+ View the NASA Portal + Near-Earth Object (NEO) Program Search JPL JPL Small-Body Database Browser Search: [ help ]   7173 Sepkoski (1988 PL1) Classification: Inner Main-belt Asteroid          SPK-ID: 2007173 [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2456400.5 (2013-Apr-18.0) TDB Reference: MPO250280 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e 0.0131016 n/a   a 1.9561416 n/a AU q 1.9305130 n/a AU i 19.58732 n/a deg node 247.09981 n/a deg peri 93.47551 n/a deg M 354.00989 n/a deg tp 2456417.1276613 (2013-May-04.62766130) n/a JED period 999.3068697 2.74 n/a n/a d yr n 0.36024970 n/a deg/d Q 1.9817702 n/a AU   Orbit Determination Parameters    # obs. used (total)      538      first obs. used      1983-??-??      last obs. used      2012-07-24      # oppositions      14      planetary ephem.      DE403      condition code      0      fit RMS      0.47      data source      MPC:mpn      producer      MPCLINUX   Additional Information  T_jup = 3.815  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 14.1 mag n/a PDS3 (MPC 27898)   rotation period rot_per 2.50 h n/a Asteroid Lightcurve DataBase (Rev. 2013-May-01) Result based on less than full coverage, so that the period may be wrong by 30 percent or so. Published Reference List: [Warner, B.D (2011) Minor Planet Bul. 38, 25-31.] [Han, X.L.; Li, B.; Zhao, H. (2013) Minor Planet Bul. 40, 14-15.] 7173 Sepkoski           Discovered 1988 Aug. 15 by C. S. Shoemaker and E. M. Shoemaker at Palomar. Named in memory of paleontologist J. John Sepkoski Jr. (1948-1999). His far-reaching work made a major contribution to quantifying the nature of life's diversity through time. The compilation of a huge database, begun while he was at the University of Rochester and continued at the University of Chicago, enabled researchers to combine mathematical modeling and paleoecology with massive data arrays. Together with his colleague David Raup, Sepkoski developed the theory that catastrophic extinction events have a 26-million-year periodicity. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: 19990728/MPCPages.arc Last Updated: 2010-06-11 Alternate Designations  1988 PL1 = 1983 WY  [ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances ] 2013-May-18 05:32 UT (server date/time)   Site Manager:   Donald K. Yeomans Webmaster:   Alan B. Chamberlin