f diameter diameter 8.4 km n/a Scotti,J (1994) BAAS 26:1375   [ show close-approach data ] Alternate Designations  Perihelion  Year (est.)  New-Style  Desig Roman  Numeral  Year/  Letter   2001.8   151P/2001 M1         1987.8   151P/1987 Q3   1987 XVII   1987w  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] 2021-Mar-05 11:48 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin