tokens: The authors thank the anonymous referee for insightful comments that greatly improved this paper. We also thank Peter Gao and Diana Powell for providing paper manuscripts, and Shigeru Ida, Hidekazu Tanaka, Xi Zhang, Chris Ormel, Ryo Tazaki, Yamira Miguel, Masahiro Ogihara, Yuichi Ito, and Yui Kawashima for helpful comments. This work was supported by JSPS Grants-in-Aid for Scientific Research (#15H02065, 16H04081, 16K17661, 18J14557) and the Foundation for Promotion of Astronomy.
ner_tags: O O O O O O O O O O O O O O O O O B-Person I-Person O B-Person I-Person O O O O O B-Person I-Person B-Person I-Person B-Person I-Person B-Person I-Person B-Person I-Person B-Person I-Person B-Person I-Person B-Person I-Person O B-Person I-Person O O O O O O O O B-Organization B-Grant I-Grant I-Grant I-Grant B-Grant B-Grant B-Grant B-Grant O O B-Organization I-Organization I-Organization I-Organization I-Organization