{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.681","julian_year":2026.681,"time":"2026-09-06T17:55:15.050Z","years_from_j2000":26.681,"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-187123-c","name":"HD 187123 c","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":149.884511066974,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":296.7428786,"dec_deg":34.41899,"epoch_ra_deg":296.994856,"epoch_dec_deg":34.484539,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 187123","semi_major_axis_km":731533587.7229999,"periapsis_km":null,"mass_kg":5.447617601301789e+27,"mass_msun":0.00273969,"constellation":"Cygnus","discovered":"2008","featured":false,"url":"https://spacecatalog.org/object/hd-187123-c","radius_km":84190.92,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 187123","host_v_mag":7.83,"eccentricity":0.252,"uncertainties":{"mass_kg":[7.972123318978228e+26,7.592498399026883e+26],"distance_ly":[0.23287565368975482,0.23352796644518828],"eccentricity":[0.033,0.033],"host_mass_solar":[0.159473,0.112096],"inclination_deg":[9.1,5.8],"host_radius_solar":[0.064626,0.055043],"host_temperature_k":[115.06,157.71],"semi_major_axis_km":[79286871.471,79286871.471],"orbital_period_days":[420,420],"argument_of_periastron_deg":[19,19]},"host_mass_solar":1.04,"inclination_deg":137.2,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":1.15043,"planets_in_system":2,"discovery_facility":"W. M. Keck Observatory","host_spectral_type":"G3 V","host_temperature_k":5790,"orbital_period_days":3810,"periastron_epoch_bjd":2453580.04,"transit_midpoint_bjd":2458871,"equilibrium_temperature_k":135.42,"argument_of_periastron_deg":243},"designations":[{"catalog":"Exoplanet","designation":"HD 187123 c"},{"catalog":"Host star","designation":"HD 187123"}],"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."}