+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   48P/Johnson Classification: Jupiter-family Comet          SPK-ID: 1000049 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] alternate orbits: [epoch=2010-Feb-01.0] 68 (default) [epoch=1997-Nov-08.0] SAO/1997 [epoch=1990-Nov-05.0] SAO/1990 [epoch=1983-Dec-12.0] SAO/1983 [epoch=1977-Jan-17.0] SAO/1977 [epoch=1970-Apr-04.0] SAO/1970 [epoch=1963-Jun-20.0] SAO/1963 [epoch=1956-Jul-26.0] SAO/1956 [epoch=1949-Sep-01.0] SAO/1949 Orbital Elements at Epoch 2455228.5 (2010-Feb-01.0) TDB Reference: JPL 68 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .3678117401626815 9.2951e-08   a 3.641982389984688 3.5222e-08 au q 2.302418509482578 3.3253e-07 au i 13.66068838516227 9.449e-06 deg node 117.2884957292427 2.0401e-05 deg peri 207.8266217590061 2.7055e-05 deg M 274.2111240551269 9.854e-06 deg tp 2455833.469759048695 (2011-Sep-28.96975905) 7.1147e-05 TDB period 2538.663793630759 6.95 3.6828e-05 1.008e-07 d yr n .1418068831734246 2.0572e-09 deg/d Q 4.981546270486797 4.8177e-08 au Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A1 [EST] 5.674272798225169E-9 8.643E-11 A2 [EST] -1.730162474683401E-10 2.599E-12   Orbit Determination Parameters    # obs. used (total)      2140      data-arc span      26012 days (71.22 yr)      first obs. used      1949-09-24      last obs. used      2020-12-12      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .74371      source      ORB      producer      Davide Farnocchia      solution date      2021-Mar-19 11:17:03   Additional Information  Earth MOID = 1.3007 au   Jupiter MOID = .474682 au   T_jup = 2.941  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes comet total magnitude M1 9.3   0.9 68 2 parameter fit from 856 observations, autocmod 2.9b comet total magnitude slope K1 15.75   n/a 68 autocmod 2.9b comet nuclear magnitude M2 13.5   0.7 68 from 985 observations, autocmod 2.9b comet nuclear magnitude slope K2 5.   n/a 68 autocmod 2.9b comet nuclear phase coefficient PC 0.03   n/a 68 autocmod 2.9b diameter diameter 5.74 km n/a Lamy,P.L.;Toth,I.;Fernandez,Y.R.;Weaver,H.A.; (2004) Comets II, pp. 223-264   48P/Johnson          Discovered 1949-Aug-25 by Johnson, Ernest Leonard at Union Observatory, South Africa discovered on plate/photo taken on discovery date Reference: comet.dis Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  Perihelion  Year (est.)  New-Style  Desig Roman  Numeral  Year/  Letter   1990.9       1990 XXIII   1990h   1983.9       1983 XVIII   1983h   1977.0       1977 I   1976h   1970.0       1970 IV   1970h   1963.1       1963 IV   1963c   1956.1   48P/1956 P1   1956 V   1956f   1949.2   48P/1949 Q1   1949 II   1949d  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-23 15:35 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin