{"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":"2026-09-06T17:28:37.111Z","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":"toi-561-c","name":"TOI-561 c","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":279.8389105171887,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":148.1851516,"dec_deg":6.216103,"epoch_ra_deg":148.538038,"epoch_dec_deg":6.089972,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"TOI-561","semi_major_axis_km":13299250.70523,"periapsis_km":null,"mass_kg":3.5414955456002878e+25,"mass_msun":0.0000178107,"constellation":"Sextans","discovered":"2020","featured":false,"url":"https://spacecatalog.org/object/toi-561-c","radius_km":18273.256500000003,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"TOI-561","host_v_mag":10.252,"eccentricity":0.023,"uncertainties":{"mass_kg":[4.001352471420224e+24,4.001352471420224e+24],"radius_km":[261.50210000000004,261.50210000000004],"distance_ly":[1.6086032548989786,1.6268680120511163],"eccentricity":[0.017,0.034],"host_mass_solar":[0.036,0.036],"inclination_deg":[0.33,0.27],"host_radius_solar":[0.005,0.005],"host_temperature_k":[54,57],"semi_major_axis_km":[194477.23190999997,194477.23190999997],"orbital_period_days":[0.000018,0.000018],"argument_of_periastron_deg":[149,87]},"host_mass_solar":0.806,"inclination_deg":89.61,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.843,"planets_in_system":4,"discovery_facility":"Transiting Exoplanet Survey Satellite (TESS)","host_spectral_type":"G9 V","host_temperature_k":5342,"orbital_period_days":10.778838,"transit_midpoint_bjd":2459238.46284,"equilibrium_temperature_k":802,"argument_of_periastron_deg":219},"designations":[{"catalog":"Exoplanet","designation":"TOI-561 c"}],"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."}