{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.670","julian_year":2026.67,"time":"2026-09-02T19:39:45.216Z","years_from_j2000":26.67,"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-99556","name":"HD 99556","class":"b3iii_iv_blue_white_giant","category":"star","object_type":"B3III/IV blue-white giant","mag":5.22,"mag_band":"V","abs_mag":-2.888,"abs_mag_band":"V","distance_ly":1364.6709000046262,"distance_method":"parallax","ra_deg":171.64761000000001,"dec_deg":-61.115167,"epoch_ra_deg":171.948504,"epoch_dec_deg":-61.262775,"epoch_moved_arcsec":0.372,"pm_ra_mas_yr":-13.83,"pm_dec_mas_yr":1.78,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Centaurus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-99556","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"11266-6107","companions":[{"measured":2015,"magnitude":14,"components":null,"discoverer_code":"RST4477","separation_arcsec":12.8,"position_angle_deg":186}],"spectral_type":"B3III/IV","color_index_bv":-0.077,"luminosity_solar":1245.0878639160544,"radial_velocity_km_s":9,"spectral_type_source":"SIMBAD (1975MSS...C01....0H, quality D)","proper_motion_ra_mas_yr":-13.83,"proper_motion_dec_mas_yr":1.78},"designations":[{"catalog":"HD","designation":"HD 99556"},{"catalog":"HIP","designation":"HIP 55831"},{"catalog":"HR","designation":"HR 4415"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-02T18:38:07.546Z","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."}