{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.667","julian_year":2026.667,"time":"2026-09-01T10:39:27.705Z","years_from_j2000":26.667,"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-154-d","name":"Kepler-154 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":2985.0223076289617,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":289.7805393,"dec_deg":49.8965624,"epoch_ra_deg":289.956537,"epoch_dec_deg":49.945181,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"Kepler-154","semi_major_axis_km":21473278.360278,"periapsis_km":null,"mass_kg":8.420756693585844e+25,"mass_msun":0.0000423492,"constellation":"Cygnus","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/kepler-154-d","radius_km":24491.904000000002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"Kepler-154","host_v_mag":14.646,"eccentricity":0,"uncertainties":{"radius_km":[1530.7440000000001,2040.9920000000002],"distance_ly":[53.2515517898127,55.18565910967299],"host_mass_solar":[0.044,0.04],"host_radius_solar":[0.059,0.082],"host_temperature_k":[70.85,78.25],"semi_major_axis_km":[234868.65699899997,234868.65699899997],"orbital_period_days":[0.00002572,0.00002572]},"host_mass_solar":0.98,"inclination_deg":88.38,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.98,"planets_in_system":5,"discovery_facility":"Kepler","host_temperature_k":5769,"orbital_period_days":20.54981883,"transit_midpoint_bjd":2455011.94612,"equilibrium_temperature_k":657},"designations":[{"catalog":"Exoplanet","designation":"Kepler-154 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."}