{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.816","julian_year":2026.816,"time":"2026-10-25T22:26:47.877Z","years_from_j2000":26.816,"frame":"date","applied":"Proper motion, then precession and nutation. The catalogued position is carried along the great circle the object's own published motion puts it on, at a constant velocity, from the epoch that position was measured at, 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. The motion runs from position_epoch_jyear where the upstream publishes one — a timed pulsar's position belongs to the year it was timed — and from J2000 where it does not. 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-198571","name":"4 Aqr","class":"f7iv_f6_v_yellow_white_subgiant","category":"star","object_type":"F7IV+F6:V: yellow-white subgiant","mag":5.99,"mag_band":"V","abs_mag":2.073,"abs_mag_band":"V","distance_ly":198.03073707638652,"distance_method":"parallax","ra_deg":312.85728,"dec_deg":-5.626633,"epoch_ra_deg":313.214412,"epoch_dec_deg":-5.525755,"epoch_moved_arcsec":2.568,"pm_ra_mas_yr":95.77,"pm_dec_mas_yr":1.25,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Aquarius","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-198571","source":{"id":"hyg","name":"HYG Database v4.1","url":"https://github.com/astronexus/HYG-Database","license":"CC-BY-SA-4.0","attribution":"HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.","commercial_use":"allowed"},"radius_km":null,"radius_kind":null,"data_quality":null,"description":null,"properties":{"wds_id":"20514-0538","companions":[{"measured":2025,"magnitude":7.43,"components":"AB","discoverer_code":"STF2729","separation_arcsec":0.7,"position_angle_deg":38},{"measured":2002,"magnitude":13.3,"components":"AC","discoverer_code":"STF2729","separation_arcsec":74.3,"position_angle_deg":311},{"measured":2012,"magnitude":9.66,"components":"AD","discoverer_code":"STF2729","separation_arcsec":137.3,"position_angle_deg":324}],"spectral_type":"F7IV+F6:V:","color_index_bv":0.464,"luminosity_solar":12.906247820605376,"metallicity_fe_h":-0.01,"radial_velocity_km_s":-25,"spectral_type_source":"SIMBAD (1980PASP...92..493C, quality C)","surface_gravity_log_g":3.79,"surface_temperature_k":6502,"metallicity_fe_h_source":"One spectroscopic determination, compiled from the literature (PASTEL, Soubiran+ 2016)","proper_motion_ra_mas_yr":95.77,"proper_motion_dec_mas_yr":1.25,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"4 Aqr"},{"catalog":"HD","designation":"HD 198571"},{"catalog":"HIP","designation":"HIP 102945"},{"catalog":"HR","designation":"HR 7982"}],"updated_at":"2026-10-01T09:42:28.932Z","citation":{"plain":"SpaceCatalog. 4 Aqr [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-198571","bibtex":"@misc{spacecatalog_hd-198571,\n  author       = {{SpaceCatalog}},\n  title        = {{4 Aqr}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-198571},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-198571","release":"DR1","doi":null},"references":[{"bibcode":"1980PASP...92..493C","ads_url":"https://ui.adsabs.harvard.edu/abs/1980PASP...92..493C/abstract","quantity":"properties.spectral_type_source"}],"attribution":"Data from SpaceCatalog.org. Each record names its upstream in `source`, with that producer's terms in `source.license`, the acknowledgement it asks for in `source.attribution`, and whether its terms allow commercial use in `source.commercial_use`; those terms govern the record, and citing SpaceCatalog does not discharge them."}