HD 344787: a true Polaris analogue?

Classical Cepheids (DCEPs) are the most important primary indicators for extragalactic distance scale, but they also objects per se, allowing us to put constraints on physics of intermediate-mass stars and pulsation theories. We have investigated peculiar DCEP HD 344787, which is known exhibit fastest positive period change among DCEPs along with a quenching amplitude light variation. used high-resolution spectra obtained HARPS-N@TNG 344787 more famous Polaris DCEP, infer their detailed chemical abundances. Results from analysis new time-series photometry by TESS satellite reported. The double mode nature HD344787 confirmed curve, although rather tiny amplitudes few tens millimag. This an indication that verge pulsation. Analysis reveals almost solar abundance no depletion carbon oxygen. Hence, star appears not gone through first dredge-up. Similar results Polaris. be both likely at crossing instability strip (IS). two opposite borders IS overtone metal Z=0.008. A comparison other thought allows speculate differences we see in Hertzsprung-Russell diagram might due properties progenitors during main sequence phase.