{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.687","julian_year":2026.687,"time":"2026-09-09T01:45:00.078Z","years_from_j2000":26.687,"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-21693-c","name":"HD 21693 c","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":108.46330340970303,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":51.8040469,"dec_deg":-58.3232726,"epoch_ra_deg":51.960281,"epoch_dec_deg":-58.229098,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 21693","semi_major_axis_km":38686009.363019995,"periapsis_km":null,"mass_kg":1.0373655586353626e+26,"mass_msun":0.0000521706,"constellation":"Reticulum","discovered":"2019","featured":false,"url":"https://spacecatalog.org/object/hd-21693-c","radius_km":27680.954,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 21693","host_v_mag":7.95,"eccentricity":0.07,"uncertainties":{"mass_kg":[1.069018048334657e+25,1.0570737125990742e+25],"distance_ly":[0.1135024194454267,0.11382857582314346],"eccentricity":[0.05,0.06],"host_radius_solar":[0.022886,0.007868],"host_temperature_k":[26,26],"semi_major_axis_km":[1690455.9389099998,1540858.06821],"orbital_period_days":[0.0309,0.0312],"argument_of_periastron_deg":[55.35,47.5]},"host_mass_solar":0.8,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":0.914378,"planets_in_system":2,"discovery_facility":"La Silla Observatory","host_spectral_type":"G8 V","host_temperature_k":5430,"orbital_period_days":53.7357,"periastron_epoch_bjd":2455528.4064,"equilibrium_temperature_k":492.36,"argument_of_periastron_deg":-17.34},"designations":[{"catalog":"Exoplanet","designation":"HD 21693 c"},{"catalog":"Host star","designation":"HD 21693"}],"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."}