{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.683","julian_year":2026.683,"time":"2026-09-07T08:29:06.485Z","years_from_j2000":26.683,"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":"hd-77946-b","name":"HD 77946 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":324.3657792030785,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":136.777644,"dec_deg":46.6724251,"epoch_ra_deg":137.231606,"epoch_dec_deg":46.564592,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 77946","semi_major_axis_km":10920644.561099999,"periapsis_km":null,"mass_kg":6.509662975892603e+25,"mass_msun":0.000032738,"constellation":"Ursa Major","discovered":"2024","featured":false,"url":"https://spacecatalog.org/object/hd-77946-b","radius_km":18473.919434844,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 77946","host_v_mag":8.99,"eccentricity":0.211,"uncertainties":{"mass_kg":[1.0152685375245345e+25,1.0749902162024483e+25],"radius_km":[907.956275149,1191.1478057900001],"distance_ly":[1.1764460544242936,1.1845999638672122],"eccentricity":[0.072,0.072],"host_mass_solar":[0.0289,0.0308],"inclination_deg":[1.05,1.31],"host_radius_solar":[0.0142,0.0249],"host_temperature_k":[88,83],"semi_major_axis_km":[1495978.707,149597.8707],"orbital_period_days":[0.000027,0.000027],"argument_of_periastron_deg":[32,32]},"host_mass_solar":1.1973,"inclination_deg":87.79,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.3174,"planets_in_system":1,"discovery_facility":"Transiting Exoplanet Survey Satellite (TESS)","host_spectral_type":"F5","host_temperature_k":6007,"orbital_period_days":6.527363,"transit_midpoint_bjd":2458875.9989,"equilibrium_temperature_k":1128.86,"argument_of_periastron_deg":9.2},"designations":[{"catalog":"Exoplanet","designation":"HD 77946 b"},{"catalog":"Host star","designation":"HD 77946"}],"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."}