{"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":"2026-09-05T07:58:50.476Z","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-152581-b","name":"HD 152581 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":540.6368117032739,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":253.4316451,"dec_deg":11.9736828,"epoch_ra_deg":253.745563,"epoch_dec_deg":11.929241,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 152581","semi_major_axis_km":248332465.36199996,"periapsis_km":null,"mass_kg":3.5476126579822305e+27,"mass_msun":0.00178415,"constellation":"Ophiuchus","discovered":"2011","featured":false,"url":"https://spacecatalog.org/object/hd-152581-b","radius_km":85466.54000000001,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 152581","host_v_mag":8.38,"eccentricity":0.04,"uncertainties":{"mass_kg":[1.3476752205282953e+26,1.3476752205282953e+26],"distance_ly":[3.820921964951649,3.820921964951649],"eccentricity":[0.031,0.031],"semi_major_axis_km":[44879361.20999999,44879361.20999999],"orbital_period_days":[4.8,4.8],"argument_of_periastron_deg":[66,66]},"host_mass_solar":1.3,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":5.14,"planets_in_system":1,"discovery_facility":"W. M. Keck Observatory","host_spectral_type":"K0","host_temperature_k":5027,"orbital_period_days":686.5,"periastron_epoch_bjd":2455040,"equilibrium_temperature_k":426.55,"argument_of_periastron_deg":181},"designations":[{"catalog":"Exoplanet","designation":"HD 152581 b"},{"catalog":"Host star","designation":"HD 152581"}],"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."}