| Full text | |
| Author(s): |
Kurtz, D. W.
;
Jayaraman, R.
;
Sowicka, P.
;
Handler, G.
;
Saio, H.
;
Labadie-Bartz, J.
;
Lee, U.
Total Authors: 7
|
| Document type: | Journal article |
| Source: | Monthly Notices of the Royal Astronomical Society; v. 521, n. 3, p. 10-pg., 2023-05-01. |
| Abstract | |
Several studies have shown that a number of stars pulsating in p modes lie between the b Cep and d Sct instability strips in the Hertzsprung-Russell (HR) Diagram. At present, there is no certain understanding of how p modes can be excited in this T-eff range. The goal of this work is to disprove the conjecture that all stars pulsating in p modes and lying in this T-eff range are the result of incorrect measurements of T-eff, contamination, or the presence of unseen cooler companions lying in the d Sct instability strip (given the high binary fraction of stars in this region of the HR Diagram). Using TESS data, we show that the A0Vnne star HD 42477 has a single p mode coupled to several r modes and/or g modes. We rule out a contaminating background star with a pixel-by-pixel examination, and we essentially rule out the possibility of a companion d Sct star in a binary. We model the pulsations in HD 42477, and suggest that the g modes are excited by overstable convective core modes. We also conjecture that the single p mode is driven by coupling with the g modes, or that the oblateness of this rapidly-rotating star permits driving by He ii ionization in the equatorial region. (AU) | |
| FAPESP's process: | 17/23731-1 - Analysis and Modeling of a Large Sample of Galactic Be Stars |
| Grantee: | Jonathan Michael Labadie-Bartz |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |