{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.667","julian_year":2026.667,"time":"2026-09-01T11:38:48.090Z","years_from_j2000":26.667,"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-6540","name":"HD 6540","class":"k2iii_orange_giant","category":"star","object_type":"K2III orange giant","mag":6.31,"mag_band":"V","abs_mag":-2.24,"abs_mag_band":"V","distance_ly":1672.5967669888923,"distance_method":"parallax","ra_deg":16.789379999999998,"dec_deg":53.498185,"epoch_ra_deg":17.189743,"epoch_dec_deg":53.641776,"epoch_moved_arcsec":0.457,"pm_ra_mas_yr":16.82,"pm_dec_mas_yr":-3.32,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cassiopeia","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-6540","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"01072+5330","companions":[{"measured":2016,"magnitude":10.56,"components":"AB","discoverer_code":"H 4  66","separation_arcsec":20.1,"position_angle_deg":75},{"measured":2016,"magnitude":11.45,"components":"AC","discoverer_code":"H 4  66","separation_arcsec":195.3,"position_angle_deg":124}],"mass_solar":6.2,"radius_solar":64.644,"spectral_type":"K2III","color_index_bv":1.499,"luminosity_solar":685.488226452662,"radial_velocity_km_s":7,"spectral_type_source":"SIMBAD (1985ApJS...59...95A, quality C)","surface_gravity_log_g":1.536,"surface_temperature_k":4472,"proper_motion_ra_mas_yr":16.82,"proper_motion_dec_mas_yr":-3.32,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":1565.8175},"designations":[{"catalog":"HD","designation":"HD 6540"},{"catalog":"HIP","designation":"HIP 5251"},{"catalog":"HR","designation":"HR 318"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-08-30T09:56:50.739Z","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."}