{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.671","julian_year":2026.671,"time":"2026-09-03T05:07:48.484Z","years_from_j2000":26.671,"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-20631","name":"HD 20631","class":"f3v_yellow_white_main_sequence_star","category":"star","object_type":"F3V yellow-white main-sequence star","mag":5.72,"mag_band":"V","abs_mag":2.881,"abs_mag_band":"V","distance_ly":120.57544665259202,"distance_method":"parallax","ra_deg":49.671435,"dec_deg":-18.559794,"epoch_ra_deg":49.978703,"epoch_dec_deg":-18.462071,"epoch_moved_arcsec":3.734,"pm_ra_mas_yr":124.9,"pm_dec_mas_yr":-63.27,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Eridanus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-20631","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"03187-1834","age_years":1227274200,"companions":[{"measured":2020,"magnitude":8.17,"components":null,"discoverer_code":"HJ 3565","separation_arcsec":8,"position_angle_deg":121}],"mass_solar":1.417,"radius_solar":1.516,"spectral_type":"F3V","color_index_bv":0.381,"luminosity_solar":6.1319696971568245,"radial_velocity_km_s":18,"spectral_type_source":"SIMBAD (1988MSS...C04....0H, quality C)","surface_gravity_log_g":4.143,"surface_temperature_k":6902,"proper_motion_ra_mas_yr":124.9,"proper_motion_dec_mas_yr":-63.27,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":4.7482},"designations":[{"catalog":"HD","designation":"HD 20631"},{"catalog":"HIP","designation":"HIP 15411"},{"catalog":"HR","designation":"HR 997"}],"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."}