+ 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 2459000.5 (2020-May-31.0) TDB Reference: JPL 29 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1738762033186803 3.678e-08   a 2.438387619948785 6.4452e-09 au q 2.014410038372817 8.9743e-08 au i 1.955299692097872 4.3029e-06 deg node 309.0739714220306 0.00010259 deg peri 345.4783519721777 0.00010333 deg M 13.57168699268721 1.215e-05 deg tp 2458948.069514653179 (2020-Apr-08.56951465) 4.696e-05 TDB period 1390.761129034731 3.81 5.5141e-06 1.51e-08 d yr n .2588510654233348 1.0263e-09 deg/d Q 2.862365201524752 7.5659e-09 au   Orbit Determination Parameters    # obs. used (total)      2101      data-arc span      14519 days (39.75 yr)      first obs. used      1981-02-12      last obs. used      2020-11-13      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .50731      source      ORB      producer      Otto Matic      solution date      2020-Dec-18 02:32:47   Additional Information  Earth MOID = .998443 au   Jupiter MOID = 2.32949 au   T_jup = 3.481  [ 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 14.5   n/a MPO473874   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-Jan-22 11:04 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin