{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.679","julian_year":2026.679,"time":"2026-09-06T04:27:14.542Z","years_from_j2000":26.679,"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-21749-c","name":"HD 21749 c","class":"terrestrial_planet","category":"exoplanet","object_type":"Terrestrial planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":53.22872084337253,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":51.7501882,"dec_deg":-63.500166,"epoch_ra_deg":51.861956,"epoch_dec_deg":-63.405895,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"GJ 143","semi_major_axis_km":10397052.01365,"periapsis_km":null,"mass_kg":2.2097021110828105e+25,"mass_msun":0.0000111129,"constellation":"Reticulum","discovered":"2019","featured":false,"url":"https://spacecatalog.org/object/hd-21749-c","radius_km":5689.265200000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"GJ 143","host_v_mag":8.08,"uncertainties":{"radius_km":[369.92980000000006,408.19840000000005],"distance_ly":[0.023157102817888783,0.023157102817888783],"host_mass_solar":[0.07,0.07],"inclination_deg":[0.37,0.5],"host_radius_solar":[0.03,0.03],"host_temperature_k":[100,100],"semi_major_axis_km":[344075.10260999994,314155.52846999996],"orbital_period_days":[0.00044,0.00051]},"host_mass_solar":0.73,"inclination_deg":88.9,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.695,"planets_in_system":2,"discovery_facility":"Transiting Exoplanet Survey Satellite (TESS)","host_spectral_type":"K4.5","host_temperature_k":4640,"orbital_period_days":7.78993,"periastron_epoch_bjd":2458332.2789,"transit_midpoint_bjd":2458371.2287,"equilibrium_temperature_k":701},"designations":[{"catalog":"Exoplanet","designation":"HD 21749 c"}],"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."}