+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   78P/Gehrels 2 Classification: Jupiter-family Comet          SPK-ID: 1000030 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] alternate orbits: [epoch=2014-Nov-09.0] K192/21 (default) [epoch=2008-Aug-26.0] K122/1 [epoch=2006-Mar-09.0] K043/41 [epoch=1989-Nov-10.0] J974/3 [epoch=1981-Nov-12.0] SAO/1981 [epoch=1973-Nov-14.0] SAO/1973 Orbital Elements at Epoch 2456970.5 (2014-Nov-09.0) TDB Reference: JPL K192/21 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .461659097412254 1.8094e-07   a 3.736357716665463 3.4865e-07 au q 2.011434185580375 8.5811e-07 au i 6.252793881955874 5.3943e-06 deg node 210.5626387396034 4.1175e-05 deg peri 192.7561165891618 4.9985e-05 deg M 140.8164144526972 1.3612e-05 deg tp 2455938.637377991260 (2012-Jan-12.13737799) 0.00011084 TDB period 2637.977577876264 7.22 0.00036924 1.011e-06 d yr n .1364681804042559 1.9101e-08 deg/d Q 5.461281247750552 5.0961e-07 au Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A1 [EST] -9.097066926152616E-10 1.094E-10 A2 [EST] 3.480228545313418E-10 1.129E-11 ALN [SET] .0408373333128795 n/a NK [SET] 2.6 n/a NM [SET] 2. n/a NN [SET] 3. n/a R0 [SET] 5. n/a   Orbit Determination Parameters    # obs. used (total)      5533      data-arc span      3311 days (9.07 yr)      first obs. used      2011-05-03      last obs. used      2020-05-26      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .60238      source      ORB      producer      Javier Roa      solution date      2021-Feb-03 22:22:20   Additional Information  Earth MOID = 1.02031 au   Jupiter MOID = .0215841 au   T_jup = 2.887  [ 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 8.8   0.8 K192/21 2 parameter fit from 1810 observations, autocmod 2.8 comet total magnitude slope K1 13.75   n/a K192/21 autocmod 2.8 comet nuclear magnitude M2 12.6   0.7 K192/21 from 3507 observations, autocmod 2.8 comet nuclear magnitude slope K2 5.   n/a K192/21 autocmod 2.8 comet nuclear phase coefficient PC 0.03   n/a K192/21 autocmod 2.8 78P/Gehrels 2          Discovered 1973-Sep-29 by Gehrels, Tom discovered on plate/photo taken on discovery date as well as 9/30, 10/4 Reference: comet.dis Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  Perihelion  Year (est.)  New-Style  Desig Roman  Numeral  Year/  Letter   1990.4       1989 XVII   1989n   1983.1   78P/1981 L1   1981 XVII   1981f   1975.9   78P/1973 S1   1973 XI   1973n  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Mar-07 09:59 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin