Evolved Massive Stars at Low-metallicity IV. Using 1.6 $μ$m "H-bump" to identify red supergiant stars: a case study of NGC 6822

no code implementations • 21 Jan 2021 • Ming Yang, Alceste Z. Bonanos, Biwei Jiang, Man I Lam, Jian Gao, Panagiotis Gavras, Grigoris Maravelias, Shu Wang, Xiao-Dian Chen, Frank Tramper, Yi Ren, Zoi T. Spetsieri

Further separating RSG candidates from the rest of the LSG candidates is done by using semi-empirical criteria on NIR CMDs and resulted in 323 RSG candidates.

Solar and Stellar Astrophysics Astrophysics of Galaxies

Possible evidence of hydrogen emission in the first-overtone and multi-mode RR Lyrae variables

no code implementations • 24 Dec 2020 • Xiao-Wei Duan, Xiao-Dian Chen, Li-Cai Deng, Fan Yang, Chao Liu, Anupam Bhardwaj, Hua-Wei Zhang

The nature of shock waves in non-fundamental mode RR Lyrae stars remains a mystery because of limited spectroscopic observations.

Solar and Stellar Astrophysics