{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.682","julian_year":2026.682,"time":"2026-09-07T01:15:53.422Z","years_from_j2000":26.682,"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-147873-c","name":"HD 147873 c","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":355.68983771899457,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":246.4380471,"dec_deg":-33.5672217,"epoch_ra_deg":246.872909,"epoch_dec_deg":-33.628599,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 147873","semi_major_axis_km":203453104.152,"periapsis_km":null,"mass_kg":4.365708460866308e+27,"mass_msun":0.00219558,"constellation":"Scorpius","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/hd-147873-c","radius_km":84828.73000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 147873","host_v_mag":7.96,"eccentricity":0.23,"uncertainties":{"mass_kg":[3.416641404156241e+26,3.416641404156241e+26],"distance_ly":[3.268086904721769,3.33005661648795],"eccentricity":[0.03,0.03],"host_mass_solar":[0.05,0.05],"host_radius_solar":[0.1,0.1],"host_temperature_k":[100,100],"semi_major_axis_km":[7479893.535,7479893.535],"orbital_period_days":[0.79,0.79],"argument_of_periastron_deg":[11.46,11.46]},"host_mass_solar":1.38,"stars_in_system":2,"discovery_method":"Radial Velocity","host_radius_solar":2.29,"planets_in_system":2,"discovery_facility":"Multiple Observatories","host_spectral_type":"G1 V","host_temperature_k":5972,"orbital_period_days":491.54,"equilibrium_temperature_k":373.68,"argument_of_periastron_deg":41.83},"designations":[{"catalog":"Exoplanet","designation":"HD 147873 c"},{"catalog":"Host star","designation":"HD 147873"}],"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."}