{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.668","julian_year":2026.668,"time":"2026-09-01T20:29:14.177Z","years_from_j2000":26.668,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued J2000 position is carried along the great circle the object's own published motion puts it on, at a constant velocity, and the result is referred to the true equator and equinox of this instant. Those are separate things: the motion moves the object, and the rotation turns the grid under it by about fifty arcseconds a year, with nutation adding up to another seventeen.","excluded":"Parallax, the radial-velocity perspective term, aberration and refraction; each is below the accuracy of the catalogued positions themselves. An object with no published proper motion comes back where the catalogue has it rather than at a fabricated zero, and says so with a null pm_ra_mas_yr. A body with no fixed position is not propagated at all — its place comes from an ephemeris, which is what /api/v1/visible answers with."},"slug":"pi-men-d","name":"π Men d","class":"neptune_like_planet","category":"exoplanet","object_type":"Neptune-like planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":59.589422521604455,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":84.2992798,"dec_deg":-80.4646041,"epoch_ra_deg":83.76057,"epoch_dec_deg":-80.446758,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 39091","semi_major_axis_km":75696522.57419999,"periapsis_km":null,"mass_kg":7.990760607104866e+25,"mass_msun":0.0000401867,"constellation":"Mensa","discovered":"2022","featured":false,"url":"https://spacecatalog.org/object/pi-men-d","radius_km":23726.532000000003,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 39091","host_v_mag":5.65,"eccentricity":0.22,"uncertainties":{"mass_kg":[8.062426621518362e+24,8.062426621518362e+24],"distance_ly":[0.07371134136398401,0.07371134136398401],"eccentricity":[0.079,0.079],"host_mass_solar":[0.04,0.04],"host_radius_solar":[0.004,0.004],"host_temperature_k":[62,62],"semi_major_axis_km":[1944772.3190999997,1795174.4483999999],"orbital_period_days":[0.52,0.48],"argument_of_periastron_deg":[73,25]},"host_mass_solar":1.07,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":1.19,"planets_in_system":3,"discovery_facility":"La Silla Observatory","host_spectral_type":"G0 V","host_temperature_k":5998,"orbital_period_days":124.64,"periastron_epoch_bjd":2457595.46,"transit_midpoint_bjd":2455218.6,"equilibrium_temperature_k":443.55,"argument_of_periastron_deg":323},"designations":[{"catalog":"Exoplanet","designation":"pi Men d"}],"source":{"id":"exoplanet_archive","name":"NASA Exoplanet Archive (Planetary Systems Composite Parameters)","url":"https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=PSCompPars","license":"Public domain (NASA)"},"updated_at":"2026-08-30T09:56:50.739Z","attribution":"Data from SpaceCatalog.org. Individual records carry their source and license in `source`; attribution is required for CC-BY and CC-BY-SA rows."}