{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.669","julian_year":2026.669,"time":"2026-09-02T05:03:05.464Z","years_from_j2000":26.669,"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-2170","name":"HD 2170","class":"g5iii_yellow_giant","category":"star","object_type":"G5III yellow giant","mag":6.71,"mag_band":"V","abs_mag":0.431,"abs_mag_band":"V","distance_ly":587.6692136827837,"distance_method":"parallax","ra_deg":6.550305,"dec_deg":56.779229,"epoch_ra_deg":6.916961,"epoch_dec_deg":56.9276,"epoch_moved_arcsec":1.799,"pm_ra_mas_yr":-49.64,"pm_dec_mas_yr":-45.66,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Cassiopeia","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-2170","radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"00262+5647","age_years":413671300,"companions":[{"measured":2021,"magnitude":9.67,"components":"AB","discoverer_code":"STT   9","separation_arcsec":2,"position_angle_deg":51},{"measured":2018,"magnitude":9.9,"components":"AC","discoverer_code":"STT   9","separation_arcsec":22.8,"position_angle_deg":4},{"measured":2015,"magnitude":11.82,"components":"AD","discoverer_code":"WAL   6","separation_arcsec":74.1,"position_angle_deg":54},{"measured":2015,"magnitude":12.75,"components":"AE","discoverer_code":"WAL   6","separation_arcsec":74.3,"position_angle_deg":88}],"mass_solar":2.882,"radius_solar":9.469,"spectral_type":"G5III","color_index_bv":0.879,"luminosity_solar":58.559855984928774,"radial_velocity_km_s":19.3,"spectral_type_source":"SIMBAD (quality D)","surface_gravity_log_g":2.877,"surface_temperature_k":5716,"proper_motion_ra_mas_yr":-49.64,"proper_motion_dec_mas_yr":-45.66,"stellar_parameters_method":"Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)","bolometric_luminosity_solar":79.9776},"designations":[{"catalog":"HD","designation":"HD 2170"},{"catalog":"HIP","designation":"HIP 2074"}],"source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0"},"updated_at":"2026-09-01T22:58:55.274Z","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."}