{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.843","julian_year":2026.843,"time":"2026-11-05T00:27:56.960Z","years_from_j2000":26.843,"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-55549","name":"HD 55549","class":"a_f_white_star","category":"star","object_type":"A/F white star","mag":7.84,"mag_band":"V","abs_mag":-0.232,"abs_mag_band":"V","distance_ly":1342.2072056457632,"distance_method":"parallax","ra_deg":109.27269709206263,"dec_deg":59.916507,"epoch_ra_deg":109.864174,"epoch_dec_deg":59.868012,"epoch_moved_arcsec":0.558,"pm_ra_mas_yr":-3.27,"pm_dec_mas_yr":-20.54,"position_epoch_jyear":null,"orbits":null,"semi_major_axis_km":null,"periapsis_km":null,"mass_kg":null,"mass_msun":null,"constellation":"Camelopardalis","discovered":null,"featured":false,"url":"https://spacecatalog.org/object/hd-55549","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":{"spectral_type":"A/F","uncertainties":{"distance_ly":[329.2993103752617,646.5510850050871]},"color_index_bv":0.67,"luminosity_solar":107.84499632938316,"spectral_type_source":"SIMBAD (2020AJ....160...52M, quality E)","surface_temperature_k":5675,"proper_motion_ra_mas_yr":-3.27,"proper_motion_dec_mas_yr":-20.54,"stellar_parameters_method":"Spectroscopic determinations compiled from the literature (PASTEL, Soubiran+ 2016) — low confidence: the literature's temperature is outside any the star's spectral class allows"},"designations":[{"catalog":"HD","designation":"HD 55549"},{"catalog":"HIP","designation":"HIP 35257"}],"updated_at":"2026-11-04T21:40:51.947Z","citation":{"plain":"SpaceCatalog. HD 55549 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-55549","bibtex":"@misc{spacecatalog_hd-55549,\n  author       = {{SpaceCatalog}},\n  title        = {{HD 55549}},\n  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},\n  year         = {2026},\n  url          = {https://spacecatalog.org/object/hd-55549},\n  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}\n}","url":"https://spacecatalog.org/object/hd-55549","release":"DR1","doi":null},"references":[{"bibcode":"2020AJ....160...52M","ads_url":"https://ui.adsabs.harvard.edu/abs/2020AJ....160...52M/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."}