+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   31P/Schwassmann-Wachmann 2 Classification: Jupiter-family Comet          SPK-ID: 1000080 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] alternate orbits: [epoch=2013-Mar-13.0] K084/11 [epoch=2010-Nov-19.0] K193/20 (default) [epoch=1994-Jan-08.0] SAO/1994 [epoch=1987-Sep-02.0] SAO/1987 [epoch=1981-Mar-17.0] SAO/1981 [epoch=1974-Sep-30.0] SAO/1974 [epoch=1968-Mar-05.0] SAO/1968 [epoch=1961-Sep-18.0] SAO/1961 [epoch=1955-Feb-22.0] SAO/1955 [epoch=1948-Sep-06.0] SAO/1948 [epoch=1942-Feb-10.0] SAO/1942 [epoch=1935-Aug-26.0] SAO/1935 [epoch=1929-Mar-10.0] SAO/1929 Orbital Elements at Epoch 2455519.5 (2010-Nov-19.0) TDB Reference: JPL K193/20 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1928816065088364 9.1075e-08   a 4.242644592056441 5.1974e-08 au q 3.424316487294568 3.8807e-07 au i 4.546588725017729 1.037e-05 deg node 114.1883629970298 0.00010925 deg peri 17.92942925321878 0.00012863 deg M 5.700608668425044 5.0739e-05 deg tp 2455468.955706155045 (2010-Sep-29.45570615) 0.00044978 TDB period 3191.930343327873 8.74 5.8654e-05 1.606e-07 d yr n .1127844160987134 2.0725e-09 deg/d Q 5.060972696818314 6.1999e-08 au Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A2 [EST] -5.324836119346194E-8 1.489E-9   Orbit Determination Parameters    # obs. used (total)      1004      data-arc span      7121 days (19.50 yr)      first obs. used      2000-11-24      last obs. used      2020-05-24      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .75926      source      ORB      producer      Shantanu Naidu      solution date      2021-Mar-23 23:56:05   Additional Information  Earth MOID = 2.44007 au   Jupiter MOID = .0555264 au   T_jup = 2.993  [ 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 5.1   0.7 K193/20 2 parameter fit from 606 observations, autocmod 2.9b comet total magnitude slope K1 21.25   n/a K193/20 autocmod 2.9b comet nuclear magnitude M2 14.0   0.6 K193/20 from 291 observations, autocmod 2.9b comet nuclear magnitude slope K2 5.   n/a K193/20 autocmod 2.9b comet nuclear phase coefficient PC 0.03   n/a K193/20 autocmod 2.9b 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   1993.3       1994 II     1984.5       1981 VI   1986h   1975.8       1974 XIII   1979k   1967.0       1968 II   1967i   1958.3       1955 I   1960j   1949.6       1948 VII   1947l   1940.8       1942 I   1941f   1932.1   31P/1929 B1   1929 I   1929a  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-18 12:22 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin