{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.683","julian_year":2026.683,"time":"2026-09-07T09:23:34.446Z","years_from_j2000":26.683,"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-121198","name":"HD 121198","class":"f8_yellow_white_star","category":"star","object_type":"F8 yellow-white star","mag":8.55,"mag_band":"V","abs_mag":3.477,"abs_mag_band":"V","distance_ly":337.286790262705,"distance_method":"parallax","ra_deg":208.43538,"dec_deg":12.680115,"epoch_ra_deg":208.764315,"epoch_dec_deg":12.547247,"epoch_moved_arcsec":1.823,"pm_ra_mas_yr":33.54,"pm_dec_mas_yr":-59.52,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Boötes","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-121198","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"13537+1241","age_years":3873265000,"companions":[{"measured":2022,"magnitude":13.35,"components":null,"discoverer_code":"UC  185","separation_arcsec":20.9,"position_angle_deg":145}],"mass_solar":1.249,"radius_solar":1.622,"spectral_type":"F8","color_index_bv":0.48,"luminosity_solar":3.5416040042646175,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1993yCat.3135....0C, quality E)","surface_gravity_log_g":4.111,"surface_temperature_k":6122,"proper_motion_ra_mas_yr":33.54,"proper_motion_dec_mas_yr":-59.52,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":3.3091},"designations":[{"catalog":"HD","designation":"HD 121198"},{"catalog":"HIP","designation":"HIP 67838"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"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."}