{"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":"2026-09-02T20:40:35.837Z","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":"k2-3-c","name":"K2-3 c","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":143.74592188196718,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":172.3353708,"dec_deg":-1.4551364,"epoch_ra_deg":172.678813,"epoch_dec_deg":-1.603039,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-3","semi_major_axis_km":20300431.053989995,"periapsis_km":null,"mass_kg":1.6005409885680896e+25,"mass_msun":0.00000804935,"constellation":"Leo","discovered":"2015","featured":false,"url":"https://spacecatalog.org/object/k2-3-c","radius_km":10090.1542,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-3","host_v_mag":12.168,"eccentricity":0.048,"uncertainties":{"mass_kg":[5.076342687622672e+24,5.076342687622672e+24],"radius_km":[325.2831,363.55170000000004],"distance_ly":[0.352738122500658,0.352738122500658],"eccentricity":[0.035,0.073],"host_mass_solar":[0.027,0.029],"inclination_deg":[0.14,0.11],"host_radius_solar":[0.016,0.018],"host_temperature_k":[63,61],"semi_major_axis_km":[329115.31554,344075.10260999994],"orbital_period_days":[0.000042,0.000044],"argument_of_periastron_deg":[110,100]},"host_mass_solar":0.549,"inclination_deg":89.84,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.546,"planets_in_system":3,"discovery_facility":"K2","host_spectral_type":"M V","host_temperature_k":3844,"orbital_period_days":24.646729,"transit_midpoint_bjd":2457329.85688,"equilibrium_temperature_k":371.8,"argument_of_periastron_deg":-180},"designations":[{"catalog":"Exoplanet","designation":"K2-3 c"},{"catalog":"Host star","designation":"K2-3"}],"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."}