{"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":"2026-09-05T05:35:00.039Z","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":"hd-39194-d","name":"HD 39194 d","class":"neptune_like_planet","category":"exoplanet","object_type":"Neptune-like planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":86.14801020270116,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":86.129071,"dec_deg":-70.1382377,"epoch_ra_deg":86.06081,"epoch_dec_deg":-70.125771,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 39194","semi_major_axis_km":29156624.999429997,"periapsis_km":null,"mass_kg":3.0816386197803517e+25,"mass_msun":0.000015498,"constellation":"Mensa","discovered":"2021","featured":false,"url":"https://spacecatalog.org/object/hd-39194-d","radius_km":13521.572000000002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 39194","host_v_mag":8.09,"uncertainties":{"mass_kg":[3.523579041996914e+24,3.523579041996914e+24],"distance_ly":[0.086431440094937,0.086431440094937],"host_mass_solar":[0.04,0.04],"host_radius_solar":[0.063077,0.038862],"host_temperature_k":[23,23],"semi_major_axis_km":[463753.39916999993,463753.39916999993],"orbital_period_days":[0.024,0.024],"argument_of_periastron_deg":[190,80]},"host_mass_solar":0.86,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":0.783742,"planets_in_system":3,"discovery_facility":"La Silla Observatory","host_spectral_type":"K0 V","host_temperature_k":5205,"orbital_period_days":33.874,"periastron_epoch_bjd":2452932.3,"eccentricity_upper_limit":0.159,"equilibrium_temperature_k":503.31,"argument_of_periastron_deg":240},"designations":[{"catalog":"Exoplanet","designation":"HD 39194 d"}],"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."}