{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.680","julian_year":2026.68,"time":"2026-09-06T06:24:35.174Z","years_from_j2000":26.68,"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-51608-c","name":"HD 51608 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":114.33509667773757,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":103.7137102,"dec_deg":-55.2600189,"epoch_ra_deg":103.847534,"epoch_dec_deg":-55.293418,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 51608","semi_major_axis_km":56981828.94963,"periapsis_km":null,"mass_kg":8.546172218809465e+25,"mass_msun":0.0000429799,"constellation":"Carina","discovered":"2019","featured":false,"url":"https://spacecatalog.org/object/hd-51608-c","radius_km":24683.247000000003,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 51608","host_v_mag":8.17,"eccentricity":0.14,"uncertainties":{"mass_kg":[9.13741683772081e+24,9.734633624499947e+24],"distance_ly":[0.10795776102424207,0.10861007377967556],"eccentricity":[0.07,0.07],"host_radius_solar":[0.056048,0.020985],"host_temperature_k":[22,22],"semi_major_axis_km":[2453405.07948,2288847.42171],"orbital_period_days":[0.1366,0.1555],"argument_of_periastron_deg":[33.93,29.34]},"host_mass_solar":0.8,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":0.916136,"planets_in_system":2,"discovery_facility":"La Silla Observatory","host_spectral_type":"G7 V","host_temperature_k":5358,"orbital_period_days":95.9446,"periastron_epoch_bjd":2455498.3725,"equilibrium_temperature_k":400.69,"argument_of_periastron_deg":-165.07},"designations":[{"catalog":"Exoplanet","designation":"HD 51608 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."}