{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.668","julian_year":2026.668,"time":"2026-09-01T23:05:54.917Z","years_from_j2000":26.668,"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-2840","name":"HD 2840","class":"a2_white_star","category":"star","object_type":"A2 white star","mag":8.89,"mag_band":"V","abs_mag":2.381,"abs_mag_band":"V","distance_ly":653.6199901953755,"distance_method":"parallax","ra_deg":7.984649999999999,"dec_deg":28.509569,"epoch_ra_deg":8.338812,"epoch_dec_deg":28.657676,"epoch_moved_arcsec":0.781,"pm_ra_mas_yr":-17.56,"pm_dec_mas_yr":-23.45,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Andromeda","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-2840","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"00320+2831","companions":[{"measured":2015,"magnitude":14.6,"components":"AC","discoverer_code":"FYM 206","separation_arcsec":14,"position_angle_deg":50},{"measured":2024,"magnitude":8.94,"components":"AB","discoverer_code":"S   386","separation_arcsec":43.4,"position_angle_deg":17}],"spectral_type":"A2","color_index_bv":0.397,"luminosity_solar":9.718517029401687,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1993yCat.3135....0C, quality E)","surface_temperature_k":6837,"proper_motion_ra_mas_yr":-17.56,"proper_motion_dec_mas_yr":-23.45,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 2840"},{"catalog":"HIP","designation":"HIP 2518"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","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."}