{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.688","julian_year":2026.688,"time":"2026-09-09T04:12:33.811Z","years_from_j2000":26.688,"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":"hip-54373-b","name":"HIP 54373 b","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":61.04603690448743,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":166.8643532,"dec_deg":-19.2916857,"epoch_ra_deg":167.196071,"epoch_dec_deg":-19.436953,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HIP 54373","semi_major_axis_km":9424665.8541,"periapsis_km":null,"mass_kg":5.148008702036168e+25,"mass_msun":0.0000258901,"constellation":"Crater","discovered":"2019","featured":false,"url":"https://spacecatalog.org/object/hip-54373-b","radius_km":18305.147,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HIP 54373","host_v_mag":10.38,"eccentricity":0.2,"uncertainties":{"mass_kg":[1.0988788876736138e+25,1.0988788876736138e+25],"distance_ly":[0.05348964594554592,0.05348964594554592],"eccentricity":[0.11,0.11],"host_mass_solar":[0.03,0.03],"host_radius_solar":[0.016704,0.016704],"host_temperature_k":[146,226],"semi_major_axis_km":[149597.8707,149597.8707],"orbital_period_days":[0.003,0.003],"argument_of_periastron_deg":[44.58,44.58]},"host_mass_solar":0.57,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":0.564998,"planets_in_system":2,"discovery_facility":"Las Campanas Observatory","host_spectral_type":"K5 V","host_temperature_k":4021,"orbital_period_days":7.76,"equilibrium_temperature_k":580.66,"argument_of_periastron_deg":72.34},"designations":[{"catalog":"Exoplanet","designation":"HIP 54373 b"}],"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":"2026-09-02T19:50:56.720Z","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."}