{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.677","julian_year":2026.677,"time":"2026-09-05T10:43:33.207Z","years_from_j2000":26.677,"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-135631","name":"HD 135631","class":"f2iv_yellow_white_subgiant","category":"star","object_type":"F2IV yellow-white subgiant","mag":7.11,"mag_band":"V","abs_mag":1.682,"abs_mag_band":"V","distance_ly":397.2672742811918,"distance_method":"parallax","ra_deg":228.73575,"dec_deg":38.301111,"epoch_ra_deg":228.991993,"epoch_dec_deg":38.201346,"epoch_moved_arcsec":1.466,"pm_ra_mas_yr":-32.35,"pm_dec_mas_yr":44.41,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Boötes","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-135631","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"15149+3818","companions":[{"measured":2014,"magnitude":8.1,"components":"Aa,Ab","discoverer_code":"GII 218","separation_arcsec":0.1,"position_angle_deg":138},{"measured":2016,"magnitude":9.01,"components":"AB","discoverer_code":"STF1926","separation_arcsec":0.3,"position_angle_deg":222}],"spectral_type":"F2IV","color_index_bv":0.359,"luminosity_solar":18.501204347718584,"radial_velocity_km_s":-34.3,"spectral_type_source":"SIMBAD (2020AJ....160...52M, quality C)","surface_temperature_k":7030,"proper_motion_ra_mas_yr":-32.35,"proper_motion_dec_mas_yr":44.41,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"HD","designation":"HD 135631"},{"catalog":"HIP","designation":"HIP 74631"}],"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."}