{"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":"2026-09-03T11:17:10.828Z","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-91121","name":"HD 91121","class":"g1wf2_5v_yellow_star","category":"star","object_type":"G1wF2/5V yellow star","mag":8.73,"mag_band":"V","abs_mag":3.964,"abs_mag_band":"V","distance_ly":292.7794909594782,"distance_method":"parallax","ra_deg":157.715745,"dec_deg":-21.226984,"epoch_ra_deg":158.036464,"epoch_dec_deg":-21.3677,"epoch_moved_arcsec":11.307,"pm_ra_mas_yr":-69.33,"pm_dec_mas_yr":-418.21,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Hydra","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-91121","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":8542667000,"mass_solar":1.05,"radius_solar":1.495,"spectral_type":"G1wF2/5V","uncertainties":{"metallicity_fe_h":[0.129,0.129]},"color_index_bv":0.552,"luminosity_solar":2.2615177461083618,"metallicity_fe_h":-1,"radial_velocity_km_s":105.7,"spectral_type_source":"SIMBAD (1988MSS...C04....0H, quality C)","surface_gravity_log_g":4.141,"surface_temperature_k":5821,"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":-69.33,"proper_motion_dec_mas_yr":-418.21,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":2.3168},"designations":[{"catalog":"HD","designation":"HD 91121"},{"catalog":"HIP","designation":"HIP 51477"}],"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."}