{"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":"2026-09-06T17:21:45.284Z","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":"hip-41378-c","name":"HIP 41378 c","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":346.6683523113494,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":126.6158279,"dec_deg":10.0803708,"epoch_ra_deg":126.981485,"epoch_dec_deg":9.992619,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HIP 41378","semi_major_axis_km":31310834.33751,"periapsis_km":null,"mass_kg":3.5653842170714533e+25,"mass_msun":0.0000179308,"constellation":"Cancer","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/hip-41378-c","radius_km":17475.994000000002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HIP 41378","host_v_mag":8.93,"eccentricity":0.044,"uncertainties":{"mass_kg":[5.136064366300586e+24,3.344414005963173e+24],"radius_km":[312.5269,274.2583],"distance_ly":[2.178724603147846,2.2048171133651855],"eccentricity":[0.044,0.022],"host_mass_solar":[0.02,0.03],"inclination_deg":[0.015,0.015],"host_radius_solar":[0.009,0.009],"host_temperature_k":[77,77],"semi_major_axis_km":[329115.31554,329115.31554],"orbital_period_days":[0.00005,0.00005],"argument_of_periastron_deg":[13,4]},"host_mass_solar":1.22,"inclination_deg":88.462,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.3,"planets_in_system":6,"discovery_facility":"K2","host_spectral_type":"F6","host_temperature_k":6290,"orbital_period_days":31.70591,"transit_midpoint_bjd":2457163.166,"equilibrium_temperature_k":757,"argument_of_periastron_deg":158},"designations":[{"catalog":"Exoplanet","designation":"HIP 41378 c"}],"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."}