{"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":"2026-09-06T18:29:08.917Z","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-31527-d","name":"HD 31527 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":125.39832100988949,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":73.9096193,"dec_deg":-23.2413163,"epoch_ra_deg":74.192416,"epoch_dec_deg":-23.198013,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 31527","semi_major_axis_km":121144355.69285999,"periapsis_km":null,"mass_kg":7.0591024197294104e+25,"mass_msun":0.0000355012,"constellation":"Lepus","discovered":"2019","featured":false,"url":"https://spacecatalog.org/object/hd-31527-d","radius_km":22068.226000000002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 31527","host_v_mag":7.49,"eccentricity":0.24,"uncertainties":{"mass_kg":[9.794355303177862e+24,1.0152685375245345e+25],"distance_ly":[0.13307180210843134,0.13307180210843134],"eccentricity":[0.13,0.13],"host_radius_solar":[0.023363,0.006374],"host_temperature_k":[13,13],"semi_major_axis_km":[4383217.611509999,4084021.87011],"orbital_period_days":[2.2471,2.1135],"argument_of_periastron_deg":[26.2,31.11]},"host_mass_solar":0.96,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":1.073694,"planets_in_system":3,"discovery_facility":"La Silla Observatory","host_spectral_type":"G2 V","host_temperature_k":5898,"orbital_period_days":271.6737,"periastron_epoch_bjd":2455718.8091,"equilibrium_temperature_k":327.48,"argument_of_periastron_deg":179},"designations":[{"catalog":"Exoplanet","designation":"HD 31527 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."}