{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.778","julian_year":2026.778,"time":"2026-10-12T00:25:10.452Z","years_from_j2000":26.778,"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":"mebsuta","name":"Mebsuta","class":"g8ib_yellow_supergiant","category":"star","object_type":"G8Ib yellow supergiant","mag":3.06,"mag_band":"V","abs_mag":-4.007,"abs_mag_band":"V","distance_ly":844.9648476849466,"distance_method":"parallax","ra_deg":100.98303,"dec_deg":25.131124,"epoch_ra_deg":101.397262,"epoch_dec_deg":25.104154,"epoch_moved_arcsec":0.378,"pm_ra_mas_yr":-5.93,"pm_dec_mas_yr":-12.81,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Gemini","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/mebsuta","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":"06439+2508","companions":[{"measured":2017,"magnitude":9.64,"components":null,"discoverer_code":"S   533","separation_arcsec":109.9,"position_angle_deg":95}],"spectral_type":"G8Ib","uncertainties":{"metallicity_fe_h":[0.13,0.13]},"color_index_bv":1.377,"luminosity_solar":3489.7956743787418,"metallicity_fe_h":-0.045,"radial_velocity_km_s":10,"spectral_type_source":"SIMBAD (1989ApJS...71..245K, quality B)","surface_gravity_log_g":0.8,"surface_temperature_k":4525,"metallicity_fe_h_source":"Median of 6 spectroscopic determinations in 7 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them","proper_motion_ra_mas_yr":-5.93,"proper_motion_dec_mas_yr":-12.81,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016)"},"designations":[{"catalog":"Bayer/Flamsteed","designation":"27 Epsilon Gem"},{"catalog":"Common name","designation":"Mebsuta"},{"catalog":"HD","designation":"HD 48329"},{"catalog":"HIP","designation":"HIP 32246"},{"catalog":"HR","designation":"HR 2473"}],"updated_at":"2026-10-01T09:42:28.932Z","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."}