{"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":"2026-09-07T19:36:44.321Z","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":"hd-16917","name":"HD 16917","class":"g5v_yellow_main_sequence_star","category":"star","object_type":"G5V yellow main-sequence star","mag":9.13,"mag_band":"V","abs_mag":5.025,"abs_mag_band":"V","distance_ly":215.99771345566876,"distance_method":"parallax","ra_deg":40.44471,"dec_deg":-34.202985,"epoch_ra_deg":40.724631,"epoch_dec_deg":-34.087668,"epoch_moved_arcsec":1.587,"pm_ra_mas_yr":51.89,"pm_dec_mas_yr":29.07,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Fornax","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-16917","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"02418-3412","age_years":5001794000,"companions":[{"measured":2016,"magnitude":13.6,"components":null,"discoverer_code":"KPP3499","separation_arcsec":3.7,"position_angle_deg":228}],"mass_solar":0.97,"radius_solar":0.962,"spectral_type":"G5V","color_index_bv":0.661,"luminosity_solar":0.8511380382023759,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1982MSS...C03....0H, quality C)","surface_gravity_log_g":4.388,"surface_temperature_k":5665,"proper_motion_ra_mas_yr":51.89,"proper_motion_dec_mas_yr":29.07,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: Gaia's classifier calls the source a binary, which GSP-Phot fitted as one star","bolometric_luminosity_solar":0.8547},"designations":[{"catalog":"HD","designation":"HD 16917"},{"catalog":"HIP","designation":"HIP 12581"}],"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."}