{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T18:13:06.681Z","years_from_j2000":26.67,"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":"kepler-981-b","name":"Kepler-981 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":2863.920444582735,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":289.2489051,"dec_deg":47.6501141,"epoch_ra_deg":289.437229,"epoch_dec_deg":47.697452,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-981","semi_major_axis_km":8003486.08245,"periapsis_km":null,"mass_kg":3.5534398813358707e+25,"mass_msun":0.0000178708,"constellation":"Cygnus","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/kepler-981-b","radius_km":14733.411000000002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-981","host_v_mag":14.875,"eccentricity":0,"uncertainties":{"radius_km":[1148.058,1913.43],"distance_ly":[46.27669765234014,46.27669765234014],"host_mass_solar":[0.052,0.045],"host_radius_solar":[0.072,0.124],"host_temperature_k":[82.87,78.23],"orbital_period_days":[0.000005863,0.000005863]},"host_mass_solar":0.98,"inclination_deg":88.32,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.96,"planets_in_system":1,"discovery_facility":"Kepler","host_temperature_k":5718,"orbital_period_days":4.469757736,"transit_midpoint_bjd":2454964.84366,"equilibrium_temperature_k":1103},"designations":[{"catalog":"Exoplanet","designation":"Kepler-981 b"},{"catalog":"Host star","designation":"Kepler-981"}],"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":"2026-09-01T22:58:55.274Z","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."}