{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.682","julian_year":2026.682,"time":"2026-09-07T02:33:00.442Z","years_from_j2000":26.682,"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":"toi-257-b","name":"TOI-257 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":250.82338684275175,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":47.5172608,"dec_deg":-50.8322632,"epoch_ra_deg":47.72801,"epoch_dec_deg":-50.729753,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"TOI-257","semi_major_axis_km":22858554.642959997,"periapsis_km":null,"mass_kg":2.6194119479031612e+26,"mass_msun":0.000131734,"constellation":"Horologium","discovered":"2021","featured":false,"url":"https://spacecatalog.org/object/toi-257-b","radius_km":45683.387891127,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"TOI-257","host_v_mag":7.57,"eccentricity":0,"uncertainties":{"mass_kg":[4.365686578843241e+25,4.365686578843241e+25],"radius_km":[929.3960031750001,929.3960031750001],"distance_ly":[0.6337218419036325,0.6369834056807999],"host_mass_solar":[0.046,0.045],"inclination_deg":[0.1,0.11],"host_radius_solar":[0.032,0.033],"host_temperature_k":[89,89],"semi_major_axis_km":[254316.38018999997,239356.59312],"orbital_period_days":[0.00084,0.00085]},"host_mass_solar":1.407,"inclination_deg":87.91,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":1.867,"planets_in_system":1,"discovery_facility":"Transiting Exoplanet Survey Satellite (TESS)","host_temperature_k":6095,"orbital_period_days":18.38818,"periastron_epoch_bjd":2458385.7601,"transit_midpoint_bjd":2458385.7601,"equilibrium_temperature_k":1027},"designations":[{"catalog":"Exoplanet","designation":"TOI-257 b"},{"catalog":"Host star","designation":"TOI-257"}],"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."}