+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   31P/Schwassmann-Wachmann 2 Classification: Jupiter-family Comet          SPK-ID: 1000080 [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] alternate orbits: [epoch=2013-03-13.0] K084/11 (default) [epoch=1994-01-08.0] SAO/1994 [epoch=1987-09-02.0] SAO/1987 [epoch=1981-03-17.0] SAO/1981 [epoch=1974-09-30.0] SAO/1974 [epoch=1968-03-05.0] SAO/1968 [epoch=1961-09-18.0] SAO/1961 [epoch=1955-02-22.0] SAO/1955 [epoch=1948-09-06.0] SAO/1948 [epoch=1942-02-10.0] SAO/1942 [epoch=1935-08-26.0] SAO/1935 [epoch=1929-03-10.0] SAO/1929 Orbital Elements at Epoch 2456364.5 (2013-Mar-13.0) TDB Reference: JPL K084/11 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1939049560064233 1.2854e-07   a 4.246480086303573 5.7928e-08 AU q 3.423066551986726 5.5102e-07 AU i 4.546633992033895 1.3784e-05 deg node 114.1548122753023 9.7233e-05 deg peri 18.01931880463022 0.00010829 deg M 100.7835205272671 1.8667e-05 deg tp 2455469.693585515710 (2010-Sep-30.19358552) 0.00017159 JED period 3196.259740968185 8.75 6.5402e-05 1.791e-07 d yr n .11263164735509 2.3047e-09 deg/d Q 5.069893620620419 6.916e-08 AU Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A1 [EST] 1.829839428080619E-8 4.936E-10 A2 [EST] -2.863799405272808E-9 2.154E-11   Orbit Determination Parameters    # obs. used (total)      935      data-arc span      9461 days (25.90 yr)      first obs. used      1986-06-26      last obs. used      2012-05-21      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      condition code      0      fit RMS      .99349      data source      ORB      producer      Ryan S. Park      solution date      2013-Mar-03 19:23:29   Additional Information  Earth MOID = 2.43779 AU   T_jup = 2.992  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes comet total magnitude M1 6.2 mag 0.7 K084/11 2 parameter fit from 511 observations, autocmod 2.5b comet total magnitude slope K1 19.   n/a K084/11 autocmod 2.5b comet nuclear magnitude M2 13.9 mag 0.6 K084/11 from 232 observations, autocmod 2.5b comet nuclear magnitude slope K2 5.   n/a K084/11 autocmod 2.5b comet nuclear phase coefficient PC 0.03   n/a K084/11 autocmod 2.5b diameter diameter 6.2 km n/a Lamy,P.L.,Toth,I.,Fernandez,Y.R.,Weaver,H.A. (2004) Comets II, pp. 223-264   31P/Schwassmann-Wachmann 2          Discovered 1929-Jan-17 by Schwassmann, A. and Wachmann, A. A. at Hamburg Observatory, Germany 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   1993.2       1994 II     1984.5       1981 VI   1986h   1975.7       1974 XIII   1979k   1967.0       1968 II   1967i   1958.2       1955 I   1954g   1949.5       1948 VII   1947l   1940.7       1942 I   1941f   1932.0   31P/1929 B1   1929 I   1929a  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2013-May-18 06:01 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin