+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   7861 Messenger (1981 EK25) Classification: Main-belt Asteroid          SPK-ID: 2007861 [ 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 30 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1736397493863122 3.6355e-08   a 2.437593040715584 6.3475e-09 au q 2.014329996019911 8.8545e-08 au i 1.95534860350594 4.1809e-06 deg node 309.0740384943005 0.0001024 deg peri 345.4243609520597 0.00010314 deg M 65.41542012883394 1.2133e-05 deg tp 2458947.909005358210 (2020-Apr-08.40900536) 4.6942e-05 TDB period 1390.081388943995 3.81 5.4297e-06 1.487e-08 d yr n .2589776417864869 1.0116e-09 deg/d Q 2.860856085411257 7.4497e-09 au   Orbit Determination Parameters    # obs. used (total)      2180      data-arc span      14579 days (39.92 yr)      first obs. used      1981-02-12      last obs. used      2021-01-12      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .50544      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 01:39:51   Additional Information  Earth MOID = .996391 au   Jupiter MOID = 2.32997 au   T_jup = 3.482  [ 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 14.52   n/a E2021B10   diameter diameter 2.822 km 0.438 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.321   0.101 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   7861 Messenger           Discovered 1981 Mar. 2 by S. J. Bus at Siding Spring in the course of the U.K. Schmidt-Caltech Asteroid Survey. Scott R. Messenger (b. 1969) is a space scientist at NASA's Johnson Space Center. He pioneered research on the identification of pre-solar molecular cloud material in interplanetary dust particles. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: 20060809/MPCPages.arc Last Updated: 2007-08-08 [ show close-approach data ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Mar-01 02:40 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin