{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.678","julian_year":2026.678,"time":"2026-09-05T17:19:48.405Z","years_from_j2000":26.678,"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-48948-d","name":"HD 48948 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":55.13445255837146,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":102.489811,"dec_deg":60.3373133,"epoch_ra_deg":103.090758,"epoch_dec_deg":60.306439,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 48948","semi_major_axis_km":73213197.92058,"periapsis_km":null,"mass_kg":6.32452577199107e+25,"mass_msun":0.000031807,"constellation":"Lynx","discovered":"2024","featured":false,"url":"https://spacecatalog.org/object/hd-48948-d","radius_km":20665.044,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 48948","host_v_mag":8.58,"eccentricity":0.055,"uncertainties":{"mass_kg":[5.972167867791379e+24,5.972167867791379e+24],"distance_ly":[0.061643555388464506,0.06196971176618125],"eccentricity":[0.044,0.044],"host_mass_solar":[0.013,0.02],"host_radius_solar":[0.004,0.004],"host_temperature_k":[60,60],"semi_major_axis_km":[628311.0569399999,628311.0569399999],"orbital_period_days":[0.44,0.44],"argument_of_periastron_deg":[69,68]},"host_mass_solar":0.686,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":0.679,"planets_in_system":3,"discovery_facility":"Roque de los Muchachos Observatory","host_spectral_type":"K3 V","host_temperature_k":4593,"orbital_period_days":151.92,"periastron_epoch_bjd":2456494.34,"equilibrium_temperature_k":349,"argument_of_periastron_deg":269},"designations":[{"catalog":"Exoplanet","designation":"HD 48948 d"},{"catalog":"Host star","designation":"HD 48948"}],"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."}