+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   12923 Zephyr (1999 GK4) Classification: Apollo [NEO, PHA]          SPK-ID: 2012923 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 311 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .4921006699433406 3.549e-08   a 1.96169731829936 3.013e-09 au q .9963447537381902 7.0161e-08 au i 5.305137601794454 3.7257e-06 deg node 168.1880790613438 3.3889e-05 deg peri 147.0837953084005 3.4261e-05 deg M 269.610483127831 6.0951e-06 deg tp 2459452.477631150525 (2021-Aug-25.97763115) 1.7298e-05 TDB period 1003.567120980144 2.75 2.3121e-06 6.33e-09 d yr n .3587204009318303 8.2645e-10 deg/d Q 2.927049882860529 4.4957e-09 au   Orbit Determination Parameters    # obs. used (total)      1772      data-arc span      24162 days (66.15 yr)      first obs. used      1955-04-21      last obs. used      2021-06-15      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .47228      source      ORB      producer      Otto Matic      solution date      2021-Jun-16 06:20:21   Additional Information  Earth MOID = .0204189 au   Jupiter MOID = 2.41057 au   T_jup = 3.717  [ 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 absolute magnitude H 15.75   n/a E2021B10   diameter diameter 2.060 km 0.013 urn:nasa:pds:neowise_diameters_albedos::2.0[neos] (http://adsabs.harvard.edu/abs/2011ApJ...743..156M)   rotation period rot_per 3.891 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Pravec, P.; Wolf, M.; Sarounova, L. (1999) http://www.asu.cas.cz/~ppravec/neo.htm] geometric albedo albedo 0.199   0.034 urn:nasa:pds:neowise_diameters_albedos::2.0[neos] (http://adsabs.harvard.edu/abs/2011ApJ...743..156M)   SMASSII spectral type spec_B S:   n/a Binzel et al. (2004) Icarus 170, 259-294 SMASSIR data only, classification consistent with specified type, but uncertain 12923 Zephyr           Discovered 1999 Apr. 11 by the Lowell Observatory Near-Earth Object Search at the Anderson Mesa Station. The word zephyr derives from the name of the ancient Greek god of the west wind, Zephyros. The name was suggested by M. Smitherman. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: 20040928/MPCPages.arc Last Updated: 2004-09-28 [ show close-approach data ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Jun-17 01:02 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin