{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.679","julian_year":2026.679,"time":"2026-09-05T23:51:36.621Z","years_from_j2000":26.679,"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":"hip-15998","name":"HIP 15998","class":"k0_orange_star","category":"star","object_type":"K0 orange star","mag":10.17,"mag_band":"V","abs_mag":6.454,"abs_mag_band":"V","distance_ly":180.596047905538,"distance_method":"parallax","ra_deg":51.517575,"dec_deg":45.457908,"epoch_ra_deg":51.982411,"epoch_dec_deg":45.550901,"epoch_moved_arcsec":8.191,"pm_ra_mas_yr":243.52,"pm_dec_mas_yr":-186.99,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Perseus","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hip-15998","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"age_years":8427468000,"mass_solar":0.852,"radius_solar":0.838,"spectral_type":"K0","color_index_bv":0.85,"luminosity_solar":0.2282443312173503,"radial_velocity_km_s":0,"spectral_type_source":"SIMBAD (1985ApJS...59..197B, quality D)","surface_gravity_log_g":4.516,"surface_temperature_k":5235,"proper_motion_ra_mas_yr":243.52,"proper_motion_dec_mas_yr":-186.99,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":0.4795},"designations":[{"catalog":"HIP","designation":"HIP 15998"}],"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."}