+ 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 31 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1736397543355195 3.594e-08   a 2.437593045140904 6.3186e-09 au q 2.014329987612666 8.7595e-08 au i 1.95534852216829 4.1687e-06 deg node 309.0740400738145 0.00010201 deg peri 345.4243593547822 0.00010275 deg M 65.41541939179901 1.2127e-05 deg tp 2458947.909007516302 (2020-Apr-08.40900752) 4.6918e-05 TDB period 1390.081392729422 3.81 5.4049e-06 1.48e-08 d yr n .2589776410812469 1.007e-09 deg/d Q 2.860856102669141 7.4157e-09 au   Orbit Determination Parameters    # obs. used (total)      2207      data-arc span      14610 days (40.00 yr)      first obs. used      1981-02-12      last obs. used      2021-02-12      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .50407      source      ORB      producer      Otto Matic      solution date      2021-Apr-12 20:06:23   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-May-08 20:39 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin