{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.677","julian_year":2026.677,"time":"2026-09-05T05:09:22.724Z","years_from_j2000":26.677,"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":"k2-104-b","name":"K2-104 b","class":"super_earth","category":"exoplanet","object_type":"Super-Earth","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":617.3781458162464,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":129.6366594,"dec_deg":19.7737202,"epoch_ra_deg":130.022497,"epoch_dec_deg":19.679704,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-104","semi_major_axis_km":3620268.4709399994,"periapsis_km":null,"mass_kg":2.305256796967472e+25,"mass_msun":0.0000115935,"constellation":"Cancer","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/k2-104-b","radius_km":11416.799,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-104","host_v_mag":15.989,"eccentricity":0.09,"uncertainties":{"radius_km":[382.68600000000004,637.8100000000001],"distance_ly":[12.514620212991446,13.033208853561067],"eccentricity":[0.07267,0.167783],"host_mass_solar":[0.02,0.02],"inclination_deg":[0.45,0.45],"host_radius_solar":[0.01,0.01],"host_temperature_k":[76,54],"semi_major_axis_km":[822788.2888499999,329115.31554],"orbital_period_days":[0.0000024,0.0000024],"argument_of_periastron_deg":[63,155]},"host_mass_solar":0.51,"inclination_deg":88.75,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.48,"planets_in_system":1,"discovery_facility":"K2","host_spectral_type":"M2.5e","host_temperature_k":3712,"orbital_period_days":1.9741954,"transit_midpoint_bjd":2457140.379979,"equilibrium_temperature_k":798,"argument_of_periastron_deg":0},"designations":[{"catalog":"Exoplanet","designation":"K2-104 b"},{"catalog":"Host star","designation":"K2-104"}],"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."}