背景のガイアは欧州宇宙機関（ESA）のプロジェクトで、10億を超える恒星の位置、距離、等級を高精度に測定することを目的としています。内容は以下のADQLクエリを使用して[Gaia Archive][1]からデータを取得します。以下に示す通りです。SELECT G.source_id, TY.id as tycho2_id, G.parallax, G.parallax_error, G.phot_G_mean_mag, G.phot_rp_mean_mag, G.phot_bp_mean_mag, G.phot_G_mean_flux_error, G.ra, G.dec, G.ra_error, G.dec_error, G.l, G.b, G.pmra, G.pmdec, AWBN.angular_distance AS allwise_ang_dist, GSBN.angular_distance AS gsc23_ang_dist, PPBN.angular_distance AS ppmxl_ang_dist, TMBN.angular_distance AS tmass_ang_dist, TYBN.angular_distance AS tycho2_ang_dist, AW.w1mpro AS allwise_w1, AW.w2mpro AS allwise_w2, AW.w3mpro AS allwise_w3, AW.w4mpro AS allwise_w4, GS.v_mag AS gsc23_v_mag, GS.b_mag AS gsc23_b_mag, PP.b1mag AS ppmxl_b1mag, PP.b2mag AS ppmxl_b2mag, PP.r1mag AS ppmxl_r1mag, PP.imag AS ppmxl_imag, TM.j_m AS tmass_j_m, TM.h_m AS tmass_h_m, TM.ks_m AS tmass_ks_m, TY.bt_mag AS tycho2_bt_mag, TY.vt_mag AS tycho2_vt_mag FROM gaiadr2.gaia_source G INNER JOIN gaiadr2.allwise_best_neighbour AWBN ON AWBN.source_id = G.source_id INNER JOIN gaiadr2.gsc23_best_neighbour GSBN ON GSBN.source_id = G.source_id INNER JOIN gaiadr2.ppmxl_best_neighbour PPBN ON PPBN.source_id = G.source_id INNER JOIN gaiadr2.tmass_best_neighbour TMBN ON TMBN.source_id = G.source_id INNER JOIN gaiadr2.tycho2_best_neighbour TYBN ON TYBN.source_id = G.source_id INNER JOIN gaiadr1.allwise_original_valid AW ON AW.designation = AWBN.original_ext_source_id INNER JOIN gaiadr1.gsc23_original_valid GS ON GS.gsc23_identifier = GSBN.original_ext_source_id INNER JOIN gaiadr1.ppmxl_original_invalid PP ON PP.ppmxl_oid = PPBN.ppmxl_oid INNER JOIN gaiadr1.tmass_original_valid TM ON TM.designation = TMBN.original_ext_source_id INNER JOIN public.tycho2 TY ON TY.id = TYBN.original_ext_source_id WHERE G.parallax >= 2.0, G.parallax_error <= 0.035, G.phot_G_mean_mag <= 13.5, G.parallax_error IS NOT NULL, G.phot_rp_mean_mag IS NOT NULL AND G.phot_bp_mean_mag IS NOT NULL AND G.phot_G_mean_flux_error IS NOT NULL AND AW.w1mpro IS NOT NULL AND AW.w2mpro IS NOT NULL, AW.w3mpro IS NOT NULL, AW.w4mpro IS NOT NULL, GS.v_mag IS NOT NULL, GS.b_mag IS NOT NULL, PP.b1mag IS NOT NULL AND PP.b2mag IS NOT NULL AND PP.r1mag IS NOT NULL AND PP.imag IS NOT NULL AND TM.j_m IS NOT NULL AND TM.h_m IS NOT NULL AND TM.ks_m IS NOT NULL AND TY.bt_mag IS NOT NULL AND TY.vt_mag IS NOT NULL, AWBN.angular_distance <= 0.15, GSBN.angular_distance <= 0.25, PPBN.angular_distance <= 0.015, TMBN.angular_distance = 0.15, TYBN.angular_distance < 1, AWBN.best_neighbor_multiplicity = 1, GSBN.best_neighbor_multiplicity = 1, PPBN.best_neighbor_multiplicity = 1, TMBN.best_neighbor_multiplicity = 1, TYBN.number_of_neighbors = 1 注釈 - データには複数の重複するsource_idが存在します。 - 等級にはデータベース間で位置ずれがあります。