HD 42477: coupled r modes, g modes, and a p mode in an A0Vnne star

• DOI: 10.1093/mnras/stad858
• Publication Date: 2023-03-21T00:35:47Z
• Authors: D W Kurtz; R Jayaraman; P Sowicka; G Handler; H Saio; J Labadie-Bartz; U Lee
• Keywords: Instability strip; Star (game theory); Hertzsprung–Russell diagram; Mode (computer interface)

Several studies have shown that a number of stars pulsating in p modes lie between the $\beta$ Cep and $\delta$ Sct instability strips Hertzsprung-Russell (HR) Diagram. At present, there is no certain understanding how p~modes can be excited this $T_{\rm eff}$ range. The goal work to disprove conjecture all lying range are result incorrect measurements eff}$, contamination, or presence unseen cooler companions strip (given high binary fraction region HR Diagram). Using TESS data, we show A0Vnne star HD 42477 has single mode coupled several r and/or g modes. We rule out contaminating background with pixel-by-pixel examination, essentially possibility companion binary. model pulsations suggest by overstable convective core also driven coupling modes, oblateness rapidly-rotating permits driving He II ionization equatorial region.