{"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":"2026-09-04T20:48:02.739Z","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-198084","name":"HD 198084","class":"f8iv_v_f9iv_v_yellow_white_subgiant","category":"star","object_type":"F8IV-V+F9IV-V yellow-white subgiant","mag":4.52,"mag_band":"V","abs_mag":2.34,"abs_mag_band":"V","distance_ly":89.01655554471992,"distance_method":"parallax","ra_deg":311.33817,"dec_deg":57.579725,"epoch_ra_deg":311.502172,"epoch_dec_deg":57.675181,"epoch_moved_arcsec":6.504,"pm_ra_mas_yr":-62.95,"pm_dec_mas_yr":-235.56,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cepheus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-198084","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"20454+5735","companions":[{"measured":2010,"magnitude":5.5,"components":"Aa,Ab","discoverer_code":"CIA   1","separation_arcsec":0.1,"position_angle_deg":105},{"measured":2004,"magnitude":9.86,"components":"AB","discoverer_code":"ENG  76","separation_arcsec":48.4,"position_angle_deg":146}],"spectral_type":"F8IV-V+F9IV-V","uncertainties":{"metallicity_fe_h":[0.051,0.051]},"color_index_bv":0.535,"luminosity_solar":10.092528860766844,"metallicity_fe_h":0.12,"radial_velocity_km_s":-32.4,"spectral_type_source":"SIMBAD (2010AJ....139.2308F, quality C)","surface_gravity_log_g":3.79,"surface_temperature_k":6170,"metallicity_fe_h_source":"Median of 5 spectroscopic determinations in 6 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-62.95,"proper_motion_dec_mas_yr":-235.56,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Gliese","designation":"GJ 9706"},{"catalog":"HD","designation":"HD 198084"},{"catalog":"HIP","designation":"HIP 102431"},{"catalog":"HR","designation":"HR 7955"}],"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."}