{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.672","julian_year":2026.672,"time":"2026-09-03T08:31:12.215Z","years_from_j2000":26.672,"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-91603","name":"HD 91603","class":"k2iii_orange_giant","category":"star","object_type":"K2III orange giant","mag":7.22,"mag_band":"V","abs_mag":0.644,"abs_mag_band":"V","distance_ly":673.8769105026071,"distance_method":"parallax","ra_deg":158.88024,"dec_deg":45.653691,"epoch_ra_deg":159.281227,"epoch_dec_deg":45.514765,"epoch_moved_arcsec":0.812,"pm_ra_mas_yr":26.4,"pm_dec_mas_yr":-15.17,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Ursa Major","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-91603","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"10355+4539","age_years":413079830,"companions":[{"measured":2015,"magnitude":11.2,"components":null,"discoverer_code":"BU 1074","separation_arcsec":2.6,"position_angle_deg":208}],"mass_solar":2.903,"radius_solar":11.752,"spectral_type":"K2III","color_index_bv":1.06,"luminosity_solar":48.128242186760225,"radial_velocity_km_s":-18,"spectral_type_source":"SIMBAD (quality C)","surface_gravity_log_g":2.413,"surface_temperature_k":4724,"proper_motion_ra_mas_yr":26.4,"proper_motion_dec_mas_yr":-15.17,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":64.1836},"designations":[{"catalog":"HD","designation":"HD 91603"},{"catalog":"HIP","designation":"HIP 51846"}],"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."}