Planet-Induced Emission Enhancements in HD 179949: Results from McDonald Observations

TL;DR

This study confirms planet-induced chromospheric emission in HD 179949 through high-resolution spectral observations, demonstrating phase shifts in star-planet interaction and analyzing activity variability.

Contribution

It provides new observational evidence of planet-induced emission effects and confirms the phase shift of star-planet interaction in HD 179949.

Findings

Confirmed planet-induced emission in Ca II K line

Detected phase shift in star-planet interaction

Observed variability unrelated to planet activity

Abstract

We monitored the Ca II H and K lines of HD 179949, a notable star in the southern hemisphere, to observe and confirm previously identified planet induced emission (PIE) as an effect of star-planet interaction. We obtained high resolution spectra (R ~ 53,000) with a signal-to-noise ratio S/N >~ 50 in the Ca II H and K cores during 10 nights of observation at the McDonald Observatory. Wide band echelle spectra were taken using the 2.7 m telescope. Detailed statistical analysis of Ca II K revealed fluctuations in the Ca II K core attributable to planet induced chromospheric emission. This result is consistent with previous studies by Shkolnik et al. (2003). Additionally, we were able to confirm the reality and temporal evolution of the phase shift of the maximum of star-planet interaction previously found. However, no identifiable fluctuations were detected in the Ca II H core. The Al I lambda 3944 A line was also monitored to gauge if the expected activity enhancements are confined to the chromospheric layer. Our observations revealed some variability, which is apparently unassociated with planet induced activity.