+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   87P/Bus Classification: Encke-type Comet          SPK-ID: 1000010 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] alternate orbits: [epoch=2016-Mar-20.0] K203/18 (default) [epoch=2003-Aug-14.0] K075/1 [epoch=2001-Jan-11.0] SAO/2000 [epoch=1994-Jun-17.0] SAO/1994 [epoch=1987-Dec-31.0] SAO/1987 [epoch=1981-Jun-05.0] SAO/1981 Orbital Elements at Epoch 2457467.5 (2016-Mar-20.0) TDB Reference: JPL K203/18 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .3893476920698341 5.0921e-07   a 3.440869358876915 2.8337e-07 au q 2.101174815284378 1.7475e-06 au i 2.6023944932398 2.6702e-05 deg node 181.8898060895848 0.00031244 deg peri 24.75638615410691 0.00066668 deg M 126.7935222833317 0.00024799 deg tp 2456646.401481615152 (2013-Dec-19.90148162) 0.0016097 TDB period 2331.313629398277 6.38 0.00028799 7.885e-07 d yr n .1544193777535276 1.9076e-08 deg/d Q 4.780563902469451 3.9371e-07 au Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A1 [EST] 1.255996545216359E-8 1.286E-9 A2 [EST] -2.017205026726924E-9 4.033E-11 A3 [EST] 5.855153256434009E-9 2.393E-10   Orbit Determination Parameters    # obs. used (total)      667      data-arc span      7602 days (20.81 yr)      first obs. used      1999-11-13      last obs. used      2020-09-05      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      1      norm. resid. RMS      .70867      source      ORB      producer      Davide Farnocchia      solution date      2020-Sep-28 09:20:31   Additional Information  Earth MOID = 1.0978 au   Jupiter MOID = .180999 au   T_jup = 3.009  [ 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 12.7   0.7 K203/18 2 parameter fit from 461 observations, autocmod 2.9a comet total magnitude slope K1 14.   n/a K203/18 autocmod 2.9a comet nuclear magnitude M2 16.1   0.7 K203/18 from 165 observations, autocmod 2.9a comet nuclear magnitude slope K2 5.   n/a K203/18 autocmod 2.9a comet nuclear phase coefficient PC 0.03   n/a K203/18 autocmod 2.9a diameter diameter 0.56 km n/a DASTCOM value unverified 87P/Bus          Discovered 1981-Mar-02 by Bus, Schelte J. at U. K. Schmidt Telescope Unit, Siding Spring 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   1994.8       1994 XVI   1993b   1988.4   87P/1987 B4   1987 XXXIV   1987f   1982.1   87P/1981 E1   1981 XI   1981b  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Mar-07 09:08 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin