{"release":{"id":"DR1","released_on":"2026-08-21","doi":null,"url":"https://spacecatalog.org/releases#dr1"},"epoch":{"requested":"now","label":"J2026.676","julian_year":2026.676,"time":"2026-09-04T19:07:41.761Z","years_from_j2000":26.676,"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":"k2-27-b","name":"K2-27 b","class":"neptune_like_planet","category":"exoplanet","object_type":"Neptune-like planet","mag":null,"mag_band":null,"abs_mag":null,"abs_mag_band":null,"distance_ly":814.2330891509641,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":171.5151874,"dec_deg":1.2306237,"epoch_ra_deg":171.859784,"epoch_dec_deg":1.083007,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-27","semi_major_axis_km":10026049.294313999,"periapsis_km":null,"mass_kg":1.8035946960729964e+26,"mass_msun":0.0000907054,"constellation":"Leo","discovered":"2016","featured":false,"url":"https://spacecatalog.org/object/k2-27-b","radius_km":30232.194000000003,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-27","host_v_mag":12.689,"eccentricity":0.251,"uncertainties":{"mass_kg":[2.1499804324048965e+25,2.090258753726983e+25],"radius_km":[382.68600000000004,829.153],"distance_ly":[7.961477180065707,8.118032241369743],"eccentricity":[0.088,0.088],"host_mass_solar":[0.03,0.03],"inclination_deg":[1.03246,0.79498],"host_radius_solar":[0.036,0.036],"host_temperature_k":[100,100],"semi_major_axis_km":[106214.488197,106214.488197],"orbital_period_days":[0.000059,0.000059]},"host_mass_solar":0.88,"inclination_deg":88.87126,"stars_in_system":3,"discovery_method":"Transit","host_radius_solar":0.876,"planets_in_system":1,"discovery_facility":"K2","host_temperature_k":5246,"orbital_period_days":6.771347,"transit_midpoint_bjd":2456812.8447,"equilibrium_temperature_k":836},"designations":[{"catalog":"Exoplanet","designation":"K2-27 b"},{"catalog":"Host star","designation":"K2-27"}],"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."}