Source data of Figs. 1, 2, 5, 7, 8, 9, 10, 11, A2, and A3 in "Oxygen isotope study of the Asuka-881020 CH chondrite II: Porphyritic chondrules" by Nakashima et al. 2023 submitted to GCA. Source data of oxygen isotope plots in Fig. A1 are available in the Supplementary Table A4.