{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.676","julian_year":2026.676,"time":"2026-09-04T23:52:38.456Z","years_from_j2000":26.676,"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-137107","name":"2 η CrB A","class":"g2v_g2v_yellow_main_sequence_star","category":"star","object_type":"G2V+G2V yellow main-sequence star","mag":4.99,"mag_band":"V","abs_mag":3.73,"abs_mag_band":"V","distance_ly":58.262944533430456,"distance_method":"parallax","ra_deg":230.80124999999998,"dec_deg":30.287812,"epoch_ra_deg":231.079616,"epoch_dec_deg":30.19051,"epoch_moved_arcsec":5.781,"pm_ra_mas_yr":125.77,"pm_dec_mas_yr":-176.48,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Corona Borealis","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-137107","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"15232+3017","companions":[{"measured":2024,"magnitude":5.95,"components":"AB","discoverer_code":"STF1937","separation_arcsec":0.7,"position_angle_deg":356},{"measured":2023,"magnitude":13.35,"components":"AB,C","discoverer_code":"STF1937","separation_arcsec":76.8,"position_angle_deg":357},{"measured":2016,"magnitude":17,"components":"AB,E","discoverer_code":"KIR   4","separation_arcsec":190,"position_angle_deg":136},{"measured":2023,"magnitude":11,"components":"AB,D","discoverer_code":"STF1937","separation_arcsec":218.1,"position_angle_deg":40}],"spectral_type":"G2V+G2V","color_index_bv":0.577,"luminosity_solar":2.805433637951713,"metallicity_fe_h":-0.04,"radial_velocity_km_s":-7.3,"spectral_type_source":"SIMBAD (1955ApJ...121..337S, quality C)","surface_gravity_log_g":4.51,"surface_temperature_k":5971,"metallicity_fe_h_source":"One spectroscopic determination, compiled from the literature (PASTEL, Soubiran+ 2016)","proper_motion_ra_mas_yr":125.77,"proper_motion_dec_mas_yr":-176.48,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"2 Eta CrB"},{"catalog":"Gliese","designation":"Gl 584A"},{"catalog":"HD","designation":"HD 137107"},{"catalog":"HIP","designation":"HIP 75312"},{"catalog":"HR","designation":"HR 5727"}],"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."}