A Spectroscopic and Photometric Investigation of the Mercury-Manganese Star KIC 6128830

Abstract

The advent of space-based photometry provides the opportunity for the first precise characterizations of variability in Mercury-Manganese (HgMn/CP3) stars, which might advance our understanding of their internal structure. We have carried out a spectroscopic and photometric investigation of the candidate CP3 star KIC 6128830. A detailed abundance analysis based on newly-acquired high-resolution spectra was performed, which confirms that the star's abundance pattern is fully consistent with its proposed classification. Photometric variability was investigated using four years of archival Kepler data. In agreement with results from the literature, we have identified a single significant and independent frequency $f_1$=0.2065424 d${}^{-1}$ with a peak-to-peak amplitude of $\sim$3.4 mmag and harmonic frequencies up to $5f_1$. Drawing on the predictions of state-of-the-art pulsation models and information on evolutionary status, we discuss the origin of the observed light changes. Our calculations predict the occurrence of g-mode pulsations at the observed variability frequency. On the other hand, the strictly mono-periodic nature of the variability strongly suggests a rotational origin. While we prefer the rotational explanation, the present data leave some uncertainty.

13 pages, 13 figures, accepted for publication in MNRAS

References in corpus (10)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Weak magnetic fields in Ap/Bp stars: Evidence for a dipole field lower limit and a tentative interpretation of the magnetic dichotomy
• Spectroscopic survey of Kepler stars. I. HERMES/Mercator observations of A- and F-type stars
• Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades
• Inhomogeneous surface distribution of chemical elements in the eclipsing binary AR Aur: A new challenge for our understanding of HgMn stars
• The Classificiation of Kepler B star Variables
• Excitation and visibility of slow modes in rotating B-type stars
• New Photometrically Variable Magnetic Chemically Peculiar Stars in the ASAS-3 Archive
• HVS7: a chemically peculiar hyper-velocity star
• Characterization of Kepler early-type targets

Cited by in corpus (8)

• TESS survey of rotational and pulsational variability of mercury-manganese stars
• The SDSS/APOGEE Catalog of HgMn Stars
• ELISa: A new tool for fast modelling of eclipsing binaries
• A spectroscopic test of the rotational modulation origin of periodic \emph{Kepler} photometric variability of A-type stars
• The nature of the photometric variability of HgMn stars: A test of simulated light curves of ϕ Phe against the TESS data
• Search for stellar spots in field blue horizontal-branch stars
• V772 Cas: an ellipsoidal HgMn star in an eclipsing binary
• Understanding the rotational variability of K2 targets. HgMn star KIC 250152017 and blue horizontal branch star KIC 249660366