{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.681","julian_year":2026.681,"time":"2026-09-06T17:53:27.854Z","years_from_j2000":26.681,"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-175541-b","name":"HD 175541 b","class":"gas_giant","category":"exoplanet","object_type":"Gas giant","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":422.708450212231,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":283.9203211,"dec_deg":4.2649344,"epoch_ra_deg":284.253636,"epoch_dec_deg":4.299112,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"HD 175541","semi_major_axis_km":145857923.93249997,"periapsis_km":null,"mass_kg":1.1350841998252402e+27,"mass_msun":0.00057085,"constellation":"Serpens","discovered":"2007","featured":false,"url":"https://spacecatalog.org/object/hd-175541-b","radius_km":89931.21,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"HD 175541","host_v_mag":8.020001,"eccentricity":0.11,"uncertainties":{"mass_kg":[5.5045889289183885e+25,5.5045889289183885e+25],"distance_ly":[3.2827639417190224,3.2827639417190224],"eccentricity":[0.049,0.049],"semi_major_axis_km":[13015014.750899998,13015014.750899998],"orbital_period_days":[0.45,0.45],"argument_of_periastron_deg":[28,28]},"host_mass_solar":1.39,"stars_in_system":1,"discovery_method":"Radial Velocity","host_radius_solar":4.19,"planets_in_system":1,"discovery_facility":"W. M. Keck Observatory","host_spectral_type":"G8 IV","host_temperature_k":5013,"orbital_period_days":298.43,"periastron_epoch_bjd":2450155,"transit_midpoint_bjd":2454003.5,"equilibrium_temperature_k":501.11,"argument_of_periastron_deg":129},"designations":[{"catalog":"Exoplanet","designation":"HD 175541 b"},{"catalog":"Host star","designation":"HD 175541"}],"source":{"id":"exoplanet_archive","name":"NASA Exoplanet Archive (Planetary Systems Composite Parameters)","url":"https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=PSCompPars","license":"Public domain (NASA)"},"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."}