{"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":"2026-09-04T20:51:31.303Z","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":"k2-277-b","name":"K2-277 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":368.95787916451167,"distance_method":"NASA Exoplanet Archive sy_dist (TICv8, 2019AJ....158..138S)","ra_deg":202.0161895,"dec_deg":-15.9379749,"epoch_ra_deg":202.375904,"epoch_dec_deg":-16.077279,"epoch_moved_arcsec":null,"pm_ra_mas_yr":null,"pm_dec_mas_yr":null,"orbits":"K2-277","semi_major_axis_km":9933298.61448,"periapsis_km":null,"mass_kg":4.419404222165621e+25,"mass_msun":0.0000222258,"constellation":"Virgo","discovered":"2018","featured":false,"url":"https://spacecatalog.org/object/k2-277-b","radius_km":13940.939983844002,"radius_kind":null,"data_quality":null,"description":null,"properties":{"host_star":"K2-277","host_v_mag":10.364,"eccentricity":0.52,"uncertainties":{"mass_kg":[1.970815396371155e+25,1.970815396371155e+25],"radius_km":[786.4120124990001,1286.8559798649999],"distance_ly":[2.2537405700226967,2.286356207794371],"eccentricity":[0.26,0.24],"host_mass_solar":[0.058,0.053],"inclination_deg":[0.96,1.6],"host_radius_solar":[0.035,0.038],"host_temperature_k":[120,120],"semi_major_axis_km":[194477.23190999997,179517.44483999998],"orbital_period_days":[0.000012,0.000015],"argument_of_periastron_deg":[120,96]},"host_mass_solar":0.974,"inclination_deg":86.83,"stars_in_system":1,"discovery_method":"Transit","host_radius_solar":0.973,"planets_in_system":1,"discovery_facility":"K2","host_temperature_k":5680,"orbital_period_days":6.326768,"transit_midpoint_bjd":2457303.4771,"equilibrium_temperature_k":1049,"argument_of_periastron_deg":46},"designations":[{"catalog":"Exoplanet","designation":"K2-277 b"},{"catalog":"Host star","designation":"K2-277"}],"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."}