+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   15420 Aedouglass (1998 HQ31) Classification: Main-belt Asteroid          SPK-ID: 2015420 [ 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 22 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2725697167370775 4.2549e-08   a 2.643096027212701 1.1802e-08 au q 1.92266809176644 1.1424e-07 au i 3.293918654503608 5.0013e-06 deg node 305.8437535943538 8.4025e-05 deg peri 358.8628006597665 8.4546e-05 deg M 17.21363374922576 8.5679e-06 deg tp 2459125.452211795297 (2020-Oct-02.95221180) 3.7262e-05 TDB period 1569.523561805085 4.30 1.0513e-05 2.878e-08 d yr n .2293689682402534 1.5363e-09 deg/d Q 3.363523962658962 1.5019e-08 au   Orbit Determination Parameters    # obs. used (total)      915      data-arc span      9150 days (25.05 yr)      first obs. used      1995-11-24      last obs. used      2020-12-12      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .55172      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 02:23:52   Additional Information  Earth MOID = .905544 au   Jupiter MOID = 1.90089 au   T_jup = 3.338  [ 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 15.13   n/a E2021B10   15420 Aedouglass           Discovered 1998 Apr. 28 by Spacewatch at Kitt Peak. Andrew Ellicott Douglass (1867-1962) was an American astronomer and developer of dendochronology. For Percival Lowell, he sited Lowell Observatory. Later he directed the Steward Observatory at the University of Arizona and in 1923 dedicated the 0.9-m telescope, which became the Spacewatch telescope in 1983. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: 20040713/MPCPages.arc Last Updated: 2004-07-14 [ show close-approach data ] Alternate Designations  1998 HQ31 = 1999 TW119  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-12 20:52 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin