+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   111P/Helin-Roman-Crockett Classification: Encke-type Comet          SPK-ID: 1000118 [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2456320.5 (2013-Jan-28.0) TDB Reference: JPL 8 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1096207704078609 5.5397e-07   a 4.160365902658368 7.3931e-07 AU q 3.704303387230362 2.0858e-06 AU i 4.228807042165645 4.2346e-05 deg node 89.79399820609125 0.00043835 deg peri 3.37794152502789 0.00045992 deg M 359.6946225231546 0.00017503 deg tp 2456323.129239941113 (2013-Jan-30.62923994) 0.0015075 JED period 3099.529109280249 8.49 0.00082619 2.262e-06 d yr n .1161466749649584 3.0959e-08 deg/d Q 4.616428418086374 8.2035e-07 AU Additional Model Parameters  Parameter Value Uncertainty (1-sigma)  A2 [EST] -1.134125358309937E-7 5.669E-9   Orbit Determination Parameters    # obs. used (total)      137      data-arc span      8753 days (23.96 yr)      first obs. used      1989-01-03      last obs. used      2012-12-21      planetary ephem.      DE405      SB-pert. ephem.      SB405-CPV-2      condition code      1      fit RMS      .79086      data source      ORB      producer      Alan B. Chamberlin      solution date      2013-Jan-28 09:17:54   Additional Information  Earth MOID = 2.72099 AU   T_jup = 3.023  [ 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 11.5 mag n/a ICQ 2005 Handbook   comet total magnitude slope K1 10.0   n/a ICQ 2005 Handbook   diameter diameter 1.2 km n/a Lamy,P.L.,Toth,I.,Fernandez,Y.R.,Weaver,H.A. (2004) Comets II, pp. 223-264   111P/Helin-Roman-Crockett          Discovered 1989-Jan-02 by Helin, Eleanor at Palomar Mountain Observatory (675) discovered on plate/photo taken on discovery date as well as 1/3,5 Reference: comet.dis Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  Perihelion  Year (est.)  New-Style  Desig Roman  Numeral  Year/  Letter   1987.6   111P/1989 A2   1988 XIII   1989b  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2013-May-20 09:13 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin