Abstract:
We report the analysis of high-precision space-based photometric and high-resolution spectroscopic observations of HD 180347.
The high-quality light curves from the Transiting Exoplanet Survey Satellite (TESS) under sectors 14, 15, and 26 were used. By
visual inspection of the light curves and the Fourier transforms, only low-frequency signals (less than 1 d−1) were detected. After
using wavelet, autocorrelation, and composite spectrum analyses, HD 180347 is classified as a rotational variable with a period
of about 4.1 ± 0.2 d. In reference to the observation limit of TESS, no pulsations were detected. For the spectroscopic analysis,
we used data collected with the High Efficiency and Resolution Mercator Echelle ´ Spectrograph (HERMES). We determined
the spectral type of this star and obtained atmospheric parameters such as the effective temperature, the surface gravity, and
the projected rotational, microturbulent, and radial velocities. We performed a detailed chemical abundance analysis. The LTE
abundances were derived for 25 chemical elements. For 13 of them, including Ca, Sc, Sr, Zr, and Ba, which are important for
the characterization of chemical peculiarities, we also present the non-local thermodynamic equilibrium (NLTE) abundances.
NLTE improves the accuracy of the derived abundances and confirms that Ca and Sc are depleted in HD 180347 relative to their
solar abundances, while the heavy elements beyond Sr are enhanced, by more than 0.7 dex. Based on the spectral class and the
element abundance pattern, we classify this star as Am (kA1hA8mA8).
