{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.684","julian_year":2026.684,"time":"2026-09-07T18:52:45.594Z","years_from_j2000":26.684,"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":"hats-18-b","name":"HATS-18 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":2036.4160524224767,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":173.9574203,"dec_deg":-29.1560639,"epoch_ra_deg":174.291837,"epoch_dec_deg":-29.304627,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HATS-18","semi_major_axis_km":2603002.9501799997,"periapsis_km":null,"mass_kg":3.7573564775151555e+27,"mass_msun":0.00188963,"constellation":"Hydra","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/hats-18-b","radius_km":95013.0313341,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HATS-18","host_v_mag":14.188,"uncertainties":{"mass_kg":[1.442581926199302e+26,1.442581926199302e+26],"radius_km":[5361.9092175,5361.9092175],"distance_ly":[50.11718899995479,52.66447030992256],"host_mass_solar":[0.047,0.047],"inclination_deg":[0.013,0.013],"host_radius_solar":[0.031,0.057],"host_temperature_k":[120,120],"semi_major_axis_km":[146605.913286,146605.913286],"orbital_period_days":[4.7e-7,4.7e-7]},"host_mass_solar":1.037,"inclination_deg":85.29,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.02,"planets_in_system":1,"discovery_facility":"Multiple Observatories","host_spectral_type":"G V","host_temperature_k":5600,"orbital_period_days":0.83784,"transit_midpoint_bjd":2458217.64374,"eccentricity_upper_limit":0.166,"equilibrium_temperature_k":2069.48},"designations":[{"catalog":"Exoplanet","designation":"HATS-18 b"},{"catalog":"Host star","designation":"HATS-18"}],"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."}